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java.net
Class URLStreamHandler  

java.lang.Object
  java.net.URLStreamHandler

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public abstract class URLStreamHandler

extends java.lang.Object

This class is the superclass of all URL protocol handlers. The URL class loads the appropriate protocol handler to establish a connection to a (possibly) remote service (eg, "http", "ftp") and to do protocol specific parsing of URL's. Refer to the URL class documentation for details on how that class locates and loads protocol handlers.

A protocol handler implementation should override the openConnection() method, and optionally override the parseURL() and toExternalForm() methods if necessary. (The default implementations will parse/write all URL's in the same form as http URL's). A protocol specific subclass of URLConnection will most likely need to be created as well.

Note that the instance methods in this class are called as if they were static methods. That is, a URL object to act on is passed with every call rather than the caller assuming the URL is stored in an instance variable of the "this" object.

The methods in this class are protected and accessible only to subclasses. URLStreamConnection objects are intended for use by the URL class only, not by other classes (unless those classes are implementing protocols).

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Constructor Summary

URLStreamHandler()           Creates a URLStreamHander

 

Method Summary
private static java.lang.String	canonicalizeFilename(java.lang.String file)
protected  boolean	equals(URL url1, URL url2)           Provides the default equals calculation.
protected  int	getDefaultPort()           Returns the default port for a URL parsed by this handler.
protected  InetAddress	getHostAddress(URL url)           Get the IP address of our host.
protected  int	hashCode(URL url)           Provides the default hash calculation.
protected  boolean	hostsEqual(URL url1, URL url2)           Compares the host components of two URLs.
protected abstract  URLConnection	openConnection(URL url)           Returns a URLConnection for the passed in URL.
protected  void	parseURL(URL url, java.lang.String spec, int start, int end)           This method parses the string passed in as a URL and set's the instance data fields in the URL object passed in to the various values parsed out of the string.
protected  boolean	sameFile(URL url1, URL url2)           Compares two URLs, excluding the fragment component
protected  void	setURL(URL u, java.lang.String protocol, java.lang.String host, int port, java.lang.String file, java.lang.String ref)           Deprecated. 1.2 Please use #setURL(URL,String,String,int,String,String,String,String);
protected  void	setURL(URL u, java.lang.String protocol, java.lang.String host, int port, java.lang.String authority, java.lang.String userInfo, java.lang.String path, java.lang.String query, java.lang.String ref)           Sets the fields of the URL argument to the indicated values
protected  java.lang.String	toExternalForm(URL url)           This method converts a URL object into a String.

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Constructor Detail

URLStreamHandler

public URLStreamHandler()

Creates a URLStreamHander

Method Detail

openConnection

protected abstract URLConnection openConnection(URL url)
                                         throws java.io.IOException

Returns a URLConnection for the passed in URL. Note that this should not actually create the connection to the (possibly) remote host, but rather simply return a URLConnection object. The connect() method of URL connection is used to establish the actual connection, possibly after the caller sets up various connection options.

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parseURL

protected void parseURL(URL url,
                        java.lang.String spec,
                        int start,
                        int end)

This method parses the string passed in as a URL and set's the instance data fields in the URL object passed in to the various values parsed out of the string. The start parameter is the position to start scanning the string. This is usually the position after the ":" which terminates the protocol name. The end parameter is the position to stop scanning. This will be either the end of the String, or the position of the "#" character, which separates the "file" portion of the URL from the "anchor" portion.

This method assumes URL's are formatted like http protocol URL's, so subclasses that implement protocols with URL's the follow a different syntax should override this method. The lone exception is that if the protocol name set in the URL is "file", this method will accept an empty hostname (i.e., "file:///"), which is legal for that protocol

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canonicalizeFilename

private static java.lang.String canonicalizeFilename(java.lang.String file)

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sameFile

protected boolean sameFile(URL url1,
                           URL url2)

Compares two URLs, excluding the fragment component

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setURL

protected void setURL(URL u,
                      java.lang.String protocol,
                      java.lang.String host,
                      int port,
                      java.lang.String file,
                      java.lang.String ref)

Deprecated. 1.2 Please use #setURL(URL,String,String,int,String,String,String,String);

This methods sets the instance variables representing the various fields of the URL to the values passed in.

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setURL

protected void setURL(URL u,
                      java.lang.String protocol,
                      java.lang.String host,
                      int port,
                      java.lang.String authority,
                      java.lang.String userInfo,
                      java.lang.String path,
                      java.lang.String query,
                      java.lang.String ref)

Sets the fields of the URL argument to the indicated values

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equals

protected boolean equals(URL url1,
                         URL url2)

Provides the default equals calculation. May be overidden by handlers for other protocols that have different requirements for equals(). This method requires that none of its arguments is null. This is guaranteed by the fact that it is only called by java.net.URL class.

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hostsEqual

protected boolean hostsEqual(URL url1,
                             URL url2)

Compares the host components of two URLs.

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getHostAddress

protected InetAddress getHostAddress(URL url)

Get the IP address of our host. An empty host field or a DNS failure will result in a null return.

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getDefaultPort

protected int getDefaultPort()

Returns the default port for a URL parsed by this handler. This method is meant to be overidden by handlers with default port numbers.

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hashCode

protected int hashCode(URL url)

Provides the default hash calculation. May be overidden by handlers for other protocols that have different requirements for hashCode calculation.

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toExternalForm

protected java.lang.String toExternalForm(URL url)

This method converts a URL object into a String. This method creates Strings in the mold of http URL's, so protocol handlers which use URL's that have a different syntax should override this method

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Home >> All >> java >> [ net overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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