/*

  * Copyright 2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl1.php

  *

  * 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.kuali.rice.core.util.jaxb;

 import java.io.Serializable;

 import java.util.AbstractList;

 import java.util.List;

 /**

  * Custom subclass of AbstractList that, whenever the "get" method is called, will pass an

  * internally-stored list's object to the given listener for conversion into another object matching

  * the list's type. This allows for the marshalling process to discard generated items after they

  * have been marshalled.

  * 

  * <p>These lists are constructed by passing in another list containing the unconverted items,

  * as well as a listener that will create items of this list's type upon each invocation of

  * the "get" method.

  * 

  * <p>This is similar to the "streaming" unmarshalling strategy used in the RiceXmlImportList

  * class, except that this list has been adapted for marshalling instead.

  * 

  * @param E The type that the list is expected to return.

  * @param T The type that the list stores internally and passes to the listener for conversion as needed. 

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public final class RiceXmlExportList<E,T> extends AbstractList<E> implements Serializable {

     private static final long serialVersionUID = 1L;

     private final List<? extends T> sourceList;

     private final RiceXmlListGetterListener<E,T> listGetterListener;

     /**

      * Constructs a new export list that will rely on the given listener for converting the provided

      * list's items into the appropriate type.

      * 

      * @param sourceList The list of objects to convert.

      * @param listGetterListener The listener to use.

      * @throws IllegalArgumentException if sourceList or listGetterListener are null.

      */

     public RiceXmlExportList(List<? extends T> sourceList, RiceXmlListGetterListener<E,T> listGetterListener) {

         super();

         if (sourceList == null) {

             throw new IllegalArgumentException("sourceList cannot be null");

         } else if (listGetterListener == null) {

             throw new IllegalArgumentException("listGetterListener cannot be null");

         }

         this.sourceList = sourceList;

         this.listGetterListener = listGetterListener;

     }

     /**

      * Passes the item at the given index of the internal list to the listener, and then returns

      * the listener's result.

      * 

      * @param index The unconverted item's index in the internal list.

      * @return The item converted by the listener at the given list index.

      */

     @Override

     public E get(int index) {

         return listGetterListener.gettingNextItem(sourceList.get(index), index);

     }

     /**

      * Returns the size of the internal list.

      * 

      * @return The size of the internal list.

      */

     @Override

     public int size() {

         return sourceList.size();

     }

 }