/*
 
* Copyright (c) 1995, 2016, 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.net;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Hashtable;
import java.util.Date;
import java.util.StringTokenizer;
import java.util.Collections;
import java.util.Map;
import java.util.List;
import java.security.Permission;
import java.security.AccessController;
import sun.security.util.SecurityConstants;
import sun.net.www.MessageHeader;

/**
 
* The abstract class {@code URLConnection} is the superclass
 
* of all classes that represent a communications link between the
 
* application and a URL. Instances of this class can be used both to
 
* read from and to write to the resource referenced by the URL. In
 
* general, creating a connection to a URL is a multistep process:
 
*
 
* <center><table border=2 summary="Describes the process of creating a connection to a URL: openConnection() and connect() over time.">
 
* <tr><th>{@code openConnection()}</th>
 
*
     
<th>{@code connect()}</th></tr>
 
* <tr><td>Manipulate parameters that affect the connection to the remote
 
*
         
resource.</td>
 
*
     
<td>Interact with the resource; query header fields and
 
*
         
contents.</td></tr>
 
* </table>
 
* ----------------------------&gt;
 
* <br>time</center>
 
*
 
* <ol>
 
* <li>The connection object is created by invoking the
 
*
     
{@code openConnection} method on a URL.
 
* <li>The setup parameters and general request properties are manipulated.
 
* <li>The actual connection to the remote object is made, using the
 
*
    
{@code connect} method.
 
* <li>The remote object becomes available. The header fields and the contents
 
*
     
of the remote object can be accessed.
 
* </ol>
 
* <p>
 
* The setup parameters are modified using the following methods:
 
* <ul>
 
*
   
<li>{@code setAllowUserInteraction}
 
*
   
<li>{@code setDoInput}
 
*
   
<li>{@code setDoOutput}
 
*
   
<li>{@code setIfModifiedSince}
 
*
   
<li>{@code setUseCaches}
 
* </ul>
 
* <p>
 
* and the general request properties are modified using the method:
 
* <ul>
 
*
   
<li>{@code setRequestProperty}
 
* </ul>
 
* <p>
 
* Default values for the {@code AllowUserInteraction} and
 
* {@code UseCaches} parameters can be set using the methods
 
* {@code setDefaultAllowUserInteraction} and
 
* {@code setDefaultUseCaches}.
 
* <p>
 
* Each of the above {@code set} methods has a corresponding
 
* {@code get} method to retrieve the value of the parameter or
 
* general request property. The specific parameters and general
 
* request properties that are applicable are protocol specific.
 
* <p>
 
* The following methods are used to access the header fields and
 
* the contents after the connection is made to the remote object:
 
* <ul>
 
*
   
<li>{@code getContent}
 
*
   
<li>{@code getHeaderField}
 
*
   
<li>{@code getInputStream}
 
*
   
<li>{@code getOutputStream}
 
* </ul>
 
* <p>
 
* Certain header fields are accessed frequently. The methods:
 
* <ul>
 
*
   
<li>{@code getContentEncoding}
 
*
   
<li>{@code getContentLength}
 
*
   
<li>{@code getContentType}
 
*
   
<li>{@code getDate}
 
*
   
<li>{@code getExpiration}
 
*
   
<li>{@code getLastModifed}
 
* </ul>
 
* <p>
 
* provide convenient access to these fields. The
 
* {@code getContentType} method is used by the
 
* {@code getContent} method to determine the type of the remote
 
* object; subclasses may find it convenient to override the
 
* {@code getContentType} method.
 
* <p>
 
* In the common case, all of the pre-connection parameters and
 
* general request properties can be ignored: the pre-connection
 
* parameters and request properties default to sensible values. For
 
* most clients of this interface, there are only two interesting
 
* methods: {@code getInputStream} and {@code getContent},
 
* which are mirrored in the {@code URL} class by convenience methods.
 
* <p>
 
* More information on the request properties and header fields of
 
* an {@code http} connection can be found at:
 
* <blockquote><pre>
 
*<a href="http://www.ietf.org/rfc/rfc2616.txt">http://www.ietf.org/rfc/rfc2616.txt</a>
 
* </pre></blockquote>
 
*
 
* Invoking the {@code close()} methods on the {@code InputStream} or {@code OutputStream} of an
 
* {@code URLConnection} after a request may free network resources associated with this
 
* instance, unless particular protocol specifications specify different behaviours
 
* for it.
 
*
 
* @author
  
James Gosling
 
* @see
     
java.net.URL#openConnection()
 
* @see
     
java.net.URLConnection#connect()
 
* @see
     
java.net.URLConnection#getContent()
 
* @see
     
java.net.URLConnection#getContentEncoding()
 
* @see
     
java.net.URLConnection#getContentLength()
 
* @see
     
java.net.URLConnection#getContentType()
 
* @see
     
java.net.URLConnection#getDate()
 
* @see
     
java.net.URLConnection#getExpiration()
 
* @see
     
java.net.URLConnection#getHeaderField(int)
 
* @see
     
java.net.URLConnection#getHeaderField(java.lang.String)
 
* @see
     
java.net.URLConnection#getInputStream()
 
* @see
     
java.net.URLConnection#getLastModified()
 
* @see
     
java.net.URLConnection#getOutputStream()
 
* @see
     
java.net.URLConnection#setAllowUserInteraction(boolean)
 
* @see
     
java.net.URLConnection#setDefaultUseCaches(boolean)
 
* @see
     
java.net.URLConnection#setDoInput(boolean)
 
* @see
     
java.net.URLConnection#setDoOutput(boolean)
 
* @see
     
java.net.URLConnection#setIfModifiedSince(long)
 
* @see
     
java.net.URLConnection#setRequestProperty(java.lang.String, java.lang.String)
 
* @see
     
java.net.URLConnection#setUseCaches(boolean)
 
* @since
   
JDK1.0
 
*/

public abstract class URLConnection {

   
/**
     
* The URL represents the remote object on the World Wide Web to
     
* which this connection is opened.
     
* <p>
     
* The value of this field can be accessed by the
     
* {@code getURL} method.
     
* <p>
     
* The default value of this variable is the value of the URL
     
* argument in the {@code URLConnection} constructor.
     
*
     
* @seejava.net.URLConnection#getURL()
     
* @seejava.net.URLConnection#url
     
*/

    
protected URL url;

   
/**
     
* This variable is set by the {@code setDoInput} method. Its
     
* value is returned by the {@code getDoInput} method.
     
* <p>
     
* A URL connection can be used for input and/or output. Setting the
     
* {@code doInput} flag to {@code true} indicates that
     
* the application intends to read data from the URL connection.
     
* <p>
     
* The default value of this field is {@code true}.
     
*
     
* @seejava.net.URLConnection#getDoInput()
     
* @seejava.net.URLConnection#setDoInput(boolean)
     
*/

    
protected boolean doInput = true;

   
/**
     
* This variable is set by the {@code setDoOutput} method. Its
     
* value is returned by the {@code getDoOutput} method.
     
* <p>
     
* A URL connection can be used for input and/or output. Setting the
     
* {@code doOutput} flag to {@code true} indicates
     
* that the application intends to write data to the URL connection.
     
* <p>
     
* The default value of this field is {@code false}.
     
*
     
* @seejava.net.URLConnection#getDoOutput()
     
* @seejava.net.URLConnection#setDoOutput(boolean)
     
*/

    
protected boolean doOutput = false;

    
private static boolean defaultAllowUserInteraction = false;

   
/**
     
* If {@code true}, this {@code URL} is being examined in
     
* a context in which it makes sense to allow user interactions such
     
* as popping up an authentication dialog. If {@code false},
     
* then no user interaction is allowed.
     
