URLStreamHandler (GNU Classpath 0.94-pre Documentation)

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).

See Also: URL

Constructor Summary
	URLStreamHandler() Creates a URLStreamHander

Method Summary
protected boolean	equals(URL url1, URL url2) This is the default method for computing whether two URLs are equivalent.
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, 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, String protocol, String host, int port, String file, String ref) This methods sets the instance variables representing the various fields of the URL to the values passed in.
protected void	setURL(URL u, String protocol, String host, int port, String authority, String userInfo, String path, String query, String ref) Sets the fields of the URL argument to the indicated values
protected String	toExternalForm(URL url) This method converts a URL object into a String.

This is the default method for computing whether two URLs are equivalent. This method assumes that neither URL is null.

Parameters: url1 An URL object url2 Another URL object

Returns: True if both given URLs are equal, false otherwise.

getDefaultPort

getHostAddress

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

Parameters: url The URL to return the host address for.

Returns: The address of the hostname in url.

hashCode

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

Parameters: url The URL to calc the hashcode for.

Returns: The hashcode for the given URL.

hostsEqual

openConnection

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.

Parameters: url The URL to get a connection object for

Returns: A URLConnection object for the given URL

Throws: IOException If an error occurs

parseURL

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

Parameters: url The URL object in which to store the results spec The String-ized URL to parse start The position in the string to start scanning from end The position in the string to stop scanning

sameFile

Compares two URLs, excluding the fragment component

Parameters: url1 The first url url2 The second url to compare with the first

Returns: True if both URLs point to the same file, false otherwise.

UNKNOWN: Now protected

setURL

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.

Parameters: u The URL to modify protocol The protocol to set host The host name to et port The port number to set file The filename to set ref The reference

Throws: SecurityException If the protocol handler of the URL is different from this one

setURL

Sets the fields of the URL argument to the indicated values

Parameters: u The URL to modify protocol The protocol to set host The host name to set port The port number to set authority The authority to set userInfo The user information to set path The path/filename to set query The query part to set ref The reference

Throws: SecurityException If the protocol handler of the URL is different from this one

toExternalForm

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

Parameters: url The URL object to convert

Returns: A string representation of the url

Class URLStreamHandler