Changeset 31692 for main/trunk/gli/src/org/greenstone/gatherer/download/DownloadScrollPane.java

Timestamp:

2017-05-18T20:38:56+12:00 (7 years ago)

Author:

ak19

Message:

Major changes to SafeProcess and classes of the download package, by bringing the final GLI (and final Greenstone) class DownloadJob over to use SafeProcess. Significant changes to SafeProcess: 1. Introduction of cancelRunningProcess as a new method, so that callers don't need to know how cancelling a process is implemented (as an interrupt) nor do they need to know what thread they ought to interrupt (which should be the thread that launched SafeProcess), nor do they need to know of the complexity surrounding the join() blocking call which should not be interrupted. 2. Introduction of the SafeProcess.MainHandler interface that provides methods that allow implementers to write hooks to various stages of the SafeProcess' internal process' life cycle. 3. moved process cleanUp() code into a reusable method within SafeProcess. Significant changes to DownloadJob and its associated DownloadProgressBar and DownloadScrollPane classes: 1. Unused member vars removed or commented out and those that can be declared final are now declared so, as a programming pricinple for thread safety, since DownloadJob and the other download classes will have to interact with multiple threads and could be called by different threads. 2. Replaced existing actionPerformed() and callDownload() of DownloadJob with SafeProcess and implemented the necessary Hooks in the SafeProcess.MainHandler() interface to ensure that perl is still told to terminate wget on a cancel action. 3. Replaced DownloadScrollPane's deleteDownloadJob() with a new version that now more responsively removes its DownloadProgressBar (with controls) for a DownloadJob. It's called by the SafeProcess.MainHandler interface hooks implemented by DownloadJob, so DownloadScrollPane no longer needs to wait() to be notify()ed when a process has cleaned up on premature termination by a cancel action. 4. Made the necessary methods in DownloadProgressBar synchronized for thread safety. 5. GShell now uses SafeProcess' new cancelRunningProcess() method in place of directly calling interrupt on the (GShell) thread that launched SafeProcess.

File:

• main/trunk/gli/src/org/greenstone/gatherer/download/DownloadScrollPane.java (modified) (4 diffs)

main/trunk/gli/src/org/greenstone/gatherer/download/DownloadScrollPane.java

@@ -44 +44 @@
 import javax.swing.tree.*;
 import org.greenstone.gatherer.*;
+import org.greenstone.gatherer.util.SafeProcess;
 
 /** This class provides access to the functionality of the WGet program, either by calling it via a shell script or by the JNI. It maintains a queue of pending jobs, and the component for showing these tasks to the user.
@@ -78 +79 @@
     }
 
-    public void deleteDownloadJob(DownloadJob delete_me) {
+    /** 
+     * To be used with DownloadJob.java's old_callDownload() and old_actionPerformed()
+     * OR by uncommenting the "synchronized(this)" section in Download.java at the end of
+     * its new callDownload() along with commenting out "mummy.deleteCurrentDownloadJob(this);"
+     * in Download.java's doneCleanup().
+    */
+    public void old_deleteDownloadJob(DownloadJob delete_me) {
     if (delete_me == job) {
         try {
@@ -86 +93 @@
         synchronized(delete_me) {
             if (!delete_me.hasSignalledStop()) { // don't wait if DownloadJob.COMPLETED 
+            ///SafeProcess.log("**************** download scrollpane waiting for downloadjob to stop");
             delete_me.wait();
             }
@@ -93 +101 @@
         }       
     }
+
+    ///System.err.println("**************** Deleting job from download scroll pane");
     // Close button pressed, get rid of this download's dedicated pane
     finishedDownloadJob(delete_me, true);
     }
+
+    /**
+     * If called to delete the current download job, this method won't do anything.
+     * But if called on any inactive download job, its display is removed.
+    */
+    public void deleteDownloadJob(DownloadJob delete_me) {
+    if (delete_me != job) {
+
+        SafeProcess.log("**************** Deleting job from download scroll pane");
+        // Close button pressed, get rid of this download's dedicated pane
+        finishedDownloadJob(delete_me, true);
+    } // else don't do anything, we'll be contacted again when the current job can be deleted
+
+    }
+
+    /**
+     * To be called when we're ready to delete the current download job,
+     * else this method won't do anything
+    */
+    public void deleteCurrentDownloadJob(DownloadJob delete_me) {
+    if (delete_me == job) {
+        SafeProcess.log("**************** Deleting current job from download scroll pane");
+        // Close button pressed, get rid of this download's dedicated pane
+        finishedDownloadJob(delete_me, true);
+    }
+    }
+
 
     /** To be called when a download job has terminated naturally or was prematurely stopped