67 lines
2.2 KiB
Java
67 lines
2.2 KiB
Java
/**
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*
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* Copyright the original author or authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jivesoftware.smackx.jingleold;
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import org.jivesoftware.smack.SmackException;
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import org.jivesoftware.smack.packet.IQ;
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import org.jivesoftware.smackx.jingleold.packet.Jingle;
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/**
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* Implement the Jingle Session state using the State Behavioral pattern.
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* (From the book Design Patterns, AKA GoF.)
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* These classes also employ the Flyweight and Singleton patterns as recommended for the State pattern by GoF.
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*
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* There seems to be three ways to go with the State pattern in Java: interface, abstract class and enums.
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* Most of the accepted models use abstract classes. It wasn't clear to me that any of the three models was
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* superior, so I went with the most common example.
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*
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* @author Jeff Williams
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*/
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public abstract class JingleSessionState {
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/**
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* Called when entering the state.
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*/
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public static JingleSessionState getInstance() {
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// Since we can never instantiate this class there is nothing to return (ever).
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return null;
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}
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/**
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* Called when entering the state.
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*/
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public abstract void enter();
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/**
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* Called when exiting the state.
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*/
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public abstract void exit();
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/**
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* Process an incoming Jingle Packet.
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* When you look at the GoF State pattern this method roughly corresponds to example on p310: ProcessOctect().
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*/
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public abstract IQ processJingle(JingleSession session, Jingle jingle, JingleActionEnum action) throws SmackException;
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/**
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* For debugging just emit the short name of the class.
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*/
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public String toString() {
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return this.getClass().getSimpleName();
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}
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}
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