/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/protocol/Protocol.java,v 1.10 2004/04/18 23:51:38 jsdever Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */
package org.apache.commons.httpclient.protocol;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.httpclient.util.LangUtils;

A class to encapsulate the specifics of a protocol.  This class class also
provides the ability to customize the set and characteristics of the
protocols used.
One use case for modifying the default set of protocols would be to set a
custom SSL socket factory.  This would look something like the following:
 
Protocol myHTTPS = new Protocol( "https", new MySSLSocketFactory(), 443 );
Protocol.registerProtocol( "https", myHTTPS );

Author:
Michael Becke, Jeff Dever, Mike Bowler
Since:
2.0/**
 * A class to encapsulate the specifics of a protocol.  This class class also
 * provides the ability to customize the set and characteristics of the
 * protocols used.
 * 
 * <p>One use case for modifying the default set of protocols would be to set a
 * custom SSL socket factory.  This would look something like the following:
 * <pre> 
 * Protocol myHTTPS = new Protocol( "https", new MySSLSocketFactory(), 443 );
 * 
 * Protocol.registerProtocol( "https", myHTTPS );
 * </pre>
 *
 * @author Michael Becke 
 * @author Jeff Dever
 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
 *  
 * @since 2.0 
 */
public class Protocol {

    
The available protocols /** The available protocols */
    private static final Map PROTOCOLS = Collections.synchronizedMap(new HashMap());

    
Registers a new protocol with the given identifier.  If a protocol with
the given ID already exists it will be overridden.  This ID is the same
one used to retrieve the protocol from getProtocol(String).
Params:
id – the identifier for this protocol
protocol – the protocol to register
See Also:
getProtocol(String)/**
     * Registers a new protocol with the given identifier.  If a protocol with
     * the given ID already exists it will be overridden.  This ID is the same
     * one used to retrieve the protocol from getProtocol(String).
     * 
     * @param id the identifier for this protocol
     * @param protocol the protocol to register
     * 
     * @see #getProtocol(String)
     */
    public static void registerProtocol(String id, Protocol protocol) {

        if (id == null) {
            throw new IllegalArgumentException("id is null");
        }
        if (protocol == null) {
            throw new IllegalArgumentException("protocol is null");
        }

        PROTOCOLS.put(id, protocol);
    }

    
Unregisters the protocol with the given ID.
Params:
id – the ID of the protocol to remove/**
     * Unregisters the protocol with the given ID.
     * 
     * @param id the ID of the protocol to remove
     */
    public static void unregisterProtocol(String id) {

        if (id == null) {
            throw new IllegalArgumentException("id is null");
        }

        PROTOCOLS.remove(id);
    }

    
Gets the protocol with the given ID.
Params:
id – the protocol ID
Throws:
IllegalStateException – if a protocol with the ID cannot be found
Returns:
Protocol a protocol/**
     * Gets the protocol with the given ID.
     * 
     * @param id the protocol ID
     * 
     * @return Protocol a protocol
     * 
     * @throws IllegalStateException if a protocol with the ID cannot be found
     */
    public static Protocol getProtocol(String id) 
        throws IllegalStateException {

        if (id == null) {
            throw new IllegalArgumentException("id is null");
        }

        Protocol protocol = (Protocol) PROTOCOLS.get(id);

        if (protocol == null) {
            protocol = lazyRegisterProtocol(id);
        }

        return protocol;
    } 

    
Lazily registers the protocol with the given id.
Params:
id – the protocol ID
Throws:
IllegalStateException – if the protocol with id is not recognized
Returns:
the lazily registered protocol/**
     * Lazily registers the protocol with the given id.
     * 
     * @param id the protocol ID
     * 
     * @return the lazily registered protocol
     * 
     * @throws IllegalStateException if the protocol with id is not recognized
     */
    private static Protocol lazyRegisterProtocol(String id) 
        throws IllegalStateException {

        if ("http".equals(id)) {
            final Protocol http 
                = new Protocol("http", DefaultProtocolSocketFactory.getSocketFactory(), 80);
            Protocol.registerProtocol("http", http);
            return http;
        }

        if ("https".equals(id)) {
            final Protocol https 
                = new Protocol("https", SSLProtocolSocketFactory.getSocketFactory(), 443);
            Protocol.registerProtocol("https", https);
            return https;
        }

        throw new IllegalStateException("unsupported protocol: '" + id + "'");
    }
    

    
the scheme of this protocol (e.g. http, https) /** the scheme of this protocol (e.g. http, https) */
    private String scheme;
    
    
The socket factory for this protocol /** The socket factory for this protocol */
    private ProtocolSocketFactory socketFactory;
    
    
The default port for this protocol /** The default port for this protocol */
    private int defaultPort;
    
    
True if this protocol is secure /** True if this protocol is secure */
    private boolean secure;
  
