--- a/jdk/test/java/lang/Thread/ThreadStateTest.java Thu Jun 23 13:00:14 2011 +0100
+++ b/jdk/test/java/lang/Thread/ThreadStateTest.java Thu Jun 23 13:15:14 2011 +0100
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -34,21 +34,16 @@
*/
import java.util.concurrent.locks.LockSupport;
-import java.util.concurrent.Semaphore;
+import java.util.concurrent.Phaser;
public class ThreadStateTest {
+ // maximum number of retries when checking for thread state.
+ static final int MAX_RETRY = 500;
+
private static boolean testFailed = false;
- static class Lock {
- private String name;
- Lock(String name) {
- this.name = name;
- }
- public String toString() {
- return name;
- }
- }
- private static Lock globalLock = new Lock("my lock");
+ // used to achieve waiting states
+ static final Object globalLock = new Object();
public static void main(String[] argv) {
// Call Thread.getState to force all initialization done
@@ -102,13 +97,27 @@
System.out.println("Unexpected exception.");
testFailed = true;
}
+
if (testFailed)
throw new RuntimeException("TEST FAILED.");
System.out.println("Test passed.");
}
private static void checkThreadState(Thread t, Thread.State expected) {
- Thread.State state = t.getState();
+ // wait for the thread to transition to the expected state.
+ // There is a small window between the thread checking the state
+ // and the thread actual entering that state.
+ Thread.State state;
+ int retryCount=0;
+ while ((state = t.getState()) != expected && retryCount < MAX_RETRY) {
+ if (state != Thread.State.RUNNABLE) {
+ throw new RuntimeException("Thread not in expected state yet," +
+ " but it should at least be RUNNABLE");
+ }
+ goSleep(10);
+ retryCount++;
+ }
+
System.out.println("Checking thread state " + state);
if (state == null) {
throw new RuntimeException(t.getName() + " expected to have " +
@@ -121,13 +130,6 @@
}
}
- private static String getLockName(Object lock) {
- if (lock == null) return null;
-
- return lock.getClass().getName() + '@' +
- Integer.toHexString(System.identityHashCode(lock));
- }
-
private static void goSleep(long ms) {
try {
Thread.sleep(ms);
@@ -139,7 +141,9 @@
}
static class MyThread extends Thread {
- private ThreadExecutionSynchronizer thrsync = new ThreadExecutionSynchronizer();
+ // Phaser to sync between the main thread putting
+ // this thread into various states
+ private Phaser phaser = new Phaser(2);
MyThread(String name) {
super(name);
@@ -153,12 +157,14 @@
private final int TIMED_PARKED = 5;
private final int SLEEPING = 6;
private final int TERMINATE = 7;
- private int state = RUNNABLE;
+
+ private volatile int state = RUNNABLE;
private boolean done = false;
public void run() {
// Signal main thread to continue.
- thrsync.signal();
+ phaser.arriveAndAwaitAdvance();
+
while (!done) {
switch (state) {
case RUNNABLE: {
@@ -172,7 +178,7 @@
}
case BLOCKED: {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to block.");
synchronized (globalLock) {
// finish blocking
@@ -183,7 +189,7 @@
case WAITING: {
synchronized (globalLock) {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to wait.");
try {
globalLock.wait();
@@ -196,7 +202,7 @@
case TIMED_WAITING: {
synchronized (globalLock) {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to timed wait.");
try {
globalLock.wait(10000);
@@ -208,7 +214,7 @@
}
case PARKED: {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to park.");
LockSupport.park();
// give a chance for the main thread to block
@@ -217,7 +223,7 @@
}
case TIMED_PARKED: {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to timed park.");
long deadline = System.currentTimeMillis() + 10000*1000;
LockSupport.parkUntil(deadline);
@@ -228,20 +234,19 @@
}
case SLEEPING: {
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
System.out.println(" myThread is going to sleep.");
try {
Thread.sleep(1000000);
} catch (InterruptedException e) {
// finish sleeping
- interrupted();
}
break;
}
case TERMINATE: {
done = true;
// signal main thread.
- thrsync.signal();
+ phaser.arrive();
break;
}
default:
@@ -249,69 +254,66 @@
}
}
}
+
public void waitUntilStarted() {
// wait for MyThread.
- thrsync.waitForSignal();
- goSleep(10);
+ phaser.arriveAndAwaitAdvance();
}
public void goBlocked() {
System.out.println("Waiting myThread to go blocked.");
setState(BLOCKED);
- // wait for MyThread to get blocked
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to a point just before being blocked
+ phaser.arriveAndAwaitAdvance();
}
public void goWaiting() {
System.out.println("Waiting myThread to go waiting.");
setState(WAITING);
- // wait for MyThread to wait on object.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before wait on object.
+ phaser.arriveAndAwaitAdvance();
}
+
public void goTimedWaiting() {
System.out.println("Waiting myThread to go timed waiting.");
setState(TIMED_WAITING);
- // wait for MyThread timed wait call.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before timed wait call.
+ phaser.arriveAndAwaitAdvance();
}
+
public void goParked() {
System.out.println("Waiting myThread to go parked.");
setState(PARKED);
- // wait for MyThread state change to PARKED.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before parked.
+ phaser.arriveAndAwaitAdvance();
}
+
public void goTimedParked() {
System.out.println("Waiting myThread to go timed parked.");
setState(TIMED_PARKED);
- // wait for MyThread.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before timed park.
+ phaser.arriveAndAwaitAdvance();
}
public void goSleeping() {
System.out.println("Waiting myThread to go sleeping.");
setState(SLEEPING);
- // wait for MyThread.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before sleeping
+ phaser.arriveAndAwaitAdvance();
}
+
public void terminate() {
System.out.println("Waiting myThread to terminate.");
setState(TERMINATE);
- // wait for MyThread.
- thrsync.waitForSignal();
- goSleep(20);
+ // wait for MyThread to get to just before terminate
+ phaser.arriveAndAwaitAdvance();
}
private void setState(int newState) {
switch (state) {
case BLOCKED:
while (state == BLOCKED) {
- goSleep(20);
+ goSleep(10);
}
state = newState;
break;
@@ -337,50 +339,4 @@
}
}
}
-
-
-
- static class ThreadExecutionSynchronizer {
-
- private boolean waiting;
- private Semaphore semaphore;
-
- public ThreadExecutionSynchronizer() {
- semaphore = new Semaphore(1);
- waiting = false;
- }
-
- // Synchronizes two threads execution points.
- // Basically any thread could get scheduled to run and
- // it is not possible to know which thread reaches expected
- // execution point. So whichever thread reaches a execution
- // point first wait for the second thread. When the second thread
- // reaches the expected execution point will wake up
- // the thread which is waiting here.
- void stopOrGo() {
- semaphore.acquireUninterruptibly(); // Thread can get blocked.
- if (!waiting) {
- waiting = true;
- // Wait for second thread to enter this method.
- while(!semaphore.hasQueuedThreads()) {
- try {
- Thread.sleep(20);
- } catch (InterruptedException xx) {}
- }
- semaphore.release();
- } else {
- waiting = false;
- semaphore.release();
- }
- }
-
- // Wrapper function just for code readability.
- void waitForSignal() {
- stopOrGo();
- }
-
- void signal() {
- stopOrGo();
- }
- }
}