/*
 
* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
 
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 
*
 
* This code is free software; you can redistribute it and/or modify it
 
* under the terms of the GNU General Public License version 2 only, as
 
* published by the Free Software Foundation.
  
Oracle designates this
 
* particular file as subject to the "Classpath" exception as provided
 
* by Oracle in the LICENSE file that accompanied this code.
 
*
 
* This code is distributed in the hope that it will be useful, but WITHOUT
 
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 
* FITNESS FOR A PARTICULAR PURPOSE.
  
See the GNU General Public License
 
* version 2 for more details (a copy is included in the LICENSE file that
 
* accompanied this code).
 
*
 
* You should have received a copy of the GNU General Public License version
 
* 2 along with this work; if not, write to the Free Software Foundation,
 
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 
*
 
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 
* or visit www.oracle.com if you need additional information or have any
 
* questions.
 
*/

package java.util;

import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.Function;
import sun.misc.SharedSecrets;

/**
 
* Hash table based implementation of the <tt>Map</tt> interface.
  
This
 
* implementation provides all of the optional map operations, and permits
 
* <tt>null</tt> values and the <tt>null</tt> key.
  
(The <tt>HashMap</tt>
 
* class is roughly equivalent to <tt>Hashtable</tt>, except that it is
 
* unsynchronized and permits nulls.)
  
This class makes no guarantees as to
 
* the order of the map; in particular, it does not guarantee that the order
 
* will remain constant over time.
 
*
 
* <p>This implementation provides constant-time performance for the basic
 
* operations (<tt>get</tt> and <tt>put</tt>), assuming the hash function
 
* disperses the elements properly among the buckets.
  
Iteration over
 
* collection views requires time proportional to the "capacity" of the
 
* <tt>HashMap</tt> instance (the number of buckets) plus its size (the number
 
* of key-value mappings).
  
Thus, it's very important not to set the initial
 
* capacity too high (or the load factor too low) if iteration performance is
 
* important.
 
*
 
* <p>An instance of <tt>HashMap</tt> has two parameters that affect its
 
* performance: <i>initial capacity</i> and <i>load factor</i>.
  
The
 
* <i>capacity</i> is the number of buckets in the hash table, and the initial
 
* capacity is simply the capacity at the time the hash table is created.
  
The
 
* <i>load factor</i> is a measure of how full the hash table is allowed to
 
* get before its capacity is automatically increased.
  
When the number of
 
* entries in the hash table exceeds the product of the load factor and the
 
* current capacity, the hash table is <i>rehashed</i> (that is, internal data
 
* structures are rebuilt) so that the hash table has approximately twice the
 
* number of buckets.
 
*
 
* <p>As a general rule, the default load factor (.75) offers a good
 
* tradeoff between time and space costs.
  
Higher values decrease the
 
* space overhead but increase the lookup cost (reflected in most of
 
* the operations of the <tt>HashMap</tt> class, including
 
* <tt>get</tt> and <tt>put</tt>).
  
The expected number of entries in
 
* the map and its load factor should be taken into account when
 
* setting its initial capacity, so as to minimize the number of
 
* rehash operations.
  
If the initial capacity is greater than the
 
* maximum number of entries divided by the load factor, no rehash
 
* operations will ever occur.
 
*
 
* <p>If many mappings are to be stored in a <tt>HashMap</tt>
 
* instance, creating it with a sufficiently large capacity will allow
 
* the mappings to be stored more efficiently than letting it perform
 
* automatic rehashing as needed to grow the table.
  
Note that using
 
* many keys with the same {@code hashCode()} is a sure way to slow
 
* down performance of any hash table. To ameliorate impact, when keys
 
* are {@link Comparable}, this class may use comparison order among
 
* keys to help break ties.
 
*
 
* <p><strong>Note that this implementation is not synchronized.</strong>
 
* If multiple threads access a hash map concurrently, and at least one of
 
* the threads modifies the map structurally, it <i>must</i> be
 
* synchronized externally.
  
(A structural modification is any operation
 
* that adds or deletes one or more mappings; merely changing the value
 
* associated with a key that an instance already contains is not a
 
* structural modification.)
  
This is typically accomplished by
 
* synchronizing on some object that naturally encapsulates the map.
 
*
 
* If no such object exists, the map should be "wrapped" using the
 
* {@link Collections#synchronizedMap Collections.synchronizedMap}
 
* method.
  
This is best done at creation time, to prevent accidental
 
* unsynchronized access to the map:<pre>
 
*
   
Map m = Collections.synchronizedMap(new HashMap(...));</pre>
 
*
 
* <p>The iterators returned by all of this class's "collection view methods"
 
* are <i>fail-fast</i>: if the map is structurally modified at any time after
 
* the iterator is created, in any way except through the iterator's own
 
* <tt>remove</tt> method, the iterator will throw a
 
* {@link ConcurrentModificationException}.
  
Thus, in the face of concurrent
 
* modification, the iterator fails quickly and cleanly, rather than risking
 
* arbitrary, non-deterministic behavior at an undetermined time in the
 
* future.
 
*
 
* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
 
* as it is, generally speaking, impossible to make any hard guarantees in the
 
* presence of unsynchronized concurrent modification.
  
Fail-fast iterators
 
* throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
 
* Therefore, it would be wrong to write a program that depended on this
 
* exception for its correctness: <i>the fail-fast behavior of iterators
 
* should be used only to detect bugs.</i>
 
*
 
* <p>This class is a member of the
 
* <a href="{@docRoot}/../technotes/guides/collections/index.html">
 
* Java Collections Framework</a>.
 
*
 
* @param <K> the type of keys maintained by this map
 
* @param <V> the type of mapped values
 
*
 
* @author
  
Doug Lea
 
* @author
  
Josh Bloch
 
* @author
  
Arthur van Hoff
 
* @author
  
Neal Gafter
 
* @see
     
Object#hashCode()
 
* @see
     
Collection
 
* @see
     
Map
 
* @see
     
TreeMap
 
* @see
     
Hashtable
 
* @since
   
1.2
 
*/

public class HashMap<K,V> extends AbstractMap<K,V>
    
implements Map<K,V>, Cloneable, Serializable {

    
private static final long serialVersionUID = 362498820763181265L;

    
/*
     
* Implementation notes.
     
*
     
* This map usually acts as a binned (bucketed) hash table, but
     
* when bins get too large, they are transformed into bins of
     
* TreeNodes, each structured similarly to those in
     
* java.util.TreeMap. Most methods try to use normal bins, but
     
* relay to TreeNode methods when applicable (simply by checking
     
* instanceof a node).
  
Bins of TreeNodes may be traversed and
     
* used like any others, but additionally support faster lookup
     
* when overpopulated. However, since the vast majority of bins in
     
* normal use are not overpopulated, checking for existence of
     
* tree bins may be delayed in the course of table methods.
     
*
     
* Tree bins (i.e., bins whose elements are all TreeNodes) are
     
* ordered primarily by hashCode, but in the case of ties, if two
     
* elements are of the same "class C implements Comparable<C>",
     
* type then their compareTo method is used for ordering. (We
     
* conservatively check generic types via reflection to validate
     
* this -- see method comparableClassFor).
  
The added complexity
     
* of tree bins is worthwhile in providing worst-case O(log n)
     
* operations when keys either have distinct hashes or are
     
* orderable, Thus, performance degrades gracefully under
     
* accidental or malicious usages in which hashCode() methods
     
* return values that are poorly distributed, as well as those in
     
* which many keys share a hashCode, so long as they are also
     
* Comparable. (If neither of these apply, we may waste about a
     
* factor of two in time and space compared to taking no
     
* precautions. But the only known cases stem from poor user
     
* programming practices that are already so slow that this makes
     
* little difference.)
     
*
     
* Because TreeNodes are about twice the size of regular nodes, we
     
* use them only when bins contain enough nodes to warrant use
     
* (see TREEIFY_THRESHOLD). And when they become too small (due to
     
* removal or resizing) they are converted back to plain bins.
  
In
     
* usages with well-distributed user hashCodes, tree bins are
     
* rarely used.
  
Ideally, under random hashCodes, the frequency of
     
* nodes in bins follows a Poisson distribution
     
* ( http://en.wikipedia.org/wiki/Poisson_distribution)
 
with a
     
* parameter of about 0.5 on average for the default resizing
     
* threshold of 0.75, although with a large variance because of
     
* resizing granularity. Ignoring variance, the expected
     
* occurrences of list size k are (exp(-0.5) * pow(0.5, k) /
     
* factorial(k)). The first values are:
     
*
     
* 0:
    
0.60653066
     
* 1:
    
0.30326533
     
* 2:
    
0.07581633
     
* 3:
    
0.01263606
     
* 4:
    
0.00157952
     
* 5:
    
0.00015795
     
* 6:
    
0.00001316
     
* 7:
    
0.00000094
     
* 8:
    
0.00000006
     
* more: less than 1 in ten million
     
*
     
* The root of a tree bin is normally its first node.
  
