handlerobjectfactory.java

用jbuilder写的源程序

/*
 * Copyright 2003-2006 the original author or authors.
 * Licensed 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.
 * 
 */
package com.jdon.model.handler;

import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import com.jdon.model.ModelHandler;
import com.jdon.model.config.PoolParameter;
import com.jdon.model.factory.ModelHandlerClassBuilder;
import com.jdon.util.Debug;

/**
 * @author <a href="mailto:[e-mail]">banq </a>
 *  
 */
public class HandlerObjectFactory {
    public final static String module = HandlerObjectFactory.class.getName();

    private final static int HANDLER_INSTANCE_COUNT = 10;

    private int poolSize;

    private ModelHandlerClassBuilder modelHandlerClassBuilder;

    //空闲ModelHandler池
    //private Map handlerFreePool = Collections.synchronizedMap(new HashMap());
    private Map handlerFreePool = new ConcurrentHashMap();

    //在使用的ModelHandler池
    //private Map handlerUsedPool = Collections.synchronizedMap(new HashMap());
    private Map handlerUsedPool = new ConcurrentHashMap();

    public HandlerObjectFactory(ModelHandlerClassBuilder modelXmlConfig, PoolParameter poolParameter) {
        this.modelHandlerClassBuilder = modelXmlConfig;
        this.poolSize = poolParameter.getHandlerPoolSize();
    }

    /**
     * 获得一个空闲的ModelHandler 如果空闲池没有，就重新生成指定个数的ModelHandler实例。 获得成功，则记入在用池。
     * 当客户端调用完毕，调用returnHandlerObject返回该ModelHandler实例备重用。
     * 
     * @param formName
     * @return
     * @throws java.lang.Exception
     */
    public ModelHandler borrowHandlerObject(String formName) {

        ModelHandler modelHandler = null;
        try {
            String poolKey = (modelHandlerClassBuilder.getModelMapping(formName)).getHandler();

            LinkedList listFree = (LinkedList) handlerFreePool.get(poolKey);
            if ((listFree == null) || (listFree.isEmpty())) { //如果空了，生产
                listFree = makeHandlerObjects(formName);
                handlerFreePool.put(poolKey, listFree);
            }
            modelHandler = (ModelHandler) listFree.removeFirst();

            //加入已经用的池
            LinkedList listUsed = (LinkedList) handlerUsedPool.get(poolKey);
            if (listUsed == null) {
                listUsed = new LinkedList();
                handlerUsedPool.put(poolKey, listUsed);
            }
            listUsed.add(modelHandler);

            Debug.logVerbose("[JdonFramework]--> borrow Modelhandler instance " + poolKey + listFree.size() + " for " + formName, module);
        } catch (Exception e) {
            Debug.logError("[JdonFramework]borrowHandlerObject error:" + e, module);
        }

        return modelHandler;
    }

    /**
     * 生成指定个数的实例
     * 
     * @param formName
     * @return
     * @throws java.lang.Exception
     */
    private synchronized LinkedList makeHandlerObjects(String formName) throws Exception {
        Debug.logVerbose("[JdonFramework]--> create Modelhandler instance " + poolSize, module);
        int count = 0;
        ModelHandler modelHandler = null;
        LinkedList list = new LinkedList();
        while (count < poolSize) {
            modelHandler = makeHandlerObject(formName);
            list.add(modelHandler);
            count++;
        }
        return list;
    }

    /**
     * 返还使用过的ModelHandler 1.从使用池中删除该实例 2.将该实例加入空闲池
     * 
     * @param modelHandler
     * @throws java.lang.Exception
     */
    public void returnHandlerObject(ModelHandler modelHandler) {
        try {
            String poolKey = modelHandler.getClass().getName();
            LinkedList listUsed = (LinkedList) handlerUsedPool.get(poolKey);
            if (listUsed == null) {
                Debug.logError("[JdonFramework]ERROR:not find the used pool: class = " + poolKey, module);
                return;
            }
            listUsed.remove(modelHandler);
            LinkedList listFree = (LinkedList) handlerFreePool.get(poolKey);
            if (listFree == null) {
                Debug.logError("[JdonFramework]ERROR:not find the free pool: class = " + poolKey, module);
                return;
            }
            listFree.add(modelHandler);
            Debug.logVerbose("[JdonFramework]--> return Modelhandler instance successfully" + poolKey + listFree.size(), module);
        } catch (Exception e) {
            Debug.logError("[JdonFramework]returnHandlerObject error:" + e, module);
        }
    }

    private synchronized ModelHandler makeHandlerObject(String formName) throws Exception {
        ModelHandler object = null;
        Class handlerClass = null;
        try {
            handlerClass = modelHandlerClassBuilder.getHandlerClasses(formName);
            if (handlerClass == null) {
                throw new Exception(" not found the handler in config xml formName=" + formName);
            }
            object = (ModelHandler) handlerClass.newInstance();
        } catch (Exception e) {
            Debug.logError("[JdonFramework]--> call Handler: " + handlerClass + " error:" + e, module);
            throw new Exception(e);
        }
        return object;
    }

}