org.objectweb.asm.tree

Class MethodNode

Implemented Interfaces:
MethodVisitor
Known Direct Subclasses:
JSRInlinerAdapter

public class MethodNode
extends MemberNode
implements MethodVisitor

A node that represents a method.
Author:
Eric Bruneton

Field Summary

int
access
The method's access flags (see Opcodes).
Object
annotationDefault
The default value of this annotation interface method.
String
desc
The method's descriptor (see Type).
List
exceptions
The internal names of the method's exception classes (see getInternalName).
InsnList
instructions
The instructions of this method.
List[]
invisibleParameterAnnotations
The runtime invisible parameter annotations of this method.
List
localVariables
The local variables of this method.
int
maxLocals
The maximum number of local variables of this method.
int
maxStack
The maximum stack size of this method.
String
name
The method's name.
String
signature
The method's signature.
List
tryCatchBlocks
The try catch blocks of this method.
List[]
visibleParameterAnnotations
The runtime visible parameter annotations of this method.

Fields inherited from class org.objectweb.asm.tree.MemberNode

attrs, invisibleAnnotations, visibleAnnotations

Constructor Summary

MethodNode()
Constructs an unitialized MethodNode.
MethodNode(int access, String name, String desc, String signature, String[] exceptions)
Constructs a new MethodNode.

Method Summary

void
accept(ClassVisitor cv)
Makes the given class visitor visit this method.
void
accept(MethodVisitor mv)
Makes the given method visitor visit this method.
protected LabelNode
getLabelNode(Label l)
Returns the LabelNode corresponding to the given Label.
AnnotationVisitor
visitAnnotationDefault()
Visits the default value of this annotation interface method.
void
visitCode()
Starts the visit of the method's code, if any (i.e.
void
visitFieldInsn(int opcode, String owner, String name, String desc)
Visits a field instruction.
void
visitFrame(int type, int nLocal, Object[] local, int nStack, Object[] stack)
Visits the current state of the local variables and operand stack elements.
void
visitIincInsn(int var, int increment)
Visits an IINC instruction.
void
visitInsn(int opcode)
Visits a zero operand instruction.
void
visitIntInsn(int opcode, int operand)
Visits an instruction with a single int operand.
void
visitJumpInsn(int opcode, Label label)
Visits a jump instruction.
void
visitLabel(Label label)
Visits a label.
void
visitLdcInsn(Object cst)
Visits a LDC instruction.
void
visitLineNumber(int line, Label start)
Visits a line number declaration.
void
visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index)
Visits a local variable declaration.
void
visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels)
Visits a LOOKUPSWITCH instruction.
void
visitMaxs(int maxStack, int maxLocals)
Visits the maximum stack size and the maximum number of local variables of the method.
void
visitMethodInsn(int opcode, String owner, String name, String desc)
Visits a method instruction.
void
visitMultiANewArrayInsn(String desc, int dims)
Visits a MULTIANEWARRAY instruction.
AnnotationVisitor
visitParameterAnnotation(int parameter, String desc, boolean visible)
Visits an annotation of a parameter this method.
void
visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels)
Visits a TABLESWITCH instruction.
void
visitTryCatchBlock(Label start, Label end, Label handler, String type)
Visits a try catch block.
void
visitTypeInsn(int opcode, String type)
Visits a type instruction.
void
visitVarInsn(int opcode, int var)
Visits a local variable instruction.

Methods inherited from class org.objectweb.asm.tree.MemberNode

visitAnnotation, visitAttribute, visitEnd

Field Details

access

public int access
The method's access flags (see Opcodes). This field also indicates if the method is synthetic and/or deprecated.

annotationDefault

public Object annotationDefault
The default value of this annotation interface method. This field must be a Byte, Boolean, Character, Short, Integer, Long, Float, Double, String or Type, or an two elements String array (for enumeration values), a AnnotationNode, or a List of values of one of the preceding types. May be null.

desc

public String desc

exceptions

public List exceptions

instructions

public InsnList instructions
The instructions of this method. This list is a list of AbstractInsnNode objects.

invisibleParameterAnnotations

public List[] invisibleParameterAnnotations

localVariables

public List localVariables

maxLocals

public int maxLocals
The maximum number of local variables of this method.

maxStack

public int maxStack
The maximum stack size of this method.

name

public String name
The method's name.

signature

public String signature
The method's signature. May be null.

tryCatchBlocks

public List tryCatchBlocks

visibleParameterAnnotations

public List[] visibleParameterAnnotations

Constructor Details

MethodNode

public MethodNode()

MethodNode

public MethodNode(int access,
                  String name,
                  String desc,
                  String signature,
                  String[] exceptions)
Parameters:
access - the method's access flags (see Opcodes). This parameter also indicates if the method is synthetic and/or deprecated.
name - the method's name.
desc - the method's descriptor (see Type).
signature - the method's signature. May be null.
exceptions - the internal names of the method's exception classes (see getInternalName). May be null.

