public abstract class URLStreamHandler extends Object
The abstract class URLStreamHandler
is the common superclass for all stream protocol handlers. A stream protocol handler knows how to make a connection for a particular protocol type, such as http
or https
.
In most cases, an instance of a URLStreamHandler
subclass is not created directly by an application. Rather, the first time a protocol name is encountered when constructing a URL
, the appropriate stream protocol handler is automatically loaded.
URL.URL(java.lang.String, java.lang.String, int, java.lang.String)
public URLStreamHandler()
protected abstract URLConnection openConnection(URL u) throws IOException
Opens a connection to the object referenced by the URL
argument. This method should be overridden by a subclass.
If for the handler's protocol (such as HTTP or JAR), there exists a public, specialized URLConnection subclass belonging to one of the following packages or one of their subpackages: java.lang, java.io, java.util, java.net, the connection returned will be of that subclass. For example, for HTTP an HttpURLConnection will be returned, and for JAR a JarURLConnection will be returned.
u
- the URL that this connects to.URLConnection
object for the URL
.IOException
- if an I/O error occurs while opening the connection.protected URLConnection openConnection(URL u, Proxy p) throws IOException
Same as openConnection(URL), except that the connection will be made through the specified proxy; Protocol handlers that do not support proxying will ignore the proxy parameter and make a normal connection. Calling this method preempts the system's default ProxySelector settings.
u
- the URL that this connects to.p
- the proxy through which the connection will be made. If direct connection is desired, Proxy.NO_PROXY should be specified.URLConnection
object for the URL
.IOException
- if an I/O error occurs while opening the connection.IllegalArgumentException
- if either u or p is null, or p has the wrong type.UnsupportedOperationException
- if the subclass that implements the protocol doesn't support this method.protected void parseURL(URL u, String spec, int start, int limit)
Parses the string representation of a URL
into a URL
object.
If there is any inherited context, then it has already been copied into the URL
argument.
The parseURL
method of URLStreamHandler
parses the string representation as if it were an http
specification. Most URL protocol families have a similar parsing. A stream protocol handler for a protocol that has a different syntax must override this routine.
u
- the URL
to receive the result of parsing the spec.spec
- the String
representing the URL that must be parsed.start
- the character index at which to begin parsing. This is just past the ':
' (if there is one) that specifies the determination of the protocol name.limit
- the character position to stop parsing at. This is the end of the string or the position of the "#
" character, if present. All information after the sharp sign indicates an anchor.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.
URL
parsed by this handler.protected boolean equals(URL u1, URL u2)
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.
u1
- a URL objectu2
- a URL objecttrue
if the two urls are considered equal, ie. they refer to the same fragment in the same file.protected int hashCode(URL u)
Provides the default hash calculation. May be overidden by handlers for other protocols that have different requirements for hashCode calculation.
u
- a URL objectint
suitable for hash table indexingprotected boolean sameFile(URL u1, URL u2)
Compare two urls to see whether they refer to the same file, i.e., having the same protocol, host, port, and path. This method requires that none of its arguments is null. This is guaranteed by the fact that it is only called indirectly by java.net.URL class.
u1
- a URL objectu2
- a URL objectprotected InetAddress getHostAddress(URL u)
Get the IP address of our host. An empty host field or a DNS failure will result in a null return.
u
- a URL objectInetAddress
representing the host IP address.protected boolean hostsEqual(URL u1, URL u2)
Compares the host components of two URLs.
u1
- the URL of the first host to compareu2
- the URL of the second host to comparetrue
if and only if they are equal, false
otherwise.protected String toExternalForm(URL u)
Converts a URL
of a specific protocol to a String
.
u
- the URL.URL
argument.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. Only classes derived from URLStreamHandler are able to use this method to set the values of the URL fields.
u
- the URL to modify.protocol
- the protocol name.host
- the remote host value for the URL.port
- the port on the remote machine.authority
- the authority part for the URL.userInfo
- the userInfo part of the URL.path
- the path component of the URL.query
- the query part for the URL.ref
- the reference.SecurityException
- if the protocol handler of the URL is different from this oneURL.set(java.lang.String, java.lang.String, int, java.lang.String, java.lang.String)
@Deprecated protected void setURL(URL u, String protocol, String host, int port, String file, String ref)
Deprecated. Use setURL(URL, String, String, int, String, String, String, String);
Sets the fields of the URL
argument to the indicated values. Only classes derived from URLStreamHandler are able to use this method to set the values of the URL fields.
u
- the URL to modify.protocol
- the protocol name. This value is ignored since 1.2.host
- the remote host value for the URL.port
- the port on the remote machine.file
- the file.ref
- the reference.SecurityException
- if the protocol handler of the URL is different from this one
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