bundles/org.eclipse.core.boot/src/org/eclipse/core/internal/boot/PlatformURLConnection.java - gerrit/platform/eclipse.platform.runtime - Git at Google

 package org.eclipse.core.internal.boot;

 /*
  * Licensed Materials - Property of IBM,
  * WebSphere Studio Workbench
  * (c) Copyright IBM Corp 2000
  */

 /**
  * Platform URL support
  */

 import java.net.*;
 import java.io.*;
 import java.util.*;

 public abstract class PlatformURLConnection extends URLConnection {

 	// URL access
 	private boolean isInCache = false;
 	private boolean isJar = false;

 //	protected URL url;				// declared in super (platform: URL)
 	private URL resolvedURL = null;	// resolved file URL (eg. http: URL)
 	private URL cachedURL = null;	// file URL in cache (file: URL)

 	private URLConnection connection = null; // actual connection

 	// local cache
 	private static Properties cacheIndex = new Properties();
 	private static String cacheLocation;
 	private static String indexName;
 	private static String filePrefix;

 	// constants
 	private static final int BUF_SIZE = 32768;
 	private static final Object NOT_FOUND = new Object();	// marker
 	private static final String CACHE_PROP = ".cache.properties";
 	private static final String CACHE_LOCATION_PROP = "location";
 	private static final String CACHE_INDEX_PROP = "index";
 	private static final String CACHE_PREFIX_PROP = "prefix";
 	private static final String CACHE_INDEX = ".index.properties";
 	private static final String CACHE_DIR = PlatformURLHandler.PROTOCOL + File.separator;

 	// debug tracing
 	public static boolean DEBUG = false;
 	public static boolean DEBUG_CONNECT = true;
 	public static boolean DEBUG_CACHE_LOOKUP = true;
 	public static boolean DEBUG_CACHE_COPY = true;
 protected PlatformURLConnection(URL url) {
 	super(url);
 }
 protected boolean allowCaching() {
 	return false;
 }
 public void connect() throws IOException {
 	connect(false);
 }
 private synchronized void connect(boolean asLocal) throws IOException {
 	if (!connected) {
 		if (shouldCache(asLocal)) {
 			try {
 				URL inCache = getURLInCache();
 				if (inCache!=null) connection = inCache.openConnection();
 			} catch(IOException e) {
 				// failed to cache ... will use resolved URL instead
 			}
 		}

 		// use resolved URL
 		if (connection==null) connection = resolvedURL.openConnection();
 		connected = true;
 		if (DEBUG && DEBUG_CONNECT)
 			debug("Connected as "+connection.getURL());
 	}
 }
 private void copyToCache() throws IOException {

 	if (isInCache | cachedURL==null) return;
 	String tmp;
 	int ix;

 	// cache entry key
 	String key;
 	if (isJar) {
 		tmp = url.getFile();
 		ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		if (ix!=-1) tmp = tmp.substring(0,ix);
 		key = tmp;
 	}
 	else key = url.getFile();

 	// source url
 	URL src;
 	if (isJar) {
 		tmp = resolvedURL.getFile();
 		ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		if (ix!=-1) tmp = tmp.substring(0,ix);
 		src = new URL(tmp);
 	}
 	else src = resolvedURL;
 	InputStream srcis = null;

 	// cache target
 	String tgt;
 	if (isJar) {
 		tmp = cachedURL.getFile();
 		ix = tmp.indexOf(PlatformURLHandler.PROTOCOL_SEPARATOR);
 		if (ix!=-1) tmp = tmp.substring(ix+1);
 		ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		if (ix!=-1) tmp = tmp.substring(0,ix);
 		tgt = tmp;
 	}
 	else tgt = cachedURL.getFile();
 	File tgtFile = null;
 	FileOutputStream tgtos = null;

 	boolean error = false;
 	long total = 0;

 	try {
 		if (DEBUG && DEBUG_CACHE_COPY) {
 			if (isJar) debug ("Caching jar as "+tgt);
 			else debug("Caching as "+tgt);
 		}

 		srcis = src.openStream();
 		byte[] buf = new byte[BUF_SIZE];
 		int count = srcis.read(buf);

 		tgtFile = new File(tgt);
 		tgtos = new FileOutputStream(tgtFile);

 		while(count!=-1) {
 			total += count;
 			tgtos.write(buf,0,count);
 			count = srcis.read(buf);
 		}

 		srcis.close();
 		srcis=null;
 		tgtos.close();
 		tgtos=null;

