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8251861: Remove unused jdk.internal.ref.SoftCleanable and WeakCleanable

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Reviewed-by: mchung, rriggs
This commit is contained in:
Kiran Sidhartha Ravikumar 2020-10-13 17:08:47 +00:00 committed by Sean Coffey
parent 6ed4c89dc8
commit ba24f9633e
4 changed files with 2 additions and 635 deletions
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115
src/java.base/share/classes/jdk/internal/ref/CleanerImpl.java
View File

@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* *
* This code is free software; you can redistribute it and/or modify it * This code is free software; you can redistribute it and/or modify it
@ -52,10 +52,6 @@ public final class CleanerImpl implements Runnable {
*/ */
final PhantomCleanable<?> phantomCleanableList; final PhantomCleanable<?> phantomCleanableList;
final WeakCleanable<?> weakCleanableList;
final SoftCleanable<?> softCleanableList;
// The ReferenceQueue of pending cleaning actions // The ReferenceQueue of pending cleaning actions
final ReferenceQueue<Object> queue; final ReferenceQueue<Object> queue;
@ -87,8 +83,6 @@ public final class CleanerImpl implements Runnable {
public CleanerImpl() { public CleanerImpl() {
queue = new ReferenceQueue<>(); queue = new ReferenceQueue<>();
phantomCleanableList = new PhantomCleanableRef(); phantomCleanableList = new PhantomCleanableRef();
weakCleanableList = new WeakCleanableRef();
softCleanableList = new SoftCleanableRef();
} }
/** /**
@ -135,9 +129,7 @@ public final class CleanerImpl implements Runnable {
InnocuousThread mlThread = (t instanceof InnocuousThread) InnocuousThread mlThread = (t instanceof InnocuousThread)
? (InnocuousThread) t ? (InnocuousThread) t
: null; : null;
while (!phantomCleanableList.isListEmpty() || while (!phantomCleanableList.isListEmpty()) {
!weakCleanableList.isListEmpty() ||
!softCleanableList.isListEmpty()) {
if (mlThread != null) { if (mlThread != null) {
// Clear the thread locals // Clear the thread locals
mlThread.eraseThreadLocals(); mlThread.eraseThreadLocals();
@ -207,109 +199,6 @@ public final class CleanerImpl implements Runnable {
} }
} }
/**
* Perform cleaning on an unreachable WeakReference.
*/
public static final class WeakCleanableRef extends WeakCleanable<Object> {
private final Runnable action;
/**
* Constructor for a weak cleanable reference.
* @param obj the object to monitor
* @param cleaner the cleaner
* @param action the action Runnable
*/
WeakCleanableRef(Object obj, Cleaner cleaner, Runnable action) {
super(obj, cleaner);
this.action = action;
}
/**
* Constructor used only for root of weak cleanable list.
*/
WeakCleanableRef() {
super();
this.action = null;
}
@Override
protected void performCleanup() {
action.run();
}
/**
* Prevent access to referent even when it is still alive.
*
* @throws UnsupportedOperationException always
*/
@Override
public Object get() {
throw new UnsupportedOperationException("get");
}
/**
* Direct clearing of the referent is not supported.
*
* @throws UnsupportedOperationException always
*/
@Override
public void clear() {
throw new UnsupportedOperationException("clear");
}
}
/**
* Perform cleaning on an unreachable SoftReference.
*/
public static final class SoftCleanableRef extends SoftCleanable<Object> {
private final Runnable action;
/**
* Constructor for a soft cleanable reference.
* @param obj the object to monitor
* @param cleaner the cleaner
* @param action the action Runnable
*/
SoftCleanableRef(Object obj, Cleaner cleaner, Runnable action) {
super(obj, cleaner);
this.action = action;
}
/**
* Constructor used only for root of soft cleanable list.
*/
SoftCleanableRef() {
super();
this.action = null;
}
@Override
protected void performCleanup() {
action.run();
}
/**
* Prevent access to referent even when it is still alive.
