org.objectweb.asm.commons
Class GeneratorAdapter

java.lang.Object
  extended by org.objectweb.asm.MethodAdapter
      extended by org.objectweb.asm.commons.LocalVariablesSorter
          extended by org.objectweb.asm.commons.GeneratorAdapter
All Implemented Interfaces:
MethodVisitor
Direct Known Subclasses:
AdviceAdapter

public class GeneratorAdapter
extends LocalVariablesSorter

A MethodAdapter with convenient methods to generate code. For example, using this adapter, the class below

 public class Example {
     public static void main(String[] args) {
         System.out.println("Hello world!");
     }
 }
 
can be generated as follows:
 ClassWriter cw = new ClassWriter(true);
 cw.visit(V1_1, ACC_PUBLIC, "Example", null, "java/lang/Object", null);
 
 Method m = Method.getMethod("void <init> ()");
 GeneratorAdapter mg = new GeneratorAdapter(ACC_PUBLIC, m, null, null, cw);
 mg.loadThis();
 mg.invokeConstructor(Type.getType(Object.class), m);
 mg.returnValue();
 mg.endMethod();
 
 m = Method.getMethod("void main (String[])");
 mg = new GeneratorAdapter(ACC_PUBLIC + ACC_STATIC, m, null, null, cw);
 mg.getStatic(Type.getType(System.class), "out", Type.getType(PrintStream.class));
 mg.push("Hello world!");
 mg.invokeVirtual(Type.getType(PrintStream.class), Method.getMethod("void println (String)"));
 mg.returnValue();
 mg.endMethod();
 
 cw.visitEnd();
 

Author:
Juozas Baliuka, Chris Nokleberg, Eric Bruneton

Field Summary
static int ADD
          Constant for the math method.
static int AND
          Constant for the math method.
static int DIV
          Constant for the math method.
static int EQ
          Constant for the ifCmp method.
static int GE
          Constant for the ifCmp method.
static int GT
          Constant for the ifCmp method.
static int LE
          Constant for the ifCmp method.
static int LT
          Constant for the ifCmp method.
static int MUL
          Constant for the math method.
static int NE
          Constant for the ifCmp method.
static int NEG
          Constant for the math method.
static int OR
          Constant for the math method.
static int REM
          Constant for the math method.
static int SHL
          Constant for the math method.
static int SHR
          Constant for the math method.
static int SUB
          Constant for the math method.
static int USHR
          Constant for the math method.
static int XOR
          Constant for the math method.
 
Fields inherited from class org.objectweb.asm.commons.LocalVariablesSorter
firstLocal, nextLocal
 
Fields inherited from class org.objectweb.asm.MethodAdapter
mv
 
Constructor Summary
GeneratorAdapter(int access, Method method, MethodVisitor mv)
          Creates a new GeneratorAdapter.
GeneratorAdapter(int access, Method method, String signature, Type[] exceptions, ClassVisitor cv)
          Creates a new GeneratorAdapter.
GeneratorAdapter(MethodVisitor mv, int access, String name, String desc)
          Creates a new GeneratorAdapter.
 
