Java example source code file (Basic.java)
The Basic.java Java example source code/*
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*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* @test
* @bug 8005697
* @summary Basic tests for StampedLock
* @author Chris Hegarty
*/
import java.util.Iterator;
import java.util.concurrent.Phaser;
import java.util.concurrent.TimeUnit;
import static java.util.concurrent.TimeUnit.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.StampedLock;
public class Basic {
static void checkResult(Locker l, Class<? extends Throwable> c) {
Throwable t = l.thrown();
if (! ((t == null && c == null) || (c != null && c.isInstance(t)))) {
fail("Mismatch in thread " +
l.getName() + ": " +
t + ", " +
(c == null ? "<null>" : c.getName()));
}
if (c == null)
check(l.stamp() != 0L); // must have acquired the lock
else
check(l.stamp() == 0L); // must NOT have acquired the lock
}
//----------------------------------------------------------------
// Mechanism to get all test threads into "running" mode.
//----------------------------------------------------------------
static void toTheStartingGate(Phaser gate) {
try {
gate.arriveAndAwaitAdvance();
} catch (Throwable t) {
unexpected(t);
}
}
static abstract class Locker extends Thread {
static AtomicInteger count = new AtomicInteger(1);
private volatile Throwable thrown;
private volatile long stamp;;
protected void thrown(Throwable thrown) { this.thrown = thrown; }
public Throwable thrown() { return thrown; }
protected void stamp(long stamp) { this.stamp = stamp; }
public long stamp() { return stamp; }
Locker() {
this("Locker");
}
Locker(String name) {
this.setName(name + ":" + count.getAndIncrement());
this.setDaemon(true);
}
}
static abstract class Reader extends Locker {
Reader() { super("Reader"); }
Reader(String name) { super(name); }
}
static Reader reader(final StampedLock sl, final Phaser gate) {
return new Reader() { public void run() {
if (gate != null ) toTheStartingGate(gate);
stamp(sl.readLock());
try {
check(sl.validate(stamp()));
check(sl.isReadLocked());
check(!sl.isWriteLocked());
} finally { sl.unlockRead(stamp()); } }};
}
static Reader readerView(final StampedLock sl, final Phaser gate) {
return new Reader("ReaderView") { public void run() {
if (gate != null ) toTheStartingGate(gate);
final Lock rl = sl.asReadLock();
rl.lock();
try {
stamp(1L); // got the lock
check(sl.isReadLocked());
check(!sl.isWriteLocked());
} finally { rl.unlock(); } }};
}
static Reader reader(StampedLock sl, Phaser gate, boolean view) {
return view ? readerView(sl, gate) : reader(sl, gate);
}
static Reader interruptibleReader(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate) {
return new Reader("InterruptibleReader") { public void run() {
if (gate != null ) toTheStartingGate(gate);
try {
if (timeout < 0)
stamp(sl.readLockInterruptibly());
else
stamp(sl.tryReadLock(timeout, unit));
check(sl.validate(stamp()));
check(sl.isReadLocked());
check(!sl.isWriteLocked());
} catch (Throwable x) { thrown(x);
} finally { if (stamp() != 0L) sl.unlockRead(stamp()); } }};
}
static Reader interruptibleReaderView(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate) {
return new Reader("InterruptibleReaderView") { public void run() {
if (gate != null ) toTheStartingGate(gate);
