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From patri...@apache.org
Subject cvs commit: jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher ChildMain.java LaunchTask.java NonBlockingInputStream.java ParentListener.java
Date Wed, 21 Aug 2002 20:53:19 GMT
patrickl    2002/08/21 13:53:19

  Modified:    daemon/src/java/org/apache/commons/launcher ChildMain.java
                        LaunchTask.java NonBlockingInputStream.java
                        ParentListener.java
  Log:
  Eliminate need for heartbeat files to monitor parent JVM
  
  Revision  Changes    Path
  1.9       +2 -9      jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/ChildMain.java
  
  Index: ChildMain.java
  ===================================================================
  RCS file: /home/cvs/jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/ChildMain.java,v
  retrieving revision 1.8
  retrieving revision 1.9
  diff -u -r1.8 -r1.9
  --- ChildMain.java	21 Aug 2002 03:09:04 -0000	1.8
  +++ ChildMain.java	21 Aug 2002 20:53:19 -0000	1.9
  @@ -109,12 +109,6 @@
           "org.apache.commons.launcher.executableName";
   
       /**
  -     * The heartbeatFile system property name.
  -     */
  -    public final static String HEARTBEAT_FILE_PROP_NAME =
  -        "org.apache.commons.launcher.heartbeatFile";
  -
  -    /**
        * The miminizedWindowTitle system property name.
        */
       public final static String MINIMIZED_WINDOW_TITLE_PROP_NAME =
  @@ -209,11 +203,10 @@
                       System.setIn(new NonBlockingInputStream(System.in));
   
                   waitForChild = true;
  -                String heartbeatFile = System.getProperty(ChildMain.HEARTBEAT_FILE_PROP_NAME);
  -                ParentListener heartbeat = new ParentListener(heartbeatFile);
  +                ParentListener heartbeat = new ParentListener();
                   // Make the thread a daemon thread so that it does not
                   // prevent this process from exiting when all of the
  -                // appliation's threads finish.
  +                // application's threads finish.
                   heartbeat.setDaemon(true);
                   heartbeat.start();
               }
  
  
  
  1.24      +0 -23     jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/LaunchTask.java
  
  Index: LaunchTask.java
  ===================================================================
  RCS file: /home/cvs/jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/LaunchTask.java,v
  retrieving revision 1.23
  retrieving revision 1.24
  diff -u -r1.23 -r1.24
  --- LaunchTask.java	31 Jul 2002 02:04:48 -0000	1.23
  +++ LaunchTask.java	21 Aug 2002 20:53:19 -0000	1.24
  @@ -58,7 +58,6 @@
   package org.apache.commons.launcher;
   
   import java.io.File;
  -import java.io.FileOutputStream;
   import java.io.IOException;
   import java.net.URL;
   import java.net.URLClassLoader;
  @@ -578,24 +577,6 @@
                   }
               }
   
  -            // Create the heartbeatFile. This file is needed by the
  -            // ParentListener class on Windows since the entire child JVM
  -            // process will block on Windows machines using some versions of
  -            // Unix shells such as MKS, etc.
  -            File heartbeatFile = null;
  -            FileOutputStream heartbeatOutputStream = null;
  -            if (filteredWaitForChild) {
  -                File tmpDir = null;
  -                String tmpDirName = (String)sysProps.get("java.io.tmpdir");
  -                if (tmpDirName != null)
  -                    tmpDir = new File(tmpDirName);
  -                heartbeatFile = File.createTempFile(ChildMain.HEARTBEAT_FILE_PROP_NAME
+ ".", "", tmpDir);
  -                // Open the heartbeat file for writing so that it the child JVM
  -                // will not be able to delete it while this process is running
  -                heartbeatOutputStream = new FileOutputStream(heartbeatFile);
  -                sysProps.put(ChildMain.HEARTBEAT_FILE_PROP_NAME, heartbeatFile.getCanonicalPath());
  -            }
  -
               // Assemble child command
               String[] cmd = new String[5 + jvmArgs.size() + sysProps.size() + appArgs.size()];
               int nextCmdArg = 0;
  @@ -697,10 +678,6 @@
                   // Let threads flush any unflushed output
                   stdout.join();
                   stderr.join();
  -                if (heartbeatOutputStream != null)
  -                    heartbeatOutputStream.close();
  -                if (heartbeatFile != null)
  -                    heartbeatFile.delete();
                   int exitValue = proc.exitValue();
                   if (filteredFailOnError && exitValue != 0)
                       throw new BuildException(Launcher.getLocalizedString("child.failed",
this.getClass().getName()) + " " + exitValue);
  