However,
     
* sometimes (currently only upon Iterator.remove), the root might
     
* be elsewhere, but can be recovered following parent links
     
* (method TreeNode.root()).
     
*
     
* All applicable internal methods accept a hash code as an
     
* argument (as normally supplied from a public method), allowing
     
* them to call each other without recomputing user hashCodes.
     
* Most internal methods also accept a "tab" argument, that is
     
* normally the current table, but may be a new or old one when
     
* resizing or converting.
     
*
     
* When bin lists are treeified, split, or untreeified, we keep
     
* them in the same relative access/traversal order (i.e., field
     
* Node.next) to better preserve locality, and to slightly
     
* simplify handling of splits and traversals that invoke
     
* iterator.remove. When using comparators on insertion, to keep a
     
* total ordering (or as close as is required here) across
     
* rebalancings, we compare classes and identityHashCodes as
     
* tie-breakers.
     
*
     
* The use and transitions among plain vs tree modes is
     
* complicated by the existence of subclass LinkedHashMap. See
     
* below for hook methods defined to be invoked upon insertion,
     
* removal and access that allow LinkedHashMap internals to
     
* otherwise remain independent of these mechanics. (This also
     
* requires that a map instance be passed to some utility methods
     
* that may create new nodes.)
     
*
     
* The concurrent-programming-like SSA-based coding style helps
     
* avoid aliasing errors amid all of the twisty pointer operations.
     
*/


    
/**
     
* The default initial capacity - MUST be a power of two.
     
*/
    
static final int DEFAULT_INITIAL_CAPACITY = 1 << 4; // aka 16

    
/**
     
* The maximum capacity, used if a higher value is implicitly specified
     
* by either of the constructors with arguments.
     
* MUST be a power of two <= 1<<30.
     
*/

    
static final int MAXIMUM_CAPACITY = 1 << 30;

    
/**
     
* The load factor used when none specified in constructor.
     
*/
    
static final float DEFAULT_LOAD_FACTOR = 0.75f;

    
/**
     
* The bin count threshold for using a tree rather than list for a
     
* bin.
  
Bins are converted to trees when adding an element to a
     
* bin with at least this many nodes. The value must be greater
     
* than 2 and should be at least 8 to mesh with assumptions in
     
* tree removal about conversion back to plain bins upon
     
* shrinkage.
     
*/

    
static final int TREEIFY_THRESHOLD = 8;

    
/**
     
* The bin count threshold for untreeifying a (split) bin during a
     
* resize operation. Should be less than TREEIFY_THRESHOLD, and at
     
* most 6 to mesh with shrinkage detection under removal.
     
*/

    
static final int UNTREEIFY_THRESHOLD = 6;

    
/**
     
* The smallest table capacity for which bins may be treeified.
     
* (Otherwise the table is resized if too many nodes in a bin.)
     
* Should be at least 4 * TREEIFY_THRESHOLD to avoid conflicts
     
* between resizing and treeification thresholds.
     
*/

    
static final int MIN_TREEIFY_CAPACITY = 64;

    
/**
     
* Basic hash bin node, used for most entries.
  
(See below for
     
* TreeNode subclass, and in LinkedHashMap for its Entry subclass.)
     
*/

    
static class Node<K,V> implements Map.Entry<K,V> {
        
final int hash;
        
final K key;
        
V value;
        
Node<K,V> next;

        
Node(int hash, K key, V value, Node<K,V> next) {
            
this.hash = hash;
            
this.key = key;
            
this.value = value;
            
this.next = next;
        
}

        
public final K getKey()
        
{ return key; }
        
public final V getValue()
      
{ return value; }
        
public final String toString() { return key + "=" + value; }

        
public final int hashCode() {
            
return Objects.hashCode(key) ^ Objects.hashCode(value);
        
}

        
public final V setValue(V newValue) {
            
V oldValue = value;
            
value = newValue;
            
return oldValue;
        
}

        
public final boolean equals(Object o) {
            
if (o == this)
                
return true;
            
if (o instanceof Map.Entry) {
                
Map.Entry<?,?> e = (Map.Entry<?,?>)o;
                
if (Objects.equals(key, e.getKey()) &&
                    
Objects.equals(value, e.getValue()))
                    
return true;
            
}
            
return false;
        
}
    
}

    
/* ---------------- Static utilities -------------- */

    
/**
     
* Computes key.hashCode() and spreads (XORs) higher bits of hash
     
* to lower.
  
Because the table uses power-of-two masking, sets of
     
* hashes that vary only in bits above the current mask will
     
* always collide. (Among known examples are sets of Float keys
     
* holding consecutive whole numbers in small tables.)
  
So we
     
* apply a transform that spreads the impact of higher bits
     
* downward. There is a tradeoff between speed, utility, and
     
* quality of bit-spreading. Because many common sets of hashes
     
* are already reasonably distributed (so don't benefit from
     
* spreading), and because we use trees to handle large sets of
     
* collisions in bins, we just XOR some shifted bits in the
     
* cheapest possible way to reduce systematic lossage, as well as
     
* to incorporate impact of the highest bits that would otherwise
     
* never be used in index calculations because of table bounds.
     
*/

    
static final int hash(Object key) {
        
int h;
        
return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
    
}

    
/**
     
* Returns x's Class if it is of the form "class C implements
     
* Comparable<C>", else null.
     
*/

    
static Class<?> comparableClassFor(Object x) {
        
if (x instanceof Comparable) {
            
Class<?> c; Type[] ts, as; Type t; ParameterizedType p;
            
if ((c = x.getClass()) == String.class) // bypass checks
                
return c;
            
if ((ts = c.getGenericInterfaces()) != null) {
                
for (int i = 0; i < ts.length; ++i) {
                    
if (((t = ts[i]) instanceof ParameterizedType) &&
                        
((p = (ParameterizedType)t).getRawType() ==
                         
Comparable.class) &&
                        
(as = p.getActualTypeArguments()) != null &&
                        
as.length == 1 && as[0] == c) // type arg is c
                        
return c;
                
}
            
}
        
}
        
return null;
    
}

    
/**
     
* Returns k.compareTo(x) if x matches kc (k's screened comparable
     
* class), else 0.
     
*/

    
@SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable
    
static int compareComparables(Class<?> kc, Object k, Object x) {
        
return (x == null || x.getClass() != kc ? 0 :
                
((Comparable)k).compareTo(x));
    
}

    
/**
     
* Returns a power of two size for the given target capacity.
     
*/

    
static final int tableSizeFor(int cap) {
        
int n = cap - 1;
        
n |= n >>> 1;
        
n |= n >>> 2;
        
n |= n >>> 4;
        
n |= n >>> 8;
        
n |= n >>> 16;
        
return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
    
}

    
/* ---------------- Fields -------------- */

    
/**
     
* The table, initialized on first use, and resized as
     
* necessary. When allocated, length is always a power of two.
     
* (We also tolerate length zero in some operations to allow
     
* bootstrapping mechanics that are currently not needed.)
     
*/

    
transient Node<K,V>[] table;

    
/**
     
* Holds cached entrySet(). Note that AbstractMap fields are used
     
* for keySet() and values().
     
*/

    
transient Set<Map.Entry<K,V>> entrySet;

    
/**
     
* The number of key-value mappings contained in this map.
     
*/
    
transient int size;

    
/**
     
* The number of times this HashMap has been structurally modified
     
* Structural modifications are those that change the number of mappings in
     
* the HashMap or otherwise modify its internal structure (e.g.,
     
* rehash).
  
This field is used to make iterators on Collection-views of
     
* the HashMap fail-fast.
  
(See ConcurrentModificationException).
     
*/

    
transient int modCount;

    
/**
     
* The next size value at which to resize (capacity * load factor).
     
*
     
* @serial
     
*/

    
// (The javadoc description is true upon serialization.
    
// Additionally, if the table array has not been allocated, this
    
// field holds the initial array capacity, or zero signifying
    
// DEFAULT_INITIAL_CAPACITY.)
    
int threshold;

    
/**
     
* The load factor for the hash table.
     
*
     
* @serial
     
*/
    
final float loadFactor;

    
/* ---------------- Public operations -------------- */

    
/**
     
* Constructs an empty <tt>HashMap</tt> with the specified initial
     
* capacity and load factor.
     
