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java.lang.Object
java.net.URLStreamHandler
public abstract class URLStreamHandler
extends Object
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).
URL
Constructor Summary | |
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Method Summary | |
protected boolean | |
protected int |
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protected InetAddress |
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protected int | |
protected boolean |
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protected abstract URLConnection |
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protected void | |
protected boolean | |
protected void | |
protected void | |
protected String |
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Methods inherited from class java.lang.Object | |
clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait |
protected boolean equals(URL url1, URL url2)
This is the default method for computing whether two URLs are equivalent. This method assumes that neither URL is null.
- Parameters:
url1
- An URL objecturl2
- Another URL object
- Returns:
- True if both given URLs are equal, false otherwise.
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.
- Returns:
- The default port number.
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.
- Parameters:
url
- The URL to return the host address for.
- Returns:
- The address of the hostname in url.
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.
- Parameters:
url
- The URL to calc the hashcode for.
- Returns:
- The hashcode for the given URL.
protected boolean hostsEqual(URL url1, URL url2)
Compares the host components of two URLs.
- Parameters:
url1
- The first URL.url2
- The second URL.
- Returns:
- True if both URLs contain the same host.
protected abstract URLConnection openConnection(URL url) throws 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.
- Parameters:
url
- The URL to get a connection object for
- Returns:
- A URLConnection object for the given URL
- Throws:
IOException
- If an error occurs
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. 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 resultsspec
- The String-ized URL to parsestart
- The position in the string to start scanning fromend
- The position in the string to stop scanning
protected boolean sameFile(URL url1, URL url2)
Compares two URLs, excluding the fragment component
- Parameters:
url1
- The first urlurl2
- The second url to compare with the first
- Returns:
- True if both URLs point to the same file, false otherwise.
protected void setURL(URL u, String protocol, String host, int port, String file, 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.
- Parameters:
u
- The URL to modifyprotocol
- The protocol to sethost
- The host name to etport
- The port number to setfile
- The filename to setref
- The reference
- Throws:
SecurityException
- If the protocol handler of the URL is different from this one
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
- Parameters:
u
- The URL to modifyprotocol
- The protocol to sethost
- The host name to setport
- The port number to setauthority
- The authority to setuserInfo
- The user information to setpath
- The path/filename to setquery
- The query part to setref
- The reference
- Throws:
SecurityException
- If the protocol handler of the URL is different from this one
protected 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
- Parameters:
url
- The URL object to convert
- Returns:
- A string representation of the url