/*

 * 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;

import org.apache.commons.collections4.Transformer;

/**

 * Transformer implementation that calls a Predicate using the input object

 * and then returns the result.

 *

 * @since 3.0

 */

public class PredicateTransformer<T> implements Transformer<T, Boolean>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = 5278818408044349346L;

    /** The closure to wrap */

    private final Predicate<? super T> iPredicate;

    /**

     * Factory method that performs validation.

     *

     * @param <T>  the input type

     * @param predicate  the predicate to call, not null

     * @return the <code>predicate</code> transformer

     * @throws IllegalArgumentException if the predicate is null

     */

    public static <T> Transformer<T, Boolean> predicateTransformer(final Predicate<? super T> predicate) {

        if (predicate == null) {

            throw new IllegalArgumentException("Predicate must not be null");

        }

        return new PredicateTransformer<>(predicate);

    }

    /**

     * Constructor that performs no validation.

     * Use <code>predicateTransformer</code> if you want that.

     *

     * @param predicate  the predicate to call, not null

     */

    public PredicateTransformer(final Predicate<? super T> predicate) {

        super();

        iPredicate = predicate;

    }

    /**

     * Transforms the input to result by calling a predicate.

     *

     * @param input  the input object to transform

     * @return the transformed result

     */

    @Override

    public Boolean transform(final T input) {

        return Boolean.valueOf(iPredicate.evaluate(input));

    }

    /**

     * Gets the predicate.

     *

     * @return the predicate

     * @since 3.1

     */

    public Predicate<? super T> getPredicate() {

        return iPredicate;

    }

}