trueclassfilter.java

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/*
 * Copyright 2002-2006 the original author or authors.
 *
 * 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 org.springframework.aop;

import java.io.Serializable;

/**
 * Canonical ClassFilter instance that matches all classes.
 *
 * @author Rod Johnson
 */
class TrueClassFilter implements ClassFilter, Serializable {
	
	public static final TrueClassFilter INSTANCE = new TrueClassFilter();
	
	/**
	 * Enforce Singleton pattern.
	 */
	private TrueClassFilter() {
	}

	public boolean matches(Class clazz) {
		return true;
	}
	
	/**
	 * Required to support serialization. Replaces with canonical
	 * instance on deserialization, protecting Singleton pattern.
	 * Alternative to overriding <code>equals()</code>.
	 */
	private Object readResolve() {
		return INSTANCE;
	}

	public String toString() {
		return "ClassFilter.TRUE";
	}

}