 		// add cache entry
 		cacheIndex.put(key,tgt);
 		isInCache = true;
 	}
 	catch(IOException e) {
 		error = true;
 		cacheIndex.put(key,NOT_FOUND);	// mark cache entry for this execution
 		if (DEBUG && DEBUG_CACHE_COPY)
 			debug("Failed to cache due to "+e);
 		throw e;
 	}
 	finally {
 		if (!error && DEBUG && DEBUG_CACHE_COPY)
 			debug(total + " bytes copied");
 		if (srcis!=null) srcis.close();
 		if (tgtos!=null) tgtos.close();
 	}
 }
 protected void debug(String s) {

 	System.out.println("URL "+getURL().toString()+"^"+Integer.toHexString(Thread.currentThread().hashCode())+" "+s);
 }
 private static void debugStartup(String s) {

 	System.out.println("URL "+s);
 }
 public synchronized InputStream getInputStream() throws IOException {
 	if (!connected) connect();
 	return connection.getInputStream();
 }
 public URL getResolvedURL() {
 	return resolvedURL;
 }
 public URL getURLAsLocal() throws IOException {
 	connect(true);	// connect and force caching if necessary
 	URL u = connection.getURL();
 	String up = u.getProtocol();
 	if (!up.equals(PlatformURLHandler.FILE) && !up.equals(PlatformURLHandler.JAR) && !up.equals(PlatformURLHandler.VA)) throw new IOException("Unable to access URL as local "+url.toString());
 	return u;
 }
 private URL getURLInCache() throws IOException {

 	if (!allowCaching()) return null;	// target should not be cached

 	if (isInCache) return cachedURL;

 	if (cacheLocation==null | cacheIndex==null) return null;	// not caching

 	// check if we are dealing with a .jar/ .zip
 	String file = "";
 	String jarEntry = null;
 	if (isJar) {
 		file = url.getFile();
 		int ix = file.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		if (ix!=-1) {
 			jarEntry = file.substring(ix+PlatformURLHandler.JAR_SEPARATOR.length());
 			file = file.substring(0,ix);
 		}
 	}
 	else {
 		file = url.getFile();
 		jarEntry = null;
 	}

 	// check for cached entry
 	String tmp = (String)cacheIndex.get(file);

 	// check for "not found" marker
 	if (tmp!=null && tmp==NOT_FOUND) throw new IOException();

 	// validate cache entry
 	if (tmp!=null && !(new File(tmp)).exists()) {
 		tmp = null;
 		cacheIndex.remove(url.getFile());
 	}

 	// found in cache
 	if (tmp!=null) {
 		if (isJar) {
 			if (DEBUG && DEBUG_CACHE_LOOKUP)
 				debug("Jar located in cache as "+tmp);
 			tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
 			cachedURL = new URL(PlatformURLHandler.JAR,null,-1,tmp);
 		}
 		else {
 			if (DEBUG && DEBUG_CACHE_LOOKUP)
 				debug("Located in cache as "+tmp);
 			cachedURL = new URL(PlatformURLHandler.FILE,null,-1,tmp);
 		}
 		isInCache = true;
 	}
 	else {
 		// attemp to cache
 		int ix = file.lastIndexOf("/");
 		tmp = file.substring(ix+1);
 		tmp = cacheLocation + filePrefix + Long.toString((new java.util.Date()).getTime(),36) + "_" + tmp;
 		tmp = tmp.replace(File.separatorChar,'/');
 		if (isJar) {
 			tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
 			cachedURL = new URL(PlatformURLHandler.JAR,null,-1,tmp);
 		}
 		else cachedURL = new URL(PlatformURLHandler.FILE,null,-1,tmp);
 		copyToCache();
 	}

 	return cachedURL;
 }
 /*
  * to be implemented by subclass
  * @return URL resolved URL
  */

 protected URL resolve() throws IOException {
 	throw new IOException();
 }
 void setResolvedURL(URL url) throws IOException {
 	if (resolvedURL==null) {
 		int ix = url.getFile().lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		isJar = -1 != ix;
 		// Resolved URLs containing !/ separator are assumed to be jar URLs.
 		// If the resolved protocol is not jar, new jar URL is created.
 		if (isJar && !url.getProtocol().equals(PlatformURLHandler.JAR)) url = new URL(PlatformURLHandler.JAR,null,-1,url.toExternalForm());
 		resolvedURL=url;
 	}
 }
 private boolean shouldCache(boolean asLocal) {