*
     
* @param
  
initialCapacity the initial capacity
     
* @param
  
loadFactor
      
the load factor
     
* @throws IllegalArgumentException if the initial capacity is negative
     
*
         
or the load factor is nonpositive
     
*/

    
public HashMap(int initialCapacity, float loadFactor) {
        
if (initialCapacity < 0)
            
throw new IllegalArgumentException("Illegal initial capacity: " +
                                               
initialCapacity);
        
if (initialCapacity > MAXIMUM_CAPACITY)
            
initialCapacity = MAXIMUM_CAPACITY;
        
if (loadFactor <= 0 || Float.isNaN(loadFactor))
            
throw new IllegalArgumentException("Illegal load factor: " +
                                               
loadFactor);
        
this.loadFactor = loadFactor;
        
this.threshold = tableSizeFor(initialCapacity);
    
}

    
/**
     
* Constructs an empty <tt>HashMap</tt> with the specified initial
     
* capacity and the default load factor (0.75).
     
*
     
* @param
  
initialCapacity the initial capacity.
     
* @throws IllegalArgumentException if the initial capacity is negative.
     
*/

    
public HashMap(int initialCapacity) {
        
this(initialCapacity, DEFAULT_LOAD_FACTOR);
    
}

    
/**
     
* Constructs an empty <tt>HashMap</tt> with the default initial capacity
     
* (16) and the default load factor (0.75).
     
*/

    
public HashMap() {
        
this.loadFactor = DEFAULT_LOAD_FACTOR; // all other fields defaulted
    
}

    
/**
     
* Constructs a new <tt>HashMap</tt> with the same mappings as the
     
* specified <tt>Map</tt>.
  
The <tt>HashMap</tt> is created with
     
* default load factor (0.75) and an initial capacity sufficient to
     
* hold the mappings in the specified <tt>Map</tt>.
     
*
     
* @param
   
m the map whose mappings are to be placed in this map
     
* @throws
  
NullPointerException if the specified map is null
     
*/

    
public HashMap(Map<? extends K, ? extends V> m) {
        
this.loadFactor = DEFAULT_LOAD_FACTOR;
        
putMapEntries(m, false);
    
}

    
/**
     
* Implements Map.putAll and Map constructor.
     
*
     
* @param m the map
     
* @param evict false when initially constructing this map, else
     
* true (relayed to method afterNodeInsertion).
     
*/

    
final void putMapEntries(Map<? extends K, ? extends V> m, boolean evict) {
        
int s = m.size();
        
if (s > 0) {
            
if (table == null) { // pre-size
                
float ft = ((float)s / loadFactor) + 1.0F;
                
int t = ((ft < (float)MAXIMUM_CAPACITY) ?
                         
(int)ft : MAXIMUM_CAPACITY);
                
if (t > threshold)
                    
threshold = tableSizeFor(t);
            
}
            
else if (s > threshold)
                
resize();
            
for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
                
K key = e.getKey();
                
V value = e.getValue();
                
putVal(hash(key), key, value, false, evict);
            
}
        
}
    
}

    
/**
     
* Returns the number of key-value mappings in this map.
     
*
     
* @return the number of key-value mappings in this map
     
*/

    
public int size() {
        
return size;
    
}

    
/**
     
* Returns <tt>true</tt> if this map contains no key-value mappings.
     
*
     
* @return <tt>true</tt> if this map contains no key-value mappings
     
*/

    
public boolean isEmpty() {
        
return size == 0;
    
}

    
/**
     
* Returns the value to which the specified key is mapped,
     
* or {@code null} if this map contains no mapping for the key.
     
*
     
* <p>More formally, if this map contains a mapping from a key
     
* {@code k} to a value {@code v} such that {@code (key==null ? k==null :
     
* key.equals(k))}, then this method returns {@code v}; otherwise
     
* it returns {@code null}.
  
(There can be at most one such mapping.)
     
*
     
* <p>A return value of {@code null} does not <i>necessarily</i>
     
* indicate that the map contains no mapping for the key; it's also
     
* possible that the map explicitly maps the key to {@code null}.
     
* The {@link #containsKey containsKey} operation may be used to
     
* distinguish these two cases.
     
*
     
* @see #put(Object, Object)
     
*/

    
public V get(Object key) {
        
Node<K,V> e;
        
return (e = getNode(hash(key), key)) == null ? null : e.value;
    
}

    
/**
     
* Implements Map.get and related methods.
     
*
     
* @param hash hash for key
     
* @param key the key
     
* @return the node, or null if none
     
*/

    
final Node<K,V> getNode(int hash, Object key) {
        
Node<K,V>[] tab; Node<K,V> first, e; int n; K k;
        
if ((tab = table) != null && (n = tab.length) > 0 &&
            
(first = tab[(n - 1) & hash]) != null) {
            
if (first.hash == hash && // always check first node
                
((k = first.key) == key || (key != null && key.equals(k))))
                
return first;
            
if ((e = first.next) != null) {
                
if (first instanceof TreeNode)
                    
return ((TreeNode<K,V>)first).getTreeNode(hash, key);
                
do {
                    
if (e.hash == hash &&
                        
((k = e.key) == key || (key != null && key.equals(k))))
                        
return e;
                
} while ((e = e.next) != null);
            
}
        
}
        
return null;
    
}

    
/**
     
* Returns <tt>true</tt> if this map contains a mapping for the
     
* specified key.
     
*
     
* @param
   
keyThe key whose presence in this map is to be tested
     
* @return <tt>true</tt> if this map contains a mapping for the specified
     
* key.
     
*/

    
public boolean containsKey(Object key) {
        
return getNode(hash(key), key) != null;
    
}

    
/**
     
* Associates the specified value with the specified key in this map.
     
* If the map previously contained a mapping for the key, the old
     
* value is replaced.
     
*
     
* @param key key with which the specified value is to be associated
     
* @param value value to be associated with the specified key
     
* @return the previous value associated with <tt>key</tt>, or
     
*
         
<tt>null</tt> if there was no mapping for <tt>key</tt>.
     
*
         
(A <tt>null</tt> return can also indicate that the map
     
*
         
previously associated <tt>null</tt> with <tt>key</tt>.)
     
*/

    
public V put(K key, V value) {
        
return putVal(hash(key), key, value, false, true);
    
}

    
/**
     
* Implements Map.put and related methods.
     
*
     
* @param hash hash for key
     
* @param key the key
     
* @param value the value to put
     
* @param onlyIfAbsent if true, don't change existing value
     
* @param evict if false, the table is in creation mode.
     
* @return previous value, or null if none
     
*/

    
final V putVal(int hash, K key, V value, boolean onlyIfAbsent,
                   
boolean evict) {
        
Node<K,V>[] tab; Node<K,V> p; int n, i;
        
if ((tab = table) == null || (n = tab.length) == 0)
            
n = (tab = resize()).length;
        
if ((p = tab[i = (n - 1) & hash]) == null)
            
tab[i] = newNode(hash, key, value, null);
        
else {
            
Node<K,V> e; K k;
            
if (p.hash == hash &&
                
((k = p.key) == key || (key != null && key.equals(k))))
                
e = p;
            
else if (p instanceof TreeNode)
                
e = ((TreeNode<K,V>)p).putTreeVal(this, tab, hash, key, value);
            
else {
                
for (int binCount = 0; ; ++binCount) {
                    
if ((e = p.next) == null) {
                        
p.next = newNode(hash, key, value, null);
                        
if (binCount >= TREEIFY_THRESHOLD - 1) // -1 for 1st
                            
treeifyBin(tab, hash);
                        
break;
                    
}
                    
if (e.hash == hash &&
                        
((k = e.key) == key || (key != null && key.equals(k))))
                        
break;
                    
p = e;
                
}
            
}
            
if (e != null) { // existing mapping for key
                
V oldValue = e.value;
                
if (!onlyIfAbsent || oldValue == null)
                    
e.value = value;
                
afterNodeAccess(e);
                
return oldValue;
            
}
        
}
        
++modCount;
        
if (++size > threshold)
            
resize();
        
afterNodeInsertion(evict);
        
return null;
    
}

    
/**
     
* Initializes or doubles table size.
  
If null, allocates in
     
* accord with initial capacity target held in field threshold.
     
* Otherwise, because we are using power-of-two expansion, the
     
* elements from each bin must either stay at same index, or move
     
* with a power of two offset in the new table.
     
*
     
* @return the table
     
*/

    
final Node<K,V>[] resize() {
        
Node<K,V>[] oldTab = table;
        
int oldCap = (oldTab == null) ? 0 : oldTab.length;
        
int oldThr = threshold;
        
int newCap, newThr = 0;
        
if (oldCap > 0) {
            
if (oldCap >= MAXIMUM_CAPACITY) {
                
threshold = Integer.MAX_VALUE;
                
return oldTab;
            
}
            
else if ((newCap = oldCap << 1) < MAXIMUM_CAPACITY &&
                     
oldCap >= DEFAULT_INITIAL_CAPACITY)
                
newThr = oldThr << 1; // double threshold
        
}
        
else if (oldThr > 0) // initial capacity was placed in threshold
            
newCap = oldThr;
        
else {
               
// zero initial threshold signifies using defaults
            
newCap = DEFAULT_INITIAL_CAPACITY;
            
newThr = (int)(DEFAULT_LOAD_FACTOR * DEFAULT_INITIAL_CAPACITY);
        
}
        
if (newThr == 0) {
            
float ft = (float)newCap * loadFactor;
            
newThr = (newCap < MAXIMUM_CAPACITY && ft < (float)MAXIMUM_CAPACITY ?
                      
