com.techtrader.modules.tools.bytecode
Class ConstantInstruction

java.lang.Object
  |
  +--com.techtrader.modules.tools.bytecode.Instruction
        |
        +--com.techtrader.modules.tools.bytecode.ConstantInstruction

public class ConstantInstruction

extends Instruction

Represents an instruction that that loads a constant onto the stack. The opcode represented by this Instruction may change depending on the type and value of the constant set. For example, if the constant value is initially set to '5', the opcode will be iconst_5; if later incremented to '6', the opcode will be changed to bipush(6).

Author:

Abe White

Fields inherited from class com.techtrader.modules.tools.bytecode.Instruction

_byteIndex, _opcode, _opcodeTypes, _owner

Constructor Summary

protected	ConstantInstruction(Code owner)
protected	ConstantInstruction(Code owner, int opcode, Object value)

Method Summary

void	acceptVisit(BCVisitor visit) Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this object.
protected void	copy(Instruction orig)
boolean	equals(Object other) ConstantInstructions are equal if the const they reference is the same, or if the const of either is unset.
Object	getConstant() Return the constant value as an Object; will be an instance of String, Integer, Float, Double, or Long, as necessary.
Class	getConstantType() Return the class of constant this instruction references.
String	getConstantTypeName() Return the class of constant this instruction references.
double	getDoubleConstant() Get the constant to double, for float constants; must be a ldc2 instruction.
float	getFloatConstant() Get the constant to load, for float constants.
int	getIntConstant() Get the constant to load, for int constants.
int	getLength() Return the length in bytes of this opcode, including all arguments.
long	getLongConstant() Get the constant to load, for float constants; must be a ldc2 instruction.
int	getStackChange() Return the number of stack positions this instruction pushes or pops during its execution.
String	getStringConstant() Get the constant to load, for String constants.
protected void	readData(DataInput in) Read the arguments for this opcode from the given stream.
ConstantInstruction	setConstant(Object value) Set the constant to the given Object value.
ConstantInstruction	setDoubleConstant(double value) Set the constant to load, for double constants; must be a ldc2 instruction.
ConstantInstruction	setFloatConstant(float value) Set the constant to load, for float constants.
ConstantInstruction	setIntConstant(int value) Set the constant to load, for int constants.
ConstantInstruction	setLongConstant(long value) Set the constant to load, for long constants; must be a ldc2 instruction.
ConstantInstruction	setStringConstant(String value) Set the constant to load, for String constants.
protected void	writeData(DataOutput out) Write the arguments for this opcode to the given stream.

Methods inherited from class com.techtrader.modules.tools.bytecode.Instruction

getByteIndex, getName, getOpCode, getOwner, invalidate, setByteIndex, setOpCode

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantInstruction

protected ConstantInstruction(Code owner)

ConstantInstruction

protected ConstantInstruction(Code owner,
                              int opcode,
                              Object value)

Method Detail

setConstant

public ConstantInstruction setConstant(Object value)

Set the constant to the given Object value. The Object should be an instance of String, Integer, Long, Double, or Float depending on the constant type.

Returns:

this Instruction, for method chaining

getConstant

public Object getConstant()

Return the constant value as an Object; will be an instance of String, Integer, Float, Double, or Long, as necessary. Returns null if the constant has not been set, or if this represents the aconst_null opcode.

getConstantType

public Class getConstantType()

Return the class of constant this instruction references. Will return one of: Object.class, String.class, int.class, long.class, double.class, float.class.

getConstantTypeName

public String getConstantTypeName()

Return the class of constant this instruction references. Will return one of: java.lang.Object, java.lang.String, int, long, double, float.

setStringConstant

public ConstantInstruction setStringConstant(String value)

Set the constant to load, for String constants.

Returns:

this Instruction, for method chaining

getStringConstant

public String getStringConstant()

Get the constant to load, for String constants.

setIntConstant

public ConstantInstruction setIntConstant(int value)

Set the constant to load, for int constants.

Returns:

this Instruction, for method chaining

getIntConstant

public int getIntConstant()

Get the constant to load, for int constants.

setFloatConstant

public ConstantInstruction setFloatConstant(float value)

Set the constant to load, for float constants.

Returns:

this Instruction, for method chaining

getFloatConstant

public float getFloatConstant()

Get the constant to load, for float constants.

setLongConstant

public ConstantInstruction setLongConstant(long value)

Set the constant to load, for long constants; must be a ldc2 instruction.

Returns:

this Instruction, for method chaining

getLongConstant

public long getLongConstant()

Get the constant to load, for float constants; must be a ldc2 instruction.

setDoubleConstant

public ConstantInstruction setDoubleConstant(double value)

Set the constant to load, for double constants; must be a ldc2 instruction.

Returns:

this Instruction, for method chaining

getDoubleConstant

public double getDoubleConstant()

Get the constant to double, for float constants; must be a ldc2 instruction.

equals

public boolean equals(Object other)

ConstantInstructions are equal if the const they reference is the same, or if the const of either is unset.

Overrides:

equals in class Instruction

getLength

public int getLength()

Description copied from class: Instruction

Return the length in bytes of this opcode, including all arguments. This method should be overridden by opcodes that take arguments.

Overrides:

getLength in class Instruction

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

Tags copied from 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

copy

protected void copy(Instruction orig)

Overrides:

copy in class Instruction

readData

protected void readData(DataInput in)
                 throws IOException

Description copied from class: Instruction

Read the arguments for this opcode from the given stream. This method should be overridden by opcodes that take arguments.

Overrides:

readData in class Instruction

writeData

protected void writeData(DataOutput out)
                  throws IOException

Description copied from class: Instruction

Write the arguments for this opcode to the given stream. This method should be overridden by opcodes that take arguments.

Overrides:

writeData in class Instruction

acceptVisit

public void acceptVisit(BCVisitor visit)

Description copied from interface: VisitAcceptor

Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this object.

Overrides:

acceptVisit in class Instruction