Changeset 31695 for main/trunk/greenstone3/src/java/org/greenstone/gsdl3/build/GS2PerlConstructor.java

Timestamp:

2017-05-22T16:43:13+12:00 (7 years ago)

Author:

ak19

Message:

Bringing GS3 src code's SafeProcess up to speed with GLI version, with some addiitonal minor changes to be included in the GLI version hereafter. Tested on Linux.

File:

• main/trunk/greenstone3/src/java/org/greenstone/gsdl3/build/GS2PerlConstructor.java (modified) (1 diff)

main/trunk/greenstone3/src/java/org/greenstone/gsdl3/build/GS2PerlConstructor.java

@@ -504 +504 @@
     // We don't include the cancel check here, as superclass CollectionConstructor.stopAction(), which set
     // this.cancel to true, never got called anywhere.
-    // But I think a proper cancel of our perl process launched by this GS2PerlConstructor Thread object
-    // and of the worker threads it launches, could be implemented with interrupts. See:
+    // But a proper cancel of our perl process launched by this GS2PerlConstructor Thread object
+    // and of the worker threads it launches is now implemented in SafeProcess.cancelRunningProcess()
+    // with interrupts. See:
     // http://stackoverflow.com/questions/6859681/better-way-to-signal-other-thread-to-stop
     // https://docs.oracle.com/javase/tutorial/essential/concurrency/interrupt.html
     // https://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html#interrupted()
     // https://praveer09.github.io/technology/2015/12/06/understanding-thread-interruption-in-java/
-    // The code that calls GS2PerlConstructor.stopAction() should also call GSPerlConstructor.interrupt()
-    // Then in SafeProcess.runProcess(), I think the waitFor() will throw an InterruptedException()
-    // This can be caught and interrupt() called on SafeProcess' workerthreads, 
-    // Any workerthreads' run() methods that block (IO, loops) can test this.isInterrupted() 
-    // and can break out of any loops and release resources in finally.
-    // Back in SafeProcess.runProcess, the InterruptedException catch block will be followed by finally
-    // that will clear up any further resources and destroy the process forcibly if it hadn't been ended.
+    // If cancel is to be implemented for GS2PerlConstructor, then the code that calls
+    // GS2PerlConstructor.stopAction() should also call or result in a call to the SafeProcess instance's
+    // cancelRunningProcess() method.
+    // For a simple example of the use of SafeProcess' cancel feature, see GLI's GShell. For a more
+    // complicated example, see GLI's DownloadJob.java, which implements SafeProcess.MainHandler to do
+    // additional work when a process is cancelled while still running (and therefore has to be prematurely
+    // terminated) a.o.t. a process that's cancelled when it's already terminated naturally.
 
     } catch(IOException e) {