/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* 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.
******************************************************************************/
package com.badlogic.gdx.utils;
/** A pool of objects that can be reused to avoid allocation.
* @see Pools
* @author Nathan Sweet */
abstract public class Pool<T> {
/** The maximum number of objects that will be pooled. */
public final int max;
/** The highest number of free objects. Can be reset any time. */
public int peak;
private final Array<T> freeObjects;
/** Creates a pool with an initial capacity of 16 and no maximum. */
public Pool () {
this(16, Integer.MAX_VALUE);
}
/** Creates a pool with the specified initial capacity and no maximum. */
public Pool (int initialCapacity) {
this(initialCapacity, Integer.MAX_VALUE);
}
/** @param max The maximum number of free objects to store in this pool. */
public Pool (int initialCapacity, int max) {
freeObjects = new Array(false, initialCapacity);
this.max = max;
}
abstract protected T newObject ();
/** Returns an object from this pool. The object may be new (from {@link #newObject()}) or reused (previously
* {@link #free(Object) freed}). */
public T obtain () {
return freeObjects.size == 0 ? newObject() : freeObjects.pop();
}
/** Puts the specified object in the pool, making it eligible to be returned by {@link #obtain()}. If the pool already contains
* {@link #max} free objects, the specified object is reset but not added to the pool. */
public void free (T object) {
if (object == null) throw new IllegalArgumentException("object cannot be null.");
if (freeObjects.size < max) {
freeObjects.add(object);
peak = Math.max(peak, freeObjects.size);
}
reset(object);
}
/** Called when an object is freed to clear the state of the object for possible later reuse. The default implementation calls
* {@link Poolable#reset()} if the object is {@link Poolable}. */
protected void reset (T object) {
if (object instanceof Poolable) ((Poolable)object).reset();
}
/** Puts the specified objects in the pool. Null objects within the array are silently ignored.
* @see #free(Object) */
public void freeAll (Array<T> objects) {
if (objects == null) throw new IllegalArgumentException("objects cannot be null.");
Array<T> freeObjects = this.freeObjects;
int max = this.max;
for (int i = 0; i < objects.size; i++) {
T object = objects.get(i);
if (object == null) continue;
if (freeObjects.size < max) freeObjects.add(object);
reset(object);
}
peak = Math.max(peak, freeObjects.size);
}
/** Removes all free objects from this pool. */
public void clear () {
freeObjects.clear();
}
/** The number of objects available to be obtained. */
public int getFree () {
return freeObjects.size;
}
/** Objects implementing this interface will have {@link #reset()} called when passed to {@link #free(Object)}. */
static public interface Poolable {
/** Resets the object for reuse. Object references should be nulled and fields may be set to default values. */
public void reset ();
}
}