 	// don't cache files that are known to be local
 	String rp = resolvedURL.getProtocol();
 	String rf = resolvedURL.getFile();
 	if (rp.equals(PlatformURLHandler.FILE) || rp.equals(PlatformURLHandler.VA)) return false;
 	if (rp.equals(PlatformURLHandler.JAR) && (rf.startsWith(PlatformURLHandler.FILE) || rf.startsWith(PlatformURLHandler.VA) )) return false;

 	// for other files force caching if local connection was requested
 	if (asLocal) return true;

 	// for now cache all files
 	// XXX: add cache policy support
 	return true;
 }
 static void shutdown() {

 	if (indexName!=null && cacheLocation!=null) {
 		// weed out "not found" entries
 		Enumeration keys = cacheIndex.keys();
 		String key;
 		Object value;
 		while (keys.hasMoreElements()) {
 			key = (String) keys.nextElement();
 			value = cacheIndex.get(key);
 			if (value==NOT_FOUND) cacheIndex.remove(key);
 		}

 		// try to save cache index
 		FileOutputStream fos = null;
 		try {
 			fos = new FileOutputStream(cacheLocation+indexName);
 			try {
 				cacheIndex.store(fos,null);
 			}
 			finally {
 				fos.close();
 			}
 		}
 		catch(IOException e) {
 			// failed to store cache index ... ignore
 		}
 	}
 }
 static void startup(String location) {


 	verifyLocation(location); // check for platform location, ignore errors
 	String cacheProps = location.trim();
 	if (!cacheProps.endsWith(File.separator)) cacheProps += File.separator;
 	cacheProps += CACHE_PROP;
 	File cachePropFile = new File(cacheProps);
 	Properties props = null;
 	FileInputStream fis;

 	if (cachePropFile.exists()) {
 		// load existing properties
 		try {
 			props = new Properties();
 			fis = new FileInputStream(cachePropFile);
 			try {
 				props.load(fis);
 			}
 			finally {
 				fis.close();
 			}
 		}
 		catch(IOException e) {
 			props = null;
 		}
 	}

 	if (props==null) {
 		// first time up, or failed to load previous settings
 		props = new Properties();
 		String tmp = System.getProperty("java.io.tmpdir");
 		if (!tmp.endsWith(File.separator)) tmp += File.separator;
 		tmp += CACHE_DIR;
 		props.put(CACHE_LOCATION_PROP,tmp);

 		tmp = Long.toString((new java.util.Date()).getTime(),36);
 		props.put(CACHE_PREFIX_PROP,tmp);

 		tmp += CACHE_INDEX;
 		props.put(CACHE_INDEX_PROP,tmp);

 		// save for next time around
 		FileOutputStream fos = null;
 		try {
 			fos = new FileOutputStream(cachePropFile);
 			try {
 				props.store(fos,null);
 			}
 			finally {
 				fos.close();
 			}
 		}
 		catch(IOException e) {
 			// failed to store cache location metadata ... ignore
 		}
 	}

 	// remember settings for shutdown processing
 	filePrefix = (String)props.get(CACHE_PREFIX_PROP);
 	indexName = (String)props.get(CACHE_INDEX_PROP);
 	cacheLocation = (String)props.get(CACHE_LOCATION_PROP);

 	if (DEBUG) {
 		debugStartup("Cache location: " + cacheLocation);
 		debugStartup("Cache index: " + indexName);
 		debugStartup("Cache file prefix: " + filePrefix);
 	}

 	// create cache directory structure if needed
 	if (!verifyLocation(cacheLocation)) {
 		indexName = null;
 		cacheLocation = null;
 		if (DEBUG)
 			debugStartup("Failed to create cache directory structure. Caching suspended");
 		return;
 	}

 	// attempt to initialize cache index
 	if (cacheLocation!=null && indexName!=null) {
 		try {
 			fis = new FileInputStream(cacheLocation+indexName);
 			try {
 				cacheIndex.load(fis);
 			}
 			finally {
 				fis.close();
 			}
 		}
 		catch(IOException e) {
 			if (DEBUG)
 				debugStartup("Failed to initialize cache");
 		}
 	}
 }
 private static boolean verifyLocation(String location) {

