/*
* Copyright 2004 Sun Microsystems, Inc.
*
* 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 com.sun.syndication.feed.synd;
import com.sun.syndication.feed.module.DCSubjectI;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.List;
/**
* List implementation for SyndCategory elements. To be directly used by the SyndFeed
* and SyndEntry classes only.
* <p>
* It acts as a facade on top of the DCSubject elements of the underlying list
* and remains in synch with it. It is possible to work on either list, the categories
* one or the subjects one and they remain in synch.
* <p>
* This is necessary because the SyndFeed categories are just a convenience to access
* the DublinCore subjects.
* <P>
* All this mess to avoid making DCSubject implement SyndCategoryI (which it would be odd).
* <p>
* @author Alejandro Abdelnur
*
*/
public class SyndCategoryListFacade extends AbstractList {
private List _subjects;
/**
* Default constructor. Creates and empty list.
*/
public SyndCategoryListFacade() {
this(new ArrayList());
}
/**
* Creates a facade list of categories on top the given subject list.
* <P>
* @param subjects the list of subjects to create the facade.
*
*/
public SyndCategoryListFacade(List subjects) {
_subjects = subjects;
}
/**
* Gets the category by index.
* <p>
* @param index the index position to retrieve the category.
* @return the SyndCategory in position index, <b>null</b> if none.
*
*/
public Object get(int index) {
return new SyndCategory((DCSubjectI) _subjects.get(index));
}
/**
* Returns the size of the list.
* <p>
* @return the size of the list.
*
*/
public int size() {
return _subjects.size();
}
/**
* Sets a category in an existing position in the list.
* <p>
* @param index position to set the category.
* @param obj the SyndCategory object to set.
* @return the SyndCategory object that is being replaced, <b>null</b> if none.
*
*/
public Object set(int index,Object obj) {
SyndCategory sCat = (SyndCategory) obj;
DCSubjectI subject = (sCat!=null) ? sCat.getSubject() : null;
subject = (DCSubjectI) _subjects.set(index,subject);
return (subject!=null) ? new SyndCategory(subject) : null;
}
/**
* Adds a category to the list.
* <p>
* @param index position to add the category.
* @param obj the SyndCategory object to add.
*
*/
public void add(int index,Object obj) {
SyndCategory sCat = (SyndCategory) obj;
DCSubjectI subject = (sCat!=null) ? sCat.getSubject() : null;
_subjects.add(index,subject);
}
/**
* Removes a category element from a specific position.
* <p>
* @param index position to remove the category from.
* @return the SyndCategory being removed from position index, <b>null</b> if none.
*
*/
public Object remove(int index) {
DCSubjectI subject = (DCSubjectI) _subjects.remove(index);
return (subject!=null) ? new SyndCategory(subject) : null;
}
/**
* Returns a list with the DCSubjectI elements of the SyndCategory list facade.
* To be used by the SyndFeed class only.
* <p>
* @param cList the list with SyndCategory elements to convert to subject list.
* @return a list with DCSubjectI elements corresponding to the categories in the given list.
*
*/
public static List convertElementsSyndCategoryToSubject(List cList) {
List sList = null;
if (cList!=null) {
sList = new ArrayList();
for (int i=0;i<cList.size();i++) {
SyndCategory sCat = (SyndCategory) cList.get(i);
DCSubjectI subject = null;
if (sCat!=null) {
subject = sCat.getSubject();
}
sList.add(subject);
}
}
return sList;
}
}