讨论一下wait() and notify(),有例题更佳！

[laughing]

讨论一下wait() and notify(),有例题更佳！

[skyyoung]

import java.io.*;

public class PipeTest
{
public static void main(String args[])
{
OilRefinery s1 = new OilRefinery();
try
{// delay arrival
Thread.currentThread().sleep(500);
}
catch(InterruptedException e)
{
}
SuperTanker s = new SuperTanker();
s1.interrupt();
try
{// delay arrival
Thread.currentThread().sleep(5000);
}
catch(InterruptedException e)
{
}

System.out.println(s1==null);
}
// This class consists of a Thread that can accept "pipline" hook-ups
// via the "clickClunk" method. Clients have to find us though from
// our Thread name "ThePipeTerminal"
static class OilRefinery extends Thread
{
static final int EOF = -1;
boolean alone = true;
// Can't connect piped until "clickClunk"
PipedReader inPipe;
PipedWriter outPipe;
public OilRefinery ()
{
start();// Start the thread
}
public synchronized void run()
{
int ch;
// Open for business
setName("ThePipeTerminal");
System.out.println("Processing plant operational and on-line");
while(alone)
{
try
{
wait();// Non-busy wait for connection
}
catch(InterruptedException ohLeaveMeAlone)
{
}
}
System.out.println("Client arrived");
// At this point, a client has connected up to the pipes
// so process the flow of oil
try
{
while((ch = inPipe.read()) != EOF)
{
// add some value to raw input...
outPipe.write(Character.toUpperCase((char)ch));
}
}
catch(IOException pipeMalfunction)
{
}
try
{
outPipe.close();// signal client "The show's over!"
}
catch(IOException ignored)
{
}
alone = true;
System.out.println("Processing plant shutting down.");
}
// This is the method clients have to call to connect up to
// the processing plant
public synchronized boolean clickClunk(PipedWriter clientOutputPipe, PipedReader clientInputPipe)
{
System.out.println("Client arrives to hook-up its pipes");
try
{
inPipe = new PipedReader(clientOutputPipe);
outPipe = new PipedWriter(clientInputPipe);
}
catch(IOException connectionFailed)
{
System.err.println("Hook up failed");
return false;
}
System.out.println("Hook-up successful");
alone = false;
notify();
return true;
}
}// End of class OilRefinery
// This class implements a processing plant client, say a
// supertanker that arrives at the plant to unload its
// crude oil and load up with refined oil
static class SuperTanker
{
OilRefinery pipeTerminal = null;
PipedReader returnPipe = new PipedReader();
PipedWriter crudePipe = new PipedWriter();
public SuperTanker ()
{
pipeTerminal = (OilRefinery)findThread("ThePipeTerminal");
if(pipeTerminal == null)
{
System.err.println("Snow blizzards prevent rendezvous");
System.exit(100);
}
else
{
if(pipeTerminal.clickClunk(crudePipe, returnPipe))
{
haveOilProcessed();
}
else
{
System.err.println("Failed to connect to processing plant");
}
try
{
crudePipe.close();
}
catch(IOException brokenValves)
{
System.err.println("Couldn't close valves!");
}
}
}
// Send data (oil) to processing plant, which refines data and
// sends it back via second pipe stream
public void haveOilProcessed()
{
String oilToBeRefined = "Crude Oil";
try
{
crudePipe.write(oilToBeRefined);
crudePipe.close();
// Get back refined oil
int ch;
while((ch = returnPipe.read()) != -1)
{
System.out.print((char)ch);
}
System.out.println();
}
catch(IOException oilFlowFailure)
{
System.err.println("Pipe malfunction");
}
}
// This generic method locates the refinery thread
// Note that threads may start/end while checking
public Thread findThread(String target)
{
int SAFETY_MARGIN = 10;
// Find master ThreadGroup which all others descend
ThreadGroup rootGroup = Thread.currentThread().getThreadGroup();
while(rootGroup.getParent() != null)
{
rootGroup = rootGroup.getParent();
}
Thread threadList[] = new Thread[rootGroup.activeGroupCount() + SAFETY_MARGIN];
int count = rootGroup.enumerate(threadList);
Thread aThread;
for(int i = 0; i < count; i ++ )
{
aThread = threadList[i];
if(aThread == null)
continue;
if(aThread.getName().equals(target))
{
return aThread;
}
}
return null;
}
}// End of class SuperTanker
}