* <p>
     
* The value of this field can be set by the
     
* {@code setAllowUserInteraction} method.
     
* Its value is returned by the
     
* {@code getAllowUserInteraction} method.
     
* Its default value is the value of the argument in the last invocation
     
* of the {@code setDefaultAllowUserInteraction} method.
     
*
     
* @seejava.net.URLConnection#getAllowUserInteraction()
     
* @seejava.net.URLConnection#setAllowUserInteraction(boolean)
     
* @seejava.net.URLConnection#setDefaultAllowUserInteraction(boolean)
     
*/

    
protected boolean allowUserInteraction = defaultAllowUserInteraction;

    
private static boolean defaultUseCaches = true;

   
/**
     
* If {@code true}, the protocol is allowed to use caching
     
* whenever it can. If {@code false}, the protocol must always
     
* try to get a fresh copy of the object.
     
* <p>
     
* This field is set by the {@code setUseCaches} method. Its
     
* value is returned by the {@code getUseCaches} method.
     
* <p>
     
* Its default value is the value given in the last invocation of the
     
* {@code setDefaultUseCaches} method.
     
*
     
* @seejava.net.URLConnection#setUseCaches(boolean)
     
* @seejava.net.URLConnection#getUseCaches()
     
* @seejava.net.URLConnection#setDefaultUseCaches(boolean)
     
*/

    
protected boolean useCaches = defaultUseCaches;

   
/**
     
* Some protocols support skipping the fetching of the object unless
     
* the object has been modified more recently than a certain time.
     
* <p>
     
* A nonzero value gives a time as the number of milliseconds since
     
* January 1, 1970, GMT. The object is fetched only if it has been
     
* modified more recently than that time.
     
* <p>
     
* This variable is set by the {@code setIfModifiedSince}
     
* method. Its value is returned by the
     
* {@code getIfModifiedSince} method.
     
* <p>
     
* The default value of this field is {@code 0}, indicating
     
* that the fetching must always occur.
     
*
     
* @seejava.net.URLConnection#getIfModifiedSince()
     
* @seejava.net.URLConnection#setIfModifiedSince(long)
     
*/

    
protected long ifModifiedSince = 0;

   
/**
     
* If {@code false}, this connection object has not created a
     
* communications link to the specified URL. If {@code true},
     
* the communications link has been established.
     
*/

    
protected boolean connected = false;

    
/**
     
* @since 1.5
     
*/
    
private int connectTimeout;
    
private int readTimeout;

    
/**
     
* @since 1.6
     
*/
    
private MessageHeader requests;

   
/**
    
* @since
   
JDK1.1
    
*/
    
private static FileNameMap fileNameMap;

    
/**
     
* @since 1.2.2
     
*/
    
private static boolean fileNameMapLoaded = false;

    
/**
     
* Loads filename map (a mimetable) from a data file. It will
     
* first try to load the user-specific table, defined
     
* by &quot;content.types.user.table&quot; property. If that fails,
     
* it tries to load the default built-in table.
     
*
     
* @return the FileNameMap
     
* @since 1.2
     
* @see #setFileNameMap(java.net.FileNameMap)
     
*/

    
public static synchronized FileNameMap getFileNameMap() {
        
if ((fileNameMap == null) && !fileNameMapLoaded) {
            
fileNameMap = sun.net.www.MimeTable.loadTable();
            
fileNameMapLoaded = true;
        
}

        
return new FileNameMap() {
            
private FileNameMap map = fileNameMap;
            
public String getContentTypeFor(String fileName) {
                
return map.getContentTypeFor(fileName);
            
}
        
};
    
}

    
/**
     
* Sets the FileNameMap.
     
* <p>
     
* If there is a security manager, this method first calls
     
* the security manager's {@code checkSetFactory} method
     
* to ensure the operation is allowed.
     
* This could result in a SecurityException.
     
*
     
* @param map the FileNameMap to be set
     
* @exception
  
SecurityExceptionif a security manager exists and its
     
*
             
{@code checkSetFactory} method doesn't allow the operation.
     
* @see
        
SecurityManager#checkSetFactory
     
*
 

     
* @since 1.2
     
*/

    
public static void setFileNameMap(FileNameMap map) {
        
SecurityManager sm = System.getSecurityManager();
        
if (sm != null) sm.checkSetFactory();
        
fileNameMap = map;
    
}

    
/**
     
* Opens a communications link to the resource referenced by this
     
* URL, if such a connection has not already been established.
     
* <p>
     
* If the {@code connect} method is called when the connection
     
* has already been opened (indicated by the {@code connected}
     
* field having the value {@code true}), the call is ignored.
     
* <p>
     
* URLConnection objects go through two phases: first they are
     
* created, then they are connected.
  
After being created, and
     
* before being connected, various options can be specified
     
* (e.g., doInput and UseCaches).
  
After connecting, it is an
     
* error to try to set them.
  
Operations that depend on being
     
* connected, like getContentLength, will implicitly perform the
     
* connection, if necessary.
     
*
     
* @throws SocketTimeoutException if the timeout expires before
     
*
               
the connection can be established
     
* @exception
  
IOExceptionif an I/O error occurs while opening the
     
*
               
connection.
     
*
 

     
*
 

     
* @see #setConnectTimeout(int)
     
*/

    
abstract public void connect() throws IOException;

    
/**
     
* Sets a specified timeout value, in milliseconds, to be used
     
* when opening a communications link to the resource referenced
     
* by this URLConnection.
  
If the timeout expires before the
     
* connection can be established, a
     
* java.net.SocketTimeoutException is raised. A timeout of zero is
     
* interpreted as an infinite timeout.

     
* <p> Some non-standard implementation of this method may ignore
     
* the specified timeout. To see the connect timeout set, please
     
* call getConnectTimeout().
     
*
     
* @param timeout an {@code int} that specifies the connect
     
*
               
timeout value in milliseconds
     
* @throws IllegalArgumentException if the timeout parameter is negative
     
*
     
*
 

     
*
 

     
* @since 1.5
     
*/

    
public void setConnectTimeout(int timeout) {
        
if (timeout < 0) {
            
throw new IllegalArgumentException("timeout can not be negative");
        
}
        
connectTimeout = timeout;
    
}

    
/**
     
* Returns setting for connect timeout.
     
* <p>
     
* 0 return implies that the option is disabled
     
* (i.e., timeout of infinity).
     
*
     
* @return an {@code int} that indicates the connect timeout
     
*
         
value in milliseconds
     
* @see #setConnectTimeout(int)
     
*
 

     
* @since 1.5
     
*/

    
public int getConnectTimeout() {
        
return connectTimeout;
    
}

    
/**
     
* Sets the read timeout to a specified timeout, in
     
* milliseconds. A non-zero value specifies the timeout when
     
* reading from Input stream when a connection is established to a
     
* resource. If the timeout expires before there is data available
     
* for read, a java.net.SocketTimeoutException is raised. A
     
* timeout of zero is interpreted as an infinite timeout.
     
*
     
*<p> Some non-standard implementation of this method ignores the
     
* specified timeout. To see the read timeout set, please call
     
* getReadTimeout().
     
*
     
* @param timeout an {@code int} that specifies the timeout
     
* value to be used in milliseconds
     
* @throws IllegalArgumentException if the timeout parameter is negative
     
*
     
*
 

     
* @see InputStream#read()
     
* @since 1.5
     
*/

    
public void setReadTimeout(int timeout) {
        
if (timeout < 0) {
            
throw new IllegalArgumentException("timeout can not be negative");
        
}
        
readTimeout = timeout;
    
}

    
/**
     
* Returns setting for read timeout. 0 return implies that the
     
* option is disabled (i.e., timeout of infinity).
     
