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Added ObjectPool factory + a 'slow' one that is compatible with android

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This commit is contained in:
nathan 2014-10-03 16:04:50 +02:00
parent 7187108f85
commit 2fb565fade
8 changed files with 195 additions and 72 deletions
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82
Dorkbox-Util/src/dorkbox/util/objectPool/FastObjectPool.java
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@ -19,44 +19,21 @@ package dorkbox.util.objectPool;
* limitations under the License.
*/
import java.lang.reflect.Field;
import java.security.AccessController;
import java.security.PrivilegedExceptionAction;
import java.util.concurrent.locks.ReentrantLock;
import sun.misc.Unsafe;
import dorkbox.util.Sys;
public class FastObjectPool<T> {
public static final Unsafe THE_UNSAFE;
static {
try {
final PrivilegedExceptionAction<Unsafe> action = new PrivilegedExceptionAction<Unsafe>() {
@Override
public Unsafe run() throws Exception {
Class<sun.misc.Unsafe> unsafeClass = sun.misc.Unsafe.class;
Field theUnsafe = unsafeClass.getDeclaredField("theUnsafe");
theUnsafe.setAccessible(true);
Object unsafeObject = theUnsafe.get(null);
if (unsafeClass.isInstance(unsafeObject)) {
return unsafeClass.cast(unsafeObject);
}
class FastObjectPool<T> implements ObjectPool<T> {
throw new NoSuchFieldError("the Unsafe");
}
};
private static final boolean FREE = true;
private static final boolean USED = false;
THE_UNSAFE = AccessController.doPrivileged(action);
}
catch (Exception e) {
throw new RuntimeException("Unable to load unsafe", e);
}
}
private Holder<T>[] objects;
private final ObjectPoolHolder<T>[] objects;
private final PoolableObject<T> poolableObject;
private volatile int takePointer;
private int releasePointer;
private volatile int releasePointer;
private final int mask;
private final long BASE;
@ -64,10 +41,11 @@ public class FastObjectPool<T> {
private final long ASHIFT;
public ReentrantLock lock = new ReentrantLock();
private ThreadLocal<Holder<T>> localValue = new ThreadLocal<>();
private ThreadLocal<ObjectPoolHolder<T>> localValue = new ThreadLocal<>();
public FastObjectPool(PoolFactory<T> factory, int size) {
FastObjectPool(PoolableObject<T> poolableObject, int size) {
this.poolableObject = poolableObject;
int newSize = 1;
while (newSize < size) {
newSize = newSize << 1;
@ -76,38 +54,48 @@ public class FastObjectPool<T> {
size = newSize;
@SuppressWarnings({"unchecked", "rawtypes"})
Holder<T>[] stuff = new Holder[size];
ObjectPoolHolder<T>[] stuff = new ObjectPoolHolder[size];
this.objects = stuff;
for (int x=0;x<size;x++) {
this.objects[x] = new Holder<T>(factory.create());
this.objects[x] = new ObjectPoolHolder<T>(poolableObject.create());
}
this.mask = size-1;
this.releasePointer = size;
this.BASE = THE_UNSAFE.arrayBaseOffset(Holder[].class);
this.INDEXSCALE = THE_UNSAFE.arrayIndexScale(Holder[].class);
this.BASE = Sys.unsafe.arrayBaseOffset(ObjectPoolHolder[].class);
this.INDEXSCALE = Sys.unsafe.arrayIndexScale(ObjectPoolHolder[].class);
this.ASHIFT = 31 - Integer.numberOfLeadingZeros((int) this.INDEXSCALE);
}
public Holder<T> take() {
@Override
public ObjectPoolHolder<T> take() {
int localTakePointer;
Holder<T> localObject = this.localValue.get();
// if we have an object available in the cache, use it instead.
ObjectPoolHolder<T> localObject = this.localValue.get();
if (localObject != null) {
if(localObject.state.compareAndSet(Holder.FREE, Holder.USED)) {
if (localObject.state.compareAndSet(FREE, USED)) {
this.poolableObject.activate(localObject.getValue());
return localObject;
}
}
sun.misc.Unsafe unsafe = Sys.unsafe;
while (this.releasePointer != (localTakePointer=this.takePointer)) {
int index = localTakePointer & this.mask;
Holder<T> holder = this.objects[index];
ObjectPoolHolder<T> holder = this.objects[index];
//if(holder!=null && THE_UNSAFE.compareAndSwapObject(objects, (index*INDEXSCALE)+BASE, holder, null))
if (holder != null && THE_UNSAFE.compareAndSwapObject(this.objects, (index<<this.ASHIFT)+this.BASE, holder, null)) {
if (holder != null && unsafe.compareAndSwapObject(this.objects, (index<<this.ASHIFT)+this.BASE, holder, null)) {
this.takePointer = localTakePointer+1;
if (holder.state.compareAndSet(Holder.FREE, Holder.USED)) {
// the use of a threadlocal reference here helps eliminates contention. This also checks OTHER threads,
// as they might have one sitting on the cache
if (holder.state.compareAndSet(FREE, USED)) {
this.localValue.set(holder);
this.poolableObject.activate(holder.getValue());
return holder;
}
}
@ -115,17 +103,19 @@ public class FastObjectPool<T> {
return null;
}
public void release(Holder<T> object) throws InterruptedException {
@Override
public void release(ObjectPoolHolder<T> object) throws InterruptedException {
this.lock.lockInterruptibly();
try {
int localValue=this.releasePointer;
int localValue = this.releasePointer;
//long index = ((localValue & mask) * INDEXSCALE ) + BASE;
long index = ((localValue & this.mask)<<this.ASHIFT ) + this.BASE;
if (object.state.compareAndSet(Holder.USED, Holder.FREE)) {
THE_UNSAFE.putOrderedObject(this.objects, index, object);
if (object.state.compareAndSet(USED, FREE)) {
Sys.unsafe.putOrderedObject(this.objects, index, object);
this.releasePointer = localValue+1;
this.poolableObject.passivate(object.getValue());
}
else {
throw new IllegalArgumentException("Invalid reference passed");

