org.biojava.utils.bytecode

Interface CodeGenerator

All Known Subinterfaces:

Instruction, ParametricCodeGenerator, PParametricCodeGenerator

All Known Implementing Classes:

IfExpression, InstructionVector, Label, MarkLabel

public interface CodeGenerator

Interface for an object which can produce Java bytecode.

Author:

Thomas Down, Matthew Pocock

Method Summary

Modifier and Type	Method and 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.
void	writeCode(CodeContext ctx) Write the byte or bytes for this CodeGenerator to a CodeContext.

Method Detail

writeCode

void writeCode(CodeContext ctx)
        throws CodeException

Write the byte or bytes for this CodeGenerator to a CodeContext.

Parameters:

ctx - a CodeContext to write to

Throws:

CodeException - if there was some failure in writing to the context

stackDepth

int stackDepth()

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.

Returns:

the stack depth needed

stackDelta

int stackDelta()

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.

Returns:

the change between stack depth before and after execution of this code