diff options
| -rw-r--r-- | src/org/jdesktop/applet/util/JNLPAppletLauncher.java | 157 |
1 files changed, 118 insertions, 39 deletions
diff --git a/src/org/jdesktop/applet/util/JNLPAppletLauncher.java b/src/org/jdesktop/applet/util/JNLPAppletLauncher.java index 5fed2e9..f3bee02 100644 --- a/src/org/jdesktop/applet/util/JNLPAppletLauncher.java +++ b/src/org/jdesktop/applet/util/JNLPAppletLauncher.java @@ -37,8 +37,8 @@ * intended for use in the design, construction, operation or * maintenance of any nuclear facility. * - * $Revision: 1.4 $ - * $Date: 2007/06/19 20:27:26 $ + * $Revision: 1.5 $ + * $Date: 2007/06/28 18:15:50 $ * $State: Exp $ */ @@ -50,8 +50,12 @@ import java.applet.AppletStub; import java.awt.BorderLayout; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; +import java.io.BufferedReader; +import java.io.BufferedWriter; import java.io.File; import java.io.FileOutputStream; +import java.io.FileReader; +import java.io.FileWriter; import java.io.FilenameFilter; import java.io.IOException; import java.io.InputStream; @@ -301,6 +305,8 @@ public class JNLPAppletLauncher extends Applet { * during validation, since multiple threads, or even multiple processes, * can access it concurrently. * + * TODO: We need a way to clear the cache. + * * We also considered, but rejected, the following solutions: * * 1. Use a temporary directory for native jars, download, verify, unpack, @@ -500,7 +506,6 @@ public class JNLPAppletLauncher extends Applet { } lckFile.createNewFile(); final FileOutputStream lckOut = new FileOutputStream(lckFile); - final FileChannel lckChannel = lckOut.getChannel(); final FileLock lckLock = lckChannel.lock(); @@ -1015,35 +1020,15 @@ public class JNLPAppletLauncher extends Applet { } // Validate the cache, download the jar if needed - if (!validateCache(conn, nativeFile, indexFile)) { - if (VERBOSE) { - System.err.println("processNativeJar: downloading " + nativeFile.getAbsolutePath()); - } - indexFile.delete(); - nativeFile.delete(); - - // Copy from URL to File - int len = conn.getContentLength(); - if (VERBOSE) { - System.err.println("Content length = " + len + " bytes"); - } - - int totalNumBytes = copyURLToFile(conn, nativeFile); - if (DEBUG) { - System.err.println("processNativeJar: " + conn.getURL().toString() + - " --> " + nativeFile.getAbsolutePath() + " : " + - totalNumBytes + " bytes written"); - } - - // TODO: Write timestamp to index file. - - } else { - if (DEBUG) { - System.err.println("processNativeJar: using previously cached: " + - nativeFile.getAbsolutePath()); - } + // TODO: rather than synchronizing on System.out during cache validation, + // we should use a System property as a lock token (protected by + // System.out) so we don't hold a synchronized lock on System.out during + // a potentially long download operation. + synchronized (System.out) { + validateCache(conn, nativeFile, indexFile); } + // Unpack the jar file displayMessage("Unpacking: " + nativeFileName); setProgress(0); @@ -1062,22 +1047,116 @@ public class JNLPAppletLauncher extends Applet { } } - // Validate the cached file. If the cached file is valid, return true, else - // return false. - private boolean validateCache(URLConnection conn, File nativeFile, File indexFile) { - // TODO: implement this for real - return nativeFile.exists(); + // Validate the cached file. If the cached file is out of date or otherwise + // invalid, download the file and store the new time stamp. + // This method must be called with a global lock being held such that + // no other thread -- even in another class loader -- can executed this + // method concurrently. + private void validateCache(URLConnection conn, + File nativeFile, + File indexFile) throws IOException { + + // Lock the cache directory + final String lckFileName = "cache.lck"; + File lckFile = new File(cacheDir, lckFileName); + lckFile.createNewFile(); + final FileOutputStream lckOut = new FileOutputStream(lckFile); + final FileChannel lckChannel = lckOut.getChannel(); + final FileLock lckLock = lckChannel.lock(); + + try { + // Check to see whether the cached jar file exists and is valid + boolean valid = false; + long cachedTimeStamp = readTimeStamp(indexFile); + long urlTimeStamp = conn.getLastModified(); + + if (nativeFile.exists() && + urlTimeStamp > 0 && + urlTimeStamp == readTimeStamp(indexFile)) { + + valid = true; + } + + // Validate the cache, download the jar if needed + if (!valid) { + if (VERBOSE) { + System.err.println("processNativeJar: downloading " + nativeFile.getAbsolutePath()); + } + indexFile.delete(); + nativeFile.delete(); + + // Copy from URL to File + int len = conn.getContentLength(); + if (VERBOSE) { + System.err.println("Content length = " + len + " bytes"); + } + + int totalNumBytes = copyURLToFile(conn, nativeFile); + if (DEBUG) { + System.err.println("processNativeJar: " + conn.getURL().toString() + + " --> " + nativeFile.getAbsolutePath() + " : " + + totalNumBytes + " bytes written"); + } + + // Write timestamp to index file. + writeTimeStamp(indexFile, urlTimeStamp); + + } else { + if (DEBUG) { + System.err.println("processNativeJar: using previously cached: " + + nativeFile.getAbsolutePath()); + } + } + } finally { + // Unlock the cache directory + lckLock.release(); + } + } + + private long readTimeStamp(File indexFile) { + try { + BufferedReader reader = new BufferedReader(new FileReader(indexFile)); + try { + String str = reader.readLine(); + return Long.parseLong(str); + } finally { + reader.close(); + } + } catch (Exception ex) { + } + return -1; + } + + private void writeTimeStamp(File indexFile, long timestamp) { + try { + BufferedWriter writer = new BufferedWriter(new FileWriter(indexFile)); + try { + writer.write("" + timestamp + "\n"); + writer.flush(); + } finally { + writer.close(); + } + } catch (Exception ex) { + displayError("Error writing time stamp for native libraries"); + } } // Copy the specified URL to the specified File private int copyURLToFile(URLConnection inConnection, File outFile) throws IOException { + int totalNumBytes = 0; InputStream in = new BufferedInputStream(inConnection.getInputStream()); - OutputStream out = new BufferedOutputStream(new FileOutputStream(outFile)); - int totalNumBytes = copyStream(in, out, inConnection.getContentLength()); - out.close(); - in.close(); + try { + OutputStream out = new BufferedOutputStream(new FileOutputStream(outFile)); + try { + totalNumBytes = copyStream(in, out, inConnection.getContentLength()); + } finally { + out.close(); + } + } finally { + in.close(); + } return totalNumBytes; } |