 	// verify cache directory exists. Create if needed
 	StringTokenizer t = new StringTokenizer(location, File.separator);
 	String cacheName = "";
 	File cacheDir;
 	boolean result = true;
 	while(t.hasMoreElements()) {
 		cacheName += t.nextElement() + File.separator;
 		cacheDir = new File(cacheName);
 		if (!cacheDir.exists()) {
 			if (!cacheDir.mkdir()) {
 				result = false;
 				break;
 			}
 		}
 	}
 	return result;
 }
 }
	package org.eclipse.core.internal.boot;

	/*
	* Licensed Materials - Property of IBM,
	* WebSphere Studio Workbench
	* (c) Copyright IBM Corp 2000
	*/

	/**
	* Platform URL support
	*/

	import java.net.*;
	import java.io.*;
	import java.util.*;

	public abstract class PlatformURLConnection extends URLConnection {

	// URL access
	private boolean isInCache = false;
	private boolean isJar = false;

	// protected URL url; // declared in super (platform: URL)
	private URL resolvedURL = null; // resolved file URL (eg. http: URL)
	private URL cachedURL = null; // file URL in cache (file: URL)

	private URLConnection connection = null; // actual connection

	// local cache
	private static Properties cacheIndex = new Properties();
	private static String cacheLocation;
	private static String indexName;
	private static String filePrefix;

	// constants
	private static final int BUF_SIZE = 32768;
	private static final Object NOT_FOUND = new Object(); // marker
	private static final String CACHE_PROP = ".cache.properties";
	private static final String CACHE_LOCATION_PROP = "location";
	private static final String CACHE_INDEX_PROP = "index";
	private static final String CACHE_PREFIX_PROP = "prefix";
	private static final String CACHE_INDEX = ".index.properties";
	private static final String CACHE_DIR = PlatformURLHandler.PROTOCOL + File.separator;

	// debug tracing
	public static boolean DEBUG = false;
	public static boolean DEBUG_CONNECT = true;
	public static boolean DEBUG_CACHE_LOOKUP = true;
	public static boolean DEBUG_CACHE_COPY = true;
	protected PlatformURLConnection(URL url) {
	super(url);
	}
	protected boolean allowCaching() {
	return false;
	}
	public void connect() throws IOException {
	connect(false);
	}
	private synchronized void connect(boolean asLocal) throws IOException {
	if (!connected) {
	if (shouldCache(asLocal)) {
	try {
	URL inCache = getURLInCache();
	if (inCache!=null) connection = inCache.openConnection();
	} catch(IOException e) {
	// failed to cache ... will use resolved URL instead
	}
	}

	// use resolved URL
	if (connection==null) connection = resolvedURL.openConnection();
	connected = true;
	if (DEBUG && DEBUG_CONNECT)
	debug("Connected as "+connection.getURL());
	}
	}
	private void copyToCache() throws IOException {

	if (isInCache \| cachedURL==null) return;
	String tmp;
	int ix;

	// cache entry key
	String key;
	if (isJar) {
	tmp = url.getFile();
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix!=-1) tmp = tmp.substring(0,ix);
	key = tmp;
	}
	else key = url.getFile();

	// source url
	URL src;
	if (isJar) {
	tmp = resolvedURL.getFile();
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix!=-1) tmp = tmp.substring(0,ix);
	src = new URL(tmp);
	}
	else src = resolvedURL;
	InputStream srcis = null;

	// cache target
	String tgt;
	if (isJar) {
	tmp = cachedURL.getFile();
	ix = tmp.indexOf(PlatformURLHandler.PROTOCOL_SEPARATOR);
	if (ix!=-1) tmp = tmp.substring(ix+1);
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix!=-1) tmp = tmp.substring(0,ix);
	tgt = tmp;
	}
	else tgt = cachedURL.getFile();
	File tgtFile = null;
	FileOutputStream tgtos = null;

	boolean error = false;
	long total = 0;

	try {
	if (DEBUG && DEBUG_CACHE_COPY) {
	if (isJar) debug ("Caching jar as "+tgt);
	else debug("Caching as "+tgt);
	}

	srcis = src.openStream();
	byte[] buf = new byte[BUF_SIZE];
	int count = srcis.read(buf);

	tgtFile = new File(tgt);
	tgtos = new FileOutputStream(tgtFile);

	while(count!=-1) {
	total += count;
	tgtos.write(buf,0,count);
	count = srcis.read(buf);
	}

	srcis.close();
	srcis=null;
	tgtos.close();
	tgtos=null;

