/*

 * 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.FunctorException;

import org.apache.commons.collections4.Predicate;

import org.apache.commons.collections4.Transformer;

/**

 * Predicate implementation that returns the result of a transformer.

 *

 * @since 3.0

 */

public final class TransformerPredicate<T> implements Predicate<T>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = -2407966402920578741L;

    /** The transformer to call */

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

    /**

     * Factory to create the predicate.

     *

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

     * @param transformer  the transformer to decorate

     * @return the predicate

     * @throws NullPointerException if the transformer is null

     */

    public static <T> Predicate<T> transformerPredicate(final Transformer<? super T, Boolean> transformer) {

        if (transformer == null) {

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

        }

        return new TransformerPredicate<>(transformer);

    }

    /**

     * Constructor that performs no validation.

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

     *

     * @param transformer  the transformer to decorate

     */

    public TransformerPredicate(final Transformer<? super T, Boolean> transformer) {

        super();

        iTransformer = transformer;

    }

    /**

     * Evaluates the predicate returning the result of the decorated transformer.

     *

     * @param object  the input object

     * @return true if decorated transformer returns Boolean.TRUE

     * @throws FunctorException if the transformer returns an invalid type

     */

    @Override

    public boolean evaluate(final T object) {

        final Boolean result = iTransformer.transform(object);

        if (result == null) {

            throw new FunctorException(

                    "Transformer must return an instanceof Boolean, it was a null object");

        }

        return result.booleanValue();

    }

    /**

     * Gets the transformer.

     *

     * @return the transformer

     * @since 3.1

     */

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

        return iTransformer;

    }

}