org.opencastproject.mediapackage.MediaPackageElementBuilderFactory Maven / Gradle / Ivy
/*
* Licensed to The Apereo Foundation under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
*
*
* The Apereo Foundation licenses this file to you 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://opensource.org/licenses/ecl2.txt
*
* 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.opencastproject.mediapackage;
import org.opencastproject.util.ConfigurationException;
/**
* Factory to retreive instances of a media package element builder. Use the static method {@link #newInstance()} to
* obtain a reference to a concrete implementation of a MediaPackageElementBuilderFactory. This instance
* can then be used to create or load media package elements.
*
* The factory can be configured by specifying the concrete implementation class through the system property
* org.opencastproject.mediapackage.elementbuilder.
*
*/
public final class MediaPackageElementBuilderFactory {
/** The implementation class name */
private static String builderClassName = "org.opencastproject.mediapackage.MediaPackageElementBuilderImpl";
/** The singleton instance of this factory */
private static final MediaPackageElementBuilderFactory factory = new MediaPackageElementBuilderFactory();
/** The default builder implementation */
private MediaPackageElementBuilder builder = null;
/**
* Returns an instance of a MediaPackageElementBuilderFactory.
*
* @return the media package element builder factory
* @throws ConfigurationException
* if the factory cannot be instantiated
*/
public static MediaPackageElementBuilderFactory newInstance() throws ConfigurationException {
return factory;
}
/**
* Factory method that returns an instance of a media package element builder.
*
* It uses the following ordered lookup procedure to determine which implementation of the
* {@link MediaPackageElementBuilder} interface to use:
*
* - Implementation specified using the
org.opencastproject.mediapackage.elementbuilder system property
*
* - Platform default implementation
*
*
* @return the media package element builder
* @throws ConfigurationException
* If the builder cannot be instantiated
*/
public MediaPackageElementBuilder newElementBuilder() throws ConfigurationException {
if (builder == null) {
try {
Class builderClass = Class.forName(builderClassName, true,
MediaPackageElementBuilderFactory.class.getClassLoader());
builder = (MediaPackageElementBuilder) builderClass.newInstance();
} catch (ClassNotFoundException e) {
throw new ConfigurationException("Class not found while creating element builder: " + e.getMessage(), e);
} catch (InstantiationException e) {
throw new ConfigurationException("Instantiation exception while creating element builder: " + e.getMessage(), e);
} catch (IllegalAccessException e) {
throw new ConfigurationException("Access exception while creating element builder: " + e.getMessage(), e);
} catch (Exception e) {
throw new ConfigurationException("Exception while creating element builder: " + e.getMessage(), e);
}
}
return builder;
}
}