[icedtea-web] RFC: Patch to stabilize applet initialization
Deepak Bhole
dbhole at redhat.com
Fri Oct 22 12:46:25 PDT 2010
* Deepak Bhole <dbhole at redhat.com> [2010-10-22 11:28]:
> * Dr Andrew John Hughes <ahughes at redhat.com> [2010-10-21 17:52]:
> > On 17:38 Thu 21 Oct , Deepak Bhole wrote:
> > > Hi,
> > >
> > > The attached patch envelopes fixes for two of Andrew's pending patches
> > > (fixing 100% CPU load and the frame pop-up issue). In addition to those,
> > > it fixes a lot of other initialization issues, particularly when
> > > initializing multiple applets and/or closing other tabs with applets
> > > which are being initialized.
> > >
> > > With this patch, I tested over 200 parallel applet inits, randomly
> > > closing tabs, and everything works correctly.
> > >
> > > One known issue is that if timed correctly, a frame can appear outside
> > > for a fraction of a second. It always goes away instantly though, and I
> > > will be posting a patch to fix that problem in the near future.
> > >
> > > Cheers,
> > > Deepak
> >
> > Do you have a ChangeLog for this? It would be good to know why each change
> > is being made.
> >
Sorry, forgot the ChangeLog:
2010-10-22 Deepak Bhole <dbhole at redhat.com>
* plugin/icedteanp/java/sun/applet/PluginAppletViewer.java:
Replace all status.put calls with calls to updateStatus().
(createPanel): Create a frame with a 0 handle. Use the new
waitForAppletInit function to wait until applet is ready.
(reFrame): Re-order code so that the panel is never parentless.
(handleMessage): Re-wrote message processing to handle destroy calls
correctly, checking for them more often to prevent a frame from popping up
if the tab/page is closed before loading finishes. Decode special
characters in the message.
(updateStatus): New function. Updates the status for the given instance if
applicable.
(destroyApplet): New function. Destroys a given applet and frees related
resources.
(waitForAppletInit): New function. Blocks until applet is initialized.
(parse): Remove part that decoded the params. Decoding is now done earlier
in handleMessage().
* plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java:
(getPriorityStrIfPriority): Mark destroy messages as priority.
(bringPriorityMessagesToFront): Scans the queue for priority messages and
brings them to the front.
(run): If the queue is not empty and there are no workers left, run
bringPriorityMessagesToFront() and retry.
> > In particular, why:
> >
> > > +
> > > + // Add first, remove later
> > > + newFrame.add("Center", panel);
> > > oldFrame.remove(panel);
> > > oldFrame.dispose();
> > > + } else {
> > > + newFrame.add("Center", panel);
> > > }
> > >
> > > - newFrame.add("Center", panel);
> >
> > is this necessary?
> >
>
> As crazy as that looks, yes. here is the full piece of the code:
>
> PluginAppletViewer newFrame = new PluginAppletViewer(handle, identifier, statusMsgStream, panel);
>
> if (oldFrame != null) {
> applets.remove(oldFrame.identifier);
> oldFrame.removeWindowListener(oldFrame.windowEventListener);
> panel.removeAppletListener(oldFrame.appletEventListener);
>
> // Add first, remove later
> newFrame.add("Center", panel);
> oldFrame.remove(panel);
> oldFrame.dispose();
> } else {
> newFrame.add("Center", panel);
> }
>
> oldFrame is an embedded frame in which an applet instance resides, newFrame is
> another embedded frame with a different handle that it needs to be moved to. In
> addition to being implanted in oldFrame, oldFrame is also registered as a
> listener for a few things. We first need to unregister those listeners. We then
> need to add it to the newFrame right away, as there are problems if the panel
> does not have a parent. Hence the add being done in the if loop.
>
> There is a second case where there may be no previous parent frame at all
> (initial embedding) -- in this case, we need to do the add() in the else
> otherwise it will get added twice.
>
> The change I alluded to in the original email (to fix the pop-out frame
> completely) will get rid of the above if/else condition btw, so it is only
> temporary.
>
> Cheers,
> Deepak
>
> > Also there seems to be some odd whitespace changes and excessive (8 space) indenting.
> >
> > > diff -r 85db7b3a1c93 plugin/icedteanp/java/sun/applet/PluginAppletViewer.java
> > > --- a/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Thu Oct 21 21:12:21 2010 +0100
> > > +++ b/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Thu Oct 21 17:22:56 2010 -0700
> > > @@ -136,12 +136,10 @@
> > > }
> > > }
> > > });
> > > +
> > > + // create the frame.
