Java tutorial
/* * Copyright 2002-2013 the original author or authors. * * 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.grails.io.support; import java.io.File; import java.io.IOException; import java.net.JarURLConnection; import java.net.URISyntaxException; import java.net.URL; import java.net.URLConnection; import java.util.Collections; import java.util.Enumeration; import java.util.LinkedHashSet; import java.util.Set; import java.util.jar.JarEntry; import java.util.jar.JarFile; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * A ResourcePatternResolver implementation that is able to resolve a * specified resource location path into one or more matching Resources. * The source path may be a simple path which has a one-to-one mapping to a * target Resource, or alternatively * may contain the special "<code>classpath*:</code>" prefix and/or * internal Ant-style regular expressions (matched using AntPathMatcher). * Both of the latter are effectively wildcards. * * <p><b>No Wildcards:</b> * * <p>In the simple case, if the specified location path does not start with the * <code>"classpath*:</code>" prefix, and does not contain a PathMatcher pattern, * this resolver will simply return a single resource via a * <code>getResource()</code> call on the underlying <code>ResourceLoader</code>. * Examples are real URLs such as "<code>file:C:/context.xml</code>", pseudo-URLs * such as "<code>classpath:/context.xml</code>", and simple unprefixed paths * such as "<code>/WEB-INF/context.xml</code>". The latter will resolve in a * fashion specific to the underlying <code>ResourceLoader</code> (e.g. * <code>ServletContextResource</code> for a <code>WebApplicationContext</code>). * * <p><b>Ant-style Patterns:</b> * * <p>When the path location contains an Ant-style pattern, e.g.: * <pre> * /WEB-INF/*-context.xml * com/mycompany/**/applicationContext.xml * file:C:/some/path/*-context.xml * classpath:com/mycompany/**/applicationContext.xml</pre> * the resolver follows a more complex but defined procedure to try to resolve * the wildcard. It produces a <code>Resource</code> for the path up to the last * non-wildcard segment and obtains a <code>URL</code> from it. If this URL is * not a "<code>jar:</code>" URL or container-specific variant (e.g. * "<code>zip:</code>" in WebLogic, "<code>wsjar</code>" in WebSphere", etc.), * then a <code>java.io.File</code> is obtained from it, and used to resolve the * wildcard by walking the filesystem. In the case of a jar URL, the resolver * either gets a <code>java.net.JarURLConnection</code> from it, or manually parses * the jar URL, and then traverses the contents of the jar file, to resolve the * wildcards. * * <p><b>Implications on portability:</b> * * <p>If the specified path is already a file URL (either explicitly, or * implicitly because the base <code>ResourceLoader</code> is a filesystem one, * then wildcarding is guaranteed to work in a completely portable fashion. * * <p>If the specified path is a classpath location, then the resolver must * obtain the last non-wildcard path segment URL via a * <code>Classloader.getResource()</code> call. Since this is just a * node of the path (not the file at the end) it is actually undefined * (in the ClassLoader Javadocs) exactly what sort of a URL is returned in * this case. In practice, it is usually a <code>java.io.File</code> representing * the directory, where the classpath resource resolves to a filesystem * location, or a jar URL of some sort, where the classpath resource resolves * to a jar location. Still, there is a portability concern on this operation. * * <p>If a jar URL is obtained for the last non-wildcard segment, the resolver * must be able to get a <code>java.net.JarURLConnection</code> from it, or * manually parse the jar URL, to be able to walk the contents of the jar, * and resolve the wildcard. This will work in most environments, but will * fail in others, and it is strongly recommended that the wildcard * resolution of resources coming from jars be thoroughly tested in your * specific environment before you rely on it. * * <p><b><code>classpath*:</code> Prefix:</b> * * <p>There is special support for retrieving multiple class path resources with * the same name, via the "<code>classpath*:</code>" prefix. For example, * "<code>classpath*:META-INF/beans.xml</code>" will find all "beans.xml" * files in the class path, be it in "classes" directories or in JAR files. * This is particularly useful for autodetecting config files of the same name * at the same location within each jar file. Internally, this happens via a * <code>ClassLoader.getResources()</code> call, and is completely portable. * * <p>The "classpath*:" prefix can also be combined with a PathMatcher pattern in * the rest of the location path, for example "classpath*:META-INF/*-beans.xml". * In this case, the resolution strategy is fairly simple: a * <code>ClassLoader.getResources()</code> call is used on the last non-wildcard * path segment to get all the matching resources in the class loader hierarchy, * and then off each resource the same PathMatcher resolution strategy described * above is used for the wildcard subpath. * * <p><b>Other notes:</b> * * <p><b>WARNING:</b> Note that "<code>classpath*:</code>" when combined with * Ant-style patterns will only work reliably with at least one root directory * before the pattern starts, unless the actual target files reside in the file * system. This means that a pattern like "<code>classpath*:*.xml</code>" will * <i>not</i> retrieve files from the root of jar files but rather only from the * root of expanded directories. This originates from a limitation in the JDK's * <code>ClassLoader.getResources()</code> method which only returns file system * locations for a passed-in empty String (indicating potential roots to search). * * <p><b>WARNING:</b> Ant-style patterns with "classpath:" resources are not * guaranteed to find matching resources if the root package to search is available * in multiple class path locations. This is because a resource such as<pre> * com/mycompany/package1/service-context.xml * </pre>may be in only one location, but when a path such as<pre> * classpath:com/mycompany/**/service-context.xml * </pre>is used to try to resolve it, the resolver will work off the (first) URL * returned by <code>getResource("com/mycompany");</code>. If this base package * node exists in multiple classloader locations, the actual end resource may * not be underneath. Therefore, preferably, use "<code>classpath*:<code>" with the same * Ant-style pattern in such a case, which will search <i>all</i> class path * locations that contain the root package. * * @author Juergen Hoeller * @author Colin Sampaleanu * @author Marius Bogoevici * @author Costin Leau * @since 1.0.2 * @see java.lang.ClassLoader#getResources(String) */ public class PathMatchingResourcePatternResolver { private static final String CLASSPATH_ALL_URL_PREFIX = "classpath*:"; private static final Log logger = LogFactory.getLog(PathMatchingResourcePatternResolver.class); private final ResourceLoader resourceLoader; private AntPathMatcher pathMatcher = new AntPathMatcher(); /** * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader. * <p>ClassLoader access will happen via the thread context class loader. */ public PathMatchingResourcePatternResolver() { resourceLoader = new DefaultResourceLoader(); } /** * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader. * @param classLoader the ClassLoader to load classpath resources with, * or <code>null</code> for using the thread context class loader * at the time of actual resource access */ public PathMatchingResourcePatternResolver(ClassLoader classLoader) { resourceLoader = new DefaultResourceLoader(classLoader); } /** * Create a new PathMatchingResourcePatternResolver. * <p>ClassLoader access will happen via the thread context class loader. * @param resourceLoader the ResourceLoader to load root directories and * actual resources with */ public PathMatchingResourcePatternResolver(ResourceLoader resourceLoader) { this.resourceLoader = resourceLoader; } /** * Return the ResourceLoader that this pattern resolver works with. */ public ResourceLoader getResourceLoader() { return resourceLoader; } /** * Return the ClassLoader that this pattern resolver works with * (never <code>null</code>). */ public ClassLoader getClassLoader() { return getResourceLoader().getClassLoader(); } /** * Set the PathMatcher implementation to use for this * resource