- /*
- * Copyright 2001-2004 The Apache Software Foundation
- *
- * 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.apache.commons.collections.functors;
-
- import java.io.Serializable;
-
- import org.apache.commons.collections.Predicate;
-
- /**
- * Predicate implementation that returns true if the input is null.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.6 $ $Date: 2004/05/16 11:16:01 $
- *
- * @author Stephen Colebourne
- */
- public final class NullPredicate implements Predicate, Serializable {
-
- /** Serial version UID */
- static final long serialVersionUID = 7533784454832764388L;
-
- /** Singleton predicate instance */
- public static final Predicate INSTANCE = new NullPredicate();
-
- /**
- * Factory returning the singleton instance.
- *
- * @return the singleton instance
- * @since Commons Collections 3.1
- */
- public static Predicate getInstance() {
- return INSTANCE;
- }
-
- /**
- * Restricted constructor.
- */
- private NullPredicate() {
- super();
- }
-
- /**
- * Evaluates the predicate returning true if the input is null.
- *
- * @param object the input object
- * @return true if input is null
- */
- public boolean evaluate(Object object) {
- return (object == null);
- }
-
- }