# Interface InstructionContext

public interface InstructionContext
An InstructionContext offers convenient access to information like control flow successors and such.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `execute(Frame inFrame, ArrayList<InstructionContext> 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.
  `Frame`
  `getInFrame()`
  `InstructionHandle`
  `getInstruction()`
  Returns the InstructionHandle this InstructionContext is wrapped around.
  `Frame`
  `getOutFrame(ArrayList<InstructionContext> 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 coloring.
  `void`
  `setTag(int tag)`
  The getTag and setTag methods may be used for temporary flagging, such as graph coloring.

- ## Method Details

  - ### execute

    boolean execute(Frame inFrame, ArrayList<InstructionContext> 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.
    See Also:
      - `ControlFlowGraph`
      - `ExecutionVisitor`
      - `getOutFrame(ArrayList)`

  - ### getExceptionHandlers

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

  - ### getInFrame

    Frame getInFrame()

  - ### getInstruction

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

  - ### getOutFrame

    Frame getOutFrame(ArrayList<InstructionContext> executionPredecessors)
    This method returns the outgoing execution frame situation; therefore it has to be calculated by execute(Frame, ArrayList) first.
    See Also:
      - `execute(Frame, ArrayList, InstConstraintVisitor, ExecutionVisitor)`

  - ### getSuccessors

    InstructionContext[] getSuccessors()
    Returns the usual control flow successors.
    See Also:
      - `getExceptionHandlers()`

  - ### getTag

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

  - ### setTag

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