Java tutorial
/* * Copyright (c) 2000-2004 Netspective Communications LLC. All rights reserved. * * Netspective Communications LLC ("Netspective") permits redistribution, modification and use of this file in source * and binary form ("The Software") under the Netspective Source License ("NSL" or "The License"). The following * conditions are provided as a summary of the NSL but the NSL remains the canonical license and must be accepted * before using The Software. Any use of The Software indicates agreement with the NSL. * * 1. Each copy or derived work of The Software must preserve the copyright notice and this notice unmodified. * * 2. Redistribution of The Software is allowed in object code form only (as Java .class files or a .jar file * containing the .class files) and only as part of an application that uses The Software as part of its primary * functionality. No distribution of the package is allowed as part of a software development kit, other library, * or development tool without written consent of Netspective. Any modified form of The Software is bound by these * same restrictions. * * 3. Redistributions of The Software in any form must include an unmodified copy of The License, normally in a plain * ASCII text file unless otherwise agreed to, in writing, by Netspective. * * 4. The names "Netspective", "Axiom", "Commons", "Junxion", and "Sparx" are trademarks of Netspective and may not be * used to endorse or appear in products derived from The Software without written consent of Netspective. * * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED REPRESENTATIONS AND * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, * ARE HEREBY DISCLAIMED. * * NETSPECTIVE AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE OR ANY THIRD PARTY AS A * RESULT OF USING OR DISTRIBUTING THE SOFTWARE. IN NO EVENT WILL NETSPECTIVE OR ITS LICENSORS BE LIABLE FOR ANY LOST * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THE SOFTWARE, EVEN * IF IT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. */ package com.netspective.commons.io; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.security.AccessController; import java.security.PrivilegedActionException; import java.security.PrivilegedExceptionAction; import java.util.Collections; import java.util.HashMap; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * A {@link com.netspective.commons.io.UriAddressableFileLocator} that uses files in a specified directory as the * source of resource. */ public class UriAddressableUniqueFileLocator implements UriAddressableFileLocator { private static final Log log = LogFactory.getLog(UriAddressableUniqueFileLocator.class); protected static final boolean SEP_IS_SLASH = File.separatorChar == '/'; private final Map cache = Collections.synchronizedMap(new HashMap()); private final String rootUrl; private final File baseDir; private final String canonicalPath; private final boolean cacheLocations; /** * Creates a new file resource locator that will use the specified directory * as the base directory for loading templates. * * @param baseDir the base directory for loading templates */ public UriAddressableUniqueFileLocator(final String rootUrl, final File baseDir, final boolean cacheLocations) throws IOException { this.rootUrl = rootUrl; this.cacheLocations = cacheLocations; try { Object[] retval = (Object[]) AccessController.doPrivileged(new PrivilegedExceptionAction() { public Object run() throws IOException { if (!baseDir.exists()) { throw new FileNotFoundException(baseDir + " does not exist."); } if (!baseDir.isDirectory()) { throw new IOException(baseDir + " is not a directory."); } Object[] retval = new Object[2]; retval[0] = baseDir.getCanonicalFile(); retval[1] = ((File) retval[0]).getPath() + File.separatorChar; return retval; } }); this.baseDir = (File) retval[0]; this.canonicalPath = (String) retval[1]; } catch (PrivilegedActionException e) { throw (IOException) e.getException(); } } public UriAddressableFile findUriAddressableFile(final String name) throws IOException { final boolean logging = log.isDebugEnabled(); if (logging) log.debug("SingleUriAddressableFileLocator searching for " + name); if (cacheLocations) { UriAddressableFile resource = (UriAddressableFile) cache.get(name); if (resource != null) { if (logging) log.debug("SingleUriAddressableFileLocator cache hit for " + resource); return resource; } } try { return (UriAddressableFile) AccessController.doPrivileged(new PrivilegedExceptionAction() { public Object run() throws IOException { File source = new File(baseDir, SEP_IS_SLASH ? name : name.replace(File.separatorChar, '/')); // Security check for inadvertently returning something outside the // resource directory. String normalized = source.getCanonicalPath(); if (!normalized.startsWith(canonicalPath)) { throw new SecurityException(); } if (logging) log.debug("SingleUriAddressableFileLocator looking for '" + name + "' as " + source); UriAddressableFile result = source.exists() ? new UriAddressableFile(rootUrl, name, source) : null; if (result != null) { if (logging) log.debug("SingleUriAddressableFileLocator found " + result); if (cacheLocations) cache.put(name, result); } return result; } }); } catch (PrivilegedActionException e) { throw (IOException) e.getException(); } } public String toString() { return getClass().getName() + " [" + hashCode() + "] baseDir = '" + baseDir + "', canonicalPath = '" + canonicalPath + "'"; } }