Package org.biojava.utils.bytecode

Class Label

  • All Implemented Interfaces:
    CodeGenerator
    public class Label
extends java.lang.Object
implements CodeGenerator
    A Label used to mark a position in byte code.

    Labels are used as the targets for jumps, and for exception handlers. Labels can be named. They implement CodeGenerator, which allows them to be added to things like an InstructionVector. The writeCode method takes care of marking the label with the context.

    Author:
    Thomas Down, Matthew Pocock

    • Field Summary

      Fields 
      Modifier and Type Field Description
      java.lang.String name  

    • Constructor Summary

      Constructors 
      Constructor Description
      Label()  
      Label​(java.lang.String name)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int stackDelta()
      Return the change in the stack dept this generator will cause.
      int stackDepth()
      Return the total depth of the stack required by this CodeGenerator.
      java.lang.String toString()  
      void writeCode​(CodeContext ctx)
      Write the byte or bytes for this CodeGenerator to a CodeContext.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • name

        public java.lang.String name

    • Constructor Detail

      • Label

        public Label()

      • Label

        public Label​(java.lang.String name)

    • Method Detail

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • writeCode

        public void writeCode​(CodeContext ctx)
               throws CodeException
        Description copied from interface: CodeGenerator
        Write the byte or bytes for this CodeGenerator to a CodeContext.
        Specified by:
        writeCode in interface CodeGenerator
        Parameters:
        ctx - a CodeContext to write to
        Throws:
        CodeException - if there was some failure in writing to the context

      • stackDepth

        public int stackDepth()
        Description copied from interface: CodeGenerator
        Return the total depth of the stack required by this CodeGenerator.

        For single byte-code instructions, this will be the same as stackDelta() if stackDelta() is positive, zero otherwise. For a compound instruction, this will be the maximum stack depth required to execute all sub-instructions.

        Specified by:
        stackDepth in interface CodeGenerator
        Returns:
        the stack depth needed

      • stackDelta

        public int stackDelta()
        Description copied from interface: CodeGenerator
        Return the change in the stack dept this generator will cause.

        In the case of an instruction that adds items to the stack, stackDelta will be positive. For instructions that removes items from the stack, this will be negative.

        Specified by:
        stackDelta in interface CodeGenerator
        Returns:
        the change between stack depth before and after execution of this code