> > > + PluginAppletViewer.reFrame(null, identifier, System.out, 0, panel);
> > >
> > > -
> > > -
> > > - // create the frame.
> > > - PluginAppletViewer.reFrame(null, identifier, System.out, handle, panel);
> > > -
> > > panel.init();
> > >
> > > // Start the applet
> > > @@ -179,15 +177,7 @@
> > >
> > > // Wait for the panel to initialize
> > > // (happens in a separate thread)
> > > - while (panel.getApplet() == null &&
> > > - ((NetxPanel) panel).isAlive()) {
> > > - try {
> > > - Thread.sleep(50);
> > > - PluginDebug.debug("Waiting for applet to initialize...");
> > > - } catch (InterruptedException ie) {
> > > - // just wait
> > > - }
> > > - }
> > > + PluginAppletViewer.waitForAppletInit((NetxPanel) panel);
> > >
> > > a = panel.getApplet();
> > >
> > > @@ -317,7 +307,17 @@
> > > */
> > > private static String defaultSaveFile = "Applet.ser";
> > >
> > > - private static enum PAV_INIT_STATUS {PRE_INIT, IN_INIT, INIT_COMPLETE, INACTIVE};
> > > +
> > > + /**
> > > + * Enumerates the current status of an applet
> > > + *
> > > + * PRE_INIT -> Parsing and initialization phase
> > > + * INIT_COMPLETE -> Initialization complete, reframe pending
> > > + * REFRAME_COMPLETE -> Reframe complete, applet is initialized and usable by the user
> > > + * INACTIVE -> Browser has directed that the applet be destroyed (this state is non-overridable except by DESTROYED)
> > > + * DESTROYED -> Applet has been destroyed
> > > + */
> > > + private static enum PAV_INIT_STATUS {PRE_INIT, INIT_COMPLETE, REFRAME_COMPLETE, INACTIVE, DESTROYED};
> > >
> > > /**
> > > * The panel in which the applet is being displayed.
> > > @@ -350,7 +350,6 @@
> > >
> > > private static HashMap<Integer, PAV_INIT_STATUS> status =
> > > new HashMap<Integer,PAV_INIT_STATUS>();
> > > -
> > >
> > > private long handle = 0;
> > > private WindowListener windowEventListener = null;
> > > @@ -380,16 +379,20 @@
> > > return;
> > >
> > > PluginAppletViewer newFrame = new PluginAppletViewer(handle, identifier, statusMsgStream, panel);
> > > -
> > > +
> > > if (oldFrame != null) {
> > > applets.remove(oldFrame.identifier);
> > > oldFrame.removeWindowListener(oldFrame.windowEventListener);
> > > panel.removeAppletListener(oldFrame.appletEventListener);
> > > +
> > > + // Add first, remove later
> > > + newFrame.add("Center", panel);
> > > oldFrame.remove(panel);
> > > oldFrame.dispose();
> > > + } else {
> > > + newFrame.add("Center", panel);
> > > }
> > >
> > > - newFrame.add("Center", panel);
> > > newFrame.pack();
> > >
> > > newFrame.appletEventListener = new AppletEventListener(newFrame, newFrame);
> > > @@ -397,11 +400,6 @@
> > >
> > > applets.put(identifier, newFrame);
> > >
> > > - // dispose oldframe if necessary
> > > - if (oldFrame != null) {
> > > - oldFrame.dispose();
> > > - }
> > > -
> > > PluginDebug.debug(panel + " reframed");
> > > }
> > >
> > > @@ -449,7 +447,7 @@
> > > this.frame = frame;
> > > this.appletViewer = appletViewer;
> > > }
> > > -
> > > +
> > > public void appletStateChanged(AppletEvent evt)
> > > {
> > > AppletPanel src = (AppletPanel)evt.getSource();
> > > @@ -483,9 +481,9 @@
> > > AppletPanel.changeFrameAppContext(frame, SunToolkit.targetToAppContext(a));
> > > else
> > > AppletPanel.changeFrameAppContext(frame, AppContext.getAppContext());
> > > -
> > > - status.put(appletViewer.identifier, PAV_INIT_STATUS.INIT_COMPLETE);
> > > -
> > > +
> > > + updateStatus(appletViewer.identifier, PAV_INIT_STATUS.INIT_COMPLETE);
> > > +
> > > break;
> > > }
> > > }
> > > @@ -510,7 +508,13 @@
> > >
> > > try {
> > > if (message.startsWith("handle")) {
> > > -
> > > +
> > > + // If there is a key for this status, it means it
> > > + // was either initialized before, or destroy has been
> > > + // processed. Stop moving further.
