/*

  * 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.functor.core.composite;

 import java.io.Serializable;

 import org.apache.commons.functor.Function;

 import org.apache.commons.functor.Procedure;

 import org.apache.commons.functor.UnaryProcedure;

 /**

  * A Procedure composed of a Function whose result is then run through a UnaryProcedure.

  * @version $Revision: 1171154 $ $Date: 2011-09-15 17:58:38 +0200 (Thu, 15 Sep 2011) $

  * @author Matt Benson

  */

 public class TransformedProcedure implements Procedure, Serializable {

     /**

      * serialVersionUID declaration.

      */

     private static final long serialVersionUID = -4111958123789033410L;

     /** Base hash integer used to shift hash */

     private static final int HASH_SHIFT = 2;

     /**

      * Type-remembering helper

      * @param <X>

      */

     private static final class Helper<X> implements Procedure, Serializable {

         /**

          * serialVersionUID declaration.

          */

         private static final long serialVersionUID = -4093503167446891318L;

         private Function<? extends X> function;

         private UnaryProcedure<? super X> procedure;

         /**

          * Create a new Helper.

          * @param function Function

          * @param procedure UnaryFunction

          */

         private Helper(Function<? extends X> function, UnaryProcedure<? super X> procedure) {

             this.function = function;

             this.procedure = procedure;

         }

         /**

          * {@inheritDoc}

          */

         public void run() {

             procedure.run(function.evaluate());

         }

     }

     private final Helper<?> helper;

     /**

      * Create a new TransformedProcedure.

      * @param <X>

      * @param function Function

      * @param procedure UnaryProcedure

      */

     public <X> TransformedProcedure(Function<? extends X> function, UnaryProcedure<? super X> procedure) {

         this.helper = new Helper<X>(function, procedure);

     }

     /**

      * {@inheritDoc}

      */

     public final void run() {

         helper.run();

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public final boolean equals(Object obj) {

         return obj == this || obj instanceof TransformedProcedure

                 && equals((TransformedProcedure) obj);

     }

     /**

      * Learn whether another TransformedProcedure is equal to <code>this</code>.

      * @param that instance to test

      * @return whether equal

      */

     public final boolean equals(TransformedProcedure that) {

         return that != null && that.helper.function.equals(this.helper.function)

                 && that.helper.procedure.equals(this.helper.procedure);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public int hashCode() {

         int result = "TransformedProcedure".hashCode();

         result <<= HASH_SHIFT;

         result |= helper.procedure.hashCode();

         result <<= HASH_SHIFT;

         result |= helper.function.hashCode();

         return result;

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public String toString() {

         return "TransformedProcedure<" + helper.function + "; " + helper.procedure + ">";

     }

 }