21
Dorkbox-Util/src/dorkbox/util/objectPool/Holder.java
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@ -1,21 +0,0 @@
package dorkbox.util.objectPool;
import java.util.concurrent.atomic.AtomicInteger;
public class Holder<T> {
private T value;
static final int FREE = 0;
static final int USED = 1;
AtomicInteger state = new AtomicInteger(FREE);
public Holder(T value) {
this.value = value;
}
public T getValue() {
return this.value;
}
}

13
Dorkbox-Util/src/dorkbox/util/objectPool/ObjectPool.java Normal file
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@ -0,0 +1,13 @@
package dorkbox.util.objectPool;
public interface ObjectPool<T> {
/**
* Takes an object from the pool
*/
public ObjectPoolHolder<T> take();
/**
* Return object to the pool
*/
public void release(ObjectPoolHolder<T> object) throws InterruptedException;
}

21
Dorkbox-Util/src/dorkbox/util/objectPool/ObjectPoolFactory.java Normal file
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@ -0,0 +1,21 @@
package dorkbox.util.objectPool;
import dorkbox.util.Sys;
public class ObjectPoolFactory<T> {
private ObjectPoolFactory() {
}
public static <T> ObjectPool<T> create(PoolableObject<T> poolableObject, int size) {
if (Sys.isAndroid) {
// unfortunately, unsafe is not available in android
SlowObjectPool<T> slowObjectPool = new SlowObjectPool<T>(poolableObject, size);
return slowObjectPool;
} else {
// here we use FAST (via UNSAFE) one!
FastObjectPool<T> fastObjectPool = new FastObjectPool<T>(poolableObject, size);
return fastObjectPool;
}
}
}

18
Dorkbox-Util/src/dorkbox/util/objectPool/ObjectPoolHolder.java Normal file
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@ -0,0 +1,18 @@
package dorkbox.util.objectPool;
import java.util.concurrent.atomic.AtomicBoolean;
public class ObjectPoolHolder<T> {
private T value;
AtomicBoolean state = new AtomicBoolean(true);
public ObjectPoolHolder(T value) {
this.value = value;
}
public T getValue() {
return this.value;
}
}

5
Dorkbox-Util/src/dorkbox/util/objectPool/PoolFactory.java
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@ -1,5 +0,0 @@
package dorkbox.util.objectPool;
public interface PoolFactory<T> {
public T create();
}

19
Dorkbox-Util/src/dorkbox/util/objectPool/PoolableObject.java Normal file
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@ -0,0 +1,19 @@
package dorkbox.util.objectPool;
public interface PoolableObject<T> {
/**
* called when a new instance is created
*/
public T create();
/**
* invoked on every instance that is borrowed from the pool
*/
public void activate(T t);
/**
* invoked on every instance that is returned to the pool
*/
public void passivate(T t);
}

88
Dorkbox-Util/src/dorkbox/util/objectPool/SlowObjectPool.java Normal file
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@ -0,0 +1,88 @@
package dorkbox.util.objectPool;
/*
*
* from: http://ashkrit.blogspot.de/2013/05/lock-less-java-object-pool.html
* https://github.com/ashkrit/blog/tree/master/FastObjectPool
* copyright ashkrit 2013
*
* MODIFIED by Nathan Robinson to be a version that is compatible with Android.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.util.concurrent.LinkedBlockingDeque;
class SlowObjectPool<T> implements ObjectPool<T> {
private static final boolean FREE = true;
private static final boolean USED = false;
private final LinkedBlockingDeque<ObjectPoolHolder<T>> queue;
private final PoolableObject<T> poolableObject;
private ThreadLocal<ObjectPoolHolder<T>> localValue = new ThreadLocal<>();
SlowObjectPool(PoolableObject<T> poolableObject, int size) {
this.queue = new LinkedBlockingDeque<ObjectPoolHolder<T>>(size);
this.poolableObject = poolableObject;
for (int x=0;x<size;x++) {
this.queue.add(new ObjectPoolHolder<T>(poolableObject.create()));
}
}
@Override
public ObjectPoolHolder<T> take() {
// if we have an object available in the cache, use it instead.
ObjectPoolHolder<T> localObject = this.localValue.get();
if (localObject != null) {
if (localObject.state.compareAndSet(FREE, USED)) {
this.poolableObject.activate(localObject.getValue());
return localObject;
}
}
ObjectPoolHolder<T> holder = this.queue.poll();
if (holder == null) {
return null;
}
// the use of a threadlocal reference here helps eliminates contention. This also checks OTHER threads,
// as they might have one sitting on the cache
if (holder.state.compareAndSet(FREE, USED)) {
this.localValue.set(holder);
this.poolableObject.activate(holder.getValue());
return holder;
} else {
// put it back into the queue
this.queue.offer(holder);
return null;
}
}
@Override
public void release(ObjectPoolHolder<T> object) throws InterruptedException {
if (object.state.compareAndSet(USED, FREE)) {
this.queue.offer(object);
this.poolableObject.passivate(object.getValue());
}
else {
throw new IllegalArgumentException("Invalid reference passed");
}
}
}