/* * Copyright 2008-2016 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 com.nominanuda.zen.stereotype; import javax.annotation.concurrent.Immutable; /** * * not necessarily {@link Immutable} * */ public interface Value extends Copyable { @Override int hashCode(); @Override boolean equals(Object obj); /** * * @param o1 * @param o2 * @return true if o1 and o2 are both null or o1.equals(o2) */ public static boolean nullSafeEquals(Object o1, Object o2) { return o1 == null ? o2 == null : o1.equals(o2); } }