    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.collections4.functors;
    018
    019import java.io.Serializable;
    020
    021import org.apache.commons.collections4.FunctorException;
    022import org.apache.commons.collections4.Predicate;
    023
    024/**
    025 * Predicate implementation that throws an exception if the input is null.
    026 *
    027 * @since 3.0
    028 */
    029public final class NullIsExceptionPredicate<T> implements PredicateDecorator<T>, Serializable {
    030
    031    /** Serial version UID */
    032    private static final long serialVersionUID = 3243449850504576071L;
    033
    034    /** The predicate to decorate */
    035    private final Predicate<? super T> iPredicate;
    036
    037    /**
    038     * Factory to create the null exception predicate.
    039     *
    040     * @param <T> the type that the predicate queries
    041     * @param predicate  the predicate to decorate, not null
    042     * @return the predicate
    043     * @throws NullPointerException if the predicate is null
    044     */
    045    public static <T> Predicate<T> nullIsExceptionPredicate(final Predicate<? super T> predicate) {
    046        if (predicate == null) {
    047            throw new NullPointerException("Predicate must not be null");
    048        }
    049        return new NullIsExceptionPredicate<>(predicate);
    050    }
    051
    052    /**
    053     * Constructor that performs no validation.
    054     * Use <code>nullIsExceptionPredicate</code> if you want that.
    055     *
    056     * @param predicate  the predicate to call after the null check
    057     */
    058    public NullIsExceptionPredicate(final Predicate<? super T> predicate) {
    059        super();
    060        iPredicate = predicate;
    061    }
    062
    063    /**
    064     * Evaluates the predicate returning the result of the decorated predicate
    065     * once a null check is performed.
    066     *
    067     * @param object  the input object
    068     * @return true if decorated predicate returns true
    069     * @throws FunctorException if input is null
    070     */
    071    @Override
    072    public boolean evaluate(final T object) {
    073        if (object == null) {
    074            throw new FunctorException("Input Object must not be null");
    075        }
    076        return iPredicate.evaluate(object);
    077    }
    078
    079    /**
    080     * Gets the predicate being decorated.
    081     *
    082     * @return the predicate as the only element in an array
    083     * @since 3.1
    084     */
    085    @Override
    086    @SuppressWarnings("unchecked")
    087    public Predicate<? super T>[] getPredicates() {
    088        return new Predicate[] { iPredicate };
    089    }
    090
    091}