(int)ft : Integer.MAX_VALUE);
        
}
        
threshold = newThr;
        
@SuppressWarnings({"rawtypes","unchecked"})
        
Node<K,V>[] newTab = (Node<K,V>[])new Node[newCap];
        
table = newTab;
        
if (oldTab != null) {
            
for (int j = 0; j < oldCap; ++j) {
                
Node<K,V> e;
                
if ((e = oldTab[j]) != null) {
                    
oldTab[j] = null;
                    
if (e.next == null)
                        
newTab[e.hash & (newCap - 1)] = e;
                    
else if (e instanceof TreeNode)
                        
((TreeNode<K,V>)e).split(this, newTab, j, oldCap);
                    
else { // preserve order
                        
Node<K,V> loHead = null, loTail = null;
                        
Node<K,V> hiHead = null, hiTail = null;
                        
Node<K,V> next;
                        
do {
                            
next = e.next;
                            
if ((e.hash & oldCap) == 0) {
                                
if (loTail == null)
                                    
loHead = e;
                                
else
                                    
loTail.next = e;
                                
loTail = e;
                            
}
                            
else {
                                
if (hiTail == null)
                                    
hiHead = e;
                                
else
                                    
hiTail.next = e;
                                
hiTail = e;
                            
}
                        
} while ((e = next) != null);
                        
if (loTail != null) {
                            
loTail.next = null;
                            
newTab[j] = loHead;
                        
}
                        
if (hiTail != null) {
                            
hiTail.next = null;
                            
newTab[j + oldCap] = hiHead;
                        
}
                    
}
                
}
            
}
        
}
        
return newTab;
    
}

    
/**
     
* Replaces all linked nodes in bin at index for given hash unless
     
* table is too small, in which case resizes instead.
     
*/

    
final void treeifyBin(Node<K,V>[] tab, int hash) {
        
int n, index; Node<K,V> e;
        
if (tab == null || (n = tab.length) < MIN_TREEIFY_CAPACITY)
            
resize();
        
else if ((e = tab[index = (n - 1) & hash]) != null) {
            
TreeNode<K,V> hd = null, tl = null;
            
do {
                
TreeNode<K,V> p = replacementTreeNode(e, null);
                
if (tl == null)
                    
hd = p;
                
else {
                    
p.prev = tl;
                    
tl.next = p;
                
}
                
tl = p;
            
} while ((e = e.next) != null);
            
if ((tab[index] = hd) != null)
                
hd.treeify(tab);
        
}
    
}

    
/**
     
* Copies all of the mappings from the specified map to this map.
     
* These mappings will replace any mappings that this map had for
     
* any of the keys currently in the specified map.
     
*
     
* @param m mappings to be stored in this map
     
* @throws NullPointerException if the specified map is null
     
*/

    
public void putAll(Map<? extends K, ? extends V> m) {
        
putMapEntries(m, true);
    
}

    
/**
     
* Removes the mapping for the specified key from this map if present.
     
*
     
* @param
  
key key whose mapping is to be removed from the map
     
* @return the previous value associated with <tt>key</tt>, or
     
*
         
<tt>null</tt> if there was no mapping for <tt>key</tt>.
     
*
         
(A <tt>null</tt> return can also indicate that the map
     
*
         
previously associated <tt>null</tt> with <tt>key</tt>.)
     
*/

    
public V remove(Object key) {
        
Node<K,V> e;
        
return (e = removeNode(hash(key), key, null, false, true)) == null ?
            
null : e.value;
    
}

    
/**
     
* Implements Map.remove and related methods.
     
*
     
* @param hash hash for key
     
* @param key the key
     
* @param value the value to match if matchValue, else ignored
     
* @param matchValue if true only remove if value is equal
     
* @param movable if false do not move other nodes while removing
     
* @return the node, or null if none
     
*/

    
final Node<K,V> removeNode(int hash, Object key, Object value,
                               
boolean matchValue, boolean movable) {
        
Node<K,V>[] tab; Node<K,V> p; int n, index;
        
if ((tab = table) != null && (n = tab.length) > 0 &&
            
(p = tab[index = (n - 1) & hash]) != null) {
            
Node<K,V> node = null, e; K k; V v;
            
if (p.hash == hash &&
                
((k = p.key) == key || (key != null && key.equals(k))))
                
node = p;
            
else if ((e = p.next) != null) {
                
if (p instanceof TreeNode)
                    
node = ((TreeNode<K,V>)p).getTreeNode(hash, key);
                
else {
                    
do {
                        
if (e.hash == hash &&
                            
((k = e.key) == key ||
                             
(key != null && key.equals(k)))) {
                            
node = e;
                            
break;
                        
}
                        
p = e;
                    
} while ((e = e.next) != null);
                
}
            
}
            
if (node != null && (!matchValue || (v = node.value) == value ||
                                 
(value != null && value.equals(v)))) {
                
if (node instanceof TreeNode)
                    
((TreeNode<K,V>)node).removeTreeNode(this, tab, movable);
                
else if (node == p)
                    
tab[index] = node.next;
                
else
                    
p.next = node.next;
                
++modCount;
                
--size;
                
afterNodeRemoval(node);
                
return node;
            
}
        
}
        
return null;
    
}

    
/**
     
* Removes all of the mappings from this map.
     
* The map will be empty after this call returns.
     
*/

    
public void clear() {
        
Node<K,V>[] tab;
        
modCount++;
        
if ((tab = table) != null && size > 0) {
            
size = 0;
            
for (int i = 0; i < tab.length; ++i)
                
tab[i] = null;
        
}
    
}

    
/**
     
* Returns <tt>true</tt> if this map maps one or more keys to the
     
* specified value.
     
*
     
* @param value value whose presence in this map is to be tested
     
* @return <tt>true</tt> if this map maps one or more keys to the
     
*
         
specified value
     
*/

    
public boolean containsValue(Object value) {
        
Node<K,V>[] tab; V v;
        
if ((tab = table) != null && size > 0) {
            
for (int i = 0; i < tab.length; ++i) {
                
for (Node<K,V> e = tab[i]; e != null; e = e.next) {
                    
if ((v = e.value) == value ||
                        
(value != null && value.equals(v)))
                        
return true;
                
}
            
}
        
}
        
return false;
    
}

    
/**
     
* Returns a {@link Set} view of the keys contained in this map.
     
* The set is backed by the map, so changes to the map are
     
* reflected in the set, and vice-versa.
  
If the map is modified
     
* while an iteration over the set is in progress (except through
     
* the iterator's own <tt>remove</tt> operation), the results of
     
* the iteration are undefined.
  
The set supports element removal,
     
* which removes the corresponding mapping from the map, via the
     
* <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
     
* <tt>removeAll</tt>, <tt>retainAll</tt>, and <tt>clear</tt>
     
* operations.
  
It does not support the <tt>add</tt> or <tt>addAll</tt>
     
* operations.
     
*
     
* @return a set view of the keys contained in this map
     
*/

    
public Set<K> keySet() {
        
Set<K> ks = keySet;
        
if (ks == null) {
            
ks = new KeySet();
            
keySet = ks;
        
}
        
return ks;
    
}

    
final class KeySet extends AbstractSet<K> {
        
public final int size()
                 
{ return size; }
        
public final void clear()
               
{ HashMap.this.clear(); }
        
public final Iterator<K> iterator()
     
{ return new KeyIterator(); }
        
public final boolean contains(Object o) { return containsKey(o); }
        
public final boolean remove(Object key) {
            
return removeNode(hash(key), key, null, false, true) != null;
        
}
        
public final Spliterator<K> spliterator() {
            
return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
        
}
        
public final void forEach(Consumer<? super K> action) {
            
Node<K,V>[] tab;
            
if (action == null)
                
throw new NullPointerException();
            
if (size > 0 && (tab = table) != null) {
                
int mc = modCount;
                
for (int i = 0; i < tab.length; ++i) {
                    
for (Node<K,V> e = tab[i]; e != null; e = e.next)
                        
action.accept(e.key);
                
}
                
if (modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}
    
}

    
/**
     
* Returns a {@link Collection} view of the values contained in this map.
     
* The collection is backed by the map, so changes to the map are
     
* reflected in the collection, and vice-versa.
  
