    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;
    020import java.util.Objects;
    021
    022import org.apache.commons.collections4.FunctorException;
    023import org.apache.commons.collections4.Predicate;
    024
    025/**
    026 * Predicate implementation that throws an exception if the input is null.
    027 *
    028 * @param <T> the type of the input to the predicate.
    029 * @since 3.0
    030 */
    031public final class NullIsExceptionPredicate<T> extends AbstractPredicate<T> implements PredicateDecorator<T>, Serializable {
    032
    033    /** Serial version UID */
    034    private static final long serialVersionUID = 3243449850504576071L;
    035
    036    /**
    037     * Creates the null exception predicate.
    038     *
    039     * @param <T> the type that the predicate queries
    040     * @param predicate  the predicate to decorate, not null
    041     * @return the predicate
    042     * @throws NullPointerException if the predicate is null
    043     */
    044    public static <T> Predicate<T> nullIsExceptionPredicate(final Predicate<? super T> predicate) {
    045        return new NullIsExceptionPredicate<>(Objects.requireNonNull(predicate, "predicate"));
    046    }
    047
    048    /** The predicate to decorate */
    049    private final Predicate<? super T> iPredicate;
    050
    051    /**
    052     * Constructor that performs no validation.
    053     * Use {@code nullIsExceptionPredicate} if you want that.
    054     *
    055     * @param predicate  the predicate to call after the null check
    056     */
    057    public NullIsExceptionPredicate(final Predicate<? super T> predicate) {
    058        iPredicate = predicate;
    059    }
    060
    061    /**
    062     * Gets the predicate being decorated.
    063     *
    064     * @return the predicate as the only element in an array
    065     * @since 3.1
    066     */
    067    @Override
    068    @SuppressWarnings("unchecked")
    069    public Predicate<? super T>[] getPredicates() {
    070        return new Predicate[] { iPredicate };
    071    }
    072
    073    /**
    074     * Evaluates the predicate returning the result of the decorated predicate
    075     * once a null check is performed.
    076     *
    077     * @param object  the input object
    078     * @return true if decorated predicate returns true
    079     * @throws FunctorException if input is null
    080     */
    081    @Override
    082    public boolean test(final T object) {
    083        if (object == null) {
    084            throw new FunctorException("Input Object must not be null");
    085        }
    086        return iPredicate.test(object);
    087    }
    088
    089}