org.apache.bcel.verifier.structurals

Interface InstructionContext

public interface InstructionContext

An InstructionContext offers convenient access to information like control flow successors and such.
Version:
$Id: InstructionContext.java,v 1.1.1.1 2001/10/29 20:00:41 jvanzyl Exp $
Author:
Enver Haase

Method Summary

boolean
execute(Frame inFrame, ArrayList executionPredecessors, InstConstraintVisitor icv, ExecutionVisitor ev)
This method symbolically executes the Instruction held in the InstructionContext.
ExceptionHandler[]
getExceptionHandlers()
Returns the exception handlers that protect this instruction.
InstructionHandle
getInstruction()
Returns the InstructionHandle this InstructionContext is wrapped around.
Frame
getOutFrame(ArrayList executionPredecessors)
This method returns the outgoing execution frame situation; therefore it has to be calculated by execute(Frame, ArrayList) first.
InstructionContext[]
getSuccessors()
Returns the usual control flow successors.
int
getTag()
The getTag and setTag methods may be used for temporary flagging, such as graph colouring.
void
setTag(int tag)
The getTag and setTag methods may be used for temporary flagging, such as graph colouring.

Method Details

execute

public boolean execute(Frame inFrame,
                       ArrayList executionPredecessors,
                       InstConstraintVisitor icv,
                       ExecutionVisitor ev)
This method symbolically executes the Instruction held in the InstructionContext. It "merges in" the incoming execution frame situation (see The Java Virtual Machine Specification, 2nd edition, page 146). By so doing, the outgoing execution frame situation is calculated. This method is JustIce-specific and is usually of no sense for users of the ControlFlowGraph class. They should use getInstruction().accept(Visitor), possibly in conjunction with the ExecutionVisitor.
Returns:
true - if and only if the "outgoing" frame situation changed from the one before execute()ing.

getExceptionHandlers

public ExceptionHandler[] getExceptionHandlers()
Returns the exception handlers that protect this instruction. They are special control flow successors.

getInstruction

public InstructionHandle getInstruction()
Returns the InstructionHandle this InstructionContext is wrapped around.
Returns:
The InstructionHandle this InstructionContext is wrapped around.

getOutFrame

public Frame getOutFrame(ArrayList executionPredecessors)
This method returns the outgoing execution frame situation; therefore it has to be calculated by execute(Frame, ArrayList) first.

getSuccessors

public InstructionContext[] getSuccessors()
Returns the usual control flow successors.

getTag

public int getTag()
The getTag and setTag methods may be used for temporary flagging, such as graph colouring. Nothing in the InstructionContext object depends on the value of the tag. JustIce does not use it.
See Also:
setTag(int tag)

setTag

public void setTag(int tag)
The getTag and setTag methods may be used for temporary flagging, such as graph colouring. Nothing in the InstructionContext object depends on the value of the tag. JustIce does not use it.