Method Summary
 void arrayLength()
          Generates the instruction to compute the length of an array.
 void arrayLoad(Type type)
          Generates the instruction to load an element from an array.
 void arrayStore(Type type)
          Generates the instruction to store an element in an array.
 void box(Type type)
          Generates the instructions to box the top stack value.
 void cast(Type from, Type to)
          Generates the instructions to cast a numerical value from one type to another.
 void catchException(Label start, Label end, Type exception)
          Marks the start of an exception handler.
 void checkCast(Type type)
          Generates the instruction to check that the top stack value is of the given type.
 void dup()
          Generates a DUP instruction.
 void dup2()
          Generates a DUP2 instruction.
 void dup2X1()
          Generates a DUP2_X1 instruction.
 void dup2X2()
          Generates a DUP2_X2 instruction.
 void dupX1()
          Generates a DUP_X1 instruction.
 void dupX2()
          Generates a DUP_X2 instruction.
 void endMethod()
          Marks the end of the visited method.
 void getField(Type owner, String name, Type type)
          Generates the instruction to push the value of a non static field on the stack.
 Type getLocalType(int local)
          Returns the type of the given local variable.
 void getStatic(Type owner, String name, Type type)
          Generates the instruction to push the value of a static field on the stack.
 void goTo(Label label)
          Generates the instruction to jump to the given label.
 void ifCmp(Type type, int mode, Label label)
          Generates the instructions to jump to a label based on the comparison of the top two stack values.
 void ifICmp(int mode, Label label)
          Generates the instructions to jump to a label based on the comparison of the top two integer stack values.
 void ifNonNull(Label label)
          Generates the instruction to jump to the given label if the top stack value is not null.
 void ifNull(Label label)
          Generates the instruction to jump to the given label if the top stack value is null.
 void ifZCmp(int mode, Label label)
          Generates the instructions to jump to a label based on the comparison of the top integer stack value with zero.
 void iinc(int local, int amount)
          Generates the instruction to increment the given local variable.
 void instanceOf(Type type)
          Generates the instruction to test if the top stack value is of the given type.
 void invokeConstructor(Type type, Method method)
          Generates the instruction to invoke a constructor.
 void invokeDynamic(Method method)
          Generates the instruction to invoke a dynamic method.
 void invokeInterface(Type owner, Method method)
          Generates the instruction to invoke an interface method.
 void invokeStatic(Type owner, Method method)
          Generates the instruction to invoke a static method.
 void invokeVirtual(Type owner, Method method)
          Generates the instruction to invoke a normal method.
 void loadArg(int arg)
          Generates the instruction to load the given method argument on the stack.
 void loadArgArray()
          Generates the instructions to load all the method arguments on the stack, as a single object array.
 void loadArgs()
          Generates the instructions to load all the method arguments on the stack.
 void loadArgs(int arg, int count)
          Generates the instructions to load the given method arguments on the stack.
 void loadLocal(int local)
          Generates the instruction to load the given local variable on the stack.
 void loadLocal(int local, Type type)
          Generates the instruction to load the given local variable on the stack.
 void loadThis()
          Generates the instruction to load 'this' on the stack.
 Label mark()
          Marks the current code position with a new label.
 void mark(Label label)
          Marks the current code position with the given label.
 void math(int op, Type type)
          Generates the instruction to do the specified mathematical or logical operation.
 void monitorEnter()
          Generates the instruction to get the monitor of the top stack value.
 void monitorExit()
          Generates the instruction to release the monitor of the top stack value.
 void newArray(Type type)
          Generates the instruction to create a new array.
 void newInstance(Type type)
          Generates the instruction to create a new object.
 Label newLabel()
          Creates a new Label.
 void not()
          Generates the instructions to compute the bitwise negation of the top stack value.
 void pop()
          Generates a POP instruction.
 void pop2()
          Generates a POP2 instruction.
 void push(boolean value)
          Generates the instruction to push the given value on the stack.
 void push(double value)
          Generates the instruction to push the given value on the stack.
 void push(float value)
          Generates the instruction to push the given value on the stack.
 void push(int value)
          Generates the instruction to push the given value on the stack.
 void push(long value)
          Generates the instruction to push the given value on the stack.
 void push(String value)
          Generates the instruction to push the given value on the stack.
 void push(Type value)
          Generates the instruction to push the given value on the stack.
 void putField(Type owner, String name, Type type)
          Generates the instruction to store the top stack value in a non static field.
 void putStatic(Type owner, String name, Type type)
          Generates the instruction to store the top stack value in a static field.
 void ret(int local)
          Generates a RET instruction.
 void returnValue()
          Generates the instruction to return the top stack value to the caller.
protected  void setLocalType(int local, Type type)
          Sets the current type of the given local variable.
 void storeArg(int arg)
          Generates the instruction to store the top stack value in the given method argument.
 void storeLocal(int local)
          Generates the instruction to store the top stack value in the given local variable.
 void storeLocal(int local, Type type)
          Generates the instruction to store the top stack value in the given local variable.
 void swap()
          Generates a SWAP instruction.
 void swap(Type prev, Type type)
          Generates the instructions to swap the top two stack values.
 void tableSwitch(int[] keys, TableSwitchGenerator generator)
          Generates the instructions for a switch statement.
 void tableSwitch(int[] keys, TableSwitchGenerator generator, boolean useTable)
          Generates the instructions for a switch statement.
 void throwException()
          Generates the instruction to throw an exception.
 void throwException(Type type, String msg)
          Generates the instructions to create and throw an exception.
 void unbox(Type type)
          Generates the instructions to unbox the top stack value.
 void valueOf(Type type)
          Generates the instructions to box the top stack value using Java 5's valueOf() method.
 
