/*

 * 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;

/**

 * Predicate implementation that transforms the given object before invoking

 * another <code>Predicate</code>.

 *

 * @since 3.1

 */

public final class TransformedPredicate<T> implements PredicateDecorator<T>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = -5596090919668315834L;

    /** The transformer to call */

    private final Transformer<? super T, ? extends T> iTransformer;

    /** The predicate to call */

    private final Predicate<? super T> iPredicate;

    /**

     * Factory to create the predicate.

     *

     * @param <T> the type that the predicate queries

     * @param transformer  the transformer to call

     * @param predicate  the predicate to call with the result of the transform

     * @return the predicate

     * @throws NullPointerException if the transformer or the predicate is null

     */

    public static <T> Predicate<T> transformedPredicate(final Transformer<? super T, ? extends T> transformer,

                                                        final Predicate<? super T> predicate) {

        if (transformer == null) {

            throw new NullPointerException("The transformer to call must not be null");

        }

        if (predicate == null) {

            throw new NullPointerException("The predicate to call must not be null");

        }

        return new TransformedPredicate<>(transformer, predicate);

    }

    /**

     * Constructor that performs no validation.

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

     *

     * @param transformer  the transformer to use

     * @param predicate  the predicate to decorate

     */

    public TransformedPredicate(final Transformer<? super T, ? extends T> transformer,

                                final Predicate<? super T> predicate) {

        iTransformer = transformer;

        iPredicate = predicate;

    }

    /**

     * Evaluates the predicate returning the result of the decorated predicate

     * once the input has been transformed

     *

     * @param object  the input object which will be transformed

     * @return true if decorated predicate returns true

     */

    @Override

    public boolean evaluate(final T object) {

        final T result = iTransformer.transform(object);

        return iPredicate.evaluate(result);

    }

    /**

     * Gets the predicate being decorated.

     *

     * @return the predicate as the only element in an array

     * @since 3.1

     */

    @Override

    @SuppressWarnings("unchecked")

    public Predicate<? super T>[] getPredicates() {

        return new Predicate[] {iPredicate};

    }

    /**

     * Gets the transformer in use.

     *

     * @return the transformer

     */

    public Transformer<? super T, ? extends T> getTransformer() {

        return iTransformer;

    }

}