85 lines
2.2 KiB
Java
85 lines
2.2 KiB
Java
|
//: concurrency/ExplicitCriticalSection.java
|
|||
|
|
// <20>2015 MindView LLC: see Copyright.txt
|
|||
|
|
// {ThrowsException} on a multiprocessor machine
|
|||
|
|
// Using explicit Lock objects to create
|
|||
|
|
// critical sections.
|
|||
|
|
package concurrency;
|
|||
|
|
import java.util.concurrent.locks.*;
|
|||
|
|
|
|||
|
|
// Synchronize the entire method:
|
|||
|
|
class ExplicitPairManager1 extends PairManager {
|
|||
|
|
private Lock lock = new ReentrantLock();
|
|||
|
|
@Override
|
|||
|
|
public void increment() {
|
|||
|
|
lock.lock();
|
|||
|
|
try {
|
|||
|
|
p.incrementX();
|
|||
|
|
p.incrementY();
|
|||
|
|
store(getPair());
|
|||
|
|
} finally {
|
|||
|
|
lock.unlock();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Use a critical section:
|
|||
|
|
class ExplicitPairManager2 extends PairManager {
|
|||
|
|
private Lock lock = new ReentrantLock();
|
|||
|
|
@Override
|
|||
|
|
public void increment() {
|
|||
|
|
Pair temp;
|
|||
|
|
lock.lock();
|
|||
|
|
try {
|
|||
|
|
p.incrementX();
|
|||
|
|
p.incrementY();
|
|||
|
|
temp = getPair();
|
|||
|
|
} finally {
|
|||
|
|
lock.unlock();
|
|||
|
|
}
|
|||
|
|
store(temp);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public class ExplicitCriticalSection {
|
|||
|
|
public static void
|
|||
|
|
main(String[] args) throws Exception {
|
|||
|
|
PairManager
|
|||
|
|
pman1 = new ExplicitPairManager1(),
|
|||
|
|
pman2 = new ExplicitPairManager2();
|
|||
|
|
CriticalSection.testApproaches(pman1, pman2);
|
|||
|
|
}
|
|||
|
|
} /* Output:
|
|||
|
|
pm1: Pair: x: 10, y: 10 checkCounter = 68453
|
|||
|
|
pm2: Pair: x: 11, y: 11 checkCounter = 663407
|
|||
|
|
___[ Error Output ]___
|
|||
|
|
Exception in thread "pool-1-thread-3"
|
|||
|
|
concurrency.Pair$PairValuesNotEqualException: Pair values
|
|||
|
|
not equal: x: 1, y: 0
|
|||
|
|
at
|
|||
|
|
concurrency.Pair.checkState(CriticalSection.java:36)
|
|||
|
|
at
|
|||
|
|
concurrency.PairChecker.run(CriticalSection.java:110)
|
|||
|
|
at
|
|||
|
|
java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown
|
|||
|
|
Source)
|
|||
|
|
at
|
|||
|
|
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown
|
|||
|
|
Source)
|
|||
|
|
at java.lang.Thread.run(Unknown Source)
|
|||
|
|
Exception in thread "pool-1-thread-4"
|
|||
|
|
concurrency.Pair$PairValuesNotEqualException: Pair values
|
|||
|
|
not equal: x: 2, y: 1
|
|||
|
|
at
|
|||
|
|
concurrency.Pair.checkState(CriticalSection.java:36)
|
|||
|
|
at
|
|||
|
|
concurrency.PairChecker.run(CriticalSection.java:110)
|
|||
|
|
at
|
|||
|
|
java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown
|
|||
|
|
Source)
|
|||
|
|
at
|
|||
|
|
java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown
|
|||
|
|
Source)
|
|||
|
|
at java.lang.Thread.run(Unknown Source)
|
|||
|
|
___[ Exception is Expected ]___
|
|||
|
|
*///:~
|