Methods inherited from class org.objectweb.asm.commons.LocalVariablesSorter
newLocal, newLocalMapping, visitFrame, visitIincInsn, visitLocalVariable, visitMaxs, visitVarInsn
 
Methods inherited from class org.objectweb.asm.MethodAdapter
visitAnnotation, visitAnnotationDefault, visitAttribute, visitCode, visitEnd, visitFieldInsn, visitInsn, visitIntInsn, visitJumpInsn, visitLabel, visitLdcInsn, visitLineNumber, visitLookupSwitchInsn, visitMethodInsn, visitMultiANewArrayInsn, visitParameterAnnotation, visitTableSwitchInsn, visitTryCatchBlock, visitTypeInsn
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

ADD

public static final int ADD
Constant for the math method.

See Also:
Constant Field Values

SUB

public static final int SUB
Constant for the math method.

See Also:
Constant Field Values

MUL

public static final int MUL
Constant for the math method.

See Also:
Constant Field Values

DIV

public static final int DIV
Constant for the math method.

See Also:
Constant Field Values

REM

public static final int REM
Constant for the math method.

See Also:
Constant Field Values

NEG

public static final int NEG
Constant for the math method.

See Also:
Constant Field Values

SHL

public static final int SHL
Constant for the math method.

See Also:
Constant Field Values

SHR

public static final int SHR
Constant for the math method.

See Also:
Constant Field Values

USHR

public static final int USHR
Constant for the math method.

See Also:
Constant Field Values

AND

public static final int AND
Constant for the math method.

See Also:
Constant Field Values

OR

public static final int OR
Constant for the math method.

See Also:
Constant Field Values

XOR

public static final int XOR
Constant for the math method.

See Also:
Constant Field Values

EQ

public static final int EQ
Constant for the ifCmp method.

See Also:
Constant Field Values

NE

public static final int NE
Constant for the ifCmp method.

See Also:
Constant Field Values

LT

public static final int LT
Constant for the ifCmp method.

See Also:
Constant Field Values

GE

public static final int GE
Constant for the ifCmp method.

See Also:
Constant Field Values

GT

public static final int GT
Constant for the ifCmp method.

See Also:
Constant Field Values

LE

public static final int LE
Constant for the ifCmp method.

See Also:
Constant Field Values
Constructor Detail

GeneratorAdapter

public GeneratorAdapter(MethodVisitor mv,
                        int access,
                        String name,
                        String desc)
Creates a new GeneratorAdapter.

Parameters:
mv - the method visitor to which this adapter delegates calls.
access - the method's access flags (see Opcodes).
name - the method's name.
desc - the method's descriptor (see Type).

GeneratorAdapter

public GeneratorAdapter(int access,
                        Method method,
                        MethodVisitor mv)
Creates a new GeneratorAdapter.

Parameters:
access - access flags of the adapted method.
method - the adapted method.
mv - the method visitor to which this adapter delegates calls.

GeneratorAdapter

public GeneratorAdapter(int access,
                        Method method,
                        String signature,
                        Type[] exceptions,
                        ClassVisitor cv)
Creates a new GeneratorAdapter.

Parameters:
access - access flags of the adapted method.
method - the adapted method.
signature - the signature of the adapted method (may be null).
exceptions - the exceptions thrown by the adapted method (may be null).
cv - the class visitor to which this adapter delegates calls.
Method Detail

push

public void push(boolean value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

push

public void push(int value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

push

public void push(long value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

push

public void push(float value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

push

public void push(double value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

push

public void push(String value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack. May be null.

push

public void push(Type value)
Generates the instruction to push the given value on the stack.

Parameters:
value - the value to be pushed on the stack.

loadThis

public void loadThis()
Generates the instruction to load 'this' on the stack.


loadArg

public void loadArg(int arg)
Generates the instruction to load the given method argument on the stack.

Parameters:
arg - the index of a method argument.

loadArgs

public void loadArgs(int arg,
                     int count)
Generates the instructions to load the given method arguments on the stack.

Parameters:
arg - the index of the first method argument to be loaded.
count - the number of method arguments to be loaded.

loadArgs

public void loadArgs()
Generates the instructions to load all the method arguments on the stack.


loadArgArray

public void loadArgArray()
Generates the instructions to load all the method arguments on the stack, as a single object array.


storeArg

public void storeArg(int arg)
Generates the instruction to store the top stack value in the given method argument.

Parameters:
arg - the index of a method argument.

getLocalType

public Type getLocalType(int local)
Returns the type of the given local variable.

Parameters:
local - a local variable identifier, as returned by newLocal().
Returns:
the type of the given local variable.

setLocalType

protected void setLocalType(int local,
                            Type type)
Description copied from class: LocalVariablesSorter
Sets the current type of the given local variable. The default implementation of this method does nothing.

