/*

  * 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.algorithm;

 import java.io.Serializable;

 import org.apache.commons.functor.BinaryPredicate;

 import org.apache.commons.functor.UnaryPredicate;

 import org.apache.commons.functor.UnaryProcedure;

 import org.apache.commons.functor.generator.Generator;

 /**

  * Tests whether a {@link Generator} contains an element that matches a {@link UnaryPredicate}.

  *

  * @version $Revision: 1156320 $ $Date: 2011-08-10 21:14:50 +0200 (Wed, 10 Aug 2011) $

  */

 public final class GeneratorContains<T> implements BinaryPredicate<Generator<? extends T>, UnaryPredicate<? super T>>,

         Serializable {

     /**

      * serialVersionUID declaration.

      */

     private static final long serialVersionUID = -1539983619621733276L;

     private static final GeneratorContains<Object> INSTANCE = new GeneratorContains<Object>();

     /**

      * Helper procedure.

      */

     private static class ContainsProcedure<T> implements UnaryProcedure<T> {

         private final UnaryPredicate<? super T> pred;

         private boolean found;

         /**

          * Create a new ContainsProcedure.

          * @pred test

          */

         public ContainsProcedure(UnaryPredicate<? super T> pred) {

             this.pred = pred;

         }

         /**

          * {@inheritDoc}

          */

         public void run(T obj) {

             found |= pred.test(obj);

         }

     }

     /**

      * {@inheritDoc}

      * @param left Generator

      * @param right UnaryPredicate

      */

     public boolean test(Generator<? extends T> left, UnaryPredicate<? super T> right) {

         ContainsProcedure<T> findProcedure = new ContainsProcedure<T>(right);

         left.run(findProcedure);

         return findProcedure.found;

     }

     /**

      * {@inheritDoc}

      */

     public boolean equals(Object obj) {

         return obj == this || obj != null && obj.getClass().equals(getClass());

     }

     /**

      * {@inheritDoc}

      */

     public int hashCode() {

         return System.identityHashCode(INSTANCE);

     }

     /**

      * Get a static {@link GeneratorContains} instance.

      * @return {@link GeneratorContains}

      */

     public static GeneratorContains<Object> instance() {

         return INSTANCE;

     }

 }