iosessionstatecontextlookup.java

mina是以Java实现的一个开源的网络程序框架

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 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *    http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.mina.statemachine.context;

import org.apache.mina.core.session.IoSession;

/**
 * MINA specific {@link StateContextLookup} which uses an {@link IoSession}
 * attribute to store the {@link StateContextLookup}.
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (Thu, 26 Jun 2008) $
 */
public class IoSessionStateContextLookup extends AbstractStateContextLookup {
    /**
     * The default name of the {@link IoSession} attribute used to store the
     * {@link StateContext} object.
     */
    public static final String DEFAULT_SESSION_ATTRIBUTE_NAME = 
        IoSessionStateContextLookup.class.getName() + ".stateContext";
    
    private final String sessionAttributeName;
    
    /**
     * Creates a new instance using a {@link DefaultStateContextFactory} to
     * create {@link StateContext} objects for new {@link IoSession}s.
     */
    public IoSessionStateContextLookup() {
        this(new DefaultStateContextFactory(), DEFAULT_SESSION_ATTRIBUTE_NAME);
    }

    /**
     * Creates a new instance using a {@link DefaultStateContextFactory} to
     * create {@link StateContext} objects for new {@link IoSession}s.
     * 
     * @param sessionAttributeName the name of the {@link IoSession} attribute
     *        used to store the {@link StateContext} object.
     */
    public IoSessionStateContextLookup(String sessionAttributeName) {
        this(new DefaultStateContextFactory(), sessionAttributeName);
    }
    
    /**
     * Creates a new instance using the specified {@link StateContextFactory} to
     * create {@link StateContext} objects for new {@link IoSession}s.
     * 
     * @param contextFactory the {@link StateContextFactory}.
     */
    public IoSessionStateContextLookup(StateContextFactory contextFactory) {
	this(contextFactory, DEFAULT_SESSION_ATTRIBUTE_NAME);
    }

    /**
     * Creates a new instance using the specified {@link StateContextFactory} to
     * create {@link StateContext} objects for new {@link IoSession}s.
     * 
     * @param contextFactory the {@link StateContextFactory}.
     * @param sessionAttributeName the name of the {@link IoSession} attribute
     *        used to store the {@link StateContext} object.
     */
    public IoSessionStateContextLookup(StateContextFactory contextFactory, String sessionAttributeName) {
        super(contextFactory);
	this.sessionAttributeName = sessionAttributeName;
    }
    
    protected StateContext lookup(Object eventArg) {
        IoSession session = (IoSession) eventArg;
        return (StateContext) session.getAttribute(sessionAttributeName);
    }

    protected void store(Object eventArg, StateContext context) {
        IoSession session = (IoSession) eventArg;
        session.setAttribute(sessionAttributeName, context);
    }

    protected boolean supports(Class<?> c) {
        return IoSession.class.isAssignableFrom(c);
    }
}