If the map is
     
* modified while an iteration over the collection is in progress
     
* (except through the iterator's own <tt>remove</tt> operation),
     
* the results of the iteration are undefined.
  
The collection
     
* supports element removal, which removes the corresponding
     
* mapping from the map, via the <tt>Iterator.remove</tt>,
     
* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
     
* <tt>retainAll</tt> and <tt>clear</tt> operations.
  
It does not
     
* support the <tt>add</tt> or <tt>addAll</tt> operations.
     
*
     
* @return a view of the values contained in this map
     
*/

    
public Collection<V> values() {
        
Collection<V> vs = values;
        
if (vs == null) {
            
vs = new Values();
            
values = vs;
        
}
        
return vs;
    
}

    
final class Values extends AbstractCollection<V> {
        
public final int size()
                 
{ return size; }
        
public final void clear()
               
{ HashMap.this.clear(); }
        
public final Iterator<V> iterator()
     
{ return new ValueIterator(); }
        
public final boolean contains(Object o) { return containsValue(o); }
        
public final Spliterator<V> spliterator() {
            
return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
        
}
        
public final void forEach(Consumer<? super V> action) {
            
Node<K,V>[] tab;
            
if (action == null)
                
throw new NullPointerException();
            
if (size > 0 && (tab = table) != null) {
                
int mc = modCount;
                
for (int i = 0; i < tab.length; ++i) {
                    
for (Node<K,V> e = tab[i]; e != null; e = e.next)
                        
action.accept(e.value);
                
}
                
if (modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}
    
}

    
/**
     
* Returns a {@link Set} view of the mappings contained in this map.
     
* The set is backed by the map, so changes to the map are
     
* reflected in the set, and vice-versa.
  
If the map is modified
     
* while an iteration over the set is in progress (except through
     
* the iterator's own <tt>remove</tt> operation, or through the
     
* <tt>setValue</tt> operation on a map entry returned by the
     
* iterator) the results of the iteration are undefined.
  
The set
     
* supports element removal, which removes the corresponding
     
* mapping from the map, via the <tt>Iterator.remove</tt>,
     
* <tt>Set.remove</tt>, <tt>removeAll</tt>, <tt>retainAll</tt> and
     
* <tt>clear</tt> operations.
  
It does not support the
     
* <tt>add</tt> or <tt>addAll</tt> operations.
     
*
     
* @return a set view of the mappings contained in this map
     
*/

    
public Set<Map.Entry<K,V>> entrySet() {
        
Set<Map.Entry<K,V>> es;
        
return (es = entrySet) == null ? (entrySet = new EntrySet()) : es;
    
}

    
final class EntrySet extends AbstractSet<Map.Entry<K,V>> {
        
public final int size()
                 
{ return size; }
        
public final void clear()
               
{ HashMap.this.clear(); }
        
public final Iterator<Map.Entry<K,V>> iterator() {
            
return new EntryIterator();
        
}
        
public final boolean contains(Object o) {
            
if (!(o instanceof Map.Entry))
                
return false;
            
Map.Entry<?,?> e = (Map.Entry<?,?>) o;
            
Object key = e.getKey();
            
Node<K,V> candidate = getNode(hash(key), key);
            
return candidate != null && candidate.equals(e);
        
}
        
public final boolean remove(Object o) {
            
if (o instanceof Map.Entry) {
                
Map.Entry<?,?> e = (Map.Entry<?,?>) o;
                
Object key = e.getKey();
                
Object value = e.getValue();
                
return removeNode(hash(key), key, value, true, true) != null;
            
}
            
return false;
        
}
        
public final Spliterator<Map.Entry<K,V>> spliterator() {
            
return new EntrySpliterator<>(HashMap.this, 0, -1, 0, 0);
        
}
        
public final void forEach(Consumer<? super Map.Entry<K,V>> action) {
            
Node<K,V>[] tab;
            
if (action == null)
                
throw new NullPointerException();
            
if (size > 0 && (tab = table) != null) {
                
int mc = modCount;
                
for (int i = 0; i < tab.length; ++i) {
                    
for (Node<K,V> e = tab[i]; e != null; e = e.next)
                        
action.accept(e);
                
}
                
if (modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}
    
}

    
// Overrides of JDK8 Map extension methods

    
@Override
    
public V getOrDefault(Object key, V defaultValue) {
        
Node<K,V> e;
        
return (e = getNode(hash(key), key)) == null ? defaultValue : e.value;
    
}

    
@Override
    
public V putIfAbsent(K key, V value) {
        
return putVal(hash(key), key, value, true, true);
    
}

    
@Override
    
public boolean remove(Object key, Object value) {
        
return removeNode(hash(key), key, value, true, true) != null;
    
}

    
@Override
    
public boolean replace(K key, V oldValue, V newValue) {
        
Node<K,V> e; V v;
        
if ((e = getNode(hash(key), key)) != null &&
            
((v = e.value) == oldValue || (v != null && v.equals(oldValue)))) {
            
e.value = newValue;
            
afterNodeAccess(e);
            
return true;
        
}
        
return false;
    
}

    
@Override
    
public V replace(K key, V value) {
        
Node<K,V> e;
        
if ((e = getNode(hash(key), key)) != null) {
            
V oldValue = e.value;
            
e.value = value;
            
afterNodeAccess(e);
            
return oldValue;
        
}
        
return null;
    
}

    
@Override
    
public V computeIfAbsent(K key,
                             
Function<? super K, ? extends V> mappingFunction) {
        
if (mappingFunction == null)
            
throw new NullPointerException();
        
int hash = hash(key);
        
Node<K,V>[] tab; Node<K,V> first; int n, i;
        
int binCount = 0;
        
TreeNode<K,V> t = null;
        
Node<K,V> old = null;
        
if (size > threshold || (tab = table) == null ||
            
(n = tab.length) == 0)
            
n = (tab = resize()).length;
        
if ((first = tab[i = (n - 1) & hash]) != null) {
            
if (first instanceof TreeNode)
                
old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
            
else {
                
Node<K,V> e = first; K k;
                
do {
                    
if (e.hash == hash &&
                        
((k = e.key) == key || (key != null && key.equals(k)))) {
                        
old = e;
                        
break;
                    
}
                    
++binCount;
                
} while ((e = e.next) != null);
            
}
            
V oldValue;
            
if (old != null && (oldValue = old.value) != null) {
                
afterNodeAccess(old);
                
return oldValue;
            
}
        
}
        
V v = mappingFunction.apply(key);
        
if (v == null) {
            
return null;
        
} else if (old != null) {
            
old.value = v;
            
afterNodeAccess(old);
            
return v;
        
}
        
else if (t != null)
            
t.putTreeVal(this, tab, hash, key, v);
        
else {
            
tab[i] = newNode(hash, key, v, first);
            
if (binCount >= TREEIFY_THRESHOLD - 1)
                
treeifyBin(tab, hash);
        
}
        
++modCount;
        
++size;
        
afterNodeInsertion(true);
        
return v;
    
}

    
public V computeIfPresent(K key,
                              
BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
        
if (remappingFunction == null)
            
throw new NullPointerException();
        
Node<K,V> e; V oldValue;
        
int hash = hash(key);
        
if ((e = getNode(hash, key)) != null &&
            
(oldValue = e.value) != null) {
            
V v = remappingFunction.apply(key, oldValue);
            
if (v != null) {
                
e.value = v;
                
afterNodeAccess(e);
                
return v;
            
}
            
else
                
removeNode(hash, key, null, false, true);
        
}
        
return null;
    
}

    
@Override
    
public V compute(K key,
                     
BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
        
if (remappingFunction == null)
            
throw new NullPointerException();
        
int hash = hash(key);
        
Node<K,V>[] tab; Node<K,V> first; int n, i;
        
int binCount = 0;
        
TreeNode<K,V> t = null;
        
Node<K,V> old = null;
        
if (size > threshold || (tab = table) == null ||
            
(n = tab.length) == 0)
            
n = (tab = resize()).length;
        
if ((first = tab[i = (n - 1) & hash]) != null) {
            
if (first instanceof TreeNode)
                
old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
            
else {
                
Node<K,V> e = first; K k;
                
do {
                    
if (e.hash == hash &&
                        
((k = e.key) == key || (key != null && key.equals(k)))) {
                        
old = e;
                        
break;
                    
}
                    
++binCount;
                
} while ((e = e.next) != null);
            
}
        
}
        
V oldValue = (old == null) ? null : old.value;
        
V v = remappingFunction.apply(key, oldValue);
        
if (old != null) {
            
if (v != null) {
                
old.value = v;
                
afterNodeAccess(old);
            
}
            
else
                
removeNode(hash, key, null, false, true);
        
