/*

  * Copyright 1999-2001,2004 The Apache Software Foundation.

  * 

  * Licensed 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.workflow.core;

 import java.util.EmptyStackException;

 import org.apache.commons.workflow.Context;

 import org.apache.commons.workflow.Descriptor;

 import org.apache.commons.workflow.StepException;

 import org.apache.commons.workflow.base.DescriptorStep;

 /**

  * <p>For each associated <code>Descriptor</code>, pop the top value from

  * the evaluation stack, and store it as specified by that Descriptor,

  * in the order that descriptors are listed.</p>

  *

  * @version $Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $

  * @author Craig R. McClanahan

  */

 public class PutStep extends DescriptorStep {

     // ----------------------------------------------------------= Constructors

     /**

      * Construct a default instance of this Step.

      */

     public PutStep() {

         super();

     }

     /**

      * Construct an instance of this Step with the specified identifier.

      *

      * @param id Step identifier

      */

     public PutStep(String id) {

         super();

         setId(id);

     }

     /**

      * Construct an instance of this Step with the specified identifier

      * and associated Descriptor.

      *

      * @param id Step identifier

      * @param descriptor Initial descriptor

      */

     public PutStep(String id, Descriptor descriptor) {

         super();

         setId(id);

         addDescriptor(descriptor);

     }

     // --------------------------------------------------------- Public Methods

     /**

      * Perform the executable actions related to this Step, in the context of

      * the specified Context.

      *

      * @param context The Context that is tracking our execution state

      *

      * @exception StepException if a processing error has occurred

      */

     public void execute(Context context) throws StepException {

         // Process all associated descriptors

         Descriptor descriptors[] = findDescriptors();

         for (int i = 0; i < descriptors.length; i++) {

             Object value = null;

             try {

                 value = context.pop();

             } catch (EmptyStackException e) {

                 throw new StepException("Evaluation stack is empty", e, this);

             }

             descriptors[i].put(context, value);

         }

     }

 }