多线程设计模式--single threaded execution
2009-09-17 00:00:00 来源:WEB开发网调用线程
Java代码
public class UserThread extends Thread {
private final Gate gate;
private final String myname;
private final String myaddress;
public UserThread(Gate gate, String myname, String myaddress) {
this.gate = gate;
this.myname = myname;
this.myaddress = myaddress;
}
public void run() {
System.out.println(myname + " BEGIN");
while (true) {
gate.pass(myname, myaddress);
}
}
}
同时只允许一个对象访问锁块.(类似于synchronized 标示的块)
这样做的主要原因是因为保护类变量不同时被多个线程修改
方法内部的变量不会在多线程同时修改.
任务
Java代码
public class Gate {
private int counter = 0;
private String name = "Nobody";
private String address = "Nowhere";
//jdk1.5新特性 效率高于synchronized
private Lock passLock = new ReentrantLock();
private Lock toStringLock = new ReentrantLock();
public void pass(String name, String address) {
//使用锁机制
passLock.lock();
try {
this.counter++;
this.name = name;
this.address = address;
check();
} finally {
//解锁
passLock.unlock();
}
}
public String toString() {
toStringLock.lock();
try {
return "No." + counter + ": " + name + ", " + address;
} finally {
toStringLock.unlock();
}
}
private void check() {
if (name.charAt(0) != address.charAt(0)) {
System.out.println("***** BROKEN ***** " + toString());
}
}
}
主程序
Java代码
public class Main {
public static void main(String[] args) {
System.out.println("Testing Gate, hit CTRL+C to exit.");
Gate gate = new Gate();
new UserThread(gate, "Alice", "Alaska").start();
new UserThread(gate, "Bobby", "Brazil").start();
new UserThread(gate, "Chris", "Canada").start();
}
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