}
        
else if (v != null) {
            
if (t != null)
                
t.putTreeVal(this, tab, hash, key, v);
            
else {
                
tab[i] = newNode(hash, key, v, first);
                
if (binCount >= TREEIFY_THRESHOLD - 1)
                    
treeifyBin(tab, hash);
            
}
            
++modCount;
            
++size;
            
afterNodeInsertion(true);
        
}
        
return v;
    
}

    
@Override
    
public V merge(K key, V value,
                   
BiFunction<? super V, ? super V, ? extends V> remappingFunction) {
        
if (value == null)
            
throw new NullPointerException();
        
if (remappingFunction == null)
            
throw new NullPointerException();
        
int hash = hash(key);
        
Node<K,V>[] tab; Node<K,V> first; int n, i;
        
int binCount = 0;
        
TreeNode<K,V> t = null;
        
Node<K,V> old = null;
        
if (size > threshold || (tab = table) == null ||
            
(n = tab.length) == 0)
            
n = (tab = resize()).length;
        
if ((first = tab[i = (n - 1) & hash]) != null) {
            
if (first instanceof TreeNode)
                
old = (t = (TreeNode<K,V>)first).getTreeNode(hash, key);
            
else {
                
Node<K,V> e = first; K k;
                
do {
                    
if (e.hash == hash &&
                        
((k = e.key) == key || (key != null && key.equals(k)))) {
                        
old = e;
                        
break;
                    
}
                    
++binCount;
                
} while ((e = e.next) != null);
            
}
        
}
        
if (old != null) {
            
V v;
            
if (old.value != null)
                
v = remappingFunction.apply(old.value, value);
            
else
                
v = value;
            
if (v != null) {
                
old.value = v;
                
afterNodeAccess(old);
            
}
            
else
                
removeNode(hash, key, null, false, true);
            
return v;
        
}
        
if (value != null) {
            
if (t != null)
                
t.putTreeVal(this, tab, hash, key, value);
            
else {
                
tab[i] = newNode(hash, key, value, first);
                
if (binCount >= TREEIFY_THRESHOLD - 1)
                    
treeifyBin(tab, hash);
            
}
            
++modCount;
            
++size;
            
afterNodeInsertion(true);
        
}
        
return value;
    
}

    
@Override
    
public void forEach(BiConsumer<? super K, ? super V> action) {
        
Node<K,V>[] tab;
        
if (action == null)
            
throw new NullPointerException();
        
if (size > 0 && (tab = table) != null) {
            
int mc = modCount;
            
for (int i = 0; i < tab.length; ++i) {
                
for (Node<K,V> e = tab[i]; e != null; e = e.next)
                    
action.accept(e.key, e.value);
            
}
            
if (modCount != mc)
                
throw new ConcurrentModificationException();
        
}
    
}

    
@Override
    
public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
        
Node<K,V>[] tab;
        
if (function == null)
            
throw new NullPointerException();
        
if (size > 0 && (tab = table) != null) {
            
int mc = modCount;
            
for (int i = 0; i < tab.length; ++i) {
                
for (Node<K,V> e = tab[i]; e != null; e = e.next) {
                    
e.value = function.apply(e.key, e.value);
                
}
            
}
            
if (modCount != mc)
                
throw new ConcurrentModificationException();
        
}
    
}

    
/* ------------------------------------------------------------ */
    
// Cloning and serialization

    
/**
     
* Returns a shallow copy of this <tt>HashMap</tt> instance: the keys and
     
* values themselves are not cloned.
     
*
     
* @return a shallow copy of this map
     
*/

    
@SuppressWarnings("unchecked")
    
@Override
    
public Object clone() {
        
HashMap<K,V> result;
        
try {
            
result = (HashMap<K,V>)super.clone();
        
} catch (CloneNotSupportedException e) {
            
// this shouldn't happen, since we are Cloneable
            
throw new InternalError(e);
        
}
        
result.reinitialize();
        
result.putMapEntries(this, false);
        
return result;
    
}

    
// These methods are also used when serializing HashSets
    
final float loadFactor() { return loadFactor; }
    
final int capacity() {
        
return (table != null) ? table.length :
            
(threshold > 0) ? threshold :
            
DEFAULT_INITIAL_CAPACITY;
    
}

    
/**
     
* Save the state of the <tt>HashMap</tt> instance to a stream (i.e.,
     
* serialize it).
     
*
     
* @serialData The <i>capacity</i> of the HashMap (the length of the
     
*
             
bucket array) is emitted (int), followed by the
     
*
             
<i>size</i> (an int, the number of key-value
     
*
             
mappings), followed by the key (Object) and value (Object)
     
*
             
for each key-value mapping.
  
The key-value mappings are
     
*
             
emitted in no particular order.
     
*/

    
private void writeObject(java.io.ObjectOutputStream s)
        
throws IOException {
        
int buckets = capacity();
        
// Write out the threshold, loadfactor, and any hidden stuff
        
s.defaultWriteObject();
        
s.writeInt(buckets);
        
s.writeInt(size);
        
internalWriteEntries(s);
    
}

    
/**
     
* Reconstitutes this map from a stream (that is, deserializes it).
     
* @param s the stream
     
* @throws ClassNotFoundException if the class of a serialized object
     
*
         
could not be found
     
* @throws IOException if an I/O error occurs
     
*/

    
private void readObject(java.io.ObjectInputStream s)
        
throws IOException, ClassNotFoundException {
        
// Read in the threshold (ignored), loadfactor, and any hidden stuff
        
s.defaultReadObject();
        
reinitialize();
        
if (loadFactor <= 0 || Float.isNaN(loadFactor))
            
throw new InvalidObjectException("Illegal load factor: " +
                                             
loadFactor);
        
s.readInt();
                
// Read and ignore number of buckets
        
int mappings = s.readInt(); // Read number of mappings (size)
        
if (mappings < 0)
            
throw new InvalidObjectException("Illegal mappings count: " +
                                             
mappings);
        
else if (mappings > 0) { // (if zero, use defaults)
            
// Size the table using given load factor only if within
            
// range of 0.25...4.0
            
float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
            
float fc = (float)mappings / lf + 1.0f;
            
int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
                       
DEFAULT_INITIAL_CAPACITY :
                       
(fc >= MAXIMUM_CAPACITY) ?
                       
MAXIMUM_CAPACITY :
                       
tableSizeFor((int)fc));
            
float ft = (float)cap * lf;
            
threshold = ((cap < MAXIMUM_CAPACITY && ft < MAXIMUM_CAPACITY) ?
                         
(int)ft : Integer.MAX_VALUE);

            
// Check Map.Entry[].class since it's the nearest public type to
            
// what we're actually creating.
            
SharedSecrets.getJavaOISAccess().checkArray(s, Map.Entry[].class, cap);
            
@SuppressWarnings({"rawtypes","unchecked"})
            
Node<K,V>[] tab = (Node<K,V>[])new Node[cap];
            
table = tab;

            
// Read the keys and values, and put the mappings in the HashMap
            
for (int i = 0; i < mappings; i++) {
                
@SuppressWarnings("unchecked")
                    
K key = (K) s.readObject();
                
@SuppressWarnings("unchecked")
                    
V value = (V) s.readObject();
                
putVal(hash(key), key, value, false, false);
            
}
        
}
    
}

    
/* ------------------------------------------------------------ */
    
// iterators

    
abstract class HashIterator {
        
Node<K,V> next;
        
// next entry to return
        
Node<K,V> current;
     
// current entry
        
int expectedModCount;
  
// for fast-fail
        
int index;
             
// current slot

        
HashIterator() {
            
expectedModCount = modCount;
            
Node<K,V>[] t = table;
            
current = next = null;
            
index = 0;
            
if (t != null && size > 0) { // advance to first entry
                
do {} while (index < t.length && (next = t[index++]) == null);
            
}
        
}

        
public final boolean hasNext() {
            
return next != null;
        
}

        
final Node<K,V> nextNode() {
            
Node<K,V>[] t;
            
Node<K,V> e = next;
            
if (modCount != expectedModCount)
                
throw new ConcurrentModificationException();
            
if (e == null)
                
throw new NoSuchElementException();
            
if ((next = (current = e).next) == null && (t = table) != null) {
                
do {} while (index < t.length && (next = t[index++]) == null);
            
}
            
return e;
        
}

        
public final void remove() {
            
Node<K,V> p = current;
            
if (p == null)
                
throw new IllegalStateException();
            
if (modCount != expectedModCount)
                
throw new ConcurrentModificationException();
            
current = null;
            
K key = p.key;
            
removeNode(hash(key), key, null, false, false);
            
expectedModCount = modCount;
        
