Java tutorial
/******************************************************************************* * Copyright (c) 2006, 2009 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 *******************************************************************************/ package org.eclipse.core.runtime; import java.io.*; import java.net.URL; import java.util.Map; import org.eclipse.core.internal.runtime.Activator; import org.eclipse.core.internal.runtime.FindSupport; import org.eclipse.osgi.service.urlconversion.URLConverter; import org.osgi.framework.Bundle; /** * This class contains a collection of helper methods for finding files in bundles. * This class can only be used if the OSGi plugin is available. * * @since org.eclipse.equinox.common 3.2 * @noinstantiate This class is not intended to be instantiated by clients. */ public final class FileLocator { private FileLocator() { // prevent instantiation } /** * Returns a URL for the given path in the given bundle. Returns <code>null</code> if the URL * could not be computed or created. * <p> * This method looks for the path in the given bundle and any attached fragments. * <code>null</code> is returned if no such entry is found. Note that * there is no specific order to the fragments. * </p><p> * The following variables may also be used as entries in the provided path: * <ul> * <li>$nl$ - for language specific information</li> * <li>$os$ - for operating system specific information</li> * <li>$ws$ - for windowing system specific information</li> * </ul> * </p><p> * A path of "$nl$/about.properties" in an environment with a default * locale of en_CA will return a URL corresponding to the first location * about.properties is found according to the following order: * <pre> * plugin root/nl/en/CA/about.properties * fragment1 root/nl/en/CA/about.properties * fragment2 root/nl/en/CA/about.properties * ... * plugin root/nl/en/about.properties * fragment1 root/nl/en/about.properties * fragment2 root/nl/en/about.properties * ... * plugin root/about.properties * fragment1 root/about.properties * fragment2 root/about.properties * ... * </pre> * </p><p> * The current environment variable values can be overridden using * the override map argument or <code>null</code> can be specified * if this is not desired. * </p> * * @param bundle the bundle in which to search * @param path file path relative to plug-in installation location * @param override map of override substitution arguments to be used for * any $arg$ path elements. The map keys correspond to the substitution * arguments (eg. "$nl$" or "$os$"). The resulting * values must be of type java.lang.String. If the map is <code>null</code>, * or does not contain the required substitution argument, the default * is used. * @return a URL for the given path or <code>null</code>. The actual form * of the returned URL is not specified. */ public static URL find(Bundle bundle, IPath path, Map override) { return FindSupport.find(bundle, path, override); } /** * This method is the same as {@link #find(Bundle, IPath, Map)} except multiple entries * can be returned if more than one entry matches the path in the host and * any of its fragments. * * @param bundle the bundle in which to search * @param path file path relative to plug-in installation location * @param override map of override substitution arguments to be used for * any $arg$ path elements. The map keys correspond to the substitution * arguments (eg. "$nl$" or "$os$"). The resulting * values must be of type java.lang.String. If the map is <code>null</code>, * or does not contain the required substitution argument, the default * is used. * @return an array of entries which match the given path. An empty * array is returned if no matches are found. * * @since org.eclipse.equinox.common 3.3 */ public static URL[] findEntries(Bundle bundle, IPath path, Map override) { return FindSupport.findEntries(bundle, path, override); } /** * Returns the URL of a resource inside a bundle corresponding to the given URL. * Returns <code>null</code> if the URL could not be computed or created. * <p> * This method looks for a bundle resource described by the given input URL, * and returns the URL of the first resource found in the bundle or any attached * fragments. <code>null</code> is returned if no such entry is found. Note that * there is no specific order to the fragments. * </p><p> * The following variables may also be used as segments in the path of the provided URL: * <ul> * <li>$nl$ - for language specific information</li> * <li>$os$ - for operating system specific information</li> * <li>$ws$ - for windowing system specific information</li> * </ul> * </p><p> * For example, a URL of "platform:/plugin/org.eclipse.core.runtime/$nl$/about.properties" in an * environment with a default locale of en_CA will return a URL corresponding to * the first location about.properties is found