*
* @throws UnsupportedOperationException always
*/
@Override
public Object get() {
throw new UnsupportedOperationException("get");
}
/**
* Direct clearing of the referent is not supported.
*
* @throws UnsupportedOperationException always
*/
@Override
public void clear() {
throw new UnsupportedOperationException("clear");
}
}
/** /**
* A ThreadFactory for InnocuousThreads. * A ThreadFactory for InnocuousThreads.
* The factory is a singleton. * The factory is a singleton.

179
src/java.base/share/classes/jdk/internal/ref/SoftCleanable.java
View File

@ -1,179 +0,0 @@
/*
* Copyright (c) 2015, 2016, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* 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
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.internal.ref;
import java.lang.ref.Cleaner;
import java.lang.ref.Reference;
import java.lang.ref.SoftReference;
import java.util.Objects;
/**
* SoftCleanable subclasses efficiently encapsulate cleanup state and
* the cleaning action.
* Subclasses implement the abstract {@link #performCleanup()} method
* to provide the cleaning action.
* When constructed, the object reference and the {@link Cleaner.Cleanable Cleanable}
* are registered with the {@link Cleaner}.
* The Cleaner invokes {@link Cleaner.Cleanable#clean() clean} after the
* referent becomes softly reachable.
*/
public abstract class SoftCleanable<T> extends SoftReference<T>
implements Cleaner.Cleanable {
/**
* Links to previous and next in a doubly-linked list.
*/
SoftCleanable<?> prev = this, next = this;
/**
* The list of SoftCleanable; synchronizes insert and remove.
*/
private final SoftCleanable<?> list;
/**
* Constructs new {@code SoftCleanableReference} with
* {@code non-null referent} and {@code non-null cleaner}.
* The {@code cleaner} is not retained by this reference; it is only used
* to register the newly constructed {@link Cleaner.Cleanable Cleanable}.
*
* @param referent the referent to track
* @param cleaner the {@code Cleaner} to register with
*/
public SoftCleanable(T referent, Cleaner cleaner) {
super(Objects.requireNonNull(referent), CleanerImpl.getCleanerImpl(cleaner).queue);
list = CleanerImpl.getCleanerImpl(cleaner).softCleanableList;
insert();
// Ensure referent and cleaner remain accessible
Reference.reachabilityFence(referent);
Reference.reachabilityFence(cleaner);
}
/**
* Construct a new root of the list; not inserted.
*/
SoftCleanable() {
super(null, null);
this.list = this;
}
/**
* Insert this SoftCleanableReference after the list head.
*/
private void insert() {
synchronized (list) {
prev = list;
next = list.next;
next.prev = this;
list.next = this;
}
}
/**
* Remove this SoftCleanableReference from the list.
*
* @return true if Cleanable was removed or false if not because
* it had already been removed before
*/
private boolean remove() {
synchronized (list) {
if (next != this) {
next.prev = prev;
prev.next = next;
prev = this;
next = this;
return true;
}
return false;
}
}
/**
* Returns true if the list's next reference refers to itself.
*
* @return true if the list is empty
*/
boolean isListEmpty() {
synchronized (list) {
return list == list.next;
}
}
/**
* Unregister this SoftCleanable reference and invoke {@link #performCleanup()},
* ensuring at-most-once semantics.
*/
@Override
public final void clean() {
if (remove()) {
super.clear();
performCleanup();
}
}
/**
* Unregister this SoftCleanable and clear the reference.
* Due to inherent concurrency, {@link #performCleanup()} may still be invoked.
*/
@Override
public void clear() {
if (remove()) {
super.clear();
}
}
/**
* The {@code performCleanup} abstract method is overridden
* to implement the cleaning logic.
* The {@code performCleanup} method should not be called except
* by the {@link #clean} method which ensures at most once semantics.
*/
protected abstract void performCleanup();
/**
* This method always throws {@link UnsupportedOperationException}.
* Enqueuing details of {@link Cleaner.Cleanable}
* are a private implementation detail.
