singletonstatecontextlookup.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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 *  KIND, either express or implied.  See the License for the
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package org.apache.mina.statemachine.context;

/**
 * {@link StateContextLookup} implementation which always returns the same
 * {@link StateContext} instance.
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 586695 $, $Date: 2007-10-20 12:01:17 +0200 (Sat, 20 Oct 2007) $
 */
public class SingletonStateContextLookup implements StateContextLookup {
    private final StateContext context;

    /**
     * Creates a new instance which always returns the same 
     * {@link DefaultStateContext} instance.
     */
    public SingletonStateContextLookup() {
        context = new DefaultStateContext();
    }
    
    /**
     * Creates a new instance which uses the specified {@link StateContextFactory}
     * to create the single instance.
     * 
     * @param contextFactory the {@link StateContextFactory} to use to create 
     *        the singleton instance.
     */
    public SingletonStateContextLookup(StateContextFactory contextFactory) {
        if (contextFactory == null) {
            throw new NullPointerException("contextFactory");
        }
        context = contextFactory.create();
    }
    
    public StateContext lookup(Object[] eventArgs) {
        return context;
    }
}