/*******************************************************************************
* Copyright (c) 2008, 2010 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Compeople AG (Stefan Liebig) - various ongoing maintenance
*******************************************************************************/
package org.eclipse.equinox.p2.repository.tools.comparator;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.RegistryFactory;
import org.eclipse.equinox.internal.p2.artifact.repository.Messages;
import org.eclipse.osgi.util.NLS;
/**
* @since 2.0
*/
public class ArtifactComparatorFactory {
private static final String comparatorPoint = "org.eclipse.equinox.p2.artifact.repository.artifactComparators"; //$NON-NLS-1$
private static final String ATTR_ID = "id"; //$NON-NLS-1$
private static final String ATTR_CLASS = "class"; //$NON-NLS-1$
public static IArtifactComparator getArtifactComparator(String comparatorID) {
IConfigurationElement[] extensions = RegistryFactory.getRegistry().getConfigurationElementsFor(comparatorPoint);
IConfigurationElement element = null;
if (comparatorID == null && extensions.length > 0) {
element = extensions[0]; //just take the first one
} else {
for (int i = 0; i < extensions.length; i++) {
if (extensions[i].getAttribute(ATTR_ID).equals(comparatorID)) {
element = extensions[i];
break;
}
}
}
if (element != null) {
try {
Object execExt = element.createExecutableExtension(ATTR_CLASS);
if (execExt instanceof IArtifactComparator)
return (IArtifactComparator) execExt;
} catch (Exception e) {
//fall through
}
}
if (comparatorID != null)
throw new IllegalArgumentException(NLS.bind(Messages.exception_comparatorNotFound, comparatorID));
throw new IllegalArgumentException(Messages.exception_noComparators);
}
}