according to the following order: * <pre> * plugin root/nl/en/CA/about.properties * fragment1 root/nl/en/CA/about.properties * fragment2 root/nl/en/CA/about.properties * ... * plugin root/nl/en/about.properties * fragment1 root/nl/en/about.properties * fragment2 root/nl/en/about.properties * ... * plugin root/about.properties * fragment1 root/about.properties * fragment2 root/about.properties * ... * </pre> * </p> * * @param url The location of a bundle entry that potentially includes the above * environment variables * @return The URL of the bundle entry matching the input URL, or <code>null</code> * if no matching entry could be found. The actual form of the returned URL is not specified. * @since org.eclipse.equinox.common 3.5 */ public static URL find(URL url) { return FindSupport.find(url); } /** * This is a convenience method, fully equivalent to {@link #findEntries(Bundle, IPath, Map)}, * with a value of <code>null</code> for the map argument. * * @param bundle the bundle in which to search * @param path file path relative to plug-in installation location * @return an array of entries which match the given path. An empty * array is returned if no matches are found. * * @since org.eclipse.equinox.common 3.3 */ public static URL[] findEntries(Bundle bundle, IPath path) { return FindSupport.findEntries(bundle, path); } /** * Returns an input stream for the specified file. The file path * must be specified relative to this plug-in's installation location. * Optionally, the path specified may contain $arg$ path elements that can * be used as substitution arguments. If this option is used then the $arg$ * path elements are processed in the same way as {@link #find(Bundle, IPath, Map)}. * <p> * The caller must close the returned stream when done. * </p> * * @param bundle the bundle in which to search * @param file path relative to plug-in installation location * @param substituteArgs <code>true</code> to process substitution arguments, * and <code>false</code> for the file exactly as specified without processing any * substitution arguments. * @return an input stream * @exception IOException if the given path cannot be found in this plug-in */ public static InputStream openStream(Bundle bundle, IPath file, boolean substituteArgs) throws IOException { return FindSupport.openStream(bundle, file, substituteArgs); } /** * Converts a URL that uses a user-defined protocol into a URL that uses the file * protocol. The contents of the URL may be extracted into a cache on the file-system * in order to get a file URL. * <p> * If the protocol for the given URL is not recognized by this converter, the original * URL is returned as-is. * </p> * @param url the original URL * @return the converted file URL or the original URL passed in if it is * not recognized by this converter * @throws IOException if an error occurs during the conversion */ public static URL toFileURL(URL url) throws IOException { URLConverter converter = Activator.getURLConverter(url); return converter == null ? url : converter.toFileURL(url); } /** * Converts a URL that uses a client-defined protocol into a URL that uses a * protocol which is native to the Java class library (file, jar, http, etc). * <p> * Note however that users of this API should not assume too much about the * results of this method. While it may consistently return a file: URL in certain * installation configurations, others may result in jar: or http: URLs. * </p> * <p> * If the protocol is not recognized by this converter, then the original URL is * returned as-is. * </p> * @param url the original URL * @return the resolved URL or the original if the protocol is unknown to this converter * @exception IOException if unable to resolve URL * @throws IOException if an error occurs during the resolution */ public static URL resolve(URL url) throws IOException { URLConverter converter = Activator.getURLConverter(url); return converter == null ? url : converter.resolve(url); } /** * Returns a file for the contents of the specified bundle. Depending * on how the bundle is installed the returned file may be a directory or a jar file * containing the bundle content. * * @param bundle the bundle * @return a file with the contents of the bundle * @throws IOException if an error occurs during the resolution * * @since org.eclipse.equinox.common 3.4 */ public static File getBundleFile(Bundle bundle) throws IOException { URL rootEntry = bundle.getEntry("/"); //$NON-NLS-1$ rootEntry = resolve(rootEntry); if ("file".equals(rootEntry.getProtocol())) //$NON-NLS-1$ return new File(rootEntry.getPath()); if ("jar".equals(rootEntry.getProtocol())) { //$NON-NLS-1$ String path = rootEntry.getPath(); if (path.startsWith("file:")) { // strip off the file: and the !/ path = path.substring(5, path.length() - 2); return new File(path); } } throw new IOException("Unknown protocol"); //$NON-NLS-1$ } }