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Reverting changes from r1661762 (LANG-1086) for now until we have consensus about this change. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1662379 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Benedikt Ritter 2015-02-26 08:13:58 +00:00
parent 4975b8903e
commit 61836183b1
6 changed files with 7 additions and 344 deletions
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1
src/changes/changes.xml
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@ -22,7 +22,6 @@
<body> <body>
<release version="3.4" date="tba" description="tba"> <release version="3.4" date="tba" description="tba">
<action issue="LANG-1086" type="update" dev="britter">Remove busy wait from AtomicSafeInitializer.get()</action>
<action issue="LANG-1081" type="fix" dev="britter" due-to="Jonathan Baker">DiffBuilder.append(String, Object left, Object right) does not do a left.equals(right) check</action> <action issue="LANG-1081" type="fix" dev="britter" due-to="Jonathan Baker">DiffBuilder.append(String, Object left, Object right) does not do a left.equals(right) check</action>
<action issue="LANG-1055" type="fix" dev="britter" due-to="Jonathan Baker">StrSubstitutor.replaceSystemProperties does not work consistently</action> <action issue="LANG-1055" type="fix" dev="britter" due-to="Jonathan Baker">StrSubstitutor.replaceSystemProperties does not work consistently</action>
<action issue="LANG-1082" type="add" dev="britter" due-to="Jonathan Baker">Add option to disable the "objectsTriviallyEqual" test in DiffBuilder</action> <action issue="LANG-1082" type="add" dev="britter" due-to="Jonathan Baker">Add option to disable the "objectsTriviallyEqual" test in DiffBuilder</action>

31
src/main/java/org/apache/commons/lang3/concurrent/AtomicSafeInitializer.java
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@ -16,7 +16,6 @@
*/ */
package org.apache.commons.lang3.concurrent; package org.apache.commons.lang3.concurrent;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicReference; import java.util.concurrent.atomic.AtomicReference;
/** /**
@ -63,44 +62,20 @@ public abstract class AtomicSafeInitializer<T> implements
/** Holds the reference to the managed object. */ /** Holds the reference to the managed object. */
private final AtomicReference<T> reference = new AtomicReference<T>(); private final AtomicReference<T> reference = new AtomicReference<T>();
/** Holds the exception that terminated the initialize() method, if an exception was thrown */
private final AtomicReference<ConcurrentException> referenceExc = new AtomicReference<ConcurrentException>();
/** Latch for those threads waiting for initialization to complete. */
private final CountDownLatch latch = new CountDownLatch(1);
/** /**
* Get (and initialize, if not initialized yet) the required object * Get (and initialize, if not initialized yet) the required object
* *
* @return lazily initialized object * @return lazily initialized object
* @throws ConcurrentException if the initialization of the object causes an * @throws ConcurrentException if the initialization of the object causes an
* exception or the thread is interrupted waiting for another thread to * exception
* complete the initialization
*/ */
@Override @Override
public final T get() throws ConcurrentException { public final T get() throws ConcurrentException {
T result; T result;
if ((result = reference.get()) == null) { while ((result = reference.get()) == null) {
if (factory.compareAndSet(null, this)) { if (factory.compareAndSet(null, this)) {
try { reference.set(initialize());
reference.set(result = initialize());
} catch ( ConcurrentException exc ) {
referenceExc.set(exc);
throw exc;
} finally {
latch.countDown();
}
} else {
try {
latch.await();
if ( referenceExc.get() != null ) {
throw new ConcurrentException(referenceExc.get().getMessage(), referenceExc.get().getCause());
}
result = reference.get();
} catch (InterruptedException intExc) {
throw new ConcurrentException("interrupted waiting for initialization to complete", intExc);
}
} }
} }

61
src/test/java/org/apache/commons/lang3/concurrent/AbstractConcurrentInitializerTest.java
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@ -18,8 +18,6 @@ package org.apache.commons.lang3.concurrent;
import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull; import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import java.util.concurrent.CountDownLatch; import java.util.concurrent.CountDownLatch;
@ -74,41 +72,7 @@ public abstract class AbstractConcurrentInitializerTest {
@Test @Test
public void testGetConcurrent() throws ConcurrentException, public void testGetConcurrent() throws ConcurrentException,
InterruptedException { InterruptedException {
final ConcurrentInitializer<Object> initializer = createInitializer();
this.testGetConcurrentOptionallyWithException(false, null, null);
}
/**
* Tests the handling of exceptions thrown on the initialized when multiple threads execute concurrently.
* Always an exception with the same message and cause should be thrown.