Method Details

accept

public void accept(ClassVisitor cv)
Makes the given class visitor visit this method.
Parameters:
cv - a class visitor.

accept

public void accept(MethodVisitor mv)
Makes the given method visitor visit this method.
Parameters:
mv - a method visitor.

getLabelNode

protected LabelNode getLabelNode(Label l)
Returns the LabelNode corresponding to the given Label. Creates a new LabelNode if necessary. The default implementation of this method uses the Label.info field to store associations between labels and label nodes.
Parameters:
l - a Label.
Returns:
the LabelNode corresponding to l.

visitAnnotationDefault

public AnnotationVisitor visitAnnotationDefault()
Visits the default value of this annotation interface method.
Specified by:
visitAnnotationDefault in interface MethodVisitor
Returns:
a visitor to the visit the actual default value of this annotation interface method, or null if this visitor is not interested in visiting this default value. The 'name' parameters passed to the methods of this annotation visitor are ignored. Moreover, exacly one visit method must be called on this annotation visitor, followed by visitEnd.

visitCode

public void visitCode()
Starts the visit of the method's code, if any (i.e. non abstract method).
Specified by:
visitCode in interface MethodVisitor

visitFieldInsn

public void visitFieldInsn(int opcode,
                           String owner,
                           String name,
                           String desc)
Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.
Specified by:
visitFieldInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
owner - the internal name of the field's owner class (see getInternalName).
name - the field's name.
desc - the field's descriptor (see Type).

visitFrame

public void visitFrame(int type,
                       int nLocal,
                       Object[] local,
                       int nStack,
                       Object[] stack)
Visits the current state of the local variables and operand stack elements. This method must(*) be called just before any instruction i that follows an unconditionnal branch instruction such as GOTO or THROW, that is the target of a jump instruction, or that starts an exception handler block. The visited types must describe the values of the local variables and of the operand stack elements just before i is executed.

(*) this is mandatory only for classes whose version is greater than or equal to
V1_6.

Packed frames are basically "deltas" from the state of the previous frame (very first frame is implicitly defined by the method's parameters and access flags):
  • Opcodes.F_SAME representing frame with exactly the same locals as the previous frame and with the empty stack.
  • Opcodes.F_SAME1 representing frame with exactly the same locals as the previous frame and with single value on the stack (nStack is 1 and stack[0] contains value for the type of the stack item).
  • Opcodes.F_APPEND representing frame with current locals are the same as the locals in the previous frame, except that additional locals are defined (nLocal is 1, 2 or 3 and local elements contains values representing added types).
  • Opcodes.F_CHOP representing frame with current locals are the same as the locals in the previous frame, except that the last 1-3 locals are absent and with the empty stack (nLocals is 1, 2 or 3).
  • Opcodes.F_FULL representing complete frame data.
Specified by:
visitFrame in interface MethodVisitor
Parameters:
type - the type of this stack map frame. Must be Opcodes.F_NEW for expanded frames, or Opcodes.F_FULL, Opcodes.F_APPEND, Opcodes.F_CHOP, Opcodes.F_SAME or Opcodes.F_APPEND, Opcodes.F_SAME1 for compressed frames.
nLocal - the number of local variables in the visited frame.
local - the local variable types in this frame. This array must not be modified. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by a single element). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).
nStack - the number of operand stack elements in the visited frame.
stack - the operand stack types in this frame. This array must not be modified. Its content has the same format as the "local" array.

visitIincInsn

public void visitIincInsn(int var,
                          int increment)
Visits an IINC instruction.
Specified by:
visitIincInsn in interface MethodVisitor
Parameters:
var - index of the local variable to be incremented.
increment - amount to increment the local variable by.

visitInsn

public void visitInsn(int opcode)
Visits a zero operand instruction.
Specified by:
visitInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

visitIntInsn

public void visitIntInsn(int opcode,
                         int operand)
Visits an instruction with a single int operand.
Specified by:
visitIntInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH or NEWARRAY.
operand - the operand of the instruction to be visited.
When opcode is BIPUSH, operand value should be between Byte.MIN_VALUE and Byte.MAX_VALUE.
When opcode is SIPUSH, operand value should be between Short.MIN_VALUE and Short.MAX_VALUE.
When opcode is NEWARRAY, operand value should be one of Opcodes.T_BOOLEAN, Opcodes.T_CHAR, Opcodes.T_FLOAT, Opcodes.T_DOUBLE, Opcodes.T_BYTE, Opcodes.T_SHORT, Opcodes.T_INT or Opcodes.T_LONG.