Overrides:
setLocalType in class LocalVariablesSorter
Parameters:
local - a local variable identifier, as returned by newLocal().
type - the type of the value being stored in the local variable

loadLocal

public void loadLocal(int local)
Generates the instruction to load the given local variable on the stack.

Parameters:
local - a local variable identifier, as returned by newLocal().

loadLocal

public void loadLocal(int local,
                      Type type)
Generates the instruction to load the given local variable on the stack.

Parameters:
local - a local variable identifier, as returned by newLocal().
type - the type of this local variable.

storeLocal

public void storeLocal(int local)
Generates the instruction to store the top stack value in the given local variable.

Parameters:
local - a local variable identifier, as returned by newLocal().

storeLocal

public void storeLocal(int local,
                       Type type)
Generates the instruction to store the top stack value in the given local variable.

Parameters:
local - a local variable identifier, as returned by newLocal().
type - the type of this local variable.

arrayLoad

public void arrayLoad(Type type)
Generates the instruction to load an element from an array.

Parameters:
type - the type of the array element to be loaded.

arrayStore

public void arrayStore(Type type)
Generates the instruction to store an element in an array.

Parameters:
type - the type of the array element to be stored.

pop

public void pop()
Generates a POP instruction.


pop2

public void pop2()
Generates a POP2 instruction.


dup

public void dup()
Generates a DUP instruction.


dup2

public void dup2()
Generates a DUP2 instruction.


dupX1

public void dupX1()
Generates a DUP_X1 instruction.


dupX2

public void dupX2()
Generates a DUP_X2 instruction.


dup2X1

public void dup2X1()
Generates a DUP2_X1 instruction.


dup2X2

public void dup2X2()
Generates a DUP2_X2 instruction.


swap

public void swap()
Generates a SWAP instruction.


swap

public void swap(Type prev,
                 Type type)
Generates the instructions to swap the top two stack values.

Parameters:
prev - type of the top - 1 stack value.
type - type of the top stack value.

math

public void math(int op,
                 Type type)
Generates the instruction to do the specified mathematical or logical operation.

Parameters:
op - a mathematical or logical operation. Must be one of ADD, SUB, MUL, DIV, REM, NEG, SHL, SHR, USHR, AND, OR, XOR.
type - the type of the operand(s) for this operation.

not

public void not()
Generates the instructions to compute the bitwise negation of the top stack value.


iinc

public void iinc(int local,
                 int amount)
Generates the instruction to increment the given local variable.

Parameters:
local - the local variable to be incremented.
amount - the amount by which the local variable must be incremented.

cast

public void cast(Type from,
                 Type to)
Generates the instructions to cast a numerical value from one type to another.

Parameters:
from - the type of the top stack value
to - the type into which this value must be cast.

box

public void box(Type type)
Generates the instructions to box the top stack value. This value is replaced by its boxed equivalent on top of the stack.

Parameters:
type - the type of the top stack value.

valueOf

public void valueOf(Type type)
Generates the instructions to box the top stack value using Java 5's valueOf() method. This value is replaced by its boxed equivalent on top of the stack.

Parameters:
type - the type of the top stack value.

unbox

public void unbox(Type type)
Generates the instructions to unbox the top stack value. This value is replaced by its unboxed equivalent on top of the stack.

Parameters:
type - the type of the top stack value.

newLabel

public Label newLabel()
Creates a new Label.

Returns:
a new Label.

mark

public void mark(Label label)
Marks the current code position with the given label.

Parameters:
label - a label.

mark

public Label mark()
Marks the current code position with a new label.

Returns:
the label that was created to mark the current code position.

ifCmp

public void ifCmp(Type type,
                  int mode,
                  Label label)
Generates the instructions to jump to a label based on the comparison of the top two stack values.

Parameters:
type - the type of the top two stack values.
mode - how these values must be compared. One of EQ, NE, LT, GE, GT, LE.
label - where to jump if the comparison result is true.

ifICmp

public void ifICmp(int mode,
                   Label label)
Generates the instructions to jump to a label based on the comparison of the top two integer stack values.

Parameters:
mode - how these values must be compared. One of EQ, NE, LT, GE, GT, LE.
label - where to jump if the comparison result is true.

ifZCmp

public void ifZCmp(int mode,
                   Label label)
Generates the instructions to jump to a label based on the comparison of the top integer stack value with zero.