pattern resolver. Default is AntPathMatcher. */ public void setPathMatcher(AntPathMatcher pathMatcher) { this.pathMatcher = pathMatcher; } /** * Return the PathMatcher that this resource pattern resolver uses. */ public AntPathMatcher getPathMatcher() { return pathMatcher; } public Resource getResource(String location) { return getResourceLoader().getResource(location); } public Resource[] getResources(String locationPattern) throws IOException { if (locationPattern.startsWith(CLASSPATH_ALL_URL_PREFIX)) { // a class path resource (multiple resources for same name possible) if (getPathMatcher().isPattern(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length()))) { // a class path resource pattern return findPathMatchingResources(locationPattern); } // all class path resources with the given name return findAllClassPathResources(locationPattern.substring(CLASSPATH_ALL_URL_PREFIX.length())); } // Only look for a pattern after a prefix here // (to not get fooled by a pattern symbol in a strange prefix). int prefixEnd = locationPattern.indexOf(":") + 1; if (getPathMatcher().isPattern(locationPattern.substring(prefixEnd))) { // a file pattern return findPathMatchingResources(locationPattern); } // a single resource with the given name return new Resource[] { getResourceLoader().getResource(locationPattern) }; } /** * Find all class location resources with the given location via the ClassLoader. * @param location the absolute path within the classpath * @return the result as Resource array * @throws IOException in case of I/O errors * @see java.lang.ClassLoader#getResources * @see #convertClassLoaderURL */ protected Resource[] findAllClassPathResources(String location) throws IOException { String path = location; if (path.startsWith("/")) { path = path.substring(1); } Enumeration<URL> resourceUrls = getClassLoader().getResources(path); Set<Resource> result = new LinkedHashSet<Resource>(16); while (resourceUrls.hasMoreElements()) { URL url = resourceUrls.nextElement(); result.add(convertClassLoaderURL(url)); } return result.toArray(new Resource[result.size()]); } /** * Convert the given URL as returned from the ClassLoader into a Resource object. * <p>The default implementation simply creates a UrlResource instance. * @param url a URL as returned from the ClassLoader * @return the corresponding Resource object * @see java.lang.ClassLoader#getResources */ protected Resource convertClassLoaderURL(URL url) { return new UrlResource(url); } /** * Find all resources that match the given location pattern via the * Ant-style PathMatcher. Supports resources in jar files and zip files * and in the file system. * @param locationPattern the location pattern to match * @return the result as Resource array * @throws IOException in case of I/O errors * @see #doFindPathMatchingJarResources * @see #doFindPathMatchingFileResources */ protected Resource[] findPathMatchingResources(String locationPattern) throws IOException { String rootDirPath = determineRootDir(locationPattern); String subPattern = locationPattern.substring(rootDirPath.length()); Resource[] rootDirResources = getResources(rootDirPath); Set<Resource> result = new LinkedHashSet<Resource>(16); for (Resource rootDirResource : rootDirResources) { rootDirResource = resolveRootDirResource(rootDirResource); if (isJarResource(rootDirResource)) { result.addAll(doFindPathMatchingJarResources(rootDirResource, subPattern)); } else { result.addAll(doFindPathMatchingFileResources(rootDirResource, subPattern)); } } return result.toArray(new Resource[result.size()]); } /** * Determine the root directory for the given location. * <p>Used for determining the starting point for file matching, * resolving the root directory location to a <code>java.io.File</code> * and passing it into <code>retrieveMatchingFiles</code>, with the * remainder of the location as pattern. * <p>Will return "/WEB-INF/" for the pattern "/WEB-INF/*.xml", * for example. * @param location the location to check * @return the part of the location that denotes the root directory * @see #retrieveMatchingFiles */ protected String determineRootDir(String location) { int prefixEnd = location.indexOf(":") + 1; int rootDirEnd = location.length(); while (rootDirEnd > prefixEnd && getPathMatcher().isPattern(location.substring(prefixEnd, rootDirEnd))) { rootDirEnd = location.lastIndexOf('/', rootDirEnd - 2) + 1; } if (rootDirEnd == 0) { rootDirEnd = prefixEnd; } return location.substring(0, rootDirEnd); } /** * Resolve the specified resource for path matching. * <p>The default implementation detects an Equinox OSGi "bundleresource:" * / "bundleentry:" URL and resolves it into a standard jar file URL that * can be traversed using Spring's standard jar file traversal algorithm. * @param original the resource to resolve * @return the resolved resource (may be identical to the passed-in resource) * @throws IOException in case of resolution failure */ protected Resource resolveRootDirResource(Resource original) throws IOException { return original; } /** * Return whether the given resource handle indicates a jar resource * that the <code>doFindPathMatchingJarResources</code> method can handle. * <p>The default implementation checks against the URL protocols * "jar", "zip" and "wsjar" (the latter are used by BEA WebLogic Server * and IBM WebSphere, respectively, but can be treated like jar files). * @param resource the resource handle to check * (usually the root directory to start path matching from) * @see #doFindPathMatchingJarResources */ protected boolean isJarResource(Resource resource) throws IOException { return GrailsResourceUtils.isJarURL(resource.getURL()); } /** * Find all resources in jar files that match the given location pattern * via the Ant-style PathMatcher. * @param rootDirResource the root directory as Resource * @param subPattern the sub pattern to match (below the root directory) * @return the Set of matching Resource instances * @throws IOException in case of I/O errors * @see java.net.JarURLConnection */ protected Set<Resource> doFindPathMatchingJarResources(Resource rootDirResource, String subPattern) throws IOException { URLConnection con = rootDirResource.getURL().openConnection(); JarFile jarFile; String jarFileUrl; String rootEntryPath; boolean newJarFile = false; if (con instanceof JarURLConnection) { // Should usually be the case for traditional JAR files. JarURLConnection jarCon = (JarURLConnection) con; GrailsResourceUtils.useCachesIfNecessary(jarCon); jarFile = jarCon.getJarFile(); jarFileUrl = jarCon.getJarFileURL().toExternalForm(); JarEntry jarEntry = jarCon.getJarEntry(); rootEntryPath = (jarEntry != null ? jarEntry.getName() : ""); } else { // No JarURLConnection -> need to resort to URL file parsing. // We'll assume URLs of the format "jar:path!/entry", with the protocol // being arbitrary as long as following the entry format. // We'll also handle paths with and without leading "file:" prefix. String urlFile = rootDirResource.getURL().getFile(); int separatorIndex = urlFile.indexOf(GrailsResourceUtils.JAR_URL_SEPARATOR); if (separatorIndex != -1) { jarFileUrl = urlFile.substring(0, separatorIndex); rootEntryPath = urlFile.substring(separatorIndex + GrailsResourceUtils.JAR_URL_SEPARATOR.length()); jarFile = getJarFile(jarFileUrl); } else { jarFile = new JarFile(urlFile); jarFileUrl = urlFile; rootEntryPath = ""; } newJarFile = true; } try { if (!"".equals(rootEntryPath) && !rootEntryPath.endsWith("/")) { // Root entry path must end with slash to allow for proper matching. // The Sun JRE does not return a slash here, but BEA JRockit does. rootEntryPath = rootEntryPath + "/"; } Set<Resource> result = new LinkedHashSet<Resource>(8); for (Enumeration<JarEntry> entries = jarFile.entries(); entries.hasMoreElements();) { JarEntry entry = entries.nextElement(); String entryPath = entry.getName(); if (entryPath.startsWith(rootEntryPath)) { String relativePath = entryPath.substring(rootEntryPath.length()); if (getPathMatcher().match(subPattern, relativePath)) { result.add(rootDirResource.createRelative(relativePath)); } } } return result; } finally { // Close jar file, but only if freshly obtained - // not from JarURLConnection, which might cache the file reference. if (newJarFile) { jarFile.close(); } } } /** * Resolve the given jar file URL into a JarFile object. */ protected JarFile getJarFile(String jarFileUrl) throws IOException { if (jarFileUrl.startsWith(GrailsResourceUtils.FILE_URL_PREFIX)) { try { return new