*
     
* @return an {@code int} that indicates the read timeout
     
*
         
value in milliseconds
     
*
     
* @see #setReadTimeout(int)
     
* @see InputStream#read()
     
* @since 1.5
     
*/

    
public int getReadTimeout() {
        
return readTimeout;
    
}

    
/**
     
* Constructs a URL connection to the specified URL. A connection to
     
* the object referenced by the URL is not created.
     
*
     
* @param
   
urlthe specified URL.
     
*/

    
protected URLConnection(URL url) {
        
this.url = url;
    
}

    
/**
     
* Returns the value of this {@code URLConnection}'s {@code URL}
     
* field.
     
*
     
* @return
  
the value of this {@code URLConnection}'s {@code URL}
     
*
          
field.
     
* @seejava.net.URLConnection#url
     
*/

    
public URL getURL() {
        
return url;
    
}

    
/**
     
* Returns the value of the {@code content-length} header field.
     
* <P>
     
* <B>Note</B>: {@link #getContentLengthLong() getContentLengthLong()}
     
* should be preferred over this method, since it returns a {@code long}
     
* instead and is therefore more portable.</P>
     
*
     
* @return
  
the content length of the resource that this connection's URL
     
*
          
references, {@code -1} if the content length is not known,
     
*
          
or if the content length is greater than Integer.MAX_VALUE.
     
*/

    
public int getContentLength() {
        
long l = getContentLengthLong();
        
if (l > Integer.MAX_VALUE)
            
return -1;
        
return (int) l;
    
}

    
/**
     
* Returns the value of the {@code content-length} header field as a
     
* long.
     
*
     
* @return
  
the content length of the resource that this connection's URL
     
*
          
references, or {@code -1} if the content length is
     
*
          
not known.
     
* @since 7.0
     
*/

    
public long getContentLengthLong() {
        
return getHeaderFieldLong("content-length", -1);
    
}

    
/**
     
* Returns the value of the {@code content-type} header field.
     
*
     
* @return
  
the content type of the resource that the URL references,
     
*
          
or {@code null} if not known.
     
* @seejava.net.URLConnection#getHeaderField(java.lang.String)
     
*/

    
public String getContentType() {
        
return getHeaderField("content-type");
    
}

    
/**
     
* Returns the value of the {@code content-encoding} header field.
     
*
     
* @return
  
the content encoding of the resource that the URL references,
     
*
          
or {@code null} if not known.
     
* @seejava.net.URLConnection#getHeaderField(java.lang.String)
     
*/

    
public String getContentEncoding() {
        
return getHeaderField("content-encoding");
    
}

    
/**
     
* Returns the value of the {@code expires} header field.
     
*
     
* @return
  
the expiration date of the resource that this URL references,
     
*
          
or 0 if not known. The value is the number of milliseconds since
     
*
          
January 1, 1970 GMT.
     
* @seejava.net.URLConnection#getHeaderField(java.lang.String)
     
*/

    
public long getExpiration() {
        
return getHeaderFieldDate("expires", 0);
    
}

    
/**
     
* Returns the value of the {@code date} header field.
     
*
     
* @return
  
the sending date of the resource that the URL references,
     
*
          
or {@code 0} if not known. The value returned is the
     
*
          
number of milliseconds since January 1, 1970 GMT.
     
* @seejava.net.URLConnection#getHeaderField(java.lang.String)
     
*/

    
public long getDate() {
        
return getHeaderFieldDate("date", 0);
    
}

    
/**
     
* Returns the value of the {@code last-modified} header field.
     
* The result is the number of milliseconds since January 1, 1970 GMT.
     
*
     
* @return
  
the date the resource referenced by this
     
*
          
{@code URLConnection} was last modified, or 0 if not known.
     
* @seejava.net.URLConnection#getHeaderField(java.lang.String)
     
*/

    
public long getLastModified() {
        
return getHeaderFieldDate("last-modified", 0);
    
}

    
/**
     
* Returns the value of the named header field.
     
* <p>
     
* If called on a connection that sets the same header multiple times
     
* with possibly different values, only the last value is returned.
     
*
     
*
     
* @param
   
namethe name of a header field.
     
* @return
  
the value of the named header field, or {@code null}
     
*
          
if there is no such field in the header.
     
*/

    
public String getHeaderField(String name) {
        
return null;
    
}

    
/**
     
* Returns an unmodifiable Map of the header fields.
     
* The Map keys are Strings that represent the
     
* response-header field names. Each Map value is an
     
* unmodifiable List of Strings that represents
     
* the corresponding field values.
     
*
     
* @return a Map of header fields
     
* @since 1.4
     
*/

    
public Map<String,List<String>> getHeaderFields() {
        
return Collections.emptyMap();
    
}

    
/**
     
* Returns the value of the named field parsed as a number.
     
* <p>
     
* This form of {@code getHeaderField} exists because some
     
* connection types (e.g., {@code http-ng}) have pre-parsed
     
* headers. Classes for that connection type can override this method
     
* and short-circuit the parsing.
     
*
     
* @param
   
name
      
the name of the header field.
     
* @param
   
Defaultthe default value.
     
* @return
  
the value of the named field, parsed as an integer. The
     
*
          
{@code Default} value is returned if the field is
     
*
          
missing or malformed.
     
*/

    
public int getHeaderFieldInt(String name, int Default) {
        
String value = getHeaderField(name);
        
try {
            
return Integer.parseInt(value);
        
} catch (Exception e) { }
        
return Default;
    
}

    
/**
     
* Returns the value of the named field parsed as a number.
     
* <p>
     
* This form of {@code getHeaderField} exists because some
     
* connection types (e.g., {@code http-ng}) have pre-parsed
     
* headers. Classes for that connection type can override this method
     
* and short-circuit the parsing.
     
*
     
* @param
   
name
      
the name of the header field.
     
* @param
   
Defaultthe default value.
     
* @return
  
the value of the named field, parsed as a long. The
     
*
          
{@code Default} value is returned if the field is
     
*
          
missing or malformed.
     
* @since 7.0
     
*/

    
public long getHeaderFieldLong(String name, long Default) {
        
String value = getHeaderField(name);
        
try {
            
return Long.parseLong(value);
        
} catch (Exception e) { }
        
return Default;
    
}

    
/**
     
* Returns the value of the named field parsed as date.
     
* The result is the number of milliseconds since January 1, 1970 GMT
     
* represented by the named field.
     
* <p>
     
* This form of {@code getHeaderField} exists because some
     
* connection types (e.g., {@code http-ng}) have pre-parsed
     
* headers. Classes for that connection type can override this method
     
* and short-circuit the parsing.
     
*
     
* @param
   
namethe name of the header field.
     
* @param
   
Defaulta default value.
     
* @return
  
the value of the field, parsed as a date. The value of the
     
*
          
{@code Default} argument is returned if the field is
     
*
          
missing or malformed.
     
*/

    
@SuppressWarnings("deprecation")
    
public long getHeaderFieldDate(String name, long Default) {
        
String value = getHeaderField(name);
        
try {
            
return Date.parse(value);
        
} catch (Exception e) { }
        
return Default;
    
}

    
/**
     
* Returns the key for the {@code n}<sup>th</sup> header field.
     
* It returns {@code null} if there are fewer than {@code n+1} fields.
     
*
     
* @param
   
nan index, where {@code n>=0}
     
* @return
  
the key for the {@code n}<sup>th</sup> header field,
     
*
          
or {@code null} if there are fewer than {@code n+1}
     
*
          
fields.
     
