/*

  * 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;

 import org.apache.commons.functor.core.composite.ConditionalUnaryProcedure;

 /**

  * Generator that filters another Generator by only passing through those elements

  * that are matched by a specified UnaryPredicate.

  *

  * @version $Revision: 1156795 $ $Date: 2011-08-11 22:08:30 +0200 (Thu, 11 Aug 2011) $

  */

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

     private final UnaryPredicate<? super E> pred;

     /**

      * Create a new FilteredGenerator.

      * @param wrapped Generator to wrap

      * @param pred filtering UnaryPredicate

      */

     public FilteredGenerator(Generator<? extends E> wrapped, UnaryPredicate<? super E> pred) {

         super(wrapped);

         if (wrapped == null) {

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

         }

         if (pred == null) {

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

         }

         this.pred = pred;

     }

     /**

      * {@inheritDoc}

      */

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

         getWrappedGenerator().run(new ConditionalUnaryProcedure<E>(pred, proc));

     }

     /**

      * {@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 FilteredGenerator<?>)) {

             return false;

         }

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

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

     }

     /**

      * {@inheritDoc}

      */

     public int hashCode() {

         int result = "FilteredGenerator".hashCode();

         result <<= 2;

         Generator<?> gen = getWrappedGenerator();

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

         result <<= 2;

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

         return result;

     }

 }