visitJumpInsn

public void visitJumpInsn(int opcode,
                          Label label)
Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.
Specified by:
visitJumpInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.

visitLabel

public void visitLabel(Label label)
Visits a label. A label designates the instruction that will be visited just after it.
Specified by:
visitLabel in interface MethodVisitor
Parameters:
label - a Label object.

visitLdcInsn

public void visitLdcInsn(Object cst)
Visits a LDC instruction.
Specified by:
visitLdcInsn in interface MethodVisitor
Parameters:
cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double a String (or a Type for .class constants, for classes whose version is 49.0 or more).

visitLineNumber

public void visitLineNumber(int line,
                            Label start)
Visits a line number declaration.
Specified by:
visitLineNumber in interface MethodVisitor
Parameters:
line - a line number. This number refers to the source file from which the class was compiled.
start - the first instruction corresponding to this line number.

visitLocalVariable

public void visitLocalVariable(String name,
                               String desc,
                               String signature,
                               Label start,
                               Label end,
                               int index)
Visits a local variable declaration.
Specified by:
visitLocalVariable in interface MethodVisitor
Parameters:
name - the name of a local variable.
desc - the type descriptor of this local variable.
signature - the type signature of this local variable. May be null if the local variable type does not use generic types.
start - the first instruction corresponding to the scope of this local variable (inclusive).
end - the last instruction corresponding to the scope of this local variable (exclusive).
index - the local variable's index.

visitLookupSwitchInsn

public void visitLookupSwitchInsn(Label dflt,
                                  int[] keys,
                                  Label[] labels)
Visits a LOOKUPSWITCH instruction.
Specified by:
visitLookupSwitchInsn in interface MethodVisitor
Parameters:
dflt - beginning of the default handler block.
keys - the values of the keys.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)
Visits the maximum stack size and the maximum number of local variables of the method.
Specified by:
visitMaxs in interface MethodVisitor
Parameters:
maxStack - maximum stack size of the method.
maxLocals - maximum number of local variables for the method.

visitMethodInsn

public void visitMethodInsn(int opcode,
                            String owner,
                            String name,
                            String desc)
Visits a method instruction. A method instruction is an instruction that invokes a method.
Specified by:
visitMethodInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
owner - the internal name of the method's owner class (see getInternalName).
name - the method's name.
desc - the method's descriptor (see Type).

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(String desc,
                                    int dims)
Visits a MULTIANEWARRAY instruction.
Specified by:
visitMultiANewArrayInsn in interface MethodVisitor
Parameters:
desc - an array type descriptor (see Type).
dims - number of dimensions of the array to allocate.

visitParameterAnnotation

public AnnotationVisitor visitParameterAnnotation(int parameter,
                                                  String desc,
                                                  boolean visible)
Visits an annotation of a parameter this method.
Specified by:
visitParameterAnnotation in interface MethodVisitor
Parameters:
parameter - the parameter index.
desc - the class descriptor of the annotation class.
visible - true if the annotation is visible at runtime.
Returns:
a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

visitTableSwitchInsn

public void visitTableSwitchInsn(int min,
                                 int max,
                                 Label dflt,
                                 Label[] labels)
Visits a TABLESWITCH instruction.
Specified by:
visitTableSwitchInsn in interface MethodVisitor
Parameters:
min - the minimum key value.
max - the maximum key value.
dflt - beginning of the default handler block.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

visitTryCatchBlock

public void visitTryCatchBlock(Label start,
                               Label end,
                               Label handler,
                               String type)
Visits a try catch block.
Specified by:
visitTryCatchBlock in interface MethodVisitor
Parameters:
start - beginning of the exception handler's scope (inclusive).
end - end of the exception handler's scope (exclusive).
handler - beginning of the exception handler's code.
type - internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).

visitTypeInsn

public void visitTypeInsn(int opcode,
                          String type)
Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.
Specified by:
visitTypeInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
type - the operand of the instruction to be visited. This operand must be the internal name of an object or array class (see getInternalName).

visitVarInsn

public void visitVarInsn(int opcode,
                         int var)
Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.
Specified by:
visitVarInsn in interface MethodVisitor
Parameters:
opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
var - the operand of the instruction to be visited. This operand is the index of a local variable.