*
* @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it
* @throws java.lang.InterruptedException because the threading API my throw it
*/
public void testGetConcurrentWithException(String expectedMessage,
Exception expectedCause)
throws ConcurrentException, InterruptedException {
this.testGetConcurrentOptionallyWithException(true, expectedMessage, expectedCause);
}
/**
* Tests whether get() can be invoked from multiple threads concurrently. Supports the exception-handling case
* and the normal, non-exception case.
*
* Always the same object should be returned, or an exception with the same message and cause should be thrown.
*
* @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it
* @throws java.lang.InterruptedException because the threading API my throw it
*/
protected void testGetConcurrentOptionallyWithException(boolean expectExceptions, String expectedMessage,
Exception expectedCause)
throws ConcurrentException, InterruptedException {
final ConcurrentInitializer<Object> initializer = expectExceptions ?
createExceptionThrowingInitializer() :
createInitializer();
final int threadCount = 20; final int threadCount = 20;
final CountDownLatch startLatch = new CountDownLatch(1); final CountDownLatch startLatch = new CountDownLatch(1);
class GetThread extends Thread { class GetThread extends Thread {
@ -142,18 +106,9 @@ public abstract class AbstractConcurrentInitializerTest {
} }
// check results // check results
if ( expectExceptions ) { final Object managedObject = initializer.get();
for (GetThread t : threads) { for (final GetThread t : threads) {
assertTrue(t.object instanceof Exception); assertEquals("Wrong object", managedObject, t.object);
Exception exc = (Exception) t.object;
assertEquals(expectedMessage, exc.getMessage());
assertSame(expectedCause, exc.getCause());
}
} else {
final Object managedObject = initializer.get();
for (final GetThread t : threads) {
assertEquals("Wrong object", managedObject, t.object);
}
} }
} }
@ -164,12 +119,4 @@ public abstract class AbstractConcurrentInitializerTest {
* @return the initializer object to be tested * @return the initializer object to be tested
*/ */
protected abstract ConcurrentInitializer<Object> createInitializer(); protected abstract ConcurrentInitializer<Object> createInitializer();
/**
* Creates a {@link ConcurrentInitializer} object that always throws
* exceptions.
*
* @return
*/
protected abstract ConcurrentInitializer<Object> createExceptionThrowingInitializer();
} }

33
src/test/java/org/apache/commons/lang3/concurrent/AtomicInitializerTest.java
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@ -16,29 +16,12 @@
*/ */
package org.apache.commons.lang3.concurrent; package org.apache.commons.lang3.concurrent;
import org.junit.Test;
/** /**
* Test class for {@code AtomicInitializer}. * Test class for {@code AtomicInitializer}.
* *
* @version $Id$ * @version $Id$
*/ */
public class AtomicInitializerTest extends AbstractConcurrentInitializerTest { public class AtomicInitializerTest extends AbstractConcurrentInitializerTest {
private Exception testCauseException;
private String testExceptionMessage;
public AtomicInitializerTest() {
testExceptionMessage = "x-test-exception-message-x";
testCauseException = new Exception(testExceptionMessage);
}
@Test
public void testGetConcurrentWithException ()
throws ConcurrentException, InterruptedException {
super.testGetConcurrentWithException(testExceptionMessage, testCauseException);
}
/** /**
* Returns the initializer to be tested. * Returns the initializer to be tested.
* *
@ -53,20 +36,4 @@ public class AtomicInitializerTest extends AbstractConcurrentInitializerTest {
} }
}; };
} }
@Override
protected ConcurrentInitializer<Object> createExceptionThrowingInitializer() {
return new ExceptionThrowingAtomicSafeInitializerTestImpl();
}
/**
* A concrete test implementation of {@code AtomicSafeInitializer}. This
* implementation always throws an exception.
