org.objectweb.asm
Interface MethodVisitor

All Known Implementing Classes:
AdviceAdapter, ASMifierMethodVisitor, CheckMethodAdapter, EmptyVisitor, GeneratorAdapter, LocalVariablesSorter, MethodAdapter, MethodNode, SAXCodeAdapter, TraceMethodVisitor

public interface MethodVisitor

A visitor to visit a Java method. The methods of this interface must be called in the following order: [ visitAnnotationDefault ] ( visitAnnotation | visitParameterAnnotation | visitAttribute )* [ visitCode ( visitXInsn | visitLabel | visitTryCatchBlock | visitLocalVariable | visitLineNumber)* visitMaxs ] visitEnd. In addition, the visitXInsn and visitLabel methods must be called in the sequential order of the bytecode instructions of the visited code, and the visitLocalVariable and visitLineNumber methods must be called after the labels passed as arguments have been visited.

Author:
Eric Bruneton

Method Summary
 AnnotationVisitor visitAnnotation(String desc, boolean visible)
          Visits an annotation of this method.
 AnnotationVisitor visitAnnotationDefault()
          Visits the default value of this annotation interface method.
 void visitAttribute(Attribute attr)
          Visits a non standard attribute of this method.
 void visitCode()
          Starts the visit of the method's code, if any (i.e.
 void visitEnd()
          Visits the end of the method.
 void visitFieldInsn(int opcode, String owner, String name, String desc)
          Visits a field instruction.
 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 desc)
          Visits a type instruction.
 void visitVarInsn(int opcode, int var)
          Visits a local variable instruction.
 

Method Detail

visitAnnotationDefault

AnnotationVisitor visitAnnotationDefault()
Visits the default value of this annotation interface method.

Returns:
a non null visitor to the visit the actual default value of this annotation interface method. 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.

visitAnnotation

AnnotationVisitor visitAnnotation(String desc,
                                  boolean visible)
Visits an annotation of this method.

Parameters:
desc - the class descriptor of the annotation class.
visible - true if the annotation is visible at runtime.
Returns:
a non null visitor to visit the annotation values.

visitParameterAnnotation

AnnotationVisitor visitParameterAnnotation(int parameter,
                                           String desc,
                                           boolean visible)
Visits an annotation of a parameter this method.

Parameters:
parameter - the parameter index.
desc - the class descriptor of the annotation class.
visible - true if the annotation is visible at runtime.
Returns:
a non null visitor to visit the annotation values.

visitAttribute

void visitAttribute(Attribute attr)
Visits a non standard attribute of this method.

Parameters:
attr - an attribute.

visitCode

void visitCode()
Starts the visit of the method's code, if any (i.e. non abstract method).


visitInsn

void visitInsn(int opcode)
Visits a zero operand instruction.

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

void visitIntInsn(int opcode,
                  int operand)
Visits an instruction with a single int operand.

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.

visitVarInsn

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.

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.

visitTypeInsn

void visitTypeInsn(int opcode,
                   String desc)
Visits a type instruction. A type instruction is an instruction that takes a type descriptor as parameter.

Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
desc - the operand of the instruction to be visited. This operand is must be a fully qualified class name in internal form, or the type descriptor of an array type (see Type).

visitFieldInsn

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.

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).

visitMethodInsn

void visitMethodInsn(int opcode,
                     String owner,
                     String name,
                     String desc)
Visits a method instruction. A method instruction is an instruction that invokes a method.

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).

visitJumpInsn

void visitJumpInsn(int opcode,
                   Label label)
Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.

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

void visitLabel(Label label)
Visits a label. A label designates the instruction that will be visited just after it.

Parameters:
label - a Label object.

visitLdcInsn

void visitLdcInsn(Object cst)
Visits a LDC instruction.

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).

visitIincInsn

void visitIincInsn(int var,
                   int increment)
Visits an IINC instruction.

Parameters:
var - index of the local variable to be incremented.
increment - amount to increment the local variable by.

visitTableSwitchInsn

void visitTableSwitchInsn(int min,
                          int max,
                          Label dflt,
                          Label[] labels)
Visits a TABLESWITCH instruction.

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.

visitLookupSwitchInsn

void visitLookupSwitchInsn(Label dflt,
                           int[] keys,
                           Label[] labels)
Visits a LOOKUPSWITCH instruction.

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.

visitMultiANewArrayInsn

void visitMultiANewArrayInsn(String desc,
                             int dims)
Visits a MULTIANEWARRAY instruction.

Parameters:
desc - an array type descriptor (see Type).
dims - number of dimensions of the array to allocate.

visitTryCatchBlock

void visitTryCatchBlock(Label start,
                        Label end,
                        Label handler,
                        String type)
Visits a try catch block.

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).

visitLocalVariable

void visitLocalVariable(String name,
                        String desc,
                        String signature,
                        Label start,
                        Label end,
                        int index)
Visits a local variable declaration.

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.
Throws:
IllegalArgumentException - if one of the labels has not already been visited by this visitor (by the visitLabel method).

visitLineNumber

void visitLineNumber(int line,
                     Label start)
Visits a line number declaration.

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.
Throws:
IllegalArgumentException - if start has not already been visited by this visitor (by the visitLabel method).

visitMaxs

void visitMaxs(int maxStack,
               int maxLocals)
Visits the maximum stack size and the maximum number of local variables of the method.

Parameters:
maxStack - maximum stack size of the method.
maxLocals - maximum number of local variables for the method.

visitEnd

void visitEnd()
Visits the end of the method. This method, which is the last one to be called, is used to inform the visitor that all the annotations and attributes of the method have been visited.