JarFile(GrailsResourceUtils.toURI(jarFileUrl).getSchemeSpecificPart()); } catch (URISyntaxException ex) { // Fallback for URLs that are not valid URIs (should hardly ever happen). return new JarFile(jarFileUrl.substring(GrailsResourceUtils.FILE_URL_PREFIX.length())); } } return new JarFile(jarFileUrl); } /** * Find all resources in the file system that match the given location pattern * via the Ant-style PathMatcher. * @param rootDirResource the root directory as Resource * @param subPattern the sub pattern to match (below the root directory) * @return the Set of matching Resource instances * @throws IOException in case of I/O errors * @see #retrieveMatchingFiles */ protected Set<Resource> doFindPathMatchingFileResources(Resource rootDirResource, String subPattern) throws IOException { File rootDir; try { rootDir = rootDirResource.getFile().getAbsoluteFile(); } catch (IOException ex) { if (logger.isWarnEnabled()) { logger.warn("Cannot search for matching files underneath " + rootDirResource + " because it does not correspond to a directory in the file system", ex); } return Collections.emptySet(); } return doFindMatchingFileSystemResources(rootDir, subPattern); } /** * Find all resources in the file system that match the given location pattern * via the Ant-style PathMatcher. * @param rootDir the root directory in the file system * @param subPattern the sub pattern to match (below the root directory) * @return the Set of matching Resource instances * @throws IOException in case of I/O errors * @see #retrieveMatchingFiles */ protected Set<Resource> doFindMatchingFileSystemResources(File rootDir, String subPattern) throws IOException { Set<File> matchingFiles = retrieveMatchingFiles(rootDir, subPattern); Set<Resource> result = new LinkedHashSet<Resource>(matchingFiles.size()); for (File file : matchingFiles) { result.add(new FileSystemResource(file)); } return result; } /** * Retrieve files that match the given path pattern, * checking the given directory and its subdirectories. * @param rootDir the directory to start from * @param pattern the pattern to match against, * relative to the root directory * @return the Set of matching File instances * @throws IOException if directory contents could not be retrieved */ protected Set<File> retrieveMatchingFiles(File rootDir, String pattern) throws IOException { if (!rootDir.exists()) { // Silently skip non-existing directories. return Collections.emptySet(); } if (!rootDir.isDirectory()) { // Complain louder if it exists but is no directory. if (logger.isWarnEnabled()) { logger.warn("Skipping [" + rootDir.getAbsolutePath() + "] because it does not denote a directory"); } return Collections.emptySet(); } if (!rootDir.canRead()) { if (logger.isWarnEnabled()) { logger.warn("Cannot search for matching files underneath directory [" + rootDir.getAbsolutePath() + "] because the application is not allowed to read the directory"); } return Collections.emptySet(); } String fullPattern = rootDir.getAbsolutePath().replace(File.separator, "/"); if (!pattern.startsWith("/")) { fullPattern += "/"; } fullPattern = fullPattern + pattern.replace(File.separator, "/"); Set<File> result = new LinkedHashSet<File>(8); doRetrieveMatchingFiles(fullPattern, rootDir, result); return result; } /** * Recursively retrieve files that match the given pattern, * adding them to the given result list. * @param fullPattern the pattern to match against, * with prepended root directory path * @param dir the current directory * @param result the Set of matching File instances to add to * @throws IOException if directory contents could not be retrieved */ protected void doRetrieveMatchingFiles(String fullPattern, File dir, Set<File> result) throws IOException { File[] dirContents = dir.listFiles(); if (dirContents == null) { if (logger.isWarnEnabled()) { logger.warn("Could not retrieve contents of directory [" + dir.getAbsolutePath() + "]"); } return; } for (File content : dirContents) { String currPath = content.getAbsolutePath().replace(File.separator, "/"); if (content.isDirectory() && getPathMatcher().matchStart(fullPattern, currPath + "/")) { if (content.canRead()) { doRetrieveMatchingFiles(fullPattern, content, result); } } if (getPathMatcher().match(fullPattern, currPath)) { result.add(content); } } } }