*/

    
public String getHeaderFieldKey(int n) {
        
return null;
    
}

    
/**
     
* Returns the value for the {@code n}<sup>th</sup> header field.
     
* It returns {@code null} if there are fewer than
     
* {@code n+1}fields.
     
* <p>
     
* This method can be used in conjunction with the
     
* {@link #getHeaderFieldKey(int) getHeaderFieldKey} method to iterate through all
     
* the headers in the message.
     
*
     
* @param
   
nan index, where {@code n>=0}
     
* @return
  
the value of the {@code n}<sup>th</sup> header field
     
*
          
or {@code null} if there are fewer than {@code n+1} fields
     
* @seejava.net.URLConnection#getHeaderFieldKey(int)
     
*/

    
public String getHeaderField(int n) {
        
return null;
    
}

    
/**
     
* Retrieves the contents of this URL connection.
     
* <p>
     
* This method first determines the content type of the object by
     
* calling the {@code getContentType} method. If this is
     
* the first time that the application has seen that specific content
     
* type, a content handler for that content type is created:
     
* <ol>
     
* <li>If the application has set up a content handler factory instance
     
*using the {@code setContentHandlerFactory} method, the
     
*{@code createContentHandler} method of that instance is called
     
*with the content type as an argument; the result is a content
     
*handler for that content type.
     
* <li>If no content handler factory has yet been set up, or if the
     
*factory's {@code createContentHandler} method returns
     
*{@code null}, then the application loads the class named:
     
*<blockquote><pre>
     
*
         
sun.net.www.content.&lt;<i>contentType</i>&gt;
     
*</pre></blockquote>
     
*where &lt;<i>contentType</i>&gt; is formed by taking the
     
*content-type string, replacing all slash characters with a
     
*{@code period} ('.'), and all other non-alphanumeric characters
     
*with the underscore character '{@code _}'. The alphanumeric
     
*characters are specifically the 26 uppercase ASCII letters
     
*'{@code A}' through '{@code Z}', the 26 lowercase ASCII
     
*letters '{@code a}' through '{@code z}', and the 10 ASCII
     
*digits '{@code 0}' through '{@code 9}'. If the specified
     
*class does not exist, or is not a subclass of
     
*{@code ContentHandler}, then an
     
*{@code UnknownServiceException} is thrown.
     
* </ol>
     
*
     
* @returnthe object fetched. The {@code instanceof} operator
     
*
               
should be used to determine the specific kind of object
     
*
               
returned.
     
* @exception
  
IOException
              
if an I/O error occurs while
     
*
               
getting the content.
     
* @exception
  
UnknownServiceExceptionif the protocol does not support
     
*
               
the content type.
     
* @see
        
java.net.ContentHandlerFactory#createContentHandler(java.lang.String)
     
* @see
        
java.net.URLConnection#getContentType()
     
* @see
        
java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory)
     
*/

    
public Object getContent() throws IOException {
        
// Must call getInputStream before GetHeaderField gets called
        
// so that FileNotFoundException has a chance to be thrown up
        
// from here without being caught.
        
getInputStream();
        
return getContentHandler().getContent(this);
    
}

    
/**
     
* Retrieves the contents of this URL connection.
     
*
     
* @param classes the {@code Class} array
     
* indicating the requested types
     
* @returnthe object fetched that is the first match of the type
     
*
               
specified in the classes array. null if none of
     
*
               
the requested types are supported.
     
*
               
The {@code instanceof} operator should be used to
     
*
               
determine the specific kind of object returned.
     
* @exception
  
IOException
              
if an I/O error occurs while
     
*
               
getting the content.
     
* @exception
  
UnknownServiceExceptionif the protocol does not support
     
*
               
the content type.
     
* @see
        
java.net.URLConnection#getContent()
     
* @see
        
java.net.ContentHandlerFactory#createContentHandler(java.lang.String)
     
* @see
        
java.net.URLConnection#getContent(java.lang.Class[])
     
* @see
        
java.net.URLConnection#setContentHandlerFactory(java.net.ContentHandlerFactory)
     
* @since 1.3
     
*/

    
public Object getContent(Class[] classes) throws IOException {
        
// Must call getInputStream before GetHeaderField gets called
        
// so that FileNotFoundException has a chance to be thrown up
        
// from here without being caught.
        
getInputStream();
        
return getContentHandler().getContent(this, classes);
    
}

    
/**
     
* Returns a permission object representing the permission
     
* necessary to make the connection represented by this
     
* object. This method returns null if no permission is
     
* required to make the connection. By default, this method
     
* returns {@code java.security.AllPermission}. Subclasses
     
* should override this method and return the permission
     
* that best represents the permission required to make a
     
* a connection to the URL. For example, a {@code URLConnection}
     
* representing a {@code file:} URL would return a
     
* {@code java.io.FilePermission} object.
     
*
     
* <p>The permission returned may dependent upon the state of the
     
* connection. For example, the permission before connecting may be
     
* different from that after connecting. For example, an HTTP
     
* sever, say foo.com, may redirect the connection to a different
     
* host, say bar.com. Before connecting the permission returned by
     
* the connection will represent the permission needed to connect
     
* to foo.com, while the permission returned after connecting will
     
* be to bar.com.
     
*
     
* <p>Permissions are generally used for two purposes: to protect
     
* caches of objects obtained through URLConnections, and to check
     
* the right of a recipient to learn about a particular URL. In
     
* the first case, the permission should be obtained
     
* <em>after</em> the object has been obtained. For example, in an
     
* HTTP connection, this will represent the permission to connect
     
* to the host from which the data was ultimately fetched. In the
     
* second case, the permission should be obtained and tested
     
* <em>before</em> connecting.
     
*
     
* @return the permission object representing the permission
     
* necessary to make the connection represented by this
     
* URLConnection.
     
*
     
* @exception IOException if the computation of the permission
     
* requires network or file I/O and an exception occurs while
     
* computing it.
     
*/

    
public Permission getPermission() throws IOException {
        
return SecurityConstants.ALL_PERMISSION;
    
}

    
/**
     
* Returns an input stream that reads from this open connection.
     
*
     
* A SocketTimeoutException can be thrown when reading from the
     
* returned input stream if the read timeout expires before data
     
* is available for read.
     
*
     
* @returnan input stream that reads from this open connection.
     
* @exception
  
IOException
              
if an I/O error occurs while
     
*
               
creating the input stream.
     
* @exception
  
UnknownServiceExceptionif the protocol does not support
     
*
               
input.
     
* @see #setReadTimeout(int)
     
*
 

     
*/

    
public InputStream getInputStream() throws IOException {
        
throw new UnknownServiceException("protocol doesn't support input");
    
}

    
/**
     
* Returns an output stream that writes to this connection.
     
*
     
* @returnan output stream that writes to this connection.
     
* @exception
  
IOException
              
if an I/O error occurs while
     
*
               
creating the output stream.
     
* @exception
  
UnknownServiceExceptionif the protocol does not support
     
*
               
output.
     
*/

    
public OutputStream getOutputStream() throws IOException {
        
throw new UnknownServiceException("protocol doesn't support output");
    
}

    
/**
     
* Returns a {@code String} representation of this URL connection.
     
*
     
* @return
  
a string representation of this {@code URLConnection}.
     
*/

    
public String toString() {
        
return this.getClass().getName() + ":" + url;
    
}

    
/**
     
* Sets the value of the {@code doInput} field for this
     
* {@code URLConnection} to the specified value.
     
* <p>
     
* A URL connection can be used for input and/or output.
  
Set the DoInput
     
* flag to true if you intend to use the URL connection for input,
     
* false if not.
  
The default is true.
     
*
     
* @param
   
doinputthe new value.
     
