org.aspectj.apache.bcel.generic

Class MethodGen

java.lang.Object

org.aspectj.apache.bcel.classfile.Modifiers

org.aspectj.apache.bcel.generic.FieldGenOrMethodGen

org.aspectj.apache.bcel.generic.MethodGen

public class MethodGen
extends FieldGenOrMethodGen

Template class for building up a method. This is done by defining exception handlers, adding thrown exceptions, local variables and attributes, whereas the 'LocalVariableTable' and 'LineNumberTable' attributes will be set automatically for the code. Use stripAttributes() if you don't like this. While generating code it may be necessary to insert NOP operations. You can use the `removeNOPs' method to get rid off them. The resulting method object can be obtained via the `getMethod()' method.

See Also:

InstructionList, Method

Field Summary

Fields inherited from class org.aspectj.apache.bcel.generic.FieldGenOrMethodGen

annotationList, cp, name, type

Fields inherited from class org.aspectj.apache.bcel.classfile.Modifiers

modifiers

Constructor Summary

Constructors

Constructor and Description
MethodGen(int access_flags, Type return_type, Type[] arg_types, java.lang.String[] arg_names, java.lