Java多线程设计模式-学习笔记-Produce/Consumer模式.

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1. 模式的形象描述:

生产者-消费者模式.

2. 模式的描述:

在这个模式中,有着建立Data参与者的线程(Producer参与者)与使用Data参与者的线程(Customer参与者)在运行,而现在要从Producer参与者,降Data参与者传递给Consumer参与者.

这时,在Producer参与者与Consumer参与者之间,安插额Channel参与者.并委托由Channel参与者来保管想要传递的Data参与者.Channel参与者的工作可说是Data参与者的中继站,桥梁以及沟通管道.

因为可能会有多个线程使用到Channel参与者,故Channel参与者中必须进行共享互斥.在Channel参与者中,”从Producer参与者接收Data参与者”与”传送Data参与者给Consumer参与者”的部分使用了Guarded Suspension Pattern..

3. 模式的参与者:

3.1 生产者-Producer:

产生数据的线程.

3.2 消费者-Consumer:

使用数据的线程.

3.3 数据对象-Data:

共享的数据,由Producer产生,在Consumer中使用.

3.4 沟通管道-Channel:

由生产者产生数据Data放到Channel中,消费者从Channel获取数据进行处理.

当程序存在多个Producer和Consumer的时候,Channel要进行共享互斥.

4. 示例程序:

4.1 示例的场景描述:

有3名厨师会一直作蛋糕放在桌上,而有3名客人会不停的吃.

4.2 Data参与者-蛋糕(String):

4.3 Producer参与者-厨师(MakerThread):

package com.quf.study.thread.produceConsumer;

import java.util.Random;

/**

* Title : MakerThread

* Description : 厨师类.

* Create on : 2008-4-29

*

* Copyright (C) QUF Software Co.,Ltd.

*

* @author renxin renxin777@126.com

* @version Java Thread Design Pattern Study

*

* 修改历史:

* 修改人修改日期修改描述

* -------------------------------------------

*

public final class MakerThread extends Thread {

/**

* <code>m_random</code>-.

private final Random m_random;

/**

* <code>m_table</code>-沟通管道.

private final Table m_table;

/**

* <code>m_id</code>-蛋糕的随机号.

private static int s_id;

/**

* 构造函数

* @param name - 线程的名称.

* @param table - 沟通管道.

* @param seed - 间隔的时间.

public MakerThread(String name,Table table,long seed){

super(name);

this.m_table = table;

this.m_random = new Random(seed);

}

/* (non-Javadoc)

* @see java.lang.Thread#run()

public void run(){

try {

while( true ) {

Thread.sleep(this.m_random.nextInt(1000));

String t_cake = " [Cake No.] " + nextId() + " by " + getName() +"";

this.m_table.put(t_cake);

}

} catch (InterruptedException e) {

// TODO: handle exception

}

/**

* 生成蛋糕的顺序号.

* @return 蛋糕的顺序号.

private static synchronized int nextId(){

return s_id++;

}

}//END CLASS OF MakerThread.

4.4 Consumer参与者-客人(EaterThread):

package com.quf.study.thread.produceConsumer;

import java.util.Random;

/**

* Title : EaterThread

* Description : 顾客类.

* Create on : 2008-4-29

*

* Copyright (C) QUF Software Co.,Ltd.

*

* @author renxin renxin777@126.com

* @version Java Thread Design Pattern Study

*

* 修改历史:

* 修改人修改日期修改描述

* -------------------------------------------

*

public final class EaterThread extends Thread {

private final Random m_random;

private final Table m_table;

/**

* 构造函数

* @param name - 线程名称.

* @param table - 沟通管道.

* @param seed - .

public EaterThread(String name,Table table,long seed){

super(name);

this.m_random = new Random(seed);

this.m_table = table;

}

/* (non-Javadoc)

* @see java.lang.Thread#run()

public void run() {

try {

while( true ){

this.m_table.take();

Thread.sleep(this.m_random.nextInt(1000));

}

} catch (InterruptedException e) {

// TODO: handle exception

}

}//END CLASS OF EaterThread.

