org.opencastproject.mediapackage.MediaPackageBuilderFactory 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 retrieve instances of a media package builder. Use the static method {@link #newInstance()} to obtain a
* reference to a concrete implementation of a MediaPackageBuilderFactory. This instance can then be used
* to create or load media packages.
*
* The factory can be configured by specifying the concrete implementation class through the system property
* org.opencastproject.mediapackage.builder.
*
*/
public final class MediaPackageBuilderFactory {
/** Class name for the default media package builder */
private static final String BUILDER_CLASS = "org.opencastproject.mediapackage.MediaPackageBuilderImpl";
/** Name of the system property */
public static final String PROPERTY_NAME = "org.opencastproject.mediapackage.builder";
/** The implementation class name */
private static String builderClassName = BUILDER_CLASS;
/** The singleton instance of this factory */
private static final MediaPackageBuilderFactory factory = new MediaPackageBuilderFactory();
/**
* Private method to create a new media package builder factory.
*/
private MediaPackageBuilderFactory() {
String className = System.getProperty(PROPERTY_NAME);
if (className != null) {
builderClassName = className;
}
}
/**
* Returns an instance of a MediaPackageBuilderFactory.
*
* @return the media package builder factory
* @throws ConfigurationException
* if the factory cannot be instantiated
*/
public static MediaPackageBuilderFactory newInstance() throws ConfigurationException {
return factory;
}
/**
* Factory method that returns an instance of a media package builder.
*
* It uses the following ordered lookup procedure to determine which implementation of the {@link MediaPackageBuilder}
* interface to use:
*
* - Implementation specified using the
org.opencastproject.mediapackage.builder system property
* - Platform default implementation
*
*
* @return the media package builder
* @throws ConfigurationException
* If the builder cannot be instantiated
*/
public MediaPackageBuilder newMediaPackageBuilder() throws ConfigurationException {
MediaPackageBuilder builder = null;
try {
Class builderClass = Class.forName(builderClassName);
builder = (MediaPackageBuilder) builderClass.newInstance();
} catch (ClassNotFoundException e) {
throw new ConfigurationException("Class not found while creating media package builder: " + e.getMessage(), e);
} catch (InstantiationException e) {
throw new ConfigurationException("Instantiation exception while creating media package builder: "
+ e.getMessage(), e);
} catch (IllegalAccessException e) {
throw new ConfigurationException("Access exception while creating media package builder: " + e.getMessage(), e);
}
return builder;
}
}