/*

 * 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.Closure;

import org.apache.commons.collections4.Transformer;

/**

 * Transformer implementation that calls a Closure using the input object

 * and then returns the input.

 *

 * @since 3.0

 */

public class ClosureTransformer<T> implements Transformer<T, T>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = 478466901448617286L;

    /** The closure to wrap */

    private final Closure<? super T> iClosure;

    /**

     * Factory method that performs validation.

     *

     * @param <T>  the type of the object to transform

     * @param closure  the closure to call, not null

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

     * @throws NullPointerException if the closure is null

     */

    public static <T> Transformer<T, T> closureTransformer(final Closure<? super T> closure) {

        if (closure == null) {

            throw new NullPointerException("Closure must not be null");

        }

        return new ClosureTransformer<>(closure);

    }

    /**

     * Constructor that performs no validation.

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

     *

     * @param closure  the closure to call, not null

     */

    public ClosureTransformer(final Closure<? super T> closure) {

        super();

        iClosure = closure;

    }

    /**

     * Transforms the input to result by executing a closure.

     *

     * @param input  the input object to transform

     * @return the transformed result

     */

    @Override

    public T transform(final T input) {

        iClosure.execute(input);

        return input;

    }

    /**

     * Gets the closure.

     *

     * @return the closure

     * @since 3.1

     */

    public Closure<? super T> getClosure() {

        return iClosure;

    }

}