public abstract class MethodVisitor
A visitor to visit a Java method. The methods of this class must be called in the following
order: (
visitParameter
)* [ visitAnnotationDefault
] ( visitAnnotation
|
visitAnnotableParameterCount
| visitParameterAnnotation
visitTypeAnnotation
| visitAttribute
)* [ visitCode
( visitFrame
|
visitXInsn
| visitLabel
| visitInsnAnnotation
|
visitTryCatchBlock
| visitTryCatchAnnotation
| visitLocalVariable
|
visitLocalVariableAnnotation
| 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, visitInsnAnnotation
must be called after the annotated instruction, visitTryCatchBlock
must be called
before the labels passed as arguments have been visited,
visitTryCatchBlockAnnotation
must be called after the corresponding try catch block has
been visited, and the visitLocalVariable
, visitLocalVariableAnnotation
and
visitLineNumber
methods must be called after the labels passed as arguments have been
visited.protected final int | The ASM API version implemented by this visitor. |
protected MethodVisitor | The method visitor to which this visitor must delegate method calls. |
public | MethodVisitor( Constructs a new MethodVisitor. |
public | MethodVisitor( Constructs a new MethodVisitor. |
public void | visitAnnotableParameterCount( Visits the number of method parameters that can have annotations. |
public AnnotationVisitor | visitAnnotation( Visits an annotation of this method. |
public AnnotationVisitor | Visits the default value of this annotation interface method. |
public void | visitAttribute( Visits a non standard attribute of this method. |
public void | Starts the visit of the method's code, if any (i.e. |
public void | visitEnd() Visits the end of the method. |
public void | visitFieldInsn( Visits a field instruction. |
public void | visitFrame( Visits the current state of the local variables and operand stack elements. |
public void | visitIincInsn( Visits an IINC instruction. |
public void | visitInsn( Visits a zero operand instruction. |
public AnnotationVisitor | visitInsnAnnotation( Visits an annotation on an instruction. |
public void | visitIntInsn( Visits an instruction with a single int operand. |
public void | visitInvokeDynamicInsn( Visits an invokedynamic instruction. |
public void | visitJumpInsn( Visits a jump instruction. |
public void | visitLabel( Visits a label. |
public void | visitLdcInsn( Visits a LDC instruction. |
public void | visitLineNumber( Visits a line number declaration. |
public void | visitLocalVariable( Visits a local variable declaration. |
public AnnotationVisitor | visitLocalVariableAnnotation( Visits an annotation on a local variable type. |
public void | visitLookupSwitchInsn( Visits a LOOKUPSWITCH instruction. |
public void | visitMaxs( Visits the maximum stack size and the maximum number of local variables of the method. |
public void | visitMethodInsn( |
public void | visitMethodInsn( Visits a method instruction. |
public void | visitMultiANewArrayInsn( Visits a MULTIANEWARRAY instruction. |
public void | visitParameter( Visits a parameter of this method. |
public AnnotationVisitor | visitParameterAnnotation( Visits an annotation of a parameter this method. |
public void | visitTableSwitchInsn( Visits a TABLESWITCH instruction. |
public AnnotationVisitor | visitTryCatchAnnotation( Visits an annotation on an exception handler type. |
public void | visitTryCatchBlock( Visits a try catch block. |
public AnnotationVisitor | visitTypeAnnotation( Visits an annotation on a type in the method signature. |
public void | visitTypeInsn( Visits a type instruction. |
public void | visitVarInsn( Visits a local variable instruction. |
The method visitor to which this visitor must delegate method calls. May be null.
Visits the number of method parameters that can have annotations. By default (i.e. when this
method is not called), all the method parameters defined by the method descriptor can have
annotations.
parameterCountthe number of method parameters than can have annotations. This number
must be less or equal than the number of parameter types in the method descriptor. It can
be strictly less when a method has synthetic parameters and when these parameters are
ignored when computing parameter indices for the purpose of parameter annotations (see
https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.18).
visibletrue to define the number of method parameters that can have
annotations visible at runtime, false to define the number of method parameters
that can have annotations invisible at runtime.
Visits an annotation of this method.
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits the default value of this annotation interface method.
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.
Visits a non standard attribute of this method.
attributean attribute.
Starts the visit of the method's code, if any (i.e. non abstract method).
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.
Visits a field instruction. A field instruction is an instruction that loads or stores the
value of a field of an object.
opcodethe opcode of the type instruction to be visited. This opcode is either
GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
ownerthe internal name of the field's owner class (see Type.getInternalName()).
namethe field's name.
descriptorthe field's descriptor (see Type).
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 unconditional 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 Opcodes.V1_6.
The frames of a method must be given either in expanded form, or in compressed form (all frames must use the same format, i.e. you must not mix expanded and compressed frames within a single method):
In both cases the first frame, corresponding to the method's parameters and access flags, is implicit and must not be visited. Also, it is illegal to visit two or more frames for the same code location (i.e., at least one instruction must be visited between two calls to visitFrame).