*/
private class ExceptionThrowingAtomicSafeInitializerTestImpl extends AtomicSafeInitializer<Object> {
@Override
protected Object initialize() throws ConcurrentException {
throw new ConcurrentException(testExceptionMessage, testCauseException);
}
}
} }

194
src/test/java/org/apache/commons/lang3/concurrent/AtomicSafeInitializerTest.java
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@ -17,11 +17,7 @@
package org.apache.commons.lang3.concurrent; package org.apache.commons.lang3.concurrent;
import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger; import java.util.concurrent.atomic.AtomicInteger;
import org.junit.Before; import org.junit.Before;
@ -34,19 +30,12 @@ import org.junit.Test;
*/ */
public class AtomicSafeInitializerTest extends public class AtomicSafeInitializerTest extends
AbstractConcurrentInitializerTest { AbstractConcurrentInitializerTest {
/** The instance to be tested. */ /** The instance to be tested. */
private AtomicSafeInitializerTestImpl initializer; private AtomicSafeInitializerTestImpl initializer;
private ExceptionThrowingAtomicSafeInitializerTestImpl exceptionThrowingInitializer;
private Exception testCauseException;
private String testExceptionMessage;
@Before @Before
public void setUp() throws Exception { public void setUp() throws Exception {
initializer = new AtomicSafeInitializerTestImpl(); initializer = new AtomicSafeInitializerTestImpl();
exceptionThrowingInitializer = new ExceptionThrowingAtomicSafeInitializerTestImpl();
testExceptionMessage = "x-test-exception-message-x";
testCauseException = new Exception(testExceptionMessage);
} }
/** /**
@ -59,17 +48,6 @@ public class AtomicSafeInitializerTest extends
return initializer; return initializer;
} }
/**
* Returns the exception-throwing initializer to be tested.
*
* @return the {@code AtomicSafeInitializer} under test when validating
* exception handling
*/
@Override
protected ConcurrentInitializer<Object> createExceptionThrowingInitializer() {
return exceptionThrowingInitializer;
}
/** /**
* Tests that initialize() is called only once. * Tests that initialize() is called only once.
* *
@ -84,92 +62,6 @@ public class AtomicSafeInitializerTest extends
initializer.initCounter.get()); initializer.initCounter.get());
} }
@Test
public void testExceptionOnInitialize() throws ConcurrentException,
InterruptedException {
testGetConcurrentWithException(testExceptionMessage, testCauseException);
}
/**
* Validate the handling of an interrupted exception on a thread waiting for another thread to finish calling the
* initialize() method.
*
* @throws Exception
*/
@Test(timeout = 3000)
public void testInterruptedWaitingOnInitialize() throws Exception {
this.execTestWithWaitingOnInitialize(true);
}
/**
* Test the success path of two threads reaching the initialization point at the same time.
*/
@Test(timeout = 3000)
public void testOneThreadWaitingForAnotherToInitialize () throws Exception {
execTestWithWaitingOnInitialize(false);
}
/**
* Execute a test that requires one thread to be waiting on the initialize() method of another thread. This test
* uses latches to guarantee the code path being tested.
*
* @throws Exception
*/
protected void execTestWithWaitingOnInitialize(boolean interruptInd) throws Exception {
final CountDownLatch startLatch = new CountDownLatch(1);
final CountDownLatch finishLatch = new CountDownLatch(1);
final WaitingInitializerTestImpl initializer = new WaitingInitializerTestImpl(startLatch, finishLatch);
InitializerTestThread execThread1 = new InitializerTestThread(initializer);
InitializerTestThread execThread2 = new InitializerTestThread(initializer);
// Start the first thread and wait for it to get into the initialize method so we are sure it is the thread
// executing initialize().
execThread1.start();
startLatch.await();
// Start the second thread and interrupt it to force the InterruptedException. There is no need to make sure
// the thread reaches the await() call before interrupting it.
execThread2.start();
if ( interruptInd ) {
// Interrupt the second thread now and wait for it to complete to ensure it reaches the wait inside the
// get() method.
execThread2.interrupt();
execThread2.join();
}
// Signal the completion of the initialize method now.
finishLatch.countDown();
// Wait for the initialize() to finish.
execThread1.join();
// Wait for thread2 to finish, if it was not already done
if ( ! interruptInd ) {
execThread2.join();
}
//
// Validate: thread1 should have the valid result; thread2 should have caught an interrupted exception, if
// interrupted, or should have the same result otherwise.
//
assertFalse(execThread1.isCaughtException());
assertSame(initializer.getAnswer(), execThread1.getResult());
if ( interruptInd ) {
assertTrue(execThread2.isCaughtException());
Exception exc = (Exception) execThread2.getResult();
assertTrue(exc.getCause() instanceof InterruptedException);
assertEquals("interrupted waiting for initialization to complete", exc.getMessage());
} else {
assertFalse(execThread2.isCaughtException());
assertSame(initializer.getAnswer(), execThread2.getResult());
}
}
/** /**
* A concrete test implementation of {@code AtomicSafeInitializer}. This * A concrete test implementation of {@code AtomicSafeInitializer}. This
* implementation also counts the number of invocations of the initialize() * implementation also counts the number of invocations of the initialize()
@ -186,90 +78,4 @@ public class AtomicSafeInitializerTest extends
return new Object(); return new Object();
} }
} }
/**
* A concrete test implementation of {@code AtomicSafeInitializer}. This
* implementation always throws an exception.