	// add cache entry
	cacheIndex.put(key,tgt);
	isInCache = true;
	}
	catch(IOException e) {
	error = true;
	cacheIndex.put(key,NOT_FOUND); // mark cache entry for this execution
	if (DEBUG && DEBUG_CACHE_COPY)
	debug("Failed to cache due to "+e);
	throw e;
	}
	finally {
	if (!error && DEBUG && DEBUG_CACHE_COPY)
	debug(total + " bytes copied");
	if (srcis!=null) srcis.close();
	if (tgtos!=null) tgtos.close();
	}
	}
	protected void debug(String s) {

	System.out.println("URL "+getURL().toString()+"^"+Integer.toHexString(Thread.currentThread().hashCode())+" "+s);
	}
	private static void debugStartup(String s) {

	System.out.println("URL "+s);
	}
	public synchronized InputStream getInputStream() throws IOException {
	if (!connected) connect();
	return connection.getInputStream();
	}
	public URL getResolvedURL() {
	return resolvedURL;
	}
	public URL getURLAsLocal() throws IOException {
	connect(true); // connect and force caching if necessary
	URL u = connection.getURL();
	String up = u.getProtocol();
	if (!up.equals(PlatformURLHandler.FILE) && !up.equals(PlatformURLHandler.JAR) && !up.equals(PlatformURLHandler.VA)) throw new IOException("Unable to access URL as local "+url.toString());
	return u;
	}
	private URL getURLInCache() throws IOException {

	if (!allowCaching()) return null; // target should not be cached

	if (isInCache) return cachedURL;

	if (cacheLocation==null \| cacheIndex==null) return null; // not caching

	// check if we are dealing with a .jar/ .zip
	String file = "";
	String jarEntry = null;
	if (isJar) {
	file = url.getFile();
	int ix = file.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix!=-1) {
	jarEntry = file.substring(ix+PlatformURLHandler.JAR_SEPARATOR.length());
	file = file.substring(0,ix);
	}
	}
	else {
	file = url.getFile();
	jarEntry = null;
	}

	// check for cached entry
	String tmp = (String)cacheIndex.get(file);

	// check for "not found" marker
	if (tmp!=null && tmp==NOT_FOUND) throw new IOException();

	// validate cache entry
	if (tmp!=null && !(new File(tmp)).exists()) {
	tmp = null;
	cacheIndex.remove(url.getFile());
	}

	// found in cache
	if (tmp!=null) {
	if (isJar) {
	if (DEBUG && DEBUG_CACHE_LOOKUP)
	debug("Jar located in cache as "+tmp);
	tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
	cachedURL = new URL(PlatformURLHandler.JAR,null,-1,tmp);
	}
	else {
	if (DEBUG && DEBUG_CACHE_LOOKUP)
	debug("Located in cache as "+tmp);
	cachedURL = new URL(PlatformURLHandler.FILE,null,-1,tmp);
	}
	isInCache = true;
	}
	else {
	// attemp to cache
	int ix = file.lastIndexOf("/");
	tmp = file.substring(ix+1);
	tmp = cacheLocation + filePrefix + Long.toString((new java.util.Date()).getTime(),36) + "_" + tmp;
	tmp = tmp.replace(File.separatorChar,'/');
	if (isJar) {
	tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
	cachedURL = new URL(PlatformURLHandler.JAR,null,-1,tmp);
	}
	else cachedURL = new URL(PlatformURLHandler.FILE,null,-1,tmp);
	copyToCache();
	}

	return cachedURL;
	}
	/*
	* to be implemented by subclass
	* @return URL resolved URL
	*/

	protected URL resolve() throws IOException {
	throw new IOException();
	}
	void setResolvedURL(URL url) throws IOException {
	if (resolvedURL==null) {
	int ix = url.getFile().lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	isJar = -1 != ix;
	// Resolved URLs containing !/ separator are assumed to be jar URLs.
	// If the resolved protocol is not jar, new jar URL is created.
	if (isJar && !url.getProtocol().equals(PlatformURLHandler.JAR)) url = new URL(PlatformURLHandler.JAR,null,-1,url.toExternalForm());
	resolvedURL=url;
	}
	}
	private boolean shouldCache(boolean asLocal) {