*
* @throws UnsupportedOperationException always
*/
@Override
public final boolean isEnqueued() {
throw new UnsupportedOperationException("isEnqueued");
}
/**
* This method always throws {@link UnsupportedOperationException}.
* Enqueuing details of {@link Cleaner.Cleanable}
* are a private implementation detail.
*
* @throws UnsupportedOperationException always
*/
@Override
public final boolean enqueue() {
throw new UnsupportedOperationException("enqueue");
}
}

180
src/java.base/share/classes/jdk/internal/ref/WeakCleanable.java
View File

@ -1,180 +0,0 @@
/*
* Copyright (c) 2015, 2016, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* 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
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 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
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package jdk.internal.ref;
import java.lang.ref.Cleaner;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.Objects;
/**
* WeakCleanable subclasses efficiently encapsulate cleanup state and
* the cleaning action.
* Subclasses implement the abstract {@link #performCleanup()} method
* to provide the cleaning action.
* When constructed, the object reference and the {@link Cleaner.Cleanable Cleanable}
* are registered with the {@link Cleaner}.
* The Cleaner invokes {@link Cleaner.Cleanable#clean() clean} after the
* referent becomes weakly reachable.
*/
public abstract class WeakCleanable<T> extends WeakReference<T>
implements Cleaner.Cleanable {
/**
* Links to previous and next in a doubly-linked list.
*/
WeakCleanable<?> prev = this, next = this;
/**
* The list of WeakCleanable; synchronizes insert and remove.
*/
private final WeakCleanable<?> list;
/**
* Constructs new {@code WeakCleanableReference} with
* {@code non-null referent} and {@code non-null cleaner}.
* The {@code cleaner} is not retained by this reference; it is only used
* to register the newly constructed {@link Cleaner.Cleanable Cleanable}.
*
* @param referent the referent to track
* @param cleaner the {@code Cleaner} to register new reference with
*/
public WeakCleanable(T referent, Cleaner cleaner) {
super(Objects.requireNonNull(referent), CleanerImpl.getCleanerImpl(cleaner).queue);
list = CleanerImpl.getCleanerImpl(cleaner).weakCleanableList;
insert();
// Ensure referent and cleaner remain accessible
Reference.reachabilityFence(referent);
Reference.reachabilityFence(cleaner);
}
/**
* Construct a new root of the list; not inserted.
*/
WeakCleanable() {
super(null, null);
this.list = this;
}
/**
* Insert this WeakCleanableReference after the list head.
*/
private void insert() {
synchronized (list) {
prev = list;
next = list.next;
next.prev = this;
list.next = this;
}
}
/**
* Remove this WeakCleanableReference from the list.
*
* @return true if Cleanable was removed or false if not because
* it had already been removed before
*/
private boolean remove() {
synchronized (list) {
if (next != this) {
next.prev = prev;
prev.next = next;
prev = this;
next = this;
return true;
}
return false;
}
}
/**
* Returns true if the list's next reference refers to itself.
*
* @return true if the list is empty
*/
boolean isListEmpty() {
synchronized (list) {
return list == list.next;
}
}
/**
* Unregister this WeakCleanable reference and invoke {@link #performCleanup()},
* ensuring at-most-once semantics.
*/
@Override
public final void clean() {
if (remove()) {
super.clear();
performCleanup();
}
}
/**
* Unregister this WeakCleanable and clear the reference.
* Due to inherent concurrency, {@link #performCleanup()} may still be invoked.
*/
@Override
public void clear() {
if (remove()) {
super.clear();
}
}
/**
* The {@code performCleanup} abstract method is overridden
* to implement the cleaning logic.
* The {@code performCleanup} method should not be called except
* by the {@link #clean} method which ensures at most once semantics.
*/
protected abstract void performCleanup();
/**
* This method always throws {@link UnsupportedOperationException}.
* Enqueuing details of {@link Cleaner.Cleanable}
* are a private implementation detail.