* @throws IllegalStateException if already connected
     
* @seejava.net.URLConnection#doInput
     
*
 

     
*/

    
public void setDoInput(boolean doinput) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
doInput = doinput;
    
}

    
/**
     
* Returns the value of this {@code URLConnection}'s
     
* {@code doInput} flag.
     
*
     
* @return
  
the value of this {@code URLConnection}'s
     
*
          
{@code doInput} flag.
     
* @see#setDoInput(boolean)
     
*/

    
public boolean getDoInput() {
        
return doInput;
    
}

    
/**
     
* Sets the value of the {@code doOutput} field for this
     
* {@code URLConnection} to the specified value.
     
* <p>
     
* A URL connection can be used for input and/or output.
  
Set the DoOutput
     
* flag to true if you intend to use the URL connection for output,
     
* false if not.
  
The default is false.
     
*
     
* @param
   
dooutputthe new value.
     
* @throws IllegalStateException if already connected
     
*
 

     
*/

    
public void setDoOutput(boolean dooutput) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
doOutput = dooutput;
    
}

    
/**
     
* Returns the value of this {@code URLConnection}'s
     
* {@code doOutput} flag.
     
*
     
* @return
  
the value of this {@code URLConnection}'s
     
*
          
{@code doOutput} flag.
     
* @see#setDoOutput(boolean)
     
*/

    
public boolean getDoOutput() {
        
return doOutput;
    
}

    
/**
     
* Set the value of the {@code allowUserInteraction} field of
     
* this {@code URLConnection}.
     
*
     
* @param
   
allowuserinteractionthe new value.
     
* @throws IllegalStateException if already connected
     
* @see#getAllowUserInteraction()
     
*/

    
public void setAllowUserInteraction(boolean allowuserinteraction) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
allowUserInteraction = allowuserinteraction;
    
}

    
/**
     
* Returns the value of the {@code allowUserInteraction} field for
     
* this object.
     
*
     
* @return
  
the value of the {@code allowUserInteraction} field for
     
*
          
this object.
     
* @see#setAllowUserInteraction(boolean)
     
*/

    
public boolean getAllowUserInteraction() {
        
return allowUserInteraction;
    
}

    
/**
     
* Sets the default value of the
     
* {@code allowUserInteraction} field for all future
     
* {@code URLConnection} objects to the specified value.
     
*
     
* @param
   
defaultallowuserinteractionthe new value.
     
* @see#getDefaultAllowUserInteraction()
     
*/

    
public static void setDefaultAllowUserInteraction(boolean defaultallowuserinteraction) {
        
defaultAllowUserInteraction = defaultallowuserinteraction;
    
}

    
/**
     
* Returns the default value of the {@code allowUserInteraction}
     
* field.
     
* <p>
     
* Ths default is "sticky", being a part of the static state of all
     
* URLConnections.
  
This flag applies to the next, and all following
     
* URLConnections that are created.
     
*
     
* @return
  
the default value of the {@code allowUserInteraction}
     
*
          
field.
     
* @see#setDefaultAllowUserInteraction(boolean)
     
*/

    
public static boolean getDefaultAllowUserInteraction() {
        
return defaultAllowUserInteraction;
    
}

    
/**
     
* Sets the value of the {@code useCaches} field of this
     
* {@code URLConnection} to the specified value.
     
* <p>
     
* Some protocols do caching of documents.
  
Occasionally, it is important
     
* to be able to "tunnel through" and ignore the caches (e.g., the
     
* "reload" button in a browser).
  
If the UseCaches flag on a connection
     
* is true, the connection is allowed to use whatever caches it can.
     
*
  
If false, caches are to be ignored.
     
*
  
The default value comes from DefaultUseCaches, which defaults to
     
* true.
     
*
     
* @param usecaches a {@code boolean} indicating whether
     
* or not to allow caching
     
* @throws IllegalStateException if already connected
     
*
 

     
*/

    
public void setUseCaches(boolean usecaches) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
useCaches = usecaches;
    
}

    
/**
     
* Returns the value of this {@code URLConnection}'s
     
* {@code useCaches} field.
     
*
     
* @return
  
the value of this {@code URLConnection}'s
     
*
          
{@code useCaches} field.
     
* @see #setUseCaches(boolean)
     
*/

    
public boolean getUseCaches() {
        
return useCaches;
    
}

    
/**
     
* Sets the value of the {@code ifModifiedSince} field of
     
* this {@code URLConnection} to the specified value.
     
*
     
* @param
   
ifmodifiedsincethe new value.
     
* @throws IllegalStateException if already connected
     
* @see#getIfModifiedSince()
     
*/

    
public void setIfModifiedSince(long ifmodifiedsince) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
ifModifiedSince = ifmodifiedsince;
    
}

    
/**
     
* Returns the value of this object's {@code ifModifiedSince} field.
     
*
     
* @return
  
the value of this object's {@code ifModifiedSince} field.
     
* @see #setIfModifiedSince(long)
     
*/

    
public long getIfModifiedSince() {
        
return ifModifiedSince;
    
}

   
/**
     
* Returns the default value of a {@code URLConnection}'s
     
* {@code useCaches} flag.
     
* <p>
     
* Ths default is "sticky", being a part of the static state of all
     
* URLConnections.
  
This flag applies to the next, and all following
     
* URLConnections that are created.
     
*
     
* @return
  
the default value of a {@code URLConnection}'s
     
*
          
{@code useCaches} flag.
     
* @see#setDefaultUseCaches(boolean)
     
*/

    
public boolean getDefaultUseCaches() {
        
return defaultUseCaches;
    
}

   
/**
     
* Sets the default value of the {@code useCaches} field to the
     
* specified value.
     
*
     
* @param
   
defaultusecachesthe new value.
     
* @see#getDefaultUseCaches()
     
*/

    
public void setDefaultUseCaches(boolean defaultusecaches) {
        
defaultUseCaches = defaultusecaches;
    
}

    
/**
     
* Sets the general request property. If a property with the key already
     
* exists, overwrite its value with the new value.
     
*
     
* <p> NOTE: HTTP requires all request properties which can
     
* legally have multiple instances with the same key
     
* to use a comma-separated list syntax which enables multiple
     
* properties to be appended into a single property.
     
*
     
* @param
   
keythe keyword by which the request is known
     
*
                  
(e.g., "{@code Accept}").
     
* @param
   
valuethe value associated with it.
     
* @throws IllegalStateException if already connected
     
* @throws NullPointerException if key is <CODE>null</CODE>
     
* @see #getRequestProperty(java.lang.String)
     
*/

    
public void setRequestProperty(String key, String value) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
if (key == null)
            
throw new NullPointerException ("key is null");

        
if (requests == null)
            
requests = new MessageHeader();

        
requests.set(key, value);
    
}

    
/**
     
* Adds a general request property specified by a
     
* key-value pair.
  
This method will not overwrite
     
* existing values associated with the same key.
     
*
     
* @param
   
keythe keyword by which the request is known
     
*
                  
(e.g., "{@code Accept}").
     
* @param
   
value
  
the value associated with it.
     
* @throws IllegalStateException if already connected
     
* @throws NullPointerException if key is null
     
*
 

     
* @since 1.4
     
*/

    
public void addRequestProperty(String key, String value) {
        
if (connected)
            
throw new IllegalStateException("Already connected");
        
if (key == null)
            
throw new NullPointerException ("key is null");

        
if (requests == null)
            
requests = new MessageHeader();

        
requests.add(key, value);
    
}


    
/**
     
* Returns the value of the named general request property for this
     
* connection.
     
*
     
* @param key the keyword by which the request is known (e.g., "Accept").
     
