Java tutorial
// ======================================================================== // $Id: Resource.java,v 1.31 2005/10/21 11:36:56 gregwilkins Exp $ // Copyright 1996-2004 Mort Bay Consulting Pty. Ltd. // ------------------------------------------------------------------------ // 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 net.lightbody.bmp.proxy.jetty.util; import net.lightbody.bmp.proxy.jetty.log.LogFactory; import org.apache.commons.logging.Log; import java.io.*; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; import java.text.DateFormat; import java.util.Arrays; import java.util.Date; /* ------------------------------------------------------------ */ /** Abstract resource class. * * @version $Id: Resource.java,v 1.31 2005/10/21 11:36:56 gregwilkins Exp $ * @author Nuno Preguia * @author Greg Wilkins (gregw) */ public abstract class Resource implements Serializable { private static Log log = LogFactory.getLog(Resource.class); Object _associate; /* ------------------------------------------------------------ */ /** Construct a resource from a url. * @param url A URL. * @return A Resource object. */ public static Resource newResource(URL url) throws IOException { if (url == null) return null; String urls = url.toExternalForm(); if (urls.startsWith("file:")) { try { FileResource fileResource = new FileResource(url); return fileResource; } catch (Exception e) { log.debug(LogSupport.EXCEPTION, e); return new BadResource(url, e.toString()); } } else if (urls.startsWith("jar:file:")) { return new JarFileResource(url); } else if (urls.startsWith("jar:")) { return new JarResource(url); } return new URLResource(url, null); } /* ------------------------------------------------------------ */ /** Construct a resource from a string. * @param resource A URL or filename. * @return A Resource object. */ public static Resource newResource(String resource) throws MalformedURLException, IOException { URL url = null; try { // Try to format as a URL? url = new URL(resource); } catch (MalformedURLException e) { if (!resource.startsWith("ftp:") && !resource.startsWith("file:") && !resource.startsWith("jar:")) { try { // It's a file. if (resource.startsWith("./")) resource = resource.substring(2); File file = new File(resource).getCanonicalFile(); url = file.toURI().toURL(); URLConnection connection = url.openConnection(); FileResource fileResource = new FileResource(url, connection, file); return fileResource; } catch (Exception e2) { log.debug(LogSupport.EXCEPTION, e2); throw e; } } else { log.warn("Bad Resource: " + resource); throw e; } } String nurl = url.toString(); if (nurl.length() > 0 && nurl.charAt(nurl.length() - 1) != resource.charAt(resource.length() - 1)) { if ((nurl.charAt(nurl.length() - 1) != '/' || nurl.charAt(nurl.length() - 2) != resource.charAt(resource.length() - 1)) && (resource.charAt(resource.length() - 1) != '/' || resource.charAt(resource.length() - 2) != nurl.charAt(nurl.length() - 1))) { return new BadResource(url, "Trailing special characters stripped by URL in " + resource); } } return newResource(url); } /* ------------------------------------------------------------ */ /** Construct a system resource from a string. * The resource is tried as classloader resource before being * treated as a normal resource. */ public static Resource newSystemResource(String resource) throws IOException { URL url = null; // Try to format as a URL? ClassLoader loader = Thread.currentThread().getContextClassLoader(); if (loader != null) { url = loader.getResource(resource); if (url == null && resource.startsWith("/")) url = loader.getResource(resource.substring(1)); } if (url == null) { loader = Resource.class.getClassLoader(); if (loader != null) { url = loader.getResource(resource); if (url == null && resource.startsWith("/")) url = loader.getResource(resource.substring(1)); } } if (url == null) { url = ClassLoader.getSystemResource(resource); if (url == null && resource.startsWith("/")) url = loader.getResource(resource.substring(1)); } if (url == null) return null; return newResource(url); } /* ------------------------------------------------------------ */ protected void finalize() { release(); } /* ------------------------------------------------------------ */ /** Release any resources held by the resource. */ public abstract void release(); /* ------------------------------------------------------------ */ /** * Returns true if the respresened resource exists. */ public abstract boolean exists(); /* ------------------------------------------------------------ */ /** * Returns true if the respresenetd resource is a container/directory. * If the resource is not a file, resources ending with "/" are * considered directories. */ public abstract boolean isDirectory(); /* ------------------------------------------------------------ */ /** * Returns the last modified time */ public