*
* @throws UnsupportedOperationException always
*/
@Override
public final boolean isEnqueued() {
throw new UnsupportedOperationException("isEnqueued");
}
/**
* This method always throws {@link UnsupportedOperationException}.
* Enqueuing details of {@link Cleaner.Cleanable}
* are a private implementation detail.
*
* @throws UnsupportedOperationException always
*/
@Override
public final boolean enqueue() {
throw new UnsupportedOperationException("enqueue");
}
}

163
test/jdk/java/lang/ref/CleanerTest.java
View File

@ -35,8 +35,6 @@ import java.util.function.Consumer;
import java.util.function.Supplier; import java.util.function.Supplier;
import jdk.internal.ref.PhantomCleanable; import jdk.internal.ref.PhantomCleanable;
import jdk.internal.ref.WeakCleanable;
import jdk.internal.ref.SoftCleanable;
import jdk.internal.ref.CleanerFactory; import jdk.internal.ref.CleanerFactory;
import sun.hotspot.WhiteBox; import sun.hotspot.WhiteBox;
@ -152,20 +150,12 @@ public class CleanerTest {
void generateCasesInternal(Cleaner cleaner, Consumer<CleanableCase>... runnables) { void generateCasesInternal(Cleaner cleaner, Consumer<CleanableCase>... runnables) {
generateCases(() -> setupPhantomSubclass(cleaner, null), generateCases(() -> setupPhantomSubclass(cleaner, null),
runnables.length, runnables); runnables.length, runnables);
generateCases(() -> setupWeakSubclass(cleaner, null),
runnables.length, runnables);
generateCases(() -> setupSoftSubclass(cleaner, null),
runnables.length, runnables);
} }
@SuppressWarnings("unchecked") @SuppressWarnings("unchecked")
void generateExceptionCasesInternal(Cleaner cleaner) { void generateExceptionCasesInternal(Cleaner cleaner) {
generateCases(() -> setupPhantomSubclassException(cleaner, null), generateCases(() -> setupPhantomSubclassException(cleaner, null),
1, c -> c.clearRef()); 1, c -> c.clearRef());
generateCases(() -> setupWeakSubclassException(cleaner, null),
1, c -> c.clearRef());
generateCases(() -> setupSoftSubclassException(cleaner, null),
1, c -> c.clearRef());
} }
/** /**
@ -346,47 +336,6 @@ public class CleanerTest {
return new CleanableCase(new PhantomReference<>(obj, null), c1, s1); return new CleanableCase(new PhantomReference<>(obj, null), c1, s1);
} }
/**
* Create a CleanableCase for a WeakReference.
* @param cleaner the cleaner to use
* @param obj an object or null to create a new Object
* @return a new CleanableCase preset with the object, cleanup, and semaphore
*/
static CleanableCase setupWeakSubclass(Cleaner cleaner, Object obj) {
if (obj == null) {
obj = new Object();
}
Semaphore s1 = new Semaphore(0);
Cleaner.Cleanable c1 = new WeakCleanable<Object>(obj, cleaner) {
protected void performCleanup() {
s1.release();
}
};
return new CleanableCase(new WeakReference<>(obj, null), c1, s1);
}
/**
* Create a CleanableCase for a SoftReference.
* @param cleaner the cleaner to use
* @param obj an object or null to create a new Object
* @return a new CleanableCase preset with the object, cleanup, and semaphore
*/
static CleanableCase setupSoftSubclass(Cleaner cleaner, Object obj) {
if (obj == null) {
obj = new Object();
}
Semaphore s1 = new Semaphore(0);
Cleaner.Cleanable c1 = new SoftCleanable<Object>(obj, cleaner) {
protected void performCleanup() {
s1.release();
}
};
return new CleanableCase(new SoftReference<>(obj, null), c1, s1);
}
/** /**
* Create a CleanableCase for a PhantomReference. * Create a CleanableCase for a PhantomReference.
