/*

  * 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.generator;

 import org.apache.commons.functor.UnaryPredicate;

 import org.apache.commons.functor.UnaryProcedure;

 /**

  * Wrap another {@link Generator} such that {@link #run(UnaryProcedure)} continues

  * as long as a condition is true (test before).

  *

  * @version $Revision: 1156802 $ $Date: 2011-08-11 22:13:34 +0200 (Thu, 11 Aug 2011) $

  */

 public class WhileGenerate<E> extends BaseGenerator<E> {

     private final UnaryPredicate<? super E> test;

     /**

      * Create a new WhileGenerate.

      * @param test {@link UnaryPredicate}

      * @param wrapped {@link Generator}

      */

     public WhileGenerate(UnaryPredicate<? super E> test, Generator<? extends E> wrapped) {

         super(wrapped);

         if (wrapped == null) {

             throw new IllegalArgumentException("Generator argument was null");

         }

         if (test == null) {

             throw new IllegalArgumentException("UnaryPredicate argument was null");

         }

         this.test = test;

     }

     /**

      * {@inheritDoc}

      */

     public void run(final UnaryProcedure<? super E> proc) {

         getWrappedGenerator().run(new UnaryProcedure<E>() {

             public void run(E obj) {

                 if (!test.test(obj)) {

                     getWrappedGenerator().stop();

                 } else {

                     proc.run(obj);

                 }

             }

         });

     }

     /**

      * {@inheritDoc}

      */

     @SuppressWarnings("unchecked")

     @Override

     protected Generator<? extends E> getWrappedGenerator() {

         return (Generator<? extends E>) super.getWrappedGenerator();

     }

     /**

      * {@inheritDoc}

      */

     public boolean equals(Object obj) {

         if (obj == this) {

             return true;

         }

         if (!(obj instanceof WhileGenerate<?>)) {

             return false;

         }

         WhileGenerate<?> other = (WhileGenerate<?>) obj;

         return other.getWrappedGenerator().equals(getWrappedGenerator()) && other.test.equals(test);

     }

     /**

      * {@inheritDoc}

      */

     public int hashCode() {

         int result = "WhileGenerate".hashCode();

         result <<= 2;

         Generator<?> gen = getWrappedGenerator();

         result ^= gen == null ? 0 : gen.hashCode();

         result <<= 2;

         result ^= test == null ? 0 : test.hashCode();

         return result;

     }

 }