> > > + if (updateStatus(identifier, PAV_INIT_STATUS.PRE_INIT) != null)
> > > + return;
> > > +
> > > // Extract the information from the message
> > > String[] msgParts = new String[4];
> > > for (int i=0; i < 3; i++) {
> > > @@ -519,32 +523,38 @@
> > > msgParts[i] = message.substring(spaceLocation + 1, nextSpaceLocation);
> > > message = message.substring(nextSpaceLocation + 1);
> > > }
> > > -
> > > +
> > > long handle = Long.parseLong(msgParts[0]);
> > > String width = msgParts[1];
> > > String height = msgParts[2];
> > > -
> > > +
> > > int spaceLocation = message.indexOf(' ', "tag".length()+1);
> > > String documentBase =
> > > UrlUtil.decode(message.substring("tag".length() + 1, spaceLocation));
> > > - String tag = message.substring(spaceLocation+1);
> > > + String tag = message.substring(spaceLocation+1);
> > > +
> > > + // Decode the tag
> > > + tag = tag.replace(">", ">");
> > > + tag = tag.replace("<", "<");
> > > + tag = tag.replace("&", "&");
> > > + tag = tag.replace(" ", "\n");
> > > + tag = tag.replace(" ", "\r");
> > > + tag = tag.replace(""", "\"");
> > >
> > > PluginDebug.debug ("Handle = " + handle + "\n" +
> > > "Width = " + width + "\n" +
> > > "Height = " + height + "\n" +
> > > "DocumentBase = " + documentBase + "\n" +
> > > "Tag = " + tag);
> > > -
> > > - status.put(identifier, PAV_INIT_STATUS.PRE_INIT);
> > > +
> > > PluginAppletViewer.parse
> > > (identifier, handle, width, height,
> > > new StringReader(tag),
> > > new URL(documentBase));
> > > -
> > >
> > > int maxWait = APPLET_TIMEOUT; // wait for applet to fully load
> > > int wait = 0;
> > > - while (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE) &&
> > > + while ( !applets.containsKey(identifier) && // Map is populated only by reFrame
> > > (wait < maxWait)) {
> > >
> > > try {
> > > @@ -555,9 +565,44 @@
> > > }
> > > }
> > >
> > > - if (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE))
> > > + // If wait exceeded maxWait, we timed out. Throw an exception
> > > + if (wait >= maxWait)
> > > throw new Exception("Applet initialization timeout");
> > >
> > > + PluginAppletViewer oldFrame = applets.get(identifier);
> > > +
> > > + // We should not try to destroy an applet during
> > > + // initialization. It may cause an inconsistent state,
> > > + // which would bad if it's a trusted applet that
> > > + // read/writes to files
> > > + waitForAppletInit((NetxPanel) applets.get(identifier).panel);
> > > +
> > > + // Should we proceed with reframing?
> > > + if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE)) {
> > > + destroyApplet(identifier);
> > > + return;
> > > + }
> > > +
> > > + // Proceed with re-framing
> > > + reFrame(oldFrame, identifier, System.out, handle, oldFrame.panel);
> > > +
> > > + // There is a slight chance that destroy can happen
> > > + // between the above and below line
> > > + if (updateStatus(identifier, PAV_INIT_STATUS.REFRAME_COMPLETE).equals(PAV_INIT_STATUS.INACTIVE)) {
> > > + destroyApplet(identifier);
> > > + }
> > > +
> > > + } else if (message.startsWith("destroy")) {
> > > +
> > > + // Set it inactive, and try to do cleanup is applicable
> > > + PAV_INIT_STATUS previousStatus = updateStatus(identifier, PAV_INIT_STATUS.INACTIVE);
> > > + PluginDebug.debug("Destroy status set for " + identifier);
> > > +
> > > + if (previousStatus != null &&
> > > + previousStatus.equals(PAV_INIT_STATUS.REFRAME_COMPLETE)) {
> > > + destroyApplet(identifier);
> > > + }
> > > +
> > > } else {
> > > PluginDebug.debug ("Handling message: " + message + " instance " + identifier + " " + Thread.currentThread());
> > >
> > > @@ -568,7 +613,7 @@
> > > status.get(identifier).equals(PAV_INIT_STATUS.PRE_INIT)
> > > )
> > > );
> > > -
> > > +
> > > // don't bother processing further for inactive applets
> > > if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE))
> > > return;
> > > @@ -580,31 +625,131 @@
> > > e.printStackTrace();
> > >
> > > // If an exception happened during pre-init, we need to update status
> > > - if (status.get(identifier).equals(PAV_INIT_STATUS.PRE_INIT))
> > > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > > + updateStatus(identifier, PAV_INIT_STATUS.INACTIVE);
> > >
> > > throw new RuntimeException("Failed to handle message: " +
> > > message + " for instance " + identifier, e);
> > > }
> > > }
> > > -
> > > +
> > > + /**
> > > + * Sets the status unless an overriding status is set (e.g. if
> > > + * status is DESTROYED, it may not be overridden).