Parameters:
mode - how these values must be compared. One of EQ, NE, LT, GE, GT, LE.
label - where to jump if the comparison result is true.

ifNull

public void ifNull(Label label)
Generates the instruction to jump to the given label if the top stack value is null.

Parameters:
label - where to jump if the condition is true.

ifNonNull

public void ifNonNull(Label label)
Generates the instruction to jump to the given label if the top stack value is not null.

Parameters:
label - where to jump if the condition is true.

goTo

public void goTo(Label label)
Generates the instruction to jump to the given label.

Parameters:
label - where to jump if the condition is true.

ret

public void ret(int local)
Generates a RET instruction.

Parameters:
local - a local variable identifier, as returned by newLocal().

tableSwitch

public void tableSwitch(int[] keys,
                        TableSwitchGenerator generator)
Generates the instructions for a switch statement.

Parameters:
keys - the switch case keys.
generator - a generator to generate the code for the switch cases.

tableSwitch

public void tableSwitch(int[] keys,
                        TableSwitchGenerator generator,
                        boolean useTable)
Generates the instructions for a switch statement.

Parameters:
keys - the switch case keys.
generator - a generator to generate the code for the switch cases.
useTable - true to use a TABLESWITCH instruction, or false to use a LOOKUPSWITCH instruction.

returnValue

public void returnValue()
Generates the instruction to return the top stack value to the caller.


getStatic

public void getStatic(Type owner,
                      String name,
                      Type type)
Generates the instruction to push the value of a static field on the stack.

Parameters:
owner - the class in which the field is defined.
name - the name of the field.
type - the type of the field.

putStatic

public void putStatic(Type owner,
                      String name,
                      Type type)
Generates the instruction to store the top stack value in a static field.

Parameters:
owner - the class in which the field is defined.
name - the name of the field.
type - the type of the field.

getField

public void getField(Type owner,
                     String name,
                     Type type)
Generates the instruction to push the value of a non static field on the stack.

Parameters:
owner - the class in which the field is defined.
name - the name of the field.
type - the type of the field.

putField

public void putField(Type owner,
                     String name,
                     Type type)
Generates the instruction to store the top stack value in a non static field.

Parameters:
owner - the class in which the field is defined.
name - the name of the field.
type - the type of the field.

invokeVirtual

public void invokeVirtual(Type owner,
                          Method method)
Generates the instruction to invoke a normal method.

Parameters:
owner - the class in which the method is defined.
method - the method to be invoked.

invokeConstructor

public void invokeConstructor(Type type,
                              Method method)
Generates the instruction to invoke a constructor.

Parameters:
type - the class in which the constructor is defined.
method - the constructor to be invoked.

invokeStatic

public void invokeStatic(Type owner,
                         Method method)
Generates the instruction to invoke a static method.

Parameters:
owner - the class in which the method is defined.
method - the method to be invoked.

invokeInterface

public void invokeInterface(Type owner,
                            Method method)
Generates the instruction to invoke an interface method.

Parameters:
owner - the class in which the method is defined.
method - the method to be invoked.

invokeDynamic

public void invokeDynamic(Method method)
Generates the instruction to invoke a dynamic method.

Parameters:
method - the method to be invoked.

newInstance

public void newInstance(Type type)
Generates the instruction to create a new object.

Parameters:
type - the class of the object to be created.

newArray

public void newArray(Type type)
Generates the instruction to create a new array.

Parameters:
type - the type of the array elements.

arrayLength

public void arrayLength()
Generates the instruction to compute the length of an array.


throwException

public void throwException()
Generates the instruction to throw an exception.


throwException

public void throwException(Type type,
                           String msg)
Generates the instructions to create and throw an exception. The exception class must have a constructor with a single String argument.

Parameters:
type - the class of the exception to be thrown.
msg - the detailed message of the exception.

checkCast

public void checkCast(Type type)
Generates the instruction to check that the top stack value is of the given type.

Parameters:
type - a class or interface type.

instanceOf

public void instanceOf(Type type)
Generates the instruction to test if the top stack value is of the given type.

Parameters:
type - a class or interface type.

monitorEnter

public void monitorEnter()
Generates the instruction to get the monitor of the top stack value.


monitorExit

public void monitorExit()
Generates the instruction to release the monitor of the top stack value.


endMethod

public void endMethod()
Marks the end of the visited method.


catchException

public void catchException(Label start,
                           Label end,
                           Type exception)
Marks the start of an exception handler.

Parameters:
start - beginning of the exception handler's scope (inclusive).
end - end of the exception handler's scope (exclusive).
exception - internal name of the type of exceptions handled by the handler.