    
Constructs a new Protocol. Whether the created protocol is secure depends on
the class of factory.
Params:
scheme – the scheme (e.g. http, https)
factory – the factory for creating sockets for communication using
this protocol
defaultPort – the port this protocol defaults to/**
     * Constructs a new Protocol. Whether the created protocol is secure depends on
     * the class of <code>factory</code>.
     * 
     * @param scheme the scheme (e.g. http, https)
     * @param factory the factory for creating sockets for communication using
     * this protocol
     * @param defaultPort the port this protocol defaults to
     */
    public Protocol(String scheme, ProtocolSocketFactory factory, int defaultPort) {
        
        if (scheme == null) {
            throw new IllegalArgumentException("scheme is null");
        }
        if (factory == null) {
            throw new IllegalArgumentException("socketFactory is null");
        }
        if (defaultPort <= 0) {
            throw new IllegalArgumentException("port is invalid: " + defaultPort);
        }
        
        this.scheme = scheme;
        this.socketFactory = factory;
        this.defaultPort = defaultPort;
        this.secure = (factory instanceof SecureProtocolSocketFactory);
    }
    
    
Constructs a new Protocol. Whether the created protocol is secure depends on
the class of factory.
Params:
scheme – the scheme (e.g. http, https)
factory – the factory for creating sockets for communication using
this protocol
defaultPort – the port this protocol defaults to
Deprecated:
Use the constructor that uses ProtocolSocketFactory, this version of
the constructor is only kept for backwards API compatibility./**
     * Constructs a new Protocol. Whether the created protocol is secure depends on
     * the class of <code>factory</code>.
     *
     * @param scheme the scheme (e.g. http, https)
     * @param factory the factory for creating sockets for communication using
     * this protocol
     * @param defaultPort the port this protocol defaults to
     * @deprecated Use the constructor that uses ProtocolSocketFactory, this version of
     * the constructor is only kept for backwards API compatibility.
     */
    public Protocol(String scheme, 
        SecureProtocolSocketFactory factory, int defaultPort) {
        this(scheme, (ProtocolSocketFactory) factory, defaultPort);   
    }    
    
    
Returns the defaultPort.
Returns:
int/**
     * Returns the defaultPort.
     * @return int
     */
    public int getDefaultPort() {
        return defaultPort;
    }

    
Returns the socketFactory.  If secure the factory is a
SecureProtocolSocketFactory.
Returns:
SocketFactory/**
     * Returns the socketFactory.  If secure the factory is a
     * SecureProtocolSocketFactory.
     * @return SocketFactory
     */
    public ProtocolSocketFactory getSocketFactory() {
        return socketFactory;
    }

    
Returns the scheme.
Returns:
The scheme/**
     * Returns the scheme.
     * @return The scheme
     */
    public String getScheme() {
        return scheme;
    }

    
Returns true if this protocol is secure
Returns:
true if this protocol is secure/**
     * Returns true if this protocol is secure
     * @return true if this protocol is secure
     */
    public boolean isSecure() {
        return secure;
    }
    
    
Resolves the correct port for this protocol.  Returns the given port if
valid or the default port otherwise.
Params:
port – the port to be resolved
Returns:
the given port or the defaultPort/**
     * Resolves the correct port for this protocol.  Returns the given port if
     * valid or the default port otherwise.
     * 
     * @param port the port to be resolved
     * 
     * @return the given port or the defaultPort
     */
    public int resolvePort(int port) {
        return port <= 0 ? getDefaultPort() : port;
    }

    
Return a string representation of this object.
Returns:
a string representation of this object./**
     * Return a string representation of this object.
     * @return a string representation of this object.
     */
    public String toString() {
        return scheme + ":" + defaultPort;
    }
    
    
Return true if the specified object equals this object.
Params:
obj – The object to compare against.
Returns:
true if the objects are equal./**
     * Return true if the specified object equals this object.
     * @param obj The object to compare against.
     * @return true if the objects are equal.
     */
    public boolean equals(Object obj) {
        
        if (obj instanceof Protocol) {
            
            Protocol p = (Protocol) obj;
            
            return (
                defaultPort == p.getDefaultPort()
                && scheme.equalsIgnoreCase(p.getScheme())
                && secure == p.isSecure()
                && socketFactory.equals(p.getSocketFactory()));
            
        } else {
            return false;
        }
        
    }

    
Return a hash code for this object
Returns:
The hash code./**
     * Return a hash code for this object
     * @return The hash code.
     */
    public int hashCode() {
        int hash = LangUtils.HASH_SEED;
        hash = LangUtils.hashCode(hash, this.defaultPort);
        hash = LangUtils.hashCode(hash, this.scheme.toLowerCase());
        hash = LangUtils.hashCode(hash, this.secure);
        hash = LangUtils.hashCode(hash, this.socketFactory);
        return hash;
    }
}