package org.apache.turbine.pipeline;

 /*

  * 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.

  */

 import java.io.IOException;

 import java.util.Iterator;

 import java.util.concurrent.CopyOnWriteArrayList;

 import javax.xml.bind.annotation.XmlAccessType;

 import javax.xml.bind.annotation.XmlAccessorType;

 import javax.xml.bind.annotation.XmlAttribute;

 import javax.xml.bind.annotation.XmlElement;

 import javax.xml.bind.annotation.XmlElementWrapper;

 import javax.xml.bind.annotation.XmlRootElement;

 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

 import org.apache.turbine.annotation.AnnotationProcessor;

 import org.apache.turbine.util.TurbineException;

 /**

  * Flexible implementation of a {@link org.apache.turbine.pipeline.Pipeline}.

  * Originally based on code from Catalina and ideas from Apache httpd.

  *

  * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>

  * @author <a href="mailto:jvanzyl@zenplex.com">Jason van Zyl</a>

  * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>

  */

 @XmlRootElement(name="pipeline")

 @XmlAccessorType(XmlAccessType.NONE)

 public class TurbinePipeline

         implements Pipeline, ValveContext

 {

     /**

      * The "Turbine Classic" pipeline.

      */

     public static final String CLASSIC_PIPELINE =

             "/WEB-INF/conf/turbine-classic-pipeline.xml";

     /**

      * Name of this pipeline.

      */

     @XmlAttribute

     private String name;

     /**

      * The set of Valves associated with this Pipeline.

      */

     private CopyOnWriteArrayList<Valve> valves = new CopyOnWriteArrayList<Valve>();

     /**

      * The per-thread execution state for processing through this pipeline.

      */

     private ThreadLocal<Iterator<Valve>> state = new ThreadLocal<Iterator<Valve>>();

     /**

      * @see org.apache.turbine.pipeline.Pipeline#initialize()

      */

     @Override

     public void initialize()

             throws Exception

     {

         // Valve implementations are added to this Pipeline using the

         // Mapper.

         // Initialize the valves

         for (Valve v : valves)

         {

             AnnotationProcessor.process(v);

             v.initialize();

         }

     }

     /**

      * Set the name of this pipeline.

      *

      * @param name

      *            Name of this pipeline.

      */

     public void setName(String name)

     {

         this.name = name;

     }

     /**

      * Get the name of this pipeline.

      *

      * @return String Name of this pipeline.

      */

     public String getName()

     {

         return name;

     }

     /**

      * @see org.apache.turbine.pipeline.Pipeline#addValve(Valve)

      */

     @Override

     public void addValve(Valve valve)

     {

         // Add this Valve to the end of the set associated with this Pipeline

         valves.add(valve);

     }

     /**

      * @see org.apache.turbine.pipeline.Pipeline#getValves()

      */

     @Override

     @XmlElementWrapper(name="valves")

     @XmlElement(name="valve")

     @XmlJavaTypeAdapter(XmlValveAdapter.class)

     public Valve[] getValves()

     {

         return valves.toArray(new Valve[0]);

     }

     /**

      * Set new valves during deserialization

      *

      * @param valves the valves to set

      */

     protected void setValves(Valve[] valves)

     {

         this.valves = new CopyOnWriteArrayList<Valve>(valves);

     }

     /**

      * @see org.apache.turbine.pipeline.Pipeline#removeValve(Valve)

      */

     @Override

     public void removeValve(Valve valve)

     {

         valves.remove(valve);

     }

     /**

      * @see org.apache.turbine.pipeline.Pipeline#invoke(PipelineData)

      */

     @Override

     public void invoke(PipelineData pipelineData)

             throws TurbineException, IOException

     {

         // Initialize the per-thread state for this thread

         state.set(valves.iterator());

         // Invoke the first Valve in this pipeline for this request

         invokeNext(pipelineData);

     }

     /**

      * @see org.apache.turbine.pipeline.ValveContext#invokeNext(PipelineData)

      */

     @Override

     public void invokeNext(PipelineData pipelineData)

             throws TurbineException, IOException

     {

         // Identify the current valve for the current request thread

         Iterator<Valve> current = state.get();

         if (current.hasNext())

         {

             // Invoke the requested Valve for the current request

             // thread and increment its thread-local state.

             current.next().invoke(pipelineData, this);

         }

     }

 }