*/
private class ExceptionThrowingAtomicSafeInitializerTestImpl extends AtomicSafeInitializer<Object> {
@Override
protected Object initialize() throws ConcurrentException {
throw new ConcurrentException(testExceptionMessage, testCauseException);
}
}
/**
* Initializer that signals it has started and waits to complete until signalled in order to enable a guaranteed
* order-of-operations. This allows the test code to peg one thread to the initialize method for a period of time
* that the test can dictate.
*/
private class WaitingInitializerTestImpl extends AtomicSafeInitializer<Object> {
private final CountDownLatch startedLatch;
private final CountDownLatch finishLatch;
private final Object answer = new Object();
public WaitingInitializerTestImpl(CountDownLatch startedLatch, CountDownLatch finishLatch) {
this.startedLatch = startedLatch;
this.finishLatch = finishLatch;
}
@Override
protected Object initialize() throws ConcurrentException {
this.startedLatch.countDown();
try {
this.finishLatch.await();
} catch (InterruptedException intExc) {
throw new ConcurrentException(intExc);
}
return answer;
}
public Object getAnswer () {
return answer;
}
}
/**
* Test executor of the initializer get() operation that captures the result.
*/
private class InitializerTestThread extends Thread {
private AtomicSafeInitializer<Object> initializer;
private Object result;
private boolean caughtException;
public InitializerTestThread(AtomicSafeInitializer<Object> initializer) {
super("AtomicSafeInitializer test thread");
this.initializer = initializer;
}
@Override
public void run() {
try {
this.result = initializer.get();
} catch ( ConcurrentException concurrentExc ) {
this.caughtException = true;
this.result = concurrentExc;
}
}
/**
* Resulting object, if the get() method returned successfully, or exception if an exception was thrown.
*
* @return resulting object or exception from the get() method call.
*/
public Object getResult () {
return this.result;
}
/**
* Determine whether an exception was caught on the get() call. Does not guarantee that the get() method was
* called or completed.
*
* @return true => exception was caught; false => exception was not caught.
*/
public boolean isCaughtException () {
return this.caughtException;
}
}
} }

31
src/test/java/org/apache/commons/lang3/concurrent/LazyInitializerTest.java
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@ -17,7 +17,6 @@
package org.apache.commons.lang3.concurrent; package org.apache.commons.lang3.concurrent;
import org.junit.Before; import org.junit.Before;
import org.junit.Test;
/** /**
* Test class for {@code LazyInitializer}. * Test class for {@code LazyInitializer}.
@ -27,16 +26,10 @@ import org.junit.Test;
public class LazyInitializerTest extends AbstractConcurrentInitializerTest { public class LazyInitializerTest extends AbstractConcurrentInitializerTest {
/** The initializer to be tested. */ /** The initializer to be tested. */
private LazyInitializerTestImpl initializer; private LazyInitializerTestImpl initializer;
private ExceptionThrowingLazyInitializerTestImpl exceptionThrowingInitializer;
private Exception testCauseException;
private String testExceptionMessage;
@Before @Before
public void setUp() throws Exception { public void setUp() throws Exception {
initializer = new LazyInitializerTestImpl(); initializer = new LazyInitializerTestImpl();
exceptionThrowingInitializer = new ExceptionThrowingLazyInitializerTestImpl();
testExceptionMessage = "x-test-exception-message-x";
testCauseException = new Exception(testExceptionMessage);
} }
/** /**
@ -50,18 +43,6 @@ public class LazyInitializerTest extends AbstractConcurrentInitializerTest {
return initializer; return initializer;
} }
@Override
protected ConcurrentInitializer<Object> createExceptionThrowingInitializer() {
return exceptionThrowingInitializer;
}
@Test
public void testGetConcurrentWithException ()
throws ConcurrentException, InterruptedException {
super.testGetConcurrentWithException(testExceptionMessage, testCauseException);
}
/** /**
* A test implementation of LazyInitializer. This class creates a plain * A test implementation of LazyInitializer. This class creates a plain
* Object. As Object does not provide a specific equals() method, it is easy * Object. As Object does not provide a specific equals() method, it is easy
@ -74,16 +55,4 @@ public class LazyInitializerTest extends AbstractConcurrentInitializerTest {
return new Object(); return new Object();
} }
} }
/**
* A concrete test implementation of {@code AtomicSafeInitializer}. This
* implementation always throws an exception.
*/
private class ExceptionThrowingLazyInitializerTestImpl extends LazyInitializer<Object> {
@Override
protected Object initialize() throws ConcurrentException {
throw new ConcurrentException(testExceptionMessage, testCauseException);
}
}
} }