serp.bytecode
Class SwitchInstruction

java.lang.Object
  serp.bytecode.Instruction
      serp.bytecode.JumpInstruction
          serp.bytecode.SwitchInstruction

All Implemented Interfaces:

BCEntity, InstructionPtr, VisitAcceptor

public abstract class SwitchInstruction
extends JumpInstruction

Contains functionality common to the different switch types (TableSwitch and LookupSwitch).

Author:

Eric Lindauer

Constructor Summary

SwitchInstruction(Code owner, int opcode)

Method Summary

SwitchInstruction	addCase(int match, Instruction target) Add a case to this switch.
abstract SwitchInstruction	addMatch(int match)
SwitchInstruction	addTarget(Instruction target) Add a target to this switch.
int	countTargets()
int	getDefaultOffset() Synonymous with JumpInstruction.getOffset().
Instruction	getDefaultTarget() Synonymous with JumpInstruction.getTarget().
abstract int[]	getMatches()
int[]	getOffsets() Returns the current byte offsets for the different switch cases in this Instruction.
int	getStackChange() Return the number of stack positions this instruction pushes or pops during its execution.
Instruction[]	getTargets() Return the targets for this switch, or empty array if not set.
void	replaceTarget(Instruction oldTarget, Instruction newTarget) Replace the given old, likely invalid, target with a new target.
SwitchInstruction	setCases(int[] matches, Instruction[] targets) Set the match-jumppt pairs for this switch.
SwitchInstruction	setDefaultOffset(int offset) Synonymous with JumpInstruction.setOffset(int).
SwitchInstruction	setDefaultTarget(Instruction ins) Synonymous with JumpInstruction.setTarget(serp.bytecode.Instruction).
SwitchInstruction	setMatches(int[] matches)
void	setOffsets(int[] offsets) Sets the offsets for the instructions representing the different switch statement cases.
SwitchInstruction	setTargets(Instruction[] targets) Set the jump points for this switch.
void	updateTargets() Use the byte indexes read from the class file to calculate and set references to the target instruction(s) for this ptr.

Methods inherited from class serp.bytecode.JumpInstruction

acceptVisit, equalsInstruction, getOffset, getTarget, setOffset, setTarget

Methods inherited from class serp.bytecode.Instruction

getByteIndex, getClassLoader, getCode, getLineNumber, getLogicalStackChange, getName, getOpcode, getPool, getProject, isValid

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface serp.bytecode.InstructionPtr

getCode

Constructor Detail

SwitchInstruction

public SwitchInstruction(Code owner,
                         int opcode)

Method Detail

getOffsets

public int[] getOffsets()

Returns the current byte offsets for the different switch cases in this Instruction.

setOffsets

public void setOffsets(int[] offsets)

Sets the offsets for the instructions representing the different switch statement cases. WARNING: these offsets will not be changed in the event that the code is modified following this call. It is typically a good idea to follow this call with a call to updateTargets as soon as the instructions at the given offsets are valid, at which point the Instructions themselves will be used as the targets and the offsets will be updated as expected.

countTargets

public int countTargets()

getDefaultTarget

public Instruction getDefaultTarget()

Synonymous with JumpInstruction.getTarget().

getDefaultOffset

public int getDefaultOffset()

Synonymous with JumpInstruction.getOffset().

setDefaultOffset

public SwitchInstruction setDefaultOffset(int offset)

Synonymous with JumpInstruction.setOffset(int).

setDefaultTarget

public SwitchInstruction setDefaultTarget(Instruction ins)

Synonymous with JumpInstruction.setTarget(serp.bytecode.Instruction).

getTargets

public Instruction[] getTargets()

Return the targets for this switch, or empty array if not set.

setTargets

public SwitchInstruction setTargets(Instruction[] targets)

Set the jump points for this switch.

Returns:

this instruction, for method chaining

addTarget

public SwitchInstruction addTarget(Instruction target)

Add a target to this switch.

Returns:

this instruction, for method chaining

getStackChange

public int getStackChange()

Description copied from class: Instruction

Return the number of stack positions this instruction pushes or pops during its execution.

Overrides:

getStackChange in class Instruction

Returns:

0 if the stack is not affected by this instruction, a positive number if it pushes onto the stack, and a negative number if it pops from the stack

updateTargets

public void updateTargets()

Description copied from interface: InstructionPtr

Use the byte indexes read from the class file to calculate and set references to the target instruction(s) for this ptr. This method will be called after the byte code has been read in for the first time and before it is written after modification.

Specified by:

updateTargets in interface InstructionPtr

Overrides:

updateTargets in class JumpInstruction

replaceTarget

public void replaceTarget(Instruction oldTarget,
                          Instruction newTarget)

Description copied from interface: InstructionPtr

Replace the given old, likely invalid, target with a new target. The new target Instruction is guaranteed to be in the same code block as this InstructionPtr.

Specified by:

replaceTarget in interface InstructionPtr

Overrides:

replaceTarget in class JumpInstruction

setCases

public SwitchInstruction setCases(int[] matches,
                                  Instruction[] targets)

Set the match-jumppt pairs for this switch.

Returns:

this instruction, for method chaining

setMatches

public SwitchInstruction setMatches(int[] matches)

addCase

public SwitchInstruction addCase(int match,
                                 Instruction target)

Add a case to this switch.

Returns:

this instruction, for method chaining

addMatch

public abstract SwitchInstruction addMatch(int match)

getMatches

public abstract int[] getMatches()