abstract long lastModified(); /* ------------------------------------------------------------ */ /** * Return the length of the resource */ public abstract long length(); /* ------------------------------------------------------------ */ /** * Returns an URL representing the given resource */ public abstract URL getURL(); /* ------------------------------------------------------------ */ /** * Returns an File representing the given resource or NULL if this * is not possible. */ public abstract File getFile() throws IOException; /* ------------------------------------------------------------ */ /** * Returns the name of the resource */ public abstract String getName(); /* ------------------------------------------------------------ */ /** * Returns an input stream to the resource */ public abstract InputStream getInputStream() throws java.io.IOException; /* ------------------------------------------------------------ */ /** * Returns an output stream to the resource */ public abstract OutputStream getOutputStream() throws java.io.IOException, SecurityException; /* ------------------------------------------------------------ */ /** * Deletes the given resource */ public abstract boolean delete() throws SecurityException; /* ------------------------------------------------------------ */ /** * Rename the given resource */ public abstract boolean renameTo(Resource dest) throws SecurityException; /* ------------------------------------------------------------ */ /** * Returns a list of resource names contained in the given resource * The resource names are not URL encoded. */ public abstract String[] list(); /* ------------------------------------------------------------ */ /** * Returns the resource contained inside the current resource with the * given name. * @param path The path segment to add, which should be encoded by the * encode method. */ public abstract Resource addPath(String path) throws IOException, MalformedURLException; /* ------------------------------------------------------------ */ /** Encode according to this resource type. * The default implementation calls URI.encodePath(uri) * @param uri * @return String encoded for this resource type. */ public String encode(String uri) { return URI.encodePath(uri); } /* ------------------------------------------------------------ */ public Object getAssociate() { return _associate; } /* ------------------------------------------------------------ */ public void setAssociate(Object o) { _associate = o; } /* ------------------------------------------------------------ */ /** * @return The canonical Alias of this resource or null if none. */ public URL getAlias() { return null; } /* ------------------------------------------------------------ */ public CachedResource cache() throws IOException { return new CachedResource(this); } /* ------------------------------------------------------------ */ /** Get the resource list as a HTML directory listing. * @param base The base URL * @param parent True if the parent directory should be included * @return String of HTML */ public String getListHTML(String base, boolean parent) throws IOException { if (!isDirectory()) return null; String[] ls = list(); if (ls == null) return null; Arrays.sort(ls); String title = "Directory: " + URI.decodePath(base); title = StringUtil.replace(StringUtil.replace(title, "<", "<"), ">", ">"); StringBuffer buf = new StringBuffer(4096); buf.append("<HTML><HEAD><TITLE>"); buf.append(title); buf.append("</TITLE></HEAD><BODY>\n<H1>"); buf.append(title); buf.append("</H1><TABLE BORDER=0>"); if (parent) { buf.append("<TR><TD><A HREF="); buf.append(URI.encodePath(URI.addPaths(base, "../"))); buf.append(">Parent Directory</A></TD><TD></TD><TD></TD></TR>\n"); } DateFormat dfmt = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM); for (int i = 0; i < ls.length; i++) { String encoded = URI.encodePath(ls[i]); Resource item = addPath(encoded); buf.append("<TR><TD><A HREF=\""); String path = URI.addPaths(base, encoded); if (item.isDirectory() && !path.endsWith("/")) path = URI.addPaths(path, "/"); buf.append(path); buf.append("\">"); buf.append(StringUtil.replace(StringUtil.replace(ls[i], "<", "<"), ">", ">")); buf.append(" "); buf.append("</TD><TD ALIGN=right>"); buf.append(item.length()); buf.append(" bytes </TD><TD>"); buf.append(dfmt.format(new Date(item.lastModified()))); buf.append("</TD></TR>\n"); } buf.append("</TABLE>\n"); buf.append("</BODY></HTML>\n"); return buf.toString(); } /* ------------------------------------------------------------ */ /** * @param out * @param start First byte to write * @param count Bytes to write or -1 for all of them. */ public void writeTo(OutputStream out, long start, long count) throws IOException { InputStream in = getInputStream(); try { in.skip(start); if (count < 0) IO.copy(in, out); else IO.copy(in, out, (int) count); } finally { in.close(); } } }