final Lock rl = sl.asReadLock();
try {
if (timeout < 0)
rl.lockInterruptibly();
else
rl.tryLock(timeout, unit);
stamp(1L); // got the lock
check(sl.isReadLocked());
check(!sl.isWriteLocked());
} catch (Throwable x) { thrown(x);
} finally { if (stamp() != 0L) rl.unlock(); } }};
}
static Reader interruptibleReader(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate,
final boolean view) {
return view ? interruptibleReaderView(sl, timeout, unit, gate)
: interruptibleReader(sl, timeout, unit, gate);
}
static abstract class Writer extends Locker {
Writer() { super("Writer"); }
Writer(String name) { super(name); }
}
static Writer writer(final StampedLock sl, final Phaser gate) {
return new Writer() { public void run() {
if (gate != null ) toTheStartingGate(gate);
try {
stamp(sl.writeLock());
check(sl.validate(stamp()));
check(!sl.isReadLocked());
check(sl.isWriteLocked());
} finally { sl.unlockWrite(stamp()); } }};
}
static Writer writerView(final StampedLock sl, final Phaser gate) {
return new Writer("WriterView") { public void run() {
if (gate != null ) toTheStartingGate(gate);
Lock wl = sl.asWriteLock();
wl.lock();
try {
stamp(1L); // got the lock
check(!sl.isReadLocked());
check(sl.isWriteLocked());
} finally { wl.unlock(); } }};
}
static Writer writer(StampedLock sl, Phaser gate, boolean view) {
return view ? writerView(sl, gate) : writer(sl, gate);
}
static Writer interruptibleWriter(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate) {
return new Writer("InterruptibleWriter") { public void run() {
if (gate != null ) toTheStartingGate(gate);
try {
if (timeout < 0)
stamp(sl.writeLockInterruptibly());
else
stamp(sl.tryWriteLock(timeout, unit));
check(sl.validate(stamp()));
check(!sl.isReadLocked());
check(sl.isWriteLocked());
} catch (Throwable x) { thrown(x);
} finally { if (stamp() != 0L) sl.unlockWrite(stamp()); } }};
}
static Writer interruptibleWriterView(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate) {
return new Writer("InterruptibleWriterView") { public void run() {
if (gate != null ) toTheStartingGate(gate);
Lock wl = sl.asWriteLock();
try {
if (timeout < 0)
wl.lockInterruptibly();
else
wl.tryLock(timeout, unit);
stamp(1L); // got the lock
check(!sl.isReadLocked());
check(sl.isWriteLocked());
} catch (Throwable x) { thrown(x);
} finally { if (stamp() != 0L) wl.unlock(); } }};
}
static Writer interruptibleWriter(final StampedLock sl,
final long timeout,
final TimeUnit unit,
final Phaser gate,
final boolean view) {
return view ? interruptibleWriterView(sl, timeout, unit, gate)
: interruptibleWriter(sl, timeout, unit, gate);
}
// Returns an infinite lazy list of all possible reader combinations.
static Iterator<Reader> readerIterator(final StampedLock sl,
final Phaser gate) {
return new Iterator<Reader>() {
int i = 0;
boolean view = false;
public boolean hasNext() { return true; }
public Reader next() {
switch ((i++)&7) {
case 1: case 4: case 7:
return reader(sl, gate, view ^= true);
case 2: case 5:
return interruptibleReader(sl, -1, SECONDS, gate, view ^= true);
default:
return interruptibleReader(sl, 30, SECONDS, gate, view ^= true); }}
public void remove() {throw new UnsupportedOperationException();}};
}
// Returns an infinite lazy list of all possible writer combinations.
