/**
* OLAT - Online Learning and Training<br>
* http://www.olat.org
* <p>
* Licensed under the Apache License, Version 2.0 (the "License"); <br>
* you may not use this file except in compliance with the License.<br>
* You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing,<br>
* software distributed under the License is distributed on an "AS IS" BASIS, <br>
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
* See the License for the specific language governing permissions and <br>
* limitations under the License.
* <p>
* Copyright (c) since 2004 at Multimedia- & E-Learning Services (MELS),<br>
* University of Zurich, Switzerland.
* <p>
*/
package org.olat.resource.references;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import org.hibernate.Hibernate;
import org.olat.core.commons.persistence.DBFactory;
import org.olat.core.gui.translator.PackageTranslator;
import org.olat.core.gui.translator.Translator;
import org.olat.core.id.OLATResourceable;
import org.olat.core.util.Util;
import org.olat.course.CourseFactory;
import org.olat.course.CourseModule;
import org.olat.course.ICourse;
import org.olat.resource.OLATResource;
import org.olat.resource.OLATResourceImpl;
import org.olat.resource.OLATResourceManager;
/**
* Initial Date: May 27, 2004
*
* @author Mike Stock
*
* Comment:
*
*/
public class ReferenceManager {
private static final String PACKAGE = Util.getPackageName(ReferenceManager.class);
private static final ReferenceManager INSTANCE = new ReferenceManager();
private OLATResourceManager resManager;
private ReferenceManager() {
resManager = OLATResourceManager.getInstance();
}
/**
* @return Singleton.
*/
public static ReferenceManager getInstance() { return INSTANCE; }
/**
* Add a new reference. The meaning of source and target is
* such as the source references the target.
*
* @param source
* @param target
* @param userdata
*/
public void addReference(OLATResourceable source, OLATResourceable target, String userdata) {
//FIXME:ms:b consider the case where source does not exists yet in the OLATResource db table
OLATResourceImpl sourceImpl = (OLATResourceImpl)resManager.findResourceable(source);
OLATResourceImpl targetImpl = (OLATResourceImpl)resManager.findResourceable(target);
ReferenceImpl ref = new ReferenceImpl(sourceImpl, targetImpl, userdata);
DBFactory.getInstance().saveObject(ref);
}
/**
* List all references the source holds.
*
* @param source
* @return List of renerences.
*/
public List getReferences(OLATResourceable source) {
OLATResourceImpl sourceImpl = (OLATResourceImpl)resManager.findResourceable(source);
if (sourceImpl == null) return new ArrayList(0);
return DBFactory.getInstance().find(
"select v from org.olat.resource.references.ReferenceImpl as v where v.source = ?",
sourceImpl.getKey(), Hibernate.LONG);
}
/**
* List all sources which hold references to the target.
*
* @param target
* @return List of references.
*/
public List getReferencesTo(OLATResourceable target) {
OLATResourceImpl targetImpl = (OLATResourceImpl)resManager.findResourceable(target);
if (targetImpl == null) return new ArrayList(0);
return DBFactory.getInstance().find(
"select v from org.olat.resource.references.ReferenceImpl as v where v.target = ?",
targetImpl.getKey(), Hibernate.LONG);
}
/**
* Check wether any references to the target exist.
* @param target
* @return True if references exist.
*/
public boolean hasReferencesTo(OLATResourceable target) {
return (getReferencesTo(target).size() > 0);
}
/**
* Get an HTML summary of existing references or null if no references exist.
* @param target
* @param locale
* @return HTML fragment or null if no references exist.
*/
public String getReferencesToSummary(OLATResourceable target, Locale locale) {
Translator translator = new PackageTranslator(PACKAGE, locale);
StringBuilder result = new StringBuilder(100);
List refs = getReferencesTo(target);
if (refs.size() == 0) return null;
for (Iterator iter = refs.iterator(); iter.hasNext();) {
ReferenceImpl ref = (ReferenceImpl) iter.next();
OLATResourceImpl source = ref.getSource();
// special treatment for referenced courses: find out the course title
if (source.getResourceableTypeName().equals(CourseModule.getCourseTypeName())) {
ICourse course = CourseFactory.loadCourse(source);
result.append(translator.translate("ref.course", new String[] { course.getCourseTitle() }));
} else {
result.append(translator.translate("ref.generic", new String[] { source.getKey().toString() }));
}
result.append("<br />");
}
return result.toString();
}
/**
* @param ref
*/
public void delete(ReferenceImpl ref) {
DBFactory.getInstance().deleteObject(ref);
}
/**
* Only for cleanup : Delete all references of an OLAT-resource.
* @param olatResource an OLAT-Resource
*/
public void deleteAllReferencesOf(OLATResource olatResource) {
List references = ReferenceManager.getInstance().getReferences(olatResource);
for (Iterator iterator = references.iterator(); iterator.hasNext();) {
ReferenceImpl ref = (ReferenceImpl) iterator.next();
ReferenceManager.getInstance().delete( ref);
}
}
}