* @return
  
the value of the named general request property for this
     
*
           
connection. If key is null, then null is returned.
     
* @throws IllegalStateException if already connected
     
* @see #setRequestProperty(java.lang.String, java.lang.String)
     
*/

    
public String getRequestProperty(String key) {
        
if (connected)
            
throw new IllegalStateException("Already connected");

        
if (requests == null)
            
return null;

        
return requests.findValue(key);
    
}

    
/**
     
* Returns an unmodifiable Map of general request
     
* properties for this connection. The Map keys
     
* are Strings that represent the request-header
     
* field names. Each Map value is a unmodifiable List
     
* of Strings that represents the corresponding
     
* field values.
     
*
     
* @return
  
a Map of the general request properties for this connection.
     
* @throws IllegalStateException if already connected
     
* @since 1.4
     
*/

    
public Map<String,List<String>> getRequestProperties() {
        
if (connected)
            
throw new IllegalStateException("Already connected");

        
if (requests == null)
            
return Collections.emptyMap();

        
return requests.getHeaders(null);
    
}

    
/**
     
* Sets the default value of a general request property. When a
     
* {@code URLConnection} is created, it is initialized with
     
* these properties.
     
*
     
* @param
   
keythe keyword by which the request is known
     
*
                  
(e.g., "{@code Accept}").
     
* @param
   
valuethe value associated with the key.
     
*
     
* @see java.net.URLConnection#setRequestProperty(java.lang.String,java.lang.String)
     
*
     
* @deprecated The instance specific setRequestProperty method
     
* should be used after an appropriate instance of URLConnection
     
* is obtained. Invoking this method will have no effect.
     
*
     
* @see #getDefaultRequestProperty(java.lang.String)
     
*/

    
@Deprecated
    
public static void setDefaultRequestProperty(String key, String value) {
    
}

    
/**
     
* Returns the value of the default request property. Default request
     
* properties are set for every connection.
     
*
     
* @param key the keyword by which the request is known (e.g., "Accept").
     
* @return
  
the value of the default request property
     
* for the specified key.
     
*
     
* @see java.net.URLConnection#getRequestProperty(java.lang.String)
     
*
     
* @deprecated The instance specific getRequestProperty method
     
* should be used after an appropriate instance of URLConnection
     
* is obtained.
     
*
     
* @see #setDefaultRequestProperty(java.lang.String, java.lang.String)
     
*/

    
@Deprecated
    
public static String getDefaultRequestProperty(String key) {
        
return null;
    
}

    
/**
     
* The ContentHandler factory.
     
*/
    
static ContentHandlerFactory factory;

    
/**
     
* Sets the {@code ContentHandlerFactory} of an
     
* application. It can be called at most once by an application.
     
* <p>
     
* The {@code ContentHandlerFactory} instance is used to
     
* construct a content handler from a content type
     
* <p>
     
* If there is a security manager, this method first calls
     
* the security manager's {@code checkSetFactory} method
     
* to ensure the operation is allowed.
     
* This could result in a SecurityException.
     
*
     
* @param
      
fac
   
the desired factory.
     
* @exception
  
Errorif the factory has already been defined.
     
* @exception
  
SecurityExceptionif a security manager exists and its
     
*
             
{@code checkSetFactory} method doesn't allow the operation.
     
* @see
        
java.net.ContentHandlerFactory
     
* @see
        
java.net.URLConnection#getContent()
     
* @see
        
SecurityManager#checkSetFactory
     
*/

    
public static synchronized void setContentHandlerFactory(ContentHandlerFactory fac) {
        
if (factory != null) {
            
throw new Error("factory already defined");
        
}
        
SecurityManager security = System.getSecurityManager();
        
if (security != null) {
            
security.checkSetFactory();
        
}
        
factory = fac;
    
}

    
private static Hashtable<String, ContentHandler> handlers = new Hashtable<>();

    
/**
     
* Gets the Content Handler appropriate for this connection.
     
*/
    
synchronized ContentHandler getContentHandler()
        
throws UnknownServiceException
    
{
        
String contentType = stripOffParameters(getContentType());
        
ContentHandler handler = null;
        
if (contentType == null)
            
throw new UnknownServiceException("no content-type");
        
try {
            
handler = handlers.get(contentType);
            
if (handler != null)
                
return handler;
        
} catch(Exception e) {
        
}

        
if (factory != null)
            
handler = factory.createContentHandler(contentType);
        
if (handler == null) {
            
try {
                
handler = lookupContentHandlerClassFor(contentType);
            
} catch(Exception e) {
                
e.printStackTrace();
                
handler = UnknownContentHandler.INSTANCE;
            
}
            
handlers.put(contentType, handler);
        
}
        
return handler;
    
}

    
/*
     
* Media types are in the format: type/subtype*(; parameter).
     
* For looking up the content handler, we should ignore those
     
* parameters.
     
*/

    
private String stripOffParameters(String contentType)
    
{
        
if (contentType == null)
            
return null;
        
int index = contentType.indexOf(';');

        
if (index > 0)
            
return contentType.substring(0, index);
        
else
            
return
contentType;
    
}

    
private static final String contentClassPrefix = "sun.net.www.content";
    
private static final String contentPathProp = "java.content.handler.pkgs";

    
/**
     
* Looks for a content handler in a user-defineable set of places.
     
* By default it looks in sun.net.www.content, but users can define a
     
* vertical-bar delimited set of class prefixes to search through in
     
* addition by defining the java.content.handler.pkgs property.
     
* The class name must be of the form:
     
* <pre>
     
*{package-prefix}.{major}.{minor}
     
* e.g.
     
*YoyoDyne.experimental.text.plain
     
* </pre>
     
*/

    
private ContentHandler lookupContentHandlerClassFor(String contentType)
        
throws InstantiationException, IllegalAccessException, ClassNotFoundException {
        
String contentHandlerClassName = typeToPackageName(contentType);

        
String contentHandlerPkgPrefixes =getContentHandlerPkgPrefixes();

        
StringTokenizer packagePrefixIter =
            
new StringTokenizer(contentHandlerPkgPrefixes, "|");

        
while (packagePrefixIter.hasMoreTokens()) {
            
String packagePrefix = packagePrefixIter.nextToken().trim();

            
try {
                
String clsName = packagePrefix + "." + contentHandlerClassName;
                
Class<?> cls = null;
                
try {
                    
cls = Class.forName(clsName);
                
} catch (ClassNotFoundException e) {
                    
ClassLoader cl = ClassLoader.getSystemClassLoader();
                    
if (cl != null) {
                        
cls = cl.loadClass(clsName);
                    
}
                
}
                
if (cls != null) {
                    
ContentHandler handler =
                        
(ContentHandler)cls.newInstance();
                    
return handler;
                
}
            
} catch(Exception e) {
            
}
        
}

        
return UnknownContentHandler.INSTANCE;
    
}

    
/**
     
* Utility function to map a MIME content type into an equivalent
     
* pair of class name components.
  
For example: "text/html" would
     
* be returned as "text.html"
     
*/

    
private String typeToPackageName(String contentType) {
        
// make sure we canonicalize the class name: all lower case
        
contentType = contentType.toLowerCase();
        
int len = contentType.length();
        
char nm[] = new char[len];
        
contentType.getChars(0, len, nm, 0);
        
for (int i = 0; i < len; i++) {
            
char c = nm[i];
            
if (c == '/') {
                
nm[i] = '.';
            
} else if (!('A' <= c && c <= 'Z' ||
                       
'a' <= c && c <= 'z' ||
                       
'0' <= c && c <= '9')) {
                
nm[i] = '_';
            
}
        
}
        
return new String(nm);
    
}


    
/**
     
* Returns a vertical bar separated list of package prefixes for potential
     
* content handlers.
  
