[jira] [Updated] (SANDBOX-500) Need a feature to re-execute same method, i.e. GOTO:

["Sainath (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SANDBOX-500?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sainath updated SANDBOX-500:
----------------------------
    Priority: Critical  (was: Major)

> Need a feature to re-execute same method, i.e. GOTO:<beginning of the method>
> -----------------------------------------------------------------------------
>
>                 Key: SANDBOX-500
>                 URL: https://issues.apache.org/jira/browse/SANDBOX-500
>             Project: Commons Sandbox
>          Issue Type: Improvement
>          Components: Javaflow
>            Reporter: Sainath
>            Priority: Critical
>
> I am trying to add new feature dropToFrame along the lines of suspend.
> i.e. in case of suspend, method will return to caller by capturing the state of information. Whereas in dropToFrame I should GOTO startLabel.
> So that in some condition I want to re-execute same method(I'll be storing thread state at the beginning, which I restore when I dropToFrame).
> I tried to the same by making following code changes.
> mv.visitLabel(startLabel); in ContinuationMethodAdapter.visitCode()
> Create a variable isDropFrame in StackRecorder.
> Added following code in ContinuationMethodAdapter.visitMethodInsn() as below.
>              Label skipDrop = new Label();
>              mv.visitVarInsn(ALOAD, stackRecorderVar);
>              mv.visitJumpInsn(IFNULL, fl);
>     	     mv.visitVarInsn(ALOAD, stackRecorderVar);
>     	     mv.visitFieldInsn(GETFIELD, STACK_RECORDER, "isDropFrame", "Z");
>     	     mv.visitJumpInsn(IFNE, fl);
>     	     mv.visitJumpInsn(GOTO, startLabel);
>              mv.visitLabel(skipDrop);
> When I run main method I am getting following exception.
> java.lang.ArrayIndexOutOfBoundsException: 0
> 	at org.objectweb.asm.Frame.merge(Frame.java:1380)
> 	at org.objectweb.asm.Frame.merge(Frame.java:1336)
> 	at org.objectweb.asm.MethodWriter.visitMaxs(MethodWriter.java:1355)
> 	at org.objectweb.asm.MethodVisitor.visitMaxs(MethodVisitor.java:577)
> 	at org.objectweb.asm.util.CheckMethodAdapter.visitMaxs(CheckMethodAdapter.java:865)
> 	at org.apache.commons.javaflow.bytecode.transformation.asm.ContinuationMethodAdapter.visitMaxs(ContinuationMethodAdapter.java:341)
> 	at org.objectweb.asm.tree.MethodNode.accept(MethodNode.java:643)
> 	at org.apache.commons.javaflow.bytecode.transformation.asm.ContinuationMethodAnalyzer.visitEnd(ContinuationMethodAnalyzer.java:146)
> 	at org.objectweb.asm.ClassReader.accept(ClassReader.java:1625)
> 	at org.objectweb.asm.ClassReader.accept(ClassReader.java:533)
> Some people told me to use visitFrame() at creation of label or at GOTO statement. I tried both in different combination but still seeing the same exception.
> I am struck at this from 5 days.
> Could you please tell what exactly I should do to get solution to my problem.(GOTO startlabel in conditions). 
> Or are there any plans to have this feature in coming releases?



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