@ -410,50 +359,6 @@ public class CleanerTest {
return new CleanableCase(new PhantomReference<>(obj, null), c1, s1, true); return new CleanableCase(new PhantomReference<>(obj, null), c1, s1, true);
} }
/**
* Create a CleanableCase for a WeakReference.
* @param cleaner the cleaner to use
* @param obj an object or null to create a new Object
* @return a new CleanableCase preset with the object, cleanup, and semaphore
*/
static CleanableCase setupWeakSubclassException(Cleaner cleaner, Object obj) {
if (obj == null) {
obj = new Object();
}
Semaphore s1 = new Semaphore(0);
Cleaner.Cleanable c1 = new WeakCleanable<Object>(obj, cleaner) {
protected void performCleanup() {
s1.release();
throw new RuntimeException("Exception thrown to cleaner thread");
}
};
return new CleanableCase(new WeakReference<>(obj, null), c1, s1, true);
}
/**
* Create a CleanableCase for a SoftReference.
* @param cleaner the cleaner to use
* @param obj an object or null to create a new Object
* @return a new CleanableCase preset with the object, cleanup, and semaphore
*/
static CleanableCase setupSoftSubclassException(Cleaner cleaner, Object obj) {
if (obj == null) {
obj = new Object();
}
Semaphore s1 = new Semaphore(0);
Cleaner.Cleanable c1 = new SoftCleanable<Object>(obj, cleaner) {
protected void performCleanup() {
s1.release();
throw new RuntimeException("Exception thrown to cleaner thread");
}
};
return new CleanableCase(new SoftReference<>(obj, null), c1, s1, true);
}
/** /**
* CleanableCase encapsulates the objects used for a test. * CleanableCase encapsulates the objects used for a test.
* The reference to the object is not held directly, * The reference to the object is not held directly,
@ -611,74 +516,6 @@ public class CleanerTest {
} }
} }
/**
* Example using a Cleaner to remove WeakKey references from a Map.
*/
@Test
void testWeakKey() {
ConcurrentHashMap<WeakKey<String>, String> map = new ConcurrentHashMap<>();
Cleaner cleaner = Cleaner.create();
String key = new String("foo"); // ensure it is not interned
String data = "bar";
map.put(new WeakKey<>(key, cleaner, map), data);
WeakKey<String> k2 = new WeakKey<>(key, cleaner, map);
Assert.assertEquals(map.get(k2), data, "value should be found in the map");
key = null;
System.gc();
Assert.assertNotEquals(map.get(k2), data, "value should not be found in the map");
final long CYCLE_MAX = Utils.adjustTimeout(30L);
for (int i = 1; map.size() > 0 && i < CYCLE_MAX; i++) {
map.forEach( (k, v) -> System.out.printf(" k: %s, v: %s%n", k, v));
try {
Thread.sleep(10L);
} catch (InterruptedException ie) {}
}
Assert.assertEquals(map.size(), 0, "Expected map to be empty;");
cleaner = null;
}
/**
* Test sample class for WeakKeys in Map.
* @param <K> A WeakKey of type K
*/
class WeakKey<K> extends WeakReference<K> {
private final int hash;
private final ConcurrentHashMap<WeakKey<K>, ?> map;
Cleaner.Cleanable cleanable;
public WeakKey(K key, Cleaner c, ConcurrentHashMap<WeakKey<K>, ?> map) {
super(key);
this.hash = key.hashCode();
this.map = map;
cleanable = new WeakCleanable<Object>(key, c) {
protected void performCleanup() {
map.remove(WeakKey.this);
}
};
}
public int hashCode() { return hash; }
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof WeakKey)) return false;
K key = get();
if (key == null) return obj == this;
return key == ((WeakKey<?>)obj).get();
}
public String toString() {
return "WeakKey:" + Objects.toString(get() + ", cleanableRef: " +
((Reference)cleanable).get());
}
}
/** /**
* Verify that casting a Cleanup to a Reference is not allowed to * Verify that casting a Cleanup to a Reference is not allowed to
* get the referent or clear the reference. * get the referent or clear the reference.