	// don't cache files that are known to be local
	String rp = resolvedURL.getProtocol();
	String rf = resolvedURL.getFile();
	if (rp.equals(PlatformURLHandler.FILE) \|\| rp.equals(PlatformURLHandler.VA)) return false;
	if (rp.equals(PlatformURLHandler.JAR) && (rf.startsWith(PlatformURLHandler.FILE) \|\| rf.startsWith(PlatformURLHandler.VA) )) return false;

	// for other files force caching if local connection was requested
	if (asLocal) return true;

	// for now cache all files
	// XXX: add cache policy support
	return true;
	}
	static void shutdown() {

	if (indexName!=null && cacheLocation!=null) {
	// weed out "not found" entries
	Enumeration keys = cacheIndex.keys();
	String key;
	Object value;
	while (keys.hasMoreElements()) {
	key = (String) keys.nextElement();
	value = cacheIndex.get(key);
	if (value==NOT_FOUND) cacheIndex.remove(key);
	}

	// try to save cache index
	FileOutputStream fos = null;
	try {
	fos = new FileOutputStream(cacheLocation+indexName);
	try {
	cacheIndex.store(fos,null);
	}
	finally {
	fos.close();
	}
	}
	catch(IOException e) {
	// failed to store cache index ... ignore
	}
	}
	}
	static void startup(String location) {


	verifyLocation(location); // check for platform location, ignore errors
	String cacheProps = location.trim();
	if (!cacheProps.endsWith(File.separator)) cacheProps += File.separator;
	cacheProps += CACHE_PROP;
	File cachePropFile = new File(cacheProps);
	Properties props = null;
	FileInputStream fis;

	if (cachePropFile.exists()) {
	// load existing properties
	try {
	props = new Properties();
	fis = new FileInputStream(cachePropFile);
	try {
	props.load(fis);
	}
	finally {
	fis.close();
	}
	}
	catch(IOException e) {
	props = null;
	}
	}

	if (props==null) {
	// first time up, or failed to load previous settings
	props = new Properties();
	String tmp = System.getProperty("java.io.tmpdir");
	if (!tmp.endsWith(File.separator)) tmp += File.separator;
	tmp += CACHE_DIR;
	props.put(CACHE_LOCATION_PROP,tmp);

	tmp = Long.toString((new java.util.Date()).getTime(),36);
	props.put(CACHE_PREFIX_PROP,tmp);

	tmp += CACHE_INDEX;
	props.put(CACHE_INDEX_PROP,tmp);

	// save for next time around
	FileOutputStream fos = null;
	try {
	fos = new FileOutputStream(cachePropFile);
	try {
	props.store(fos,null);
	}
	finally {
	fos.close();
	}
	}
	catch(IOException e) {
	// failed to store cache location metadata ... ignore
	}
	}

	// remember settings for shutdown processing
	filePrefix = (String)props.get(CACHE_PREFIX_PROP);
	indexName = (String)props.get(CACHE_INDEX_PROP);
	cacheLocation = (String)props.get(CACHE_LOCATION_PROP);

	if (DEBUG) {
	debugStartup("Cache location: " + cacheLocation);
	debugStartup("Cache index: " + indexName);
	debugStartup("Cache file prefix: " + filePrefix);
	}

	// create cache directory structure if needed
	if (!verifyLocation(cacheLocation)) {
	indexName = null;
	cacheLocation = null;
	if (DEBUG)
	debugStartup("Failed to create cache directory structure. Caching suspended");
	return;
	}

	// attempt to initialize cache index
	if (cacheLocation!=null && indexName!=null) {
	try {
	fis = new FileInputStream(cacheLocation+indexName);
	try {
	cacheIndex.load(fis);
	}
	finally {
	fis.close();
	}
	}
	catch(IOException e) {
	if (DEBUG)
	debugStartup("Failed to initialize cache");
	}
	}
	}
	private static boolean verifyLocation(String location) {

	// verify cache directory exists. Create if needed
	StringTokenizer t = new StringTokenizer(location, File.separator);
	String cacheName = "";
	File cacheDir;
	boolean result = true;
	while(t.hasMoreElements()) {
	cacheName += t.nextElement() + File.separator;
	cacheDir = new File(cacheName);
	if (!cacheDir.exists()) {
	if (!cacheDir.mkdir()) {
	result = false;
	break;
	}
	}
	}
	return result;
	}
	}