}
    
}

    
final class KeyIterator extends HashIterator
        
implements Iterator<K> {
        
public final K next() { return nextNode().key; }
    
}

    
final class ValueIterator extends HashIterator
        
implements Iterator<V> {
        
public final V next() { return nextNode().value; }
    
}

    
final class EntryIterator extends HashIterator
        
implements Iterator<Map.Entry<K,V>> {
        
public final Map.Entry<K,V> next() { return nextNode(); }
    
}

    
/* ------------------------------------------------------------ */
    
// spliterators

    
static class HashMapSpliterator<K,V> {
        
final HashMap<K,V> map;
        
Node<K,V> current;
          
// current node
        
int index;
                  
// current index, modified on advance/split
        
int fence;
                  
// one past last index
        
int est;
                    
// size estimate
        
int expectedModCount;
       
// for comodification checks

        
HashMapSpliterator(HashMap<K,V> m, int origin,
                           
int fence, int est,
                           
int expectedModCount) {
            
this.map = m;
            
this.index = origin;
            
this.fence = fence;
            
this.est = est;
            
this.expectedModCount = expectedModCount;
        
}

        
final int getFence() { // initialize fence and size on first use
            
int hi;
            
if ((hi = fence) < 0) {
                
HashMap<K,V> m = map;
                
est = m.size;
                
expectedModCount = m.modCount;
                
Node<K,V>[] tab = m.table;
                
hi = fence = (tab == null) ? 0 : tab.length;
            
}
            
return hi;
        
}

        
public final long estimateSize() {
            
getFence(); // force init
            
return (long) est;
        
}
    
}

    
static final class KeySpliterator<K,V>
        
extends HashMapSpliterator<K,V>
        
implements Spliterator<K> {
        
KeySpliterator(HashMap<K,V> m, int origin, int fence, int est,
                       
int expectedModCount) {
            
super(m, origin, fence, est, expectedModCount);
        
}

        
public KeySpliterator<K,V> trySplit() {
            
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
            
return (lo >= mid || current != null) ? null :
                
new KeySpliterator<>(map, lo, index = mid, est >>>= 1,
                                        
expectedModCount);
        
}

        
public void forEachRemaining(Consumer<? super K> action) {
            
int i, hi, mc;
            
if (action == null)
                
throw new NullPointerException();
            
HashMap<K,V> m = map;
            
Node<K,V>[] tab = m.table;
            
if ((hi = fence) < 0) {
                
mc = expectedModCount = m.modCount;
                
hi = fence = (tab == null) ? 0 : tab.length;
            
}
            
else
                
mc = expectedModCount;
            
if (tab != null && tab.length >= hi &&
                
(i = index) >= 0 && (i < (index = hi) || current != null)) {
                
Node<K,V> p = current;
                
current = null;
                
do {
                    
if (p == null)
                        
p = tab[i++];
                    
else {
                        
action.accept(p.key);
                        
p = p.next;
                    
}
                
} while (p != null || i < hi);
                
if (m.modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}

        
public boolean tryAdvance(Consumer<? super K> action) {
            
int hi;
            
if (action == null)
                
throw new NullPointerException();
            
Node<K,V>[] tab = map.table;
            
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
                
while (current != null || index < hi) {
                    
if (current == null)
                        
current = tab[index++];
                    
else {
                        
K k = current.key;
                        
current = current.next;
                        
action.accept(k);
                        
if (map.modCount != expectedModCount)
                            
throw new ConcurrentModificationException();
                        
return true;
                    
}
                
}
            
}
            
return false;
        
}

        
public int characteristics() {
            
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
                
Spliterator.DISTINCT;
        
}
    
}

    
static final class ValueSpliterator<K,V>
        
extends HashMapSpliterator<K,V>
        
implements Spliterator<V> {
        
ValueSpliterator(HashMap<K,V> m, int origin, int fence, int est,
                         
int expectedModCount) {
            
super(m, origin, fence, est, expectedModCount);
        
}

        
public ValueSpliterator<K,V> trySplit() {
            
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
            
return (lo >= mid || current != null) ? null :
                
new ValueSpliterator<>(map, lo, index = mid, est >>>= 1,
                                          
expectedModCount);
        
}

        
public void forEachRemaining(Consumer<? super V> action) {
            
int i, hi, mc;
            
if (action == null)
                
throw new NullPointerException();
            
HashMap<K,V> m = map;
            
Node<K,V>[] tab = m.table;
            
if ((hi = fence) < 0) {
                
mc = expectedModCount = m.modCount;
                
hi = fence = (tab == null) ? 0 : tab.length;
            
}
            
else
                
mc = expectedModCount;
            
if (tab != null && tab.length >= hi &&
                
(i = index) >= 0 && (i < (index = hi) || current != null)) {
                
Node<K,V> p = current;
                
current = null;
                
do {
                    
if (p == null)
                        
p = tab[i++];
                    
else {
                        
action.accept(p.value);
                        
p = p.next;
                    
}
                
} while (p != null || i < hi);
                
if (m.modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}

        
public boolean tryAdvance(Consumer<? super V> action) {
            
int hi;
            
if (action == null)
                
throw new NullPointerException();
            
Node<K,V>[] tab = map.table;
            
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
                
while (current != null || index < hi) {
                    
if (current == null)
                        
current = tab[index++];
                    
else {
                        
V v = current.value;
                        
current = current.next;
                        
action.accept(v);
                        
if (map.modCount != expectedModCount)
                            
throw new ConcurrentModificationException();
                        
return true;
                    
}
                
}
            
}
            
return false;
        
}

        
public int characteristics() {
            
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0);
        
}
    
}

    
static final class EntrySpliterator<K,V>
        
extends HashMapSpliterator<K,V>
        
implements Spliterator<Map.Entry<K,V>> {
        
EntrySpliterator(HashMap<K,V> m, int origin, int fence, int est,
                         
int expectedModCount) {
            
super(m, origin, fence, est, expectedModCount);
        
}

        
public EntrySpliterator<K,V> trySplit() {
            
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
            
return (lo >= mid || current != null) ? null :
                
new EntrySpliterator<>(map, lo, index = mid, est >>>= 1,
                                          
expectedModCount);
        
}

        
public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) {
            
int i, hi, mc;
            
if (action == null)
                
throw new NullPointerException();
            
HashMap<K,V> m = map;
            
Node<K,V>[] tab = m.table;
            
if ((hi = fence) < 0) {
                
mc = expectedModCount = m.modCount;
                
hi = fence = (tab == null) ? 0 : tab.length;
            
}
            
else
                
mc = expectedModCount;
            
if (tab != null && tab.length >= hi &&
                
(i = index) >= 0 && (i < (index = hi) || current != null)) {
                
Node<K,V> p = current;
                
current = null;
                
do {
                    
if (p == null)
                        
p = tab[i++];
                    
else {
                        
action.accept(p);
                        
p = p.next;
                    
}
                
} while (p != null || i < hi);
                
if (m.modCount != mc)
                    
throw new ConcurrentModificationException();
            
}
        
}

        
public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) {
            
int hi;
            
if (action == null)
                
throw new NullPointerException();
            
Node<K,V>[] tab = map.table;
            
if (tab != null && tab.length >= (hi = getFence()) && index >= 0) {
                
while (current != null || index < hi) {
                    
if (current == null)
                        
current = tab[index++];
                    
else {
                        
Node<K,V> e = current;
                        
current = current.next;
                        
action.accept(e);
                        
if (map.modCount != expectedModCount)
                            
throw new ConcurrentModificationException();
                        
return true;
                    
}
                
}
            
}
            
return false;
        
}

        
public int characteristics() {
            
return (fence < 0 || est == map.size ? Spliterator.SIZED : 0) |
                
Spliterator.DISTINCT;
        
}
    
}

    
/* ------------------------------------------------------------ */
    
// LinkedHashMap support


    
/*
     
* The following package-protected methods are designed to be
     
* overridden by LinkedHashMap, but not by any other subclass.
     
* Nearly all other internal methods are also package-protected
     
* but are declared final, so can be used by LinkedHashMap, view
     
* classes, and HashSet.
     
*/


    
// Create a regular (non-tree) node
    
Node<K,V> newNode(int hash, K key, V value, Node<K,V> next) {
        
return new Node<>(hash, key, value, next);
    
}

    
// For conversion from TreeNodes to plain nodes
    
Node<K,V> replacementNode(Node<K,V> p, Node<K,V> next) {
        
return new Node<>(p.hash, p.key, p.value, next);
    
}

    
// Create a tree bin node
    
TreeNode<K,V> newTreeNode(int hash, K key, V value, Node<K,V> next) {
        
return new TreeNode<>(hash, key, value, next);
    
}

    
// For treeifyBin
    
TreeNode<K,V> replacementTreeNode(Node<K,V> p, Node<K,V> next) {
        
return new TreeNode<>(p.hash, p.key, p.value, next);
    
}

    
/**
     
* Reset to initial default state.
  
Called by clone and readObject.
     
