Java tutorial
/** * Copyright (C) cedarsoft GmbH. * * Licensed under the GNU General Public License version 3 (the "License") * with Classpath Exception; you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.cedarsoft.org/gpl3ce * (GPL 3 with Classpath Exception) * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 3 only, as * published by the Free Software Foundation. cedarsoft GmbH designates this * particular file as subject to the "Classpath" exception as provided * by cedarsoft GmbH in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 3 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 3 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact cedarsoft GmbH, 72810 Gomaringen, Germany, * or visit www.cedarsoft.com if you need additional information or * have any questions. */ package com.cedarsoft.serialization.serializers.jackson.registry; import com.cedarsoft.exceptions.StillContainedException; import org.apache.commons.io.filefilter.DirectoryFileFilter; import javax.annotation.Nonnull; import java.io.File; import java.io.FileFilter; import java.io.FileNotFoundException; import java.io.IOException; import java.util.HashSet; import java.util.Set; /** * Implementation that is based on simple files. */ public class DirBasedObjectsAccess implements AbstractRegistrySerializingStrategy.ObjectsAccess { @Nonnull private final File baseDir; public DirBasedObjectsAccess(@Nonnull File baseDir) { assert baseDir.exists(); assert baseDir.isDirectory(); this.baseDir = baseDir; } /** * Provides the ids * * @return the ids * * @throws FileNotFoundException */ @Nonnull @Override public Set<? extends String> getIds() throws IOException { assert baseDir.exists(); File[] dirs = baseDir.listFiles((FileFilter) DirectoryFileFilter.DIRECTORY); if (dirs == null) { throw new FileNotFoundException("Could not list dirs in " + baseDir.getAbsolutePath()); } Set<String> ids = new HashSet<String>(); for (File dir : dirs) { ids.add(dir.getName()); } return ids; } @Nonnull public File addDirectory(@Nonnull String id) throws StillContainedException { File dir = getDirInternal(id); if (dir.exists()) { throw new StillContainedException(id); } dir.mkdir(); return dir; } @Nonnull public File getDirectory(@Nonnull String id) throws FileNotFoundException { File directory = getDirInternal(id); if (!directory.exists()) { throw new FileNotFoundException("No dir found for <" + id + "> at " + directory.getAbsolutePath()); } return directory; } @Nonnull private File getDirInternal(@Nonnull String id) { return new File(baseDir, id); } @Nonnull public File getBaseDir() { return baseDir; } }