resourcecatalog.java

编写程序

/*
 * @(#)ResourceCatalog.java	1.9 03/05/18
 * 
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package jnlp.sample.servlet;
import java.util.HashMap;
import java.util.List;
import java.util.ArrayList;
import java.io.File;
import java.io.BufferedInputStream;
import javax.servlet.ServletContext;
import javax.xml.parsers.*;
import org.xml.sax.*;
import org.w3c.dom.*;
import jnlp.sample.util.VersionString;
import jnlp.sample.util.VersionID;

public class ResourceCatalog {
    public static final String VERSION_XML_FILENAME = "version.xml";
    
    private Logger _log = null;
    private ServletContext _servletContext = null;
    
    private HashMap _entries;
    
    /** Class to contain the information we know
     *  about a specific directory
     */
    static private class PathEntries {
	/* Version-based entries at this particular path */
	private List _versionXmlList;
	private List _directoryList;
	private List _platformList;
	/* Last time this entry was updated */
	private long _lastModified; // Last modified time of entry;
	
	public PathEntries(List versionXmlList, List directoryList, List platformList, long lastModified) {
	    _versionXmlList = versionXmlList;
	    _directoryList = directoryList;
	    _platformList = platformList;
	    _lastModified = lastModified;
	}
	
	
	public void setDirectoryList(List dirList) {
	    _directoryList = dirList;
	}

	public List getVersionXmlList() { return _versionXmlList; }
	public List getDirectoryList()  { return _directoryList; }
	public List getPlatformList()   { return _platformList; }
	
	public long getLastModified() { return _lastModified; }
    }
    
    public ResourceCatalog(ServletContext servletContext, Logger log) {
	_entries = new HashMap();
	_servletContext = servletContext;
	_log = log;
    }
    
    
    public JnlpResource lookupResource(DownloadRequest dreq) throws ErrorResponseException {
	// Split request up into path and name
	String path = dreq.getPath();
	String name = null;
	String dir  = null;
	int idx = path.lastIndexOf('/');
	if (idx == -1) {
	    name = path;
	} else {
	    name = path.substring(idx + 1); // Exclude '/'
	    dir  = path.substring(0, idx + 1); // Include '/'
	}
	
	// Lookup up already parsed entries, and san directory for entries if neccesary
	PathEntries pentries =  (PathEntries)_entries.get(dir);
	JnlpResource xmlVersionResPath = new JnlpResource(_servletContext, dir + VERSION_XML_FILENAME);
	if (pentries == null || (xmlVersionResPath.exists() && xmlVersionResPath.getLastModified() > pentries.getLastModified())) {
	    _log.addInformational("servlet.log.scandir", dir);
	    List dirList = scanDirectory(dir, dreq);
	    // Scan XML file
	    List versionList = new ArrayList();
	    List platformList = new ArrayList();
	    parseVersionXML(versionList, platformList, dir, xmlVersionResPath);
	    pentries = new PathEntries(versionList, dirList, platformList, xmlVersionResPath.getLastModified());
	    _entries.put(dir, pentries);
	}
	
	// Search for a match
	JnlpResource[] result = new JnlpResource[1];
	
	if (dreq.isPlatformRequest()) {
	    int sts = findMatch(pentries.getPlatformList(), name, dreq, result);
	    if (sts != DownloadResponse.STS_00_OK) {
		throw new ErrorResponseException(DownloadResponse.getJnlpErrorResponse(sts));
	    }
	} else {
	    // First lookup in versions.xml file
	    int sts1 = findMatch(pentries.getVersionXmlList(), name, dreq, result);
	    if (sts1 != DownloadResponse.STS_00_OK) {
		// Then lookup in directory
		int sts2 = findMatch(pentries.getDirectoryList(), name, dreq, result);	
		if (sts2 != DownloadResponse.STS_00_OK) {

		    // fix for 4450104
		    // try rescan and see if it helps
		    pentries.setDirectoryList(scanDirectory(dir, dreq));
		    sts2 = findMatch(pentries.getDirectoryList(), name, dreq, result);		   
		    // try again after rescanning directory
		    if (sts2 != DownloadResponse.STS_00_OK) {
			// Throw the most specific error code
			throw new ErrorResponseException(DownloadResponse.getJnlpErrorResponse(Math.max(sts1, sts2)));
		    }
		}
	    }
	}
	return result[0];
    }
    
