/*
* #!
* Ontopia Engine
* #-
* 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.utils;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import net.ontopia.topicmaps.core.TopicIF;
import net.ontopia.topicmaps.core.TopicNameIF;
import net.ontopia.utils.GrabberIF;
/**
* INTERNAL: Grabber that grabs the most appropriate basename from a topic.
*/
public class TopicNameGrabber implements GrabberIF<TopicIF, TopicNameIF> {
/**
* PROTECTED: The comparator used to sort the base names.
*/
protected Comparator<TopicNameIF> comparator;
/**
* INTERNAL: Creates a grabber; uses a BaseComparator with the given
* scope.
*
* @param scope A scope; a collection of TopicIF objects.
*/
public TopicNameGrabber(Collection<TopicIF> scope) {
this.comparator = new TopicNameComparator(scope);
}
/**
* INTERNAL: Creates a grabber which uses the given comparator.
*
* @param comparator The given comparator
*/
public TopicNameGrabber(Comparator<TopicNameIF> comparator) {
this.comparator = comparator;
}
/**
* INTERNAL: Grabs the most appropriate base name for the given topic,
* using the comparator established at creation to compare available
* base names.
*
* @param topic A topic; formally an Object, but must implement TopicIF.
*
* @exception throws OntopiaRuntimeException if the given topic is not
* a TopicIF object.
*/
public TopicNameIF grab(TopicIF topic) {
if (topic == null)
return null;
List<TopicNameIF> basenames = new ArrayList<TopicNameIF>(topic.getTopicNames());
// If there is no base name return null
if (basenames.isEmpty())
return null;
// If there are multiple basenames rank them.
Collections.sort(basenames, comparator);
return basenames.iterator().next();
}
}