Tries to get the java.content.handler.pkgs property
     
* to use as a set of package prefixes to search.
  
Whether or not
     
* that property has been defined, the sun.net.www.content is always
     
* the last one on the returned package list.
     
*/

    
private String getContentHandlerPkgPrefixes() {
        
String packagePrefixList = AccessController.doPrivileged(
            
new sun.security.action.GetPropertyAction(contentPathProp, ""));

        
if (packagePrefixList != "") {
            
packagePrefixList += "|";
        
}

        
return packagePrefixList + contentClassPrefix;
    
}

    
/**
     
* Tries to determine the content type of an object, based
     
* on the specified "file" component of a URL.
     
* This is a convenience method that can be used by
     
* subclasses that override the {@code getContentType} method.
     
*
     
* @param
   
fnamea filename.
     
* @return
  
a guess as to what the content type of the object is,
     
*
          
based upon its file name.
     
* @seejava.net.URLConnection#getContentType()
     
*/

    
public static String guessContentTypeFromName(String fname) {
        
return getFileNameMap().getContentTypeFor(fname);
    
}

    
/**
     
* Tries to determine the type of an input stream based on the
     
* characters at the beginning of the input stream. This method can
     
* be used by subclasses that override the
     
* {@code getContentType} method.
     
* <p>
     
* Ideally, this routine would not be needed. But many
     
* {@code http} servers return the incorrect content type; in
     
* addition, there are many nonstandard extensions. Direct inspection
     
* of the bytes to determine the content type is often more accurate
     
* than believing the content type claimed by the {@code http} server.
     
*
     
* @param
      
is
   
an input stream that supports marks.
     
* @returna guess at the content type, or {@code null} if none
     
*
             
can be determined.
     
* @exception
  
IOExceptionif an I/O error occurs while reading the
     
*
               
input stream.
     
* @see
        
java.io.InputStream#mark(int)
     
* @see
        
java.io.InputStream#markSupported()
     
* @see
        
java.net.URLConnection#getContentType()
     
*/

    
static public String guessContentTypeFromStream(InputStream is)
                        
throws IOException {
        
// If we can't read ahead safely, just give up on guessing
        
if (!is.markSupported())
            
return null;

        
is.mark(16);
        
int c1 = is.read();
        
int c2 = is.read();
        
int c3 = is.read();
        
int c4 = is.read();
        
int c5 = is.read();
        
int c6 = is.read();
        
int c7 = is.read();
        
int c8 = is.read();
        
int c9 = is.read();
        
int c10 = is.read();
        
int c11 = is.read();
        
int c12 = is.read();
        
int c13 = is.read();
        
int c14 = is.read();
        
int c15 = is.read();
        
int c16 = is.read();
        
is.reset();

        
if (c1 == 0xCA && c2 == 0xFE && c3 == 0xBA && c4 == 0xBE) {
            
return "application/java-vm";
        
}

        
if (c1 == 0xAC && c2 == 0xED) {
            
// next two bytes are version number, currently 0x00 0x05
            
return "application/x-java-serialized-object";
        
}

        
if (c1 == '<') {
            
if (c2 == '!'
                
|| ((c2 == 'h' && (c3 == 't' && c4 == 'm' && c5 == 'l' ||
                                   
c3 == 'e' && c4 == 'a' && c5 == 'd') ||
                
(c2 == 'b' && c3 == 'o' && c4 == 'd' && c5 == 'y'))) ||
                
((c2 == 'H' && (c3 == 'T' && c4 == 'M' && c5 == 'L' ||
                                
c3 == 'E' && c4 == 'A' && c5 == 'D') ||
                
(c2 == 'B' && c3 == 'O' && c4 == 'D' && c5 == 'Y')))) {
                
return "text/html";
            
}

            
if (c2 == '?' && c3 == 'x' && c4 == 'm' && c5 == 'l' && c6 == ' ') {
                
return "application/xml";
            
}
        
}

        
// big and little (identical) endian UTF-8 encodings, with BOM
        
if (c1 == 0xef &&
  
c2 == 0xbb &&
  
c3 == 0xbf) {
            
if (c4 == '<' &&
  
c5 == '?' &&
  
c6 == 'x') {
                
return "application/xml";
            
}
        
}

        
// big and little endian UTF-16 encodings, with byte order mark
        
if (c1 == 0xfe && c2 == 0xff) {
            
if (c3 == 0 && c4 == '<' && c5 == 0 && c6 == '?' &&
                
c7 == 0 && c8 == 'x') {
                
return "application/xml";
            
}
        
}

        
if (c1 == 0xff && c2 == 0xfe) {
            
if (c3 == '<' && c4 == 0 && c5 == '?' && c6 == 0 &&
                
c7 == 'x' && c8 == 0) {
                
return "application/xml";
            
}
        
}

        
// big and little endian UTF-32 encodings, with BOM
        
if (c1 == 0x00 &&
  
c2 == 0x00 &&
  
c3 == 0xfe &&
  
c4 == 0xff) {
            
if (c5
  
== 0 && c6
  
== 0 && c7
  
== 0 && c8
  
== '<' &&
                
c9
  
== 0 && c10 == 0 && c11 == 0 && c12 == '?' &&
                
c13 == 0 && c14 == 0 && c15 == 0 && c16 == 'x') {
                
return "application/xml";
            
}
        
}

        
if (c1 == 0xff &&
  
c2 == 0xfe &&
  
c3 == 0x00 &&
  
c4 == 0x00) {
            
if (c5
  
== '<' && c6
  
== 0 && c7
  
== 0 && c8
  
== 0 &&
                
c9
  
== '?' && c10 == 0 && c11 == 0 && c12 == 0 &&
                
c13 == 'x' && c14 == 0 && c15 == 0 && c16 == 0) {
                
return "application/xml";
            
}
        
}

        
if (c1 == 'G' && c2 == 'I' && c3 == 'F' && c4 == '8') {
            
return "image/gif";
        
}

        
if (c1 == '#' && c2 == 'd' && c3 == 'e' && c4 == 'f') {
            
return "image/x-bitmap";
        
}

        
if (c1 == '!' && c2 == ' ' && c3 == 'X' && c4 == 'P' &&
                        
c5 == 'M' && c6 == '2') {
            
return "image/x-pixmap";
        
}

        
if (c1 == 137 && c2 == 80 && c3 == 78 &&
                
c4 == 71 && c5 == 13 && c6 == 10 &&
                
c7 == 26 && c8 == 10) {
            
return "image/png";
        
}

        
if (c1 == 0xFF && c2 == 0xD8 && c3 == 0xFF) {
            
if (c4 == 0xE0 || c4 == 0xEE) {
                
return "image/jpeg";
            
}

            
/**
             
* File format used by digital cameras to store images.
             
* Exif Format can be read by any application supporting
             
* JPEG. Exif Spec can be found at:
             
*
 
http://www.pima.net/standards/it10/PIMA15740/Exif_2-1.PDF
             
*/

            
if ((c4 == 0xE1) &&
                
(c7 == 'E' && c8 == 'x' && c9 == 'i' && c10 =='f' &&
                 
c11 == 0)) {
                
return "image/jpeg";
            
}
        
}

        
if (c1 == 0xD0 && c2 == 0xCF && c3 == 0x11 && c4 == 0xE0 &&
            
c5 == 0xA1 && c6 == 0xB1 && c7 == 0x1A && c8 == 0xE1) {

            
/* Above is signature of Microsoft Structured Storage.
             
* Below this, could have tests for various SS entities.
             
* For now, just test for FlashPix.
             