> > > + *
> > > + * @param identifier The identifier for which the status is to be set
> > > + * @param status The status to switch to
> > > + * @return The previous status
> > > + */
> > > + private static synchronized PAV_INIT_STATUS updateStatus(int identifier, PAV_INIT_STATUS newStatus) {
> > > +
> > > + PAV_INIT_STATUS prev = status.get(identifier);
> > > +
> > > + // If the status is set
> > > + if (status.containsKey(identifier)) {
> > > +
> > > + // Nothing may override destroyed status
> > > + if (status.get(identifier).equals(PAV_INIT_STATUS.DESTROYED)) {
> > > + return prev;
> > > + }
> > > +
> > > + // If status is inactive, only DESTROYED may override it
> > > + if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE)) {
> > > + if (!newStatus.equals(PAV_INIT_STATUS.DESTROYED)) {
> > > + return prev;
> > > + }
> > > + }
> > > + }
> > > +
> > > + // Else set to given status
> > > + status.put(identifier, newStatus);
> > > +
> > > + return prev;
> > > + }
> > > +
> > > + /**
> > > + * Destroys the given applet instance.
> > > + *
> > > + * This function may be called multiple times without problems.
> > > + * It does a synchronized check on the status and will only
> > > + * attempt to destroy the applet if not previously destroyed.
> > > + *
> > > + * @param identifier The instance which is to be destroyed
> > > + */
> > > +
> > > + private static synchronized void destroyApplet(int identifier) {
> > > +
> > > + PluginDebug.debug("DestroyApplet called for " + identifier);
> > > +
> > > + PAV_INIT_STATUS prev = updateStatus(identifier, PAV_INIT_STATUS.DESTROYED);
> > > +
> > > + // If already destroyed, return
> > > + if (prev.equals(PAV_INIT_STATUS.DESTROYED)) {
> > > + PluginDebug.debug(identifier + " already destroyed. Returning.");
> > > + return;
> > > + }
> > > +
> > > + // If already disposed, return
> > > + if (applets.get(identifier).panel.applet == null) {
> > > + // Try to still dispose the panel itself -- no harm done with double dispose
> > > + applets.get(identifier).dispose();
> > > +
> > > + PluginDebug.debug(identifier + " inactive. Returning.");
> > > + return;
> > > + }
> > > +
> > > + PluginDebug.debug("Attempting to destroy " + identifier);
> > > +
> > > + final int fIdentifier = identifier;
> > > + SwingUtilities.invokeLater(new Runnable() {
> > > + public void run() {
> > > + applets.get(fIdentifier).appletClose();
> > > + }
> > > + });
> > > +
> > > + PluginDebug.debug(identifier + " destroyed");
> > > + }
> > > +
> > > + /**
> > > + * Function to block until applet initialization is complete
> > > + *
> > > + * @param identifier The instance to wait for
> > > + */
> > > + public static void waitForAppletInit(NetxPanel panel) {
> > > +
> > > + int waitTime = 0;
> > > +
> > > + // Wait till initialization finishes
> > > + while (panel.getApplet() == null &&
> > > + panel.isAlive() &&
> > > + waitTime < APPLET_TIMEOUT) {
> > > + try {
> > > + if (waitTime%500 == 0)
> > > + PluginDebug.debug("Waiting for applet panel " + panel + " to initialize...");
> > > +
> > > + Thread.sleep(waitTime += 50);
> > > + } catch (InterruptedException ie) {
> > > + // just wait
> > > + }
> > > + }
> > > +
> > > + PluginDebug.debug("Applet panel " + panel + " initialized");
> > > + }
> > > +
> > > public void handleMessage(int reference, String message)
> > > {
> > > if (message.startsWith("width")) {
> > >
> > > // Wait for panel to come alive
> > > int maxWait = APPLET_TIMEOUT; // wait for panel to come alive
> > > - int wait = 0;
> > > + int wait = 0;
> > > while (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE) && wait < maxWait) {
> > > -
> > > - try {