(*) this is mandatory only for classes whose version is greater than or equal to Opcodes.V1_6.
The frames of a method must be given either in expanded form, or in compressed form (all frames must use the same format, i.e. you must not mix expanded and compressed frames within a single method):
- In expanded form, all frames must have the F_NEW type.
- In compressed form, frames are basically "deltas" from the state of the previous frame:
- 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 (
numStack
is 1 andstack[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 (
numLocal
is 1, 2 or 3 andlocal
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 (
numLocal
is 1, 2 or 3). - Opcodes.F_FULL representing complete frame data.
In both cases the first frame, corresponding to the method's parameters and access flags, is implicit and must not be visited. Also, it is illegal to visit two or more frames for the same code location (i.e., at least one instruction must be visited between two calls to visitFrame).
typethe 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.
numLocalthe number of local variables in the visited frame.
localthe 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).
numStackthe number of operand stack elements in the visited frame.
stackthe operand stack types in this frame. This array must not be modified. Its
content has the same format as the "local" array.
Visits an IINC instruction.
varindex of the local variable to be incremented.
incrementamount to increment the local variable by.
Visits a zero operand instruction.
opcodethe 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.
public AnnotationVisitor visitInsnAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible)
Visits an annotation on an instruction. This method must be called just after the
annotated instruction. It can be called several times for the same instruction.
typeRefa reference to the annotated type. The sort of this type reference must be
TypeReference.INSTANCEOF, TypeReference.NEW, TypeReference.CONSTRUCTOR_REFERENCE, TypeReference.METHOD_REFERENCE, TypeReference.CAST, TypeReference.CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT, TypeReference.METHOD_INVOCATION_TYPE_ARGUMENT, TypeReference.CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT, or TypeReference.METHOD_REFERENCE_TYPE_ARGUMENT. See TypeReference.
typePaththe path to the annotated type argument, wildcard bound, array element type, or
static inner type within 'typeRef'. May be null if the annotation targets
'typeRef' as a whole.
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits an instruction with a single int operand.
opcodethe opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH
or NEWARRAY.
operandthe 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.
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.
public void visitInvokeDynamicInsn(String name, String descriptor, Handle bootstrapMethodHandle, Object... bootstrapMethodArguments)
Visits an invokedynamic instruction.
namethe method's name.
descriptorthe method's descriptor (see Type).
bootstrapMethodHandlethe bootstrap method.
Visits a jump instruction. A jump instruction is an instruction that may jump to another
instruction.
opcodethe 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.
labelthe operand of the instruction to be visited. This operand is a label that
designates the instruction to which the jump instruction may jump.
Visits a label. A label designates the instruction that will be visited just after it.
labela Label object.
Visits a LDC instruction. Note that new constant types may be added in future versions of the
Java Virtual Machine. To easily detect new constant types, implementations of this method
should check for unexpected constant types, like this:
if (cst instanceof Integer) { // ... } else if (cst instanceof Float) { // ... } else if (cst instanceof Long) { // ... } else if (cst instanceof Double) { // ... } else if (cst instanceof String) { // ... } else if (cst instanceof Type) { int sort = ((Type) cst).getSort(); if (sort == Type.OBJECT) { // ... } else if (sort == Type.ARRAY) { // ... } else if (sort == Type.METHOD) { // ... } else { // throw an exception } } else if (cst instanceof Handle) { // ... } else if (cst instanceof ConstantDynamic) { // ... } else { // throw an exception }
valuethe constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double, a String, a Type of OBJECT or ARRAY sort for
.class
constants, for classes whose version is
49, a Type of METHOD sort for MethodType, a Handle for MethodHandle
constants, for classes whose version is 51 or a ConstantDynamic for a constant
dynamic for classes whose version is 55.Visits a line number declaration.
linea line number. This number refers to the source file from which the class was
compiled.
startthe first instruction corresponding to this line number.
public void visitLocalVariable(String name, String descriptor, String signature, Label start, Label end, int index)
Visits a local variable declaration.
namethe name of a local variable.
descriptorthe type descriptor of this local variable.
signaturethe type signature of this local variable. May be null if the local
variable type does not use generic types.
startthe first instruction corresponding to the scope of this local variable
(inclusive).
endthe last instruction corresponding to the scope of this local variable (exclusive).
indexthe local variable's index.
public AnnotationVisitor visitLocalVariableAnnotation(int typeRef, TypePath typePath, Label[] start, Label[] end, int[] index, String descriptor, boolean visible)
Visits an annotation on a local variable type.
typeRefa reference to the annotated type. The sort of this type reference must be
TypeReference.LOCAL_VARIABLE or TypeReference.RESOURCE_VARIABLE. See TypeReference.
typePaththe path to the annotated type argument, wildcard bound, array element type, or
static inner type within 'typeRef'. May be null if the annotation targets
'typeRef' as a whole.
startthe fist instructions corresponding to the continuous ranges that make the scope
of this local variable (inclusive).
endthe last instructions corresponding to the continuous ranges that make the scope of
this local variable (exclusive). This array must have the same size as the 'start' array.
indexthe local variable's index in each range. This array must have the same size as
the 'start' array.
