/*

  * 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.pipeline.stage;

 import java.util.Collection;

 import java.util.Collections;

 import org.apache.commons.pipeline.validation.ConsumedTypes;

 import org.apache.commons.pipeline.validation.ProducesConsumed;

 /**

  * This is a simple stage in the pipeline which will add each processed object 

  * to the specified collection. 

  *

  * For the purposes of validation, this stage is considered to be able to consume

  * objects of any class although the process() method may throw a ClassCastException

  * if a processed object cannot be added to the collection.

  */

 @ConsumedTypes(Object.class)

 @ProducesConsumed

 public class AddToCollectionStage<T> extends BaseStage {

     /**

      * Holds value of property collection.

      */

     private Collection<T> collection;

     /** 

      * Creates a new instance of AddToCollectionStage.  This constructor

      * will synchronized the collection by default.

      */

     public AddToCollectionStage(Collection<T> collection) {

         this(collection, true);

     }

     /** 

      * Creates a new instance of AddToCollectionStage.

      * @param collection The collection in which to add objects to

      * @param synchronized A flag value that determines whether or not accesses

      * to the underlying collection are synchronized.

      */

     public AddToCollectionStage(Collection<T> collection, boolean synchronize) {

         if (collection == null){

             throw new IllegalArgumentException("Argument 'collection' can not be null.");

         }

         this.collection = synchronize ? Collections.synchronizedCollection(collection) : collection;

     }

     /** 

      * Adds the object to the underlying collection.

      *

      * @throws ClassCastException if the object is not of a suitable type to be added

      * to the collection.

      */

     public void process(Object obj) throws org.apache.commons.pipeline.StageException {

         this.collection.add((T) obj);

         this.emit(obj);

     }

     /**

      * Returns the collection to which elements have been added during

      * processing.

      */

     public Collection<T> getCollection() {

         return this.collection;

     }    

 }