  
  
  1.2       +10 -23    jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/NonBlockingInputStream.java
  
  Index: NonBlockingInputStream.java
  ===================================================================
  RCS file: /home/cvs/jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/NonBlockingInputStream.java,v
  retrieving revision 1.1
  retrieving revision 1.2
  diff -u -r1.1 -r1.2
  --- NonBlockingInputStream.java	21 Aug 2002 03:09:04 -0000	1.1
  +++ NonBlockingInputStream.java	21 Aug 2002 20:53:19 -0000	1.2
  @@ -98,11 +98,8 @@
        */
       public synchronized int read() throws IOException {
   
  -        int available = waitForAvailable();
  -        if (available > 0)
  -            return super.read();
  -        else
  -            return available;
  +        waitForAvailable();
  +        return super.read();
   
       }
   
  @@ -119,10 +116,7 @@
       public synchronized int read(byte[] b) throws IOException {
   
           int available = waitForAvailable();
  -        if (available > 0)
  -            return super.read(b, 0, available);
  -        else
  -            return available;
  +        return super.read(b, 0, available);
   
       }
   
  @@ -144,13 +138,9 @@
       {
   
           int available = waitForAvailable();
  -        if (available > 0) {
  -            if (available < len)
  -                len = available;
  -            return super.read(b, off, len);
  -        } else {
  -            return available;
  -        }
  +        if (available < len)
  +            len = available;
  +        return super.read(b, off, len);
   
       }
   
  @@ -167,13 +157,9 @@
       public synchronized long skip(long n) throws IOException {
   
           int available = waitForAvailable();
  -        if (available > 0) {
  -            if (available < n)
  -                n = available;
  -            return super.skip(n);
  -        } else {
  -            return available;
  -        }
  +        if (available < n)
  +            n = available;
  +        return super.skip(n);
   
       }
   
  @@ -192,6 +178,7 @@
   
           int available = 0;
           while ((available = available()) == 0) {
  +            Thread.currentThread().yield();
               try {
                   Thread.currentThread().sleep(100);
               } catch (Exception e) {}
  
  
  
  1.4       +18 -98    jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/ParentListener.java
  
  Index: ParentListener.java
  ===================================================================
  RCS file: /home/cvs/jakarta-commons-sandbox/daemon/src/java/org/apache/commons/launcher/ParentListener.java,v
  retrieving revision 1.3
  retrieving revision 1.4
  diff -u -r1.3 -r1.4
  --- ParentListener.java	31 Jul 2002 01:20:09 -0000	1.3
  +++ ParentListener.java	21 Aug 2002 20:53:19 -0000	1.4
  @@ -57,9 +57,7 @@
   
   package org.apache.commons.launcher;
   
  -import java.io.File;
  -import java.io.InputStream;
  -import java.io.IOException;
  +import java.io.PrintStream;
   
   /**
    * A class for detecting if the parent JVM that launched this process has
  @@ -69,110 +67,32 @@
    */
   public class ParentListener extends Thread {
   
  -    //------------------------------------------------------------------ Fields
  -
  -    /**
  -     * Cached heartbeat file.
  -     */
  -    private File heartbeatFile = null;
  -
  -    //------------------------------------------------------------ Constructors
  -
  -    /**
  -     * Validates and caches a lock file created by the parent JVM.
  -     *
  -     * @param path the lock file that the parent JVM has an open
  -     *  FileOutputStream
  -     * @throws IOException if the heartbeat cannot be converted into a valid
  -     *  File object
  -     */
  -    public ParentListener(String path) throws IOException {
  -
  -        if (path == null)
  -            throw new IOException();
  -
  -        // Make sure we have a valid path
  -        heartbeatFile = new File(path);
  -        heartbeatFile.getCanonicalPath();
  -
  -    }
   
