fr.aliasource.utils.RunnableExtensionLoader.java Source code

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Here is the source code for fr.aliasource.utils.RunnableExtensionLoader.java

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/* ***** BEGIN LICENSE BLOCK *****
 * Version: GPL 2.0
 *
 * The contents of this file are subject to the GNU General Public
 * License Version 2 or later (the "GPL").
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Initial Developer of the Original Code is
 *   MiniG.org project members
 *
 * ***** END LICENSE BLOCK ***** */

package fr.aliasource.utils;

import java.util.LinkedList;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.Platform;

/**
 * Loads plugins based on some interface
 * 
 * @author tom
 * 
 * @param <T>
 */
public class RunnableExtensionLoader<T> {

    private Log logger;

    public RunnableExtensionLoader() {
        logger = LogFactory.getLog(getClass());
    }

    /**
     * Loads plugins declaring an executable extension
     * 
     * @param pluginId
     * @param pointName
     * @param element
     * @param attribute
     * @return
     */
    @SuppressWarnings("unchecked")
    public List<T> loadExtensions(String pluginId, String pointName, String element, String attribute) {

        List<T> factories = new LinkedList<T>();
        IExtensionPoint point = Platform.getExtensionRegistry().getExtensionPoint(pluginId, pointName);
        if (point == null) {
            logger.error(
                    "point " + pluginId + "." + pointName + " [" + element + " " + attribute + "=XXX] not found.");
            return factories;
        }
        IExtension[] extensions = point.getExtensions();

        for (IExtension ie : extensions) {
            for (IConfigurationElement e : ie.getConfigurationElements()) {
                if (element.equals(e.getName())) {
                    try {
                        T factory = (T) e.createExecutableExtension(attribute);
                        factories.add(factory);
                        logger.info(factory.getClass().getSimpleName() + " loaded.");
                    } catch (CoreException ce) {
                        ce.printStackTrace();
                    }

                }
            }
        }
        logger.info("Loaded " + factories.size() + " implementors of " + pluginId + "." + pointName);
        return factories;
    }

}