> > > - Thread.sleep(50);
> > > - wait += 50;
> > > - } catch (InterruptedException ie) {
> > > - // just wait
> > > - }
> > > - }
> > > -
> > > + try {
> > > + Thread.sleep(50);
> > > + wait += 50;
> > > + } catch (InterruptedException ie) {
> > > + // just wait
> > > + }
> > > + }
> > >
> > > // 0 => width, 1=> width_value, 2 => height, 3=> height_value
> > > String[] dimMsg = message.split(" ");
> > > @@ -636,7 +781,7 @@
> > >
> > > panel.setSize(width, height);
> > > panel.validate();
> > > -
> > > +
> > > panel.applet.resize(width, height);
> > > panel.applet.validate();
> > > }
> > > @@ -649,9 +794,6 @@
> > > e.printStackTrace();
> > > }
> > >
> > > - } else if (message.startsWith("destroy")) {
> > > - dispose();
> > > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > > } else if (message.startsWith("GetJavaObject")) {
> > >
> > > // FIXME: how do we determine what security context this
> > > @@ -672,15 +814,7 @@
> > >
> > > // Wait for the panel to initialize
> > > // (happens in a separate thread)
> > > - while (panel.getApplet() == null &&
> > > - ((NetxPanel) panel).isAlive()) {
> > > - try {
> > > - Thread.sleep(50);
> > > - PluginDebug.debug("Waiting for applet to initialize...");
> > > - } catch (InterruptedException ie) {
> > > - // just wait
> > > - }
> > > - }
> > > + waitForAppletInit((NetxPanel) panel);
> > >
> > > PluginDebug.debug(panel + " -- " + panel.getApplet() + " -- " + ((NetxPanel) panel).isAlive());
> > >
> > > @@ -1548,10 +1682,11 @@
> > > if (countApplets() == 0) {
> > > appletSystemExit();
> > > }
> > > +
> > > + updateStatus(identifier, PAV_INIT_STATUS.DESTROYED);
> > > }
> > > }).start();
> > >
> > > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > > }
> > >
> > > /**
> > > @@ -1677,18 +1812,6 @@
> > > val = buf.toString();
> > > }
> > >
> > > - att = att.replace(">", ">");
> > > - att = att.replace("<", "<");
> > > - att = att.replace("&", "&");
> > > - att = att.replace(" ", "\n");
> > > - att = att.replace(" ", "\r");
> > > -
> > > - val = val.replace(">", ">");
> > > - val = val.replace("<", "<");
> > > - val = val.replace("&", "&");
> > > - val = val.replace(" ", "\n");
> > > - val = val.replace(" ", "\r");
> > > -
> > > PluginDebug.debug("PUT " + att + " = '" + val + "'");
> > > atts.put(att.toLowerCase(java.util.Locale.ENGLISH), val);
> > >
> > > @@ -1708,7 +1831,6 @@
> > > // private static final == inline
> > > private static final boolean isInt(Object o) {
> > > boolean isInt = false;
> > > -
> > > try {
> > > Integer.parseInt((String) o);
> > > isInt = true;
> > > @@ -1763,7 +1885,6 @@
> > > } catch (IOException ioe) {
> > > return ioe;
> > > }
> > > -
> > > return null;
> > > }
> > > };
> > > @@ -1785,6 +1906,7 @@
> > > boolean isObjectTag = false;
> > > boolean isEmbedTag = false;
> > > boolean objectTagAlreadyParsed = false;
> > > +
> > > // The current character
> > > // FIXME: This is an evil hack to force pass-by-reference.. the
> > > // parsing code needs to be rewritten from scratch to prevent such
> > > @@ -1879,19 +2001,6 @@
> > > if (val == null) {
> > > statusMsgStream.println(requiresNameWarning);
> > > } else if (atts != null) {
> > > - att = att.replace(">", ">");
> > > - att = att.replace("<", "<");
> > > - att = att.replace("&", "&");
> > > - att = att.replace(" ", "\n");
> > > - att = att.replace(" ", "\r");
> > > - att = att.replace(""", "\"");
> > > -
> > > - val = val.replace(">", ">");
> > > - val = val.replace("<", "<");
> > > - val = val.replace("&", "&");
> > > - val = val.replace(" ", "\n");
> > > - val = val.replace(" ", "\r");
> > > - val = val.replace(""", "\"");
> > > PluginDebug.debug("PUT " + att + " = " + val);
