org.apache.commons.collections4.functors.NullIsFalsePredicate Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.collections4.functors;
import java.io.Serializable;
import org.apache.commons.collections4.Predicate;
/**
* Predicate implementation that returns false if the input is null.
*
* @since 3.0
*/
public final class NullIsFalsePredicate implements PredicateDecorator, Serializable {
/** Serial version UID */
private static final long serialVersionUID = -2997501534564735525L;
/** The predicate to decorate */
private final Predicate iPredicate;
/**
* Factory to create the null false predicate.
*
* @param the type that the predicate queries
* @param predicate the predicate to decorate, not null
* @return the predicate
* @throws NullPointerException if the predicate is null
*/
public static Predicate nullIsFalsePredicate(final Predicate predicate) {
if (predicate == null) {
throw new NullPointerException("Predicate must not be null");
}
return new NullIsFalsePredicate<>(predicate);
}
/**
* Constructor that performs no validation.
* Use nullIsFalsePredicate if you want that.
*
* @param predicate the predicate to call after the null check
*/
public NullIsFalsePredicate(final Predicate predicate) {
super();
iPredicate = predicate;
}
/**
* Evaluates the predicate returning the result of the decorated predicate
* once a null check is performed.
*
* @param object the input object
* @return true if decorated predicate returns true, false if input is null
*/
@Override
public boolean evaluate(final T object) {
if (object == null) {
return false;
}
return iPredicate.evaluate(object);
}
/**
* Gets the predicate being decorated.
*
* @return the predicate as the only element in an array
* @since 3.1
*/
@Override
@SuppressWarnings("unchecked")
public Predicate[] getPredicates() {
return new Predicate[] { iPredicate };
}
}