       //----------------------------------------------------------------- Methods
   
       /**
  -     * Periodically check that the parent JVM has not terminated. On all
  -     * platforms other than Windows, this method will check that System.in has
  -     * not been closed. On Windows NT, 2000, and XP the lock file specified in
  -     * the {@link #ParentListener(String)} constructor is monitored as reading
  -     * System.in will block the entire process on Windows machines that use
  -     * some versions of Unix shells such as MKS, etc. No monitoring is done
  -     * on Window 95, 98, and ME.
  +     * Periodically check that the parent JVM has not terminated by checking
  +     * if {@link System#err} is open. If {@link System#err} is in an error
  +     * state, the parent JVM is assumed to be terminated and this method will
  +     * invoke {@link Syste#exit(int)}. This method <b>must</b> be executed
  +     * <b>before</b> {@link System#setErr(int)} is ever invoked.
  +     * <p>
  +     * TODO: {@link System#err} never seems to close while System.in is
  +     * being read on Windows platforms. Need to find a workaround for this
  +     * case.
        */ 
       public void run() {
   
  -        String osname = System.getProperty("os.name").toLowerCase();
  -
  -        // We need to use file locking on Windows since reading System.in
  -        // will block the entire process on some Windows machines.
  -        if (osname.indexOf("windows") >= 0) {
  -
  -            // Do nothing if this is a Windows 9x platform since our file
  -            // locking mechanism does not work on the early versions of
  -            // Windows
  -            if (osname.indexOf("nt") == -1 && osname.indexOf("2000") == -1 &&
osname.indexOf("xp") == -1)
  -                return;
  -
  -            // If we can delete the heartbeatFile on Windows, it means that
  -            // the parent JVM has closed its FileOutputStream on the file.
  -            // Note that the parent JVM's stream should only be closed when
  -            // it exits.
  -            for ( ; ; ) {
  -                if (heartbeatFile.delete())
  -                    break;
  -                // Wait awhile before we try again
  -                yield();
  -                try {
  -                    sleep(5000);
  -                } catch (Exception e) {}
  -            }
  -
  -        } else {
  -
  -            // Cache System.in in case the application redirects
  -            InputStream is = System.in;
  -            int bytesAvailable = 0;
  -            int bytesRead = 0;
  -            byte[] buf = new byte[1024];
  +        // Save System.err in case the application invokes System.setErr()
  +        // later
  +        PrintStream err = System.err;
  +        while (!err.checkError()) {
  +            // Wait a while before the next loop
  +            yield();
               try {
  -                while (true) {
  -                    synchronized (is) {
  -                        // Mark the stream position so that other threads can
  -                        // reread the strea
  -                        is.mark(buf.length);
  -                        // Read one more byte than has already been read to
  -                        // force the stream to wait for input
  -                        bytesAvailable = is.available();
  -                        if (bytesAvailable < buf.length) {
  -                            bytesRead = is.read(buf, 0, bytesAvailable + 1);
  -                            // Reset so that we "unread" the bytes that we read
  -                            is.reset();
  -                            if (bytesRead == -1)
  -                                break;
  -                        } else {
  -                            // Make the buffer larger
  -                            if (buf.length < Integer.MAX_VALUE / 2)
  -                                buf = new byte[buf.length * 2];
  -                        }
  -                    }
  -                    yield();
  -                }
  -            } catch (IOException ioe) {}
  -
  +                sleep(3000);
  +            } catch (Exception e) {}
           }
  -
  -        // Clean up before exiting
  -        if (heartbeatFile != null)
  -            heartbeatFile.delete();
   
           // Exit this process since the parent JVM has exited
           System.exit(0);
  
  
  

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