static Iterator<Writer> writerIterator(final StampedLock sl,
final Phaser gate) {
return new Iterator<Writer>() {
int i = 0;
boolean view = false;
public boolean hasNext() { return true; }
public Writer next() {
switch ((i++)&7) {
case 1: case 4: case 7:
return writer(sl, gate, view ^= true);
case 2: case 5:
return interruptibleWriter(sl, -1, SECONDS, gate, view ^= true);
default:
return interruptibleWriter(sl, 30, SECONDS, gate, view ^= true); }}
public void remove() {throw new UnsupportedOperationException();}};
}
private static void realMain(String[] args) throws Throwable {
Thread.currentThread().setName("mainThread");
//----------------------------------------------------------------
// Some basic sanity
//----------------------------------------------------------------
try {
final StampedLock sl = new StampedLock();
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
long stamp = sl.tryOptimisticRead();
check(stamp != 0L);
check(sl.validate(stamp));
check(!sl.validate(0));
stamp = sl.writeLock();
try {
check(sl.validate(stamp));
check(!sl.isReadLocked());
check(sl.isWriteLocked());
check(sl.tryReadLock() == 0L);
check(sl.tryReadLock(100, MILLISECONDS) == 0L);
check(sl.tryOptimisticRead() == 0L);
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(100, MILLISECONDS) == 0L);
check(!sl.tryUnlockRead());
check(sl.tryConvertToWriteLock(stamp) == stamp);
try {
sl.unlockRead(stamp);
fail("Expected unlockRead to throw when not holding read lock");
} catch (IllegalMonitorStateException x) {
pass();
}
check(sl.validate(stamp));
} finally {
sl.unlockWrite(stamp);
}
check(!sl.isWriteLocked());
stamp = sl.readLock();
try {
check(sl.validate(stamp));
check(sl.isReadLocked());
check(!sl.isWriteLocked());
check(sl.tryOptimisticRead() != 0L);
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(100, MILLISECONDS) == 0L);
check(!sl.tryUnlockWrite());
check(sl.tryConvertToReadLock(stamp) == stamp);
try {
sl.unlockWrite(stamp);
fail("Expected unlockWrite to throw when not holding read lock");
} catch (IllegalMonitorStateException x) {
pass();
}
check(sl.validate(stamp));
} finally {
sl.unlockRead(stamp);
}
check(!sl.isReadLocked());
stamp = sl.tryReadLock(100, MILLISECONDS);
try {
check(stamp != 0L);
} finally {
sl.unlockRead(stamp);
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// Multiple writers single reader
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
Phaser gate = new Phaser(102);
Iterator<Writer> writers = writerIterator(sl, gate);
Iterator<Reader> readers = readerIterator(sl, gate);
for (int i = 0; i < 10; i++) {
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
check(sl.tryOptimisticRead() != 0L);
Locker[] wThreads = new Locker[100];;
for (int j=0; j<100; j++)
wThreads[j] = writers.next();
for (int j=0; j<100; j++)
wThreads[j].start();
Reader reader = readers.next(); reader.start();
toTheStartingGate(gate);
reader.join();
for (int j=0; j<100; j++)
wThreads[j].join();
for (int j=0; j<100; j++)
checkResult(wThreads[j], null);
checkResult(reader, null);
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// Multiple readers single writer
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
Phaser gate = new Phaser(102);
Iterator<Writer> writers = writerIterator(sl, gate);
Iterator<Reader> readers = readerIterator(sl, gate);
for (int i = 0; i < 10; i++) {
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
check(sl.tryOptimisticRead() != 0L);
Locker[] rThreads = new Locker[100];;
for (int j=0; j<100; j++)
rThreads[j] = readers.next();
for (int j=0; j<100; j++)
rThreads[j].start();
Writer writer = writers.next(); writer.start();
toTheStartingGate(gate);
writer.join();
for (int j=0; j<100; j++)
rThreads[j].join();
for (int j=0; j<100; j++)
checkResult(rThreads[j], null);
checkResult(writer, null);
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// thread interrupted
//----------------------------------------------------------------
try {
boolean view = false;
StampedLock sl = new StampedLock();
for (long timeout : new long[] { -1L, 30L, -1L, 30L }) {
long stamp = sl.writeLock();
try {
Reader r = interruptibleReader(sl, timeout, SECONDS, null, view);
r.start();
// allow r to block
Thread.sleep(2000);
r.interrupt();
r.join();
checkResult(r, InterruptedException.class);
} finally {
sl.unlockWrite(stamp);
}