*/

            
if (checkfpx(is)) {
                
return "image/vnd.fpx";
            
}
        
}

        
if (c1 == 0x2E && c2 == 0x73 && c3 == 0x6E && c4 == 0x64) {
            
return "audio/basic";
  
// .au format, big endian
        
}

        
if (c1 == 0x64 && c2 == 0x6E && c3 == 0x73 && c4 == 0x2E) {
            
return "audio/basic";
  
// .au format, little endian
        
}

        
if (c1 == 'R' && c2 == 'I' && c3 == 'F' && c4 == 'F') {
            
/* I don't know if this is official but evidence
             
* suggests that .wav files start with "RIFF" - brown
             
*/

            
return "audio/x-wav";
        
}
        
return null;
    
}

    
/**
     
* Check for FlashPix image data in InputStream is.
  
Return true if
     
* the stream has FlashPix data, false otherwise.
  
Before calling this
     
* method, the stream should have already been checked to be sure it
     
* contains Microsoft Structured Storage data.
     
*/

    
static private boolean checkfpx(InputStream is) throws IOException {

        
/* Test for FlashPix image data in Microsoft Structured Storage format.
         
* In general, should do this with calls to an SS implementation.
         
* Lacking that, need to dig via offsets to get to the FlashPix
         
* ClassID.
  
Details:
         
*
         
* Offset to Fpx ClsID from beginning of stream should be:
         
*
         
* FpxClsidOffset = rootEntryOffset + clsidOffset
         
*
         
* where: clsidOffset = 0x50.
         
*
        
rootEntryOffset = headerSize + sectorSize*sectDirStart
         
*
                          
+ 128*rootEntryDirectory
         
*
         
*
        
where:
  
headerSize = 0x200 (always)
         
*
                
sectorSize = 2 raised to power of uSectorShift,
         
*
                             
which is found in the header at
         
*
                             
offset 0x1E.
         
*
                
sectDirStart = found in the header at offset 0x30.
         
*
                
rootEntryDirectory = in general, should search for
         
*
                                     
directory labelled as root.
         
*
                                     
We will assume value of 0 (i.e.,
         
*
                                     
rootEntry is in first directory)
         
*/


        
// Mark the stream so we can reset it. 0x100 is enough for the first
        
// few reads, but the mark will have to be reset and set again once
        
// the offset to the root directory entry is computed. That offset
        
// can be very large and isn't know until the stream has been read from
        
is.mark(0x100);

        
// Get the byte ordering located at 0x1E. 0xFE is Intel,
        
// 0xFF is other
        
long toSkip = (long)0x1C;
        
long posn;

        
if ((posn = skipForward(is, toSkip)) < toSkip) {
          
is.reset();
          
return false;
        
}

        
int c[] = new int[16];
        
if (readBytes(c, 2, is) < 0) {
            
is.reset();
            
return false;
        
}

        
int byteOrder = c[0];

        
posn+=2;
        
int uSectorShift;
        
if (readBytes(c, 2, is) < 0) {
            
is.reset();
            
return false;
        
}

        
if(byteOrder == 0xFE) {
            
uSectorShift = c[0];
            
uSectorShift += c[1] << 8;
        
}
        
else {
            
uSectorShift = c[0] << 8;
            
uSectorShift += c[1];
        
}

        
posn += 2;
        
toSkip = (long)0x30 - posn;
        
long skipped = 0;
        
if ((skipped = skipForward(is, toSkip)) < toSkip) {
          
is.reset();
          
return false;
        
}
        
posn += skipped;

        
if (readBytes(c, 4, is) < 0) {
            
is.reset();
            
return false;
        
}

        
int sectDirStart;
        
if(byteOrder == 0xFE) {
            
sectDirStart = c[0];
            
sectDirStart += c[1] << 8;
            
sectDirStart += c[2] << 16;
            
sectDirStart += c[3] << 24;
        
} else {
            
sectDirStart =
  
c[0] << 24;
            
sectDirStart += c[1] << 16;
            
sectDirStart += c[2] << 8;
            
sectDirStart += c[3];
        
}
        
posn += 4;
        
is.reset(); // Reset back to the beginning

        
toSkip = 0x200L + (long)(1<<uSectorShift)*sectDirStart + 0x50L;

        
// Sanity check!
        
if (toSkip < 0) {
            
return false;
        
}

        
/*
         
* How far can we skip? Is there any performance problem here?
         
* This skip can be fairly long, at least 0x4c650 in at least
         
* one case. Have to assume that the skip will fit in an int.
         
* Leave room to read whole root dir
         
*/

        
is.mark((int)toSkip+0x30);

        
if ((skipForward(is, toSkip)) < toSkip) {
            
is.reset();
            
return false;
        
}

        
/* should be at beginning of ClassID, which is as follows
         
* (in Intel byte order):
         
*
    
00 67 61 56 54 C1 CE 11 85 53 00 AA 00 A1 F9 5B
         
*
         
* This is stored from Windows as long,short,short,char[8]
         
* so for byte order changes, the order only changes for
         
* the first 8 bytes in the ClassID.
         
*
         
* Test against this, ignoring second byte (Intel) since
         
* this could change depending on part of Fpx file we have.
         
*/


        
if (readBytes(c, 16, is) < 0) {
            
is.reset();
            
return false;
        
}

        
// intel byte order
        
if (byteOrder == 0xFE &&
            
c[0] == 0x00 && c[2] == 0x61 && c[3] == 0x56 &&
            
c[4] == 0x54 && c[5] == 0xC1 && c[6] == 0xCE &&
            
c[7] == 0x11 && c[8] == 0x85 && c[9] == 0x53 &&
            
c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 &&
            
c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) {
            
is.reset();
            
return true;
        
}

        
// non-intel byte order
        
else if (c[3] == 0x00 && c[1] == 0x61 && c[0] == 0x56 &&
            
c[5] == 0x54 && c[4] == 0xC1 && c[7] == 0xCE &&
            
c[6] == 0x11 && c[8] == 0x85 && c[9] == 0x53 &&
            
c[10]== 0x00 && c[11]== 0xAA && c[12]== 0x00 &&
            
c[13]== 0xA1 && c[14]== 0xF9 && c[15]== 0x5B) {
            
is.reset();
            
return true;
        
}
        
is.reset();
        
return false;
    
}

    
/**
     
* Tries to read the specified number of bytes from the stream
     
* Returns -1, If EOF is reached before len bytes are read, returns 0
     
* otherwise
     
*/

    
static private int readBytes(int c[], int len, InputStream is)
                
throws IOException {

        
byte buf[] = new byte[len];
        
if (is.read(buf, 0, len) < len) {
            
return -1;
        
}

        
// fill the passed in int array
        
for (int i = 0; i < len; i++) {
             
c[i] = buf[i] & 0xff;
        
}
        
return 0;
    
}


    
/**
     
* Skips through the specified number of bytes from the stream
     
* until either EOF is reached, or the specified
     
* number of bytes have been skipped
     
*/

    
static private long skipForward(InputStream is, long toSkip)
                
throws IOException {

        
long eachSkip = 0;
        
long skipped = 0;

        
while (skipped != toSkip) {
            
eachSkip = is.skip(toSkip - skipped);

            
// check if EOF is reached
            
if (eachSkip <= 0) {
                
if (is.read() == -1) {
                    
return skipped ;
                
} else {
                    
skipped++;
                
}
            
}
            
skipped += eachSkip;
        
}
        
return skipped;
    
}

}


class UnknownContentHandler extends ContentHandler {
    
static final ContentHandler INSTANCE = new UnknownContentHandler();

    
public Object getContent(URLConnection uc) throws IOException {
        
return uc.getInputStream();
    
}
}