4.5 Channel参与者-桌子(Table):

package com.quf.study.thread.produceConsumer;

import java.io.Serializable;

import org.apache.log4j.Logger;

import org.apache.commons.lang.builder.ToStringBuilder;

import org.apache.commons.lang.builder.HashCodeBuilder;

/**

* Title : Table

* Description : 沟通管道实现类

* Create on : 2008-4-29

*

* Copyright (C) QUF Software Co.,Ltd.

*

* @author renxin renxin777@126.com

* @version Java Thread Design Pattern Study

*

* 修改历史:

* 修改人修改日期修改描述

* -------------------------------------------

*

public class Table implements Serializable {

/**

* <code>serialVersionUID</code>-注释

private static final long serialVersionUID = -1212823669535279450L;

private static final Logger s_logger = Logger.getLogger(Table.class);

/**

* <code>m_buffer</code>-蛋糕存放的数组.

private final String[] m_buffer;

/**

* <code>m_tail</code>-下一个put的地方.

private int m_tail;

/**

* <code>m_head</code>-下一个take的地方.

private int m_head;

/**

* <code>m_count</code>-buffer内的蛋糕数量.

private int m_count;

/**

* 构造函数

public Table(int count) {

// TODO Auto-generated constructor stub

this.m_buffer = new String[count];

this.m_head = 0;

this.m_count = 0;

}

/**

* 放蛋糕.

* @param cake - 蛋糕.

* @throws InterruptedException

public synchronized void put(String cake) throws InterruptedException {

if ( s_logger.isDebugEnabled() ) {

s_logger.debug(Thread.currentThread().getName().concat("puts").concat(cake));

}

while( this.m_count >= this.m_buffer.length ) {

wait();

}

this.m_buffer[this.m_tail] = cake;

this.m_tail = (this.m_tail+1)%this.m_buffer.length;

this.m_count++;

notifyAll();

}

/**

* 获取蛋糕.

* @return 蛋糕.

* @throws InterruptedException

public synchronized String take() throws InterruptedException{

while( this.m_count <= 0 ) {

wait();

}

String t_cake = this.m_buffer[this.m_head];

this.m_head = (this.m_head+1) % this.m_buffer.length;

this.m_count--;

notifyAll();

if ( s_logger.isDebugEnabled() ) {

s_logger.debug(Thread.currentThread().getName().concat("takes:").concat(t_cake));

}

System.out.println(Thread.currentThread().getName().concat(" takes:").concat(t_cake));

return t_cake;

}

/**

* @see java.lang.Object#toString()

public String toString() {

return new ToStringBuilder(this).toString();

}

/**

* @see java.lang.Object#hashCode()

public int hashCode() {

return new HashCodeBuilder(-1073141277, -504257843).appendSuper(

super.hashCode()).append(this.m_count).append(this.m_tail)

.append(this.m_head).append(this.m_buffer).toHashCode();

}

}//END CLASS OF Table.

4.6 测试类-ProduceConsumerTest:

package com.quf.study.thread.produceConsumer;

/**

* Title : ProduceConsumerTest

* Description : Produce-Consumer模式的测试类

* Create on : 2008-4-29

*

* Copyright (C) QUF Software Co.,Ltd.

*

* @author renxin renxin777@126.com

* @version Java Thread Design Pattern Study

*

* 修改历史:

* 修改人修改日期修改描述

* -------------------------------------------

*

public class ProduceConsumerTest {

/**

* 构造函数

public ProduceConsumerTest() {

// TODO Auto-generated constructor stub

}

/**

* 主方法.

* @param args

public static void main( String[] args ){

Table t_table = new Table(3);

new MakerThread("MakerThread-1",t_table,31415).start();

new MakerThread("MakerThread-2",t_table,92653).start();

new MakerThread("MakerThread-3",t_table,58979).start();

new EaterThread("EaterThread-1",t_table,32384).start();

new EaterThread("EaterThread-2",t_table,62643).start();

new EaterThread("EaterThread-3",t_table,38327).start();

}

}//END CLASS OF ProduceConsumerTest .

5. 相关知识:

5.1 以什么顺序传递Data对象:

1. 队列.

2. 堆栈.

3. 优先队列.

5.2 线程互斥/合作:

1. 线程的合作要想"放到中间的东西".

2. 线程互斥要想"应保护什么东西".