Changeset 31670 for main

Timestamp:

2017-05-10T18:31:55+12:00 (7 years ago)

Author:

ak19

Message:

Changing the EventListeners list in GShell over to be CopyOnWriteArrayList because it is threadsafe, as is needed here, though the change comes at the expense of reduced efficiency. Also removed Imagemagick test debug statements in Gatherer.

Location:

main/trunk/gli/src/org/greenstone/gatherer

Files:

• Gatherer.java (modified) (2 diffs)
• shell/GShell.java (modified) (10 diffs)

main/trunk/gli/src/org/greenstone/gatherer/Gatherer.java

@@ -1676 +1676 @@
                 }
                 DebugStream.println("***** Running ImageMagickTest command: " + cmd_str);
-                System.err.println("***** Running ImageMagickTest command: " + cmd_str);
                
                 SafeProcess image_magick_process = new SafeProcess(command_parts);
@@ -1684 +1683 @@
                 String output = image_magick_process.getStdOutput().toLowerCase();
                 if (output.indexOf("version") != -1 || output.indexOf("imagemagick") != -1) {
-                System.err.println("*** ImageMagickTest output: " + output);
                 found = true;
                 } // else found var remains false   

main/trunk/gli/src/org/greenstone/gatherer/shell/GShell.java

@@ -41 +41 @@
 import java.util.ArrayList;
 import java.util.Enumeration;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.regex.*;
 import javax.swing.*;
@@ -68 +69 @@
     private boolean cancel = false;
     private BufferedOutputStream buffered_output_stream = null;
-    /** The list of listeners associated with this class. */
-    private EventListenerList listeners = null;
+    /** The list of listeners associated with this class. 
+     * Make it a CopyOnWriteArrayList to make it threadsafe at a cost of decreased efficiency. 
+     * see http://stackoverflow.com/questions/8259479/should-i-synchronize-listener-notifications-or-not
+     */
+    private final CopyOnWriteArrayList<GShellListener> listeners;
     /** The current status of this shell process. */
     private int status = -1;
@@ -85 +89 @@
     private String commandOutput = null;
 
-    /** The process safely run in this GShell. Make sure to set to null when done with. */
-    SafeProcess prcs = null;
+    /** The process safely run in this GShell Thread. Make sure to set to prcs to null when done with. */
+    private SafeProcess prcs = null;
 
     /** Elements in process type enumeration. */
@@ -136 +140 @@
     // Lower this jobs priority
     this.setPriority(Thread.MIN_PRIORITY);
-    listeners = new EventListenerList();
-    listeners.add(GShellListener.class, caller);
+    listeners = new CopyOnWriteArrayList<GShellListener>();
+    listeners.add(caller);
     }
     /** This method adds another shell listener to this process.
@@ -143 +147 @@
      */
     public void addGShellListener(GShellListener listener) {
-    listeners.add(GShellListener.class, listener);
+    listeners.add(listener);
     }
     /** This method removes a certain shell listener from this process.
@@ -149 +153 @@
      */
     /* private void removeGShellListener(GShellListener listener) {
-       listeners.remove(GShellListener.class, listener);
+       listeners.remove(listener);
        } */
 
@@ -549 +553 @@
         // If the event hasn't been vetoed, pass it on to other listeners
         if(!current_event.isVetoed()) {
-        Object[] concerned = listeners.getListenerList();
-        for(int i = 0; i < concerned.length ; i++) {
-            if(concerned[i] == GShellListener.class) {
-            ((GShellListener)concerned[i+1]).message(current_event);
-            }
-        }
-        concerned = null;
+        // See http://stackoverflow.com/questions/8259479/should-i-synchronize-listener-notifications-or-not
+        for (GShellListener l: this.listeners) {
+            l.message(current_event);
+        }
         }
     }
@@ -585 +586 @@
     // Fire an event
     GShellEvent event = new GShellEvent(this, 0, type, "", status);
-    Object[] concerned = listeners.getListenerList();
-    for(int i = 0; i < concerned.length ; i++) {
-        if(concerned[i] == GShellListener.class) {
-        ((GShellListener)concerned[i+1]).processBegun(event);
-        }
+    for (GShellListener l: this.listeners) {
+        l.processBegun(event);
     }
     }
@@ -607 +605 @@
     if(status == CANCELLED && Configuration.getMode() <= Configuration.LIBRARIAN_MODE) {
         GShellEvent current_event = new GShellEvent(this, 0, type, Dictionary.get("GShell.Build.BuildCancelled"), status);
-        Object[] concerned = listeners.getListenerList();
-        for(int i = 0; i < concerned.length ; i++) {
-        if(concerned[i] == GShellListener.class) {
-            ((GShellListener)concerned[i+1]).message(current_event);
-        }
-        }
-        concerned = null;
+        for (GShellListener l: this.listeners) {
+        l.message(current_event);
+        }
     }
     
@@ -623 +617 @@
     // And firing off an event
     GShellEvent event = new GShellEvent(this, 0, type, msg, status);
-    Object[] concerned = listeners.getListenerList();
-    for(int i = 0; i < concerned.length ; i++) {
-        if(concerned[i] == GShellListener.class) {
-        ((GShellListener)concerned[i+1]).processComplete(event);
-        }
+    for (GShellListener l: this.listeners) {
+        l.processComplete(event);
     }
     }