Java tutorial
package org.apache.torque.generator.configuration; /* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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. */ import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; import java.util.Collection; import java.util.Enumeration; import java.util.List; import java.util.jar.JarEntry; import java.util.jar.JarFile; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.torque.generator.configuration.paths.ProjectPaths; import org.apache.torque.generator.configuration.paths.TorqueGeneratorPaths; /** * Provides InputStreams to read a configuration of a unit of generation from a * jar file. */ public class JarConfigurationProvider extends AbstractConfigurationProvider { /** The logger. */ private static Log log = LogFactory.getLog(JarConfigurationProvider.class); /** * The paths needed to interact with the enclosing project, not null. */ private ProjectPaths projectPaths; /** * The internal directory structure of the generator configuration files, * not null. */ private TorqueGeneratorPaths configurationPaths; /** * The jar file from which the configuration should be read, not null. */ private JarFile jarFile; /** * Constructor. * @param projectPaths the paths needed to interact with the enclosing * project, not null. * @param configurationPaths The internal directory structure of the * generator configuration files, not null. * * @throws NullPointerException if projectPaths or configurationPaths * are null. * @throws ConfigurationException if the jar file can not be accessed. */ public JarConfigurationProvider(ProjectPaths projectPaths, TorqueGeneratorPaths configurationPaths) throws ConfigurationException { super(configurationPaths); if (projectPaths == null) { throw new NullPointerException("projectPaths is null"); } this.projectPaths = projectPaths; this.configurationPaths = configurationPaths; try { jarFile = new JarFile(projectPaths.getConfigurationPath()); } catch (IOException e) { log.error("Could not open jar File " + projectPaths.getConfigurationPath().getAbsolutePath()); throw new ConfigurationException(e); } } public String getControlConfigurationLocation() throws ConfigurationException { return projectPaths.getConfigurationPath() + ":" + configurationPaths.getConfigurationDirectory() + "/" + configurationPaths.getControlConfigurationFile(); } protected InputStream getInputStream(String name, String directory, String description) throws ConfigurationException { String fileName = directory + "/" + name; InputStream inputStream = null; try { JarEntry jarEntry = jarFile.getJarEntry(fileName); inputStream = jarFile.getInputStream(jarEntry); } catch (IOException e) { throw new ConfigurationException("Could not read " + description + " file " + fileName + " in jar file " + projectPaths.getConfigurationPath(), e); } BufferedInputStream bis = new BufferedInputStream(inputStream); if (log.isDebugEnabled()) { log.debug("Reading " + description + " file: '" + projectPaths.getConfigurationPath() + "' in jar file " + projectPaths.getConfigurationPath()); } return bis; } public Collection<String> getOutletConfigurationNames() throws ConfigurationException { return getOutletConfigurationNames(jarFile, configurationPaths.getOutletDirectory()); } /** * Extracts the outlet configuration files from a jar file. * @param jarFile the jar file to process, not null. * @param outletConfigurationDirectory the name of the directory * which contains the outlet configuration files. Cannot be * a composite path like parent/child. * @return a set with the names of all outlet configuration files * contained in the jar file. * @throws NullPointerException if jarFile * or outletConfigurationDirectory is null */ static Collection<String> getOutletConfigurationNames(JarFile jarFile, String outletConfigurationDirectory) { if (log.isDebugEnabled()) { log.debug("Analyzing jar file " + jarFile.getName() + " seeking Directory " + outletConfigurationDirectory); } List<String> result = new ArrayList<String>(); Enumeration<JarEntry> entries = jarFile.entries(); while (entries.hasMoreElements()) { JarEntry jarEntry = entries.nextElement(); if (jarEntry.isDirectory()) { continue; } String rawName = jarEntry.getName(); if (!rawName.startsWith(outletConfigurationDirectory)) { continue; } String name = rawName.substring(rawName.lastIndexOf('/') + 1); int expectedRawNameLength = outletConfigurationDirectory.length() + name.length() + 1; if (rawName.length() != expectedRawNameLength) { // file is in a subdirectory of outletConfigurationSubdir, // we only consider files directly in // outletConfigurationSubdir continue; } result.add(name); } if (log.isDebugEnabled()) { log.debug("Found the following outlet configuration files " + result); } return result; } }