Java tutorial
/*! ****************************************************************************** * * Pentaho Data Integration * * Copyright (C) 2002-2013 by Pentaho : http://www.pentaho.com * ******************************************************************************* * * Licensed under the Apache 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://www.apache.org/licenses/LICENSE-2.0 * * 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.pentaho.di.core.plugins; import java.io.IOException; import java.util.HashMap; import java.util.Map; import org.apache.commons.vfs.FileObject; import org.apache.commons.vfs.FileSystemException; import org.pentaho.di.core.exception.KettleFileException; import org.scannotation.AnnotationDB; public class JarFileCache { private static JarFileCache cache; private final Map<PluginFolderInterface, FileObject[]> folderMap; private final Map<FileObject, AnnotationDB> annotationMap; private JarFileCache() { annotationMap = new HashMap<FileObject, AnnotationDB>(); folderMap = new HashMap<PluginFolderInterface, FileObject[]>(); } public static JarFileCache getInstance() { if (cache == null) { cache = new JarFileCache(); } return cache; } public AnnotationDB getAnnotationDB(FileObject fileObject) throws FileSystemException, IOException { AnnotationDB result = annotationMap.get(fileObject); if (result == null) { result = new AnnotationDB(); result.scanArchives(fileObject.getURL()); annotationMap.put(fileObject, result); } return result; } public FileObject[] getFileObjects(PluginFolderInterface pluginFolderInterface) throws KettleFileException { FileObject[] result = folderMap.get(pluginFolderInterface); if (result == null) { result = pluginFolderInterface.findJarFiles(); folderMap.put(pluginFolderInterface, result); } return result; } public void clear() { annotationMap.clear(); folderMap.clear(); } }