Class BranchInstruction

java.lang.Object
org.apache.bcel.generic.Instruction
org.apache.bcel.generic.BranchInstruction
All Implemented Interfaces:
Serializable, Cloneable, InstructionTargeter
Direct Known Subclasses:
GotoInstruction, IfInstruction, JsrInstruction, Select
public abstract class BranchInstruction extends Instruction implements InstructionTargeter
Abstract super class for branching instructions like GOTO, IFEQ, etc.. Branch instructions may have a variable length, namely GOTO, JSR, LOOKUPSWITCH and TABLESWITCH.
See Also:

  • Field Details

    • index

      protected int index

    • target

      protected InstructionHandle target

    • position

      protected int position

  • Constructor Details

    • BranchInstruction

      protected BranchInstruction(short opcode, InstructionHandle target)
      Common super constructor
      Parameters:
      opcode - Instruction opcode
      target - instruction to branch to

  • Method Details

    • dump

      public void dump(DataOutputStream out) throws IOException
      Dump instruction as byte code to stream out.
      Overrides:
      dump in class Instruction
      Parameters:
      out - Output stream
      Throws:
      IOException

    • getTargetOffset

      protected int getTargetOffset(InstructionHandle _target)
      Parameters:
      _target - branch target
      Returns:
      the offset to `target' relative to this instruction

    • getTargetOffset

      protected int getTargetOffset()
      Returns:
      the offset to this instruction's target

    • updatePosition

      protected int updatePosition(int offset, int max_offset)
      Called by InstructionList.setPositions when setting the position for every instruction. In the presence of variable length instructions `setPositions' performs multiple passes over the instruction list to calculate the correct (byte) positions and offsets by calling this function.
      Parameters:
      offset - additional offset caused by preceding (variable length) instructions
      max_offset - the maximum offset that may be caused by these instructions
      Returns:
      additional offset caused by possible change of this instruction's length

    • toString

      public String toString(boolean verbose)
      Long output format: <position in byte code> <name of opcode> "["<opcode number>"]" "("<length of instruction>")" "<"<target instruction>">" "@"<branch target offset>
      Overrides:
      toString in class Instruction
      Parameters:
      verbose - long/short format switch
      Returns:
      mnemonic for instruction

    • initFromFile

      protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
      Read needed data (e.g. index) from file. Conversion to a InstructionHandle is done in InstructionList(byte[]).
      Overrides:
      initFromFile in class Instruction
      Parameters:
      bytes - input stream
      wide - wide prefix?
      Throws:
      IOException - may be thrown if the implementation needs to read data from the file
      See Also:

    • getIndex

      public final int getIndex()
      Returns:
      target offset in byte code

    • getTarget

      public InstructionHandle getTarget()
      Returns:
      target of branch instruction

    • setTarget

      public void setTarget(InstructionHandle target)
      Set branch target
      Parameters:
      target - branch target

    • updateTarget

      public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih)
      Specified by:
      updateTarget in interface InstructionTargeter
      Parameters:
      old_ih - old target
      new_ih - new target

    • containsTarget

      public boolean containsTarget(InstructionHandle ih)
      Specified by:
      containsTarget in interface InstructionTargeter
      Returns:
      true, if ih is target of this instruction