    /** This method finds the best match, or return the best error code. The
     *  result parameter must be an array with room for one element.
     *
     *  If a match is found, the method returns DownloadResponse.STS_00_OK
     *  If one or more entries matches on: name, version-id, os, arch, and locale,
     *  then the one with the highest version-id is set in the result[0] field.
     *
     *  If a match is not found, it returns an error code, either: ERR_10_NO_RESOURCE,
     *  ERR_11_NO_VERSION, ERR_20_UNSUP_OS, ERR_21_UNSUP_ARCH, ERR_22_UNSUP_LOCALE,
     *  ERR_23_UNSUP_JRE.
     *
     */
    public int findMatch(List list, String name, DownloadRequest dreq, JnlpResource[] result) {
	if (list == null) return DownloadResponse.ERR_10_NO_RESOURCE;
	// Setup return values
	VersionID bestVersionId = null;
	int error = DownloadResponse.ERR_10_NO_RESOURCE;
	VersionString vs = new VersionString(dreq.getVersion());
	// Iterate through entries
	for(int i = 0; i < list.size(); i++) {
	    JnlpResource respath = (JnlpResource)list.get(i);
	    VersionID vid = new VersionID(respath.getVersionId());	
	    int sts = matchEntry(name, vs, dreq, respath, vid);
	    if (sts == DownloadResponse.STS_00_OK) {
		if (result[0] == null || vid.isGreaterThan(bestVersionId)) {
		    result[0] = respath;
		    bestVersionId = vid;
		}
	    } else {
		error = Math.max(error, sts);
	    }
	}
	return (result[0] != null) ? DownloadResponse.STS_00_OK : error;
    }
    
    public int matchEntry(String name, VersionString vs, DownloadRequest dreq, JnlpResource jnlpres, VersionID vid) {
	if (!name.equals(jnlpres.getName())) {
	    return DownloadResponse.ERR_10_NO_RESOURCE;
	}
	if (!vs.contains(vid)) {
	    return DownloadResponse.ERR_11_NO_VERSION;
	}
	if (!prefixMatchLists(jnlpres.getOSList(), dreq.getOS())) {
	    return DownloadResponse.ERR_20_UNSUP_OS;
	}
	if (!prefixMatchLists(jnlpres.getArchList(), dreq.getArch())) {
	    return DownloadResponse.ERR_21_UNSUP_ARCH;
	}
	if (!prefixMatchLists(jnlpres.getLocaleList(), dreq.getLocale())) {
	    return DownloadResponse.ERR_22_UNSUP_LOCALE;
	}
	return DownloadResponse.STS_00_OK;
    }

       
    private static boolean prefixMatchStringList(String[] prefixList, String target) {
        // No prefixes matches everything
        if (prefixList == null) return true;
	// No target, but a prefix list does not match anything
	if (target == null) return false;
        for(int i = 0; i < prefixList.length; i++) {
            if (target.startsWith(prefixList[i])) return true;
        }
        return false;
    }
    
    /* Return true if at least one of the strings in 'prefixes' are a prefix
     * to at least one of the 'keys'.
     */
    public boolean prefixMatchLists(String[] prefixes, String[] keys) {
	// The prefixes are part of the server resources. If none is given,
	// everything matches
	if (prefixes == null) return true;
	// If no os keyes was given, and the server resource is keyed of this,
	// then return false.
	if (keys  == null) return false;
	// Check for a match on a key
	for(int i = 0; i < keys.length; i++) {
	    if (prefixMatchStringList(prefixes, keys[i])) return true;
	}
	return false;
    }
    
    /** This method scans the directory pointed to by the
     *  given path and creates a list of ResourcePath elements
     *  that contains information about all the entries
     *
     *  The version-based information is encoded in the file name
     *  given the following format:
     *
     *     entry ::= <name> __ ( <options> ). <ext>
     *     options ::= <option> ( __ <options>  )?
     *     option  ::= V<version-id>
     *               | O<os>
     *               | A<arch>
     *               | L<locale>
     *
     */


    private String jnlpGetPath(DownloadRequest dreq) {
	// fix for 4474021
	// try to manuually generate the filename	   
	// extract file name
	String path = dreq.getPath();	     
	String filename = path.substring(path.lastIndexOf("/") + 1);
	path = path.substring(0, path.lastIndexOf("/") + 1);
	String name = filename;
	String ext = null;
	
	if (filename.lastIndexOf(".") != -1) {
	    ext = filename.substring(filename.lastIndexOf(".") + 1);
	    
	    filename = filename.substring(0, filename.lastIndexOf("."));
	    
	} 
	if (dreq.getVersion() != null) {
	    filename += "__V" + dreq.getVersion();
	}
	
	String[] temp = dreq.getOS();