gdx/src/com/badlogic/gdx/utils/ReflectionPool.java

/*******************************************************************************
 * 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;

import com.badlogic.gdx.utils.reflect.ClassReflection;
import com.badlogic.gdx.utils.reflect.Constructor;
import com.badlogic.gdx.utils.reflect.ReflectionException;

/** Pool that creates new instances of a type using reflection. The type must have a zero argument constructor.
 * {@link Constructor#setAccessible(boolean)} will be used if the class and/or constructor is not visible.
 * @author Nathan Sweet */
public class ReflectionPool<T> extends Pool<T> {
	private final Constructor constructor;

	public ReflectionPool (Class<T> type) {
		this(type, 16, Integer.MAX_VALUE);
	}

	public ReflectionPool (Class<T> type, int initialCapacity) {
		this(type, initialCapacity, Integer.MAX_VALUE);
	}

	public ReflectionPool (Class<T> type, int initialCapacity, int max) {
		super(initialCapacity, max);
		constructor = findConstructor(type);
		if (constructor == null)
			throw new RuntimeException("Class cannot be created (missing no-arg constructor): " + type.getName());
	}

	private Constructor findConstructor (Class<T> type) {
		try {
			return ClassReflection.getConstructor(type, (Class[])null);
		} catch (Exception ex1) {
			try {
				Constructor constructor = ClassReflection.getDeclaredConstructor(type, (Class[])null);
				constructor.setAccessible(true);
				return constructor;
			} catch (ReflectionException ex2) {
				return null;
			}
		}
	}

	protected T newObject () {
		try {
			return (T)constructor.newInstance((Object[])null);
		} catch (Exception ex) {
			throw new GdxRuntimeException("Unable to create new instance: " + constructor.getDeclaringClass().getName(), ex);
		}
	}
}