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 java.lang.reflect.Constructor;

/**
 * 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 Class<T> type;

	public ReflectionPool(Class<T> type) {
		this.type = type;
	}

	public ReflectionPool(Class<T> type, int initialCapacity, int max) {
		super(initialCapacity, max);
		this.type = type;
	}

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

	protected T newObject() {
		try {
			return type.newInstance();
		} catch (Exception ex) {
			Constructor ctor;
			try {
				ctor = type.getConstructor((Class[]) null);
			} catch (Exception ex2) {
				try {
					ctor = type.getDeclaredConstructor((Class[]) null);
					ctor.setAccessible(true);
				} catch (NoSuchMethodException ex3) {
					throw new RuntimeException("Class cannot be created (missing no-arg constructor): "
							+ type.getName());
				}
			}
			try {
				return (T) ctor.newInstance();
			} catch (Exception ex3) {
				throw new GdxRuntimeException("Unable to create new instance: " + type.getName(), ex);
			}
		}
	}
}