> > > atts.put(att.toLowerCase(), val);
> > > } else {
> > > @@ -1920,8 +2029,8 @@
> > >
> > > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > > atts.put("width", width);
> > > - }
> > > -
> > > + }
> > > +
> > > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > > atts.put("height", height);
> > > }
> > > @@ -1974,7 +2083,7 @@
> > > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > > atts.put("width", width);
> > > }
> > > -
> > > +
> > > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > > atts.put("height", height);
> > > }
> > > @@ -2023,10 +2132,11 @@
> > > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > > atts.put("width", width);
> > > }
> > > -
> > > +
> > > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > > atts.put("height", height);
> > > }
> > > +
> > > }
> > > }
> > > }
> > > diff -r 85db7b3a1c93 plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java
> > > --- a/plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java Thu Oct 21 21:12:21 2010 +0100
> > > +++ b/plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java Thu Oct 21 17:22:56 2010 -0700
> > > @@ -126,6 +126,10 @@
> > > }
> > >
> > > private String getPriorityStrIfPriority(String message) {
> > > +
> > > + // Destroy messages are permanently high priority
> > > + if (message.endsWith("destroy"))
> > > + return "destroy";
> > >
> > > synchronized (priorityWaitQueue) {
> > > Iterator<String> it = priorityWaitQueue.iterator();
> > > @@ -150,7 +154,6 @@
> > > }
> > > }
> > >
> > > -
> > > public void notifyWorkerIsFree(PluginMessageHandlerWorker worker) {
> > > synchronized (initWorkers) {
> > > Iterator<Integer> i = initWorkers.keySet().iterator();
> > > @@ -176,6 +179,32 @@
> > > }
> > >
> > > protected class ConsumerThread extends Thread {
> > > +
> > > + /**
> > > + * Scans the readQueue for priority messages and brings them to the front
> > > + */
> > > + private void bringPriorityMessagesToFront() {
> > > + synchronized (readQueue) {
> > > +
> > > + // iterate through the list
> > > + for (int i=0; i < readQueue.size(); i++) {
> > > +
> > > + // remove element at i to inspect it
> > > + String message = readQueue.remove(i);
> > > +
> > > + // if element at i is a priority msg, bring it forward
> > > + if (getPriorityStrIfPriority(message) != null) {
> > > + readQueue.addFirst(message);
> > > + } else { // else keep it where it was
> > > + readQueue.add(i, message);
> > > + }
> > > +
> > > + // by the end the queue size is the same, so the
> > > + // position indicator (i) is still valid
> > > + }
> > > + }
> > > + }
> > > +
> > > public void run() {
> > >
> > > while (true) {
> > > @@ -190,7 +219,6 @@
> > >
> > > String[] msgParts = message.split(" ");
> > >
> > > -
> > > String priorityStr = getPriorityStrIfPriority(message);
> > > boolean isPriorityResponse = (priorityStr != null);
> > >
> > > @@ -199,9 +227,12 @@
> > >
> > > if (worker == null) {
> > > synchronized(readQueue) {
> > > - readQueue.addLast(message);
> > > + readQueue.addFirst(message);
> > > }
> > >
> > > + // re-scan to see if any priority message came in
> > > + bringPriorityMessagesToFront();
> > > +
> > > continue; // re-loop to try next msg
> > > }
> > >
> >
> >
> > --
> > Andrew :)
> >
> > Free Java Software Engineer
> > Red Hat, Inc. (http://www.redhat.com)
> >
> > Support Free Java!
> > Contribute to GNU Classpath and the OpenJDK
> > http://www.gnu.org/software/classpath
> > http://openjdk.java.net
> > PGP Key: 94EFD9D8 (http://subkeys.pgp.net)
> > Fingerprint = F8EF F1EA 401E 2E60 15FA 7927 142C 2591 94EF D9D8
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