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits a LOOKUPSWITCH instruction.
dfltbeginning of the default handler block.
keysthe values of the keys.
labelsbeginnings of the handler blocks.
labels[i]
is the beginning of the
handler block for the keys[i]
key.Visits the maximum stack size and the maximum number of local variables of the method.
maxStackmaximum stack size of the method.
maxLocalsmaximum number of local variables for the method.
Visits a method instruction. A method instruction is an instruction that invokes a method.
opcodethe opcode of the type instruction to be visited. This opcode is either
INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
ownerthe internal name of the method's owner class (see Type.getInternalName()).
namethe method's name.
descriptorthe method's descriptor (see Type).
public void visitMethodInsn(int opcode, String owner, String name, String descriptor, boolean isInterface)
Visits a method instruction. A method instruction is an instruction that invokes a method.
opcodethe opcode of the type instruction to be visited. This opcode is either
INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
ownerthe internal name of the method's owner class (see Type.getInternalName()).
namethe method's name.
descriptorthe method's descriptor (see Type).
isInterfaceif the method's owner class is an interface.
Visits a MULTIANEWARRAY instruction.
descriptoran array type descriptor (see Type).
numDimensionsthe number of dimensions of the array to allocate.
Visits a parameter of this method.
nameparameter name or null if none is provided.
accessthe parameter's access flags, only
ACC_FINAL
, ACC_SYNTHETIC
or/and ACC_MANDATED
are allowed (see Opcodes).public AnnotationVisitor visitParameterAnnotation(int parameter, String descriptor, boolean visible)
Visits an annotation of a parameter this method.
parameterthe parameter index. This index must be strictly smaller than the number of
parameters in the method descriptor, and strictly smaller than the parameter count
specified in visitAnnotableParameterCount(int, boolean) . Important note: a parameter index i
is not required to correspond to the i'th parameter descriptor in the method
descriptor, in particular in case of synthetic parameters (see
https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.18).
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits a TABLESWITCH instruction.
minthe minimum key value.
maxthe maximum key value.
dfltbeginning of the default handler block.
labelsbeginnings of the handler blocks.
labels[i]
is the beginning of the
handler block for the min + i
key.public AnnotationVisitor visitTryCatchAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible)
Visits an annotation on an exception handler type. This method must be called after the
visitTryCatchBlock(Label, Label, Label, String) for the annotated exception handler. It can be called several times
for the same exception handler.
typeRefa reference to the annotated type. The sort of this type reference must be
TypeReference.EXCEPTION_PARAMETER. See TypeReference.
typePaththe path to the annotated type argument, wildcard bound, array element type, or
static inner type within 'typeRef'. May be null if the annotation targets
'typeRef' as a whole.
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits a try catch block.
startthe beginning of the exception handler's scope (inclusive).
endthe end of the exception handler's scope (exclusive).
handlerthe beginning of the exception handler's code.
typethe internal name of the type of exceptions handled by the handler, or
null to catch any exceptions (for "finally" blocks).
public AnnotationVisitor visitTypeAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible)
Visits an annotation on a type in the method signature.
typeRefa reference to the annotated type. The sort of this type reference must be
TypeReference.METHOD_TYPE_PARAMETER, TypeReference.METHOD_TYPE_PARAMETER_BOUND, TypeReference.METHOD_RETURN, TypeReference.METHOD_RECEIVER, TypeReference.METHOD_FORMAL_PARAMETER or TypeReference.THROWS. See TypeReference.
typePaththe path to the annotated type argument, wildcard bound, array element type, or
static inner type within 'typeRef'. May be null if the annotation targets
'typeRef' as a whole.
descriptorthe class descriptor of the annotation class.
visibletrue if the annotation is visible at runtime.
a visitor to visit the annotation values, or null if this visitor is not
interested in visiting this annotation.
Visits a type instruction. A type instruction is an instruction that takes the internal name of
a class as parameter.
opcodethe opcode of the type instruction to be visited. This opcode is either NEW,
ANEWARRAY, CHECKCAST or INSTANCEOF.
typethe operand of the instruction to be visited. This operand must be the internal
name of an object or array class (see Type.getInternalName()).
Visits a local variable instruction. A local variable instruction is an instruction that loads
or stores the value of a local variable.
opcodethe 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.
varthe operand of the instruction to be visited. This operand is the index of a local
variable.