stamp = sl.readLock();
try {
Writer w = interruptibleWriter(sl, timeout, SECONDS, null, view);
w.start();
// allow w to block
Thread.sleep(2000);
w.interrupt();
w.join();
checkResult(w, InterruptedException.class);
} finally {
sl.unlockRead(stamp);
}
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
check(sl.tryOptimisticRead() != 0L);
if (timeout == 30L)
view = true;
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// timeout
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
for (long timeout : new long[] { 0L, 5L }) {
long stamp = sl.writeLock();
try {
check(sl.tryReadLock(timeout, SECONDS) == 0L);
} finally {
sl.unlockWrite(stamp);
}
stamp = sl.readLock();
try {
check(sl.tryWriteLock(timeout, SECONDS) == 0L);
} finally {
sl.unlockRead(stamp);
}
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
check(sl.tryOptimisticRead() != 0L);
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// optimistic read
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
Iterator<Writer> writers = writerIterator(sl, null);
Iterator<Reader> readers = readerIterator(sl, null);
for (int i = 0; i < 10; i++) {
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
long stamp = sl.tryOptimisticRead();
check(stamp != 0L);
check(sl.tryConvertToOptimisticRead(stamp) == stamp);
Reader r = readers.next(); r.start();
r.join();
checkResult(r, null);
check(sl.validate(stamp));
check(sl.tryConvertToOptimisticRead(stamp) == stamp);
Writer w = writers.next(); w.start();
w.join();
checkResult(w, null);
check(sl.validate(stamp) == false);
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// convert
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
for (int i = 0; i < 2; i++) {
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(!sl.tryUnlockRead());
check(!sl.tryUnlockWrite());
long stamp = sl.tryOptimisticRead();
check(stamp != 0L);
check((stamp = sl.tryConvertToReadLock(stamp)) != 0L);
check(sl.validate(stamp));
check(sl.isReadLocked());
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(1L, SECONDS) == 0L);
check((stamp = sl.tryConvertToWriteLock(stamp)) != 0L);
check(sl.validate(stamp));
check(!sl.isReadLocked());
check(sl.isWriteLocked());
check(sl.tryReadLock(1L, SECONDS) == 0L);
if (i != 0) {
sl.unlockWrite(stamp);
continue;
}
// convert down
check((stamp = sl.tryConvertToReadLock(stamp)) != 0L);
check(sl.validate(stamp));
check(sl.isReadLocked());
check(!sl.isWriteLocked());
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(1L, SECONDS) == 0L);
check((stamp = sl.tryConvertToOptimisticRead(stamp)) != 0L);
check(sl.validate(stamp));
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
check(sl.validate(stamp));
}
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// views
//----------------------------------------------------------------
try {
StampedLock sl = new StampedLock();
Lock rl = sl.asReadLock();
Lock wl = sl.asWriteLock();
for (int i = 0; i < 2; i++) {
rl.lock();
try {
check(sl.isReadLocked());
check(!sl.isWriteLocked());
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(1L, SECONDS) == 0L);
} finally {
rl.unlock();
}
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
wl.lock();
try {
check(!sl.isReadLocked());
check(sl.isWriteLocked());
check(sl.tryWriteLock() == 0L);
check(sl.tryWriteLock(1L, SECONDS) == 0L);
} finally {
wl.unlock();
}
check(!sl.isReadLocked());
check(!sl.isWriteLocked());
ReadWriteLock rwl = sl.asReadWriteLock();
rl = rwl.readLock();
wl = rwl.writeLock();
}
} catch (Throwable t) { unexpected(t); }
}
//--------------------- Infrastructure ---------------------------
static volatile int passed = 0, failed = 0;
static void pass() {passed++;}
static void fail() {failed++; Thread.dumpStack();}
static void fail(String msg) {System.out.println(msg); fail();}
static void unexpected(Throwable t) {failed++; t.printStackTrace();}
static void check(boolean cond) {if (cond) pass(); else fail();}
static void equal(Object x, Object y) {
if (x == null ? y == null : x.equals(y)) pass();
else fail(x + " not equal to " + y);}
public static void main(String[] args) throws Throwable {
try {realMain(args);} catch (Throwable t) {unexpected(t);}
System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
if (failed > 0) throw new AssertionError("Some tests failed");}
}
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