/*
* #!
* Ontopia Navigator
* #-
* Copyright (C) 2001 - 2013 The Ontopia Project
* #-
* 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 net.ontopia.topicmaps.nav2.taglibs.TMvalue;
import java.util.Iterator;
import java.util.Collection;
import java.util.Collections;
import java.util.ArrayList;
import javax.servlet.jsp.JspTagException;
import net.ontopia.topicmaps.core.ReifiableIF;
import net.ontopia.topicmaps.core.TopicIF;
import net.ontopia.topicmaps.nav2.core.NavigatorRuntimeException;
import net.ontopia.topicmaps.nav2.taglibs.value.BaseValueProducingAndAcceptingTag;
/**
* INTERNAL: Finds the topic map objects which are reified by topics in
* the input collection.
*/
public class ReifiedTag extends BaseValueProducingAndAcceptingTag {
public Collection process(Collection topics) throws JspTagException {
// Find all topics which are reified by topic map objects in collection
if (topics == null)
return Collections.EMPTY_SET;
else {
ArrayList reifiedObjects = new ArrayList();
Iterator iter = topics.iterator();
ReifiableIF reifiedObject;
// Loop over the topic map objects
while (iter.hasNext()) {
// Get the topic map object that is reified by the given topic
try {
TopicIF topic = (TopicIF) iter.next();
reifiedObject = topic.getReified();
// If an object was found add it to the result list.
if (reifiedObject != null)
reifiedObjects.add(reifiedObject);
} catch (ClassCastException e) {
throw new NavigatorRuntimeException("'reified' tag got a collection containing non-topic objects.");
}
} // while
// Return all reified objects found.
return reifiedObjects;
}
}
}