*/

    
void reinitialize() {
        
table = null;
        
entrySet = null;
        
keySet = null;
        
values = null;
        
modCount = 0;
        
threshold = 0;
        
size = 0;
    
}

    
// Callbacks to allow LinkedHashMap post-actions
    
void afterNodeAccess(Node<K,V> p) { }
    
void afterNodeInsertion(boolean evict) { }
    
void afterNodeRemoval(Node<K,V> p) { }

    
// Called only from writeObject, to ensure compatible ordering.
    
void internalWriteEntries(java.io.ObjectOutputStream s) throws IOException {
        
Node<K,V>[] tab;
        
if (size > 0 && (tab = table) != null) {
            
for (int i = 0; i < tab.length; ++i) {
                
for (Node<K,V> e = tab[i]; e != null; e = e.next) {
                    
s.writeObject(e.key);
                    
s.writeObject(e.value);
                
}
            
}
        
}
    
}

    
/* ------------------------------------------------------------ */
    
// Tree bins

    
/**
     
* Entry for Tree bins. Extends LinkedHashMap.Entry (which in turn
     
* extends Node) so can be used as extension of either regular or
     
* linked node.
     
*/

    
static final class TreeNode<K,V> extends LinkedHashMap.Entry<K,V> {
        
TreeNode<K,V> parent;
  
// red-black tree links
        
TreeNode<K,V> left;
        
TreeNode<K,V> right;
        
TreeNode<K,V> prev;
    
// needed to unlink next upon deletion
        
boolean red;
        
TreeNode(int hash, K key, V val, Node<K,V> next) {
            
super(hash, key, val, next);
        
}

        
/**
         
* Returns root of tree containing this node.
         
*/
        
final TreeNode<K,V> root() {
            
for (TreeNode<K,V> r = this, p;;) {
                
if ((p = r.parent) == null)
                    
return r;
                
r = p;
            
}
        
}

        
/**
         
* Ensures that the given root is the first node of its bin.
         
*/
        
static <K,V> void moveRootToFront(Node<K,V>[] tab, TreeNode<K,V> root) {
            
int n;
            
if (root != null && tab != null && (n = tab.length) > 0) {
                
int index = (n - 1) & root.hash;
                
TreeNode<K,V> first = (TreeNode<K,V>)tab[index];
                
if (root != first) {
                    
Node<K,V> rn;
                    
tab[index] = root;
                    
TreeNode<K,V> rp = root.prev;
                    
if ((rn = root.next) != null)
                        
((TreeNode<K,V>)rn).prev = rp;
                    
if (rp != null)
                        
rp.next = rn;
                    
if (first != null)
                        
first.prev = root;
                    
root.next = first;
                    
root.prev = null;
                
}
                
assert checkInvariants(root);
            
}
        
}

        
/**
         
* Finds the node starting at root p with the given hash and key.
         
* The kc argument caches comparableClassFor(key) upon first use
         
* comparing keys.
         
*/

        
final TreeNode<K,V> find(int h, Object k, Class<?> kc) {
            
TreeNode<K,V> p = this;
            
do {
                
int ph, dir; K pk;
                
TreeNode<K,V> pl = p.left, pr = p.right, q;
                
if ((ph = p.hash) > h)
                    
p = pl;
                
else if (ph < h)
                    
p = pr;
                
else if ((pk = p.key) == k || (k != null && k.equals(pk)))
                    
return p;
                
else if (pl == null)
                    
p = pr;
                
else if (pr == null)
                    
p = pl;
                
else if ((kc != null ||
                          
(kc = comparableClassFor(k)) != null) &&
                         
(dir = compareComparables(kc, k, pk)) != 0)
                    
p = (dir < 0) ? pl : pr;
                
else if ((q = pr.find(h, k, kc)) != null)
                    
return q;
                
else
                    
p = pl;
            
} while (p != null);
            
return null;
        
}

        
/**
         
* Calls find for root node.
         
*/
        
final TreeNode<K,V> getTreeNode(int h, Object k) {
            
return ((parent != null) ? root() : this).find(h, k, null);
        
}

        
/**
         
* Tie-breaking utility for ordering insertions when equal
         
* hashCodes and non-comparable. We don't require a total
         
* order, just a consistent insertion rule to maintain
         
* equivalence across rebalancings. Tie-breaking further than
         
* necessary simplifies testing a bit.
         
*/

        
static int tieBreakOrder(Object a, Object b) {
            
int d;
            
if (a == null || b == null ||
                
(d = a.getClass().getName().
                 
compareTo(b.getClass().getName())) == 0)
                
d = (System.identityHashCode(a) <= System.identityHashCode(b) ?
                     
-1 : 1);
            
return d;
        
}

        
/**
         
* Forms tree of the nodes linked from this node.
         
*/
        
final void treeify(Node<K,V>[] tab) {
            
TreeNode<K,V> root = null;
            
for (TreeNode<K,V> x = this, next; x != null; x = next) {
                
next = (TreeNode<K,V>)x.next;
                
x.left = x.right = null;
                
if (root == null) {
                    
x.parent = null;
                    
x.red = false;
                    
root = x;
                
}
                
else {
                    
K k = x.key;
                    
int h = x.hash;
                    
Class<?> kc = null;
                    
for (TreeNode<K,V> p = root;;) {
                        
int dir, ph;
                        
K pk = p.key;
                        
if ((ph = p.hash) > h)
                            
dir = -1;
                        
else if (ph < h)
                            
dir = 1;
                        
else if ((kc == null &&
                                  
(kc = comparableClassFor(k)) == null) ||
                                 
(dir = compareComparables(kc, k, pk)) == 0)
                            
dir = tieBreakOrder(k, pk);

                        
TreeNode<K,V> xp = p;
                        
if ((p = (dir <= 0) ? p.left : p.right) == null) {
                            
x.parent = xp;
                            
if (dir <= 0)
                                
xp.left = x;
                            
else
                                
xp.right = x;
                            
root = balanceInsertion(root, x);
                            
break;
                        
}
                    
}
                
}
            
}
            
moveRootToFront(tab, root);
        
}

        
/**
         
* Returns a list of non-TreeNodes replacing those linked from
         
* this node.
         
*/

        
final Node<K,V> untreeify(HashMap<K,V> map) {
            
Node<K,V> hd = null, tl = null;
            
for (Node<K,V> q = this; q != null; q = q.next) {
                
Node<K,V> p = map.replacementNode(q, null);
                
if (tl == null)
                    
hd = p;
                
else
                    
tl.next = p;
                
tl = p;
            
}
            
return hd;
        
}

        
/**
         
* Tree version of putVal.
         
*/
        
final TreeNode<K,V> putTreeVal(HashMap<K,V> map, Node<K,V>[] tab,
                                       
int h, K k, V v) {
            
Class<?> kc = null;
            
boolean searched = false;
            
TreeNode<K,V> root = (parent != null) ? root() : this;
            
for (TreeNode<K,V> p = root;;) {
                
int dir, ph; K pk;
                
if ((ph = p.hash) > h)
                    
dir = -1;
                
else if (ph < h)
                    
dir = 1;
                
else if ((pk = p.key) == k || (k != null && k.equals(pk)))
                    
return p;
                
else if ((kc == null &&
                          
(kc = comparableClassFor(k)) == null) ||
                         
(dir = compareComparables(kc, k, pk)) == 0) {
                    
if (!searched) {
                        
TreeNode<K,V> q, ch;
                        
searched = true;
                        
if (((ch = p.left) != null &&
                             
(q = ch.find(h, k, kc)) != null) ||
                            
((ch = p.right) != null &&
                             
(q = ch.find(h, k, kc)) != null))
                            
return q;
                    
}
                    
dir = tieBreakOrder(k, pk);
                
}

                
TreeNode<K,V> xp = p;
                
if ((p = (dir <= 0) ? p.left : p.right) == null) {
                    
Node<K,V> xpn = xp.next;
                    
TreeNode<K,V> x = map.newTreeNode(h, k, v, xpn);
                    
if (dir <= 0)
                        
xp.left = x;
                    
else
                        
xp.right = x;
                    
xp.next = x;
                    
x.parent = x.prev = xp;
                    
if (xpn != null)
                        
((TreeNode<K,V>)xpn).prev = x;
                    
moveRootToFront(tab, balanceInsertion(root, x));
                    
return null;
                
}
            
}
        
}

        
/**
         
* Removes the given node, that must be present before this call.
         
* This is messier than typical red-black deletion code because we
         
* cannot swap the contents of an interior node with a leaf
         
* successor that is pinned by "next" pointers that are accessible
         
* independently during traversal. So instead we swap the tree
         
* linkages. If the current tree appears to have too few nodes,
         
* the bin is converted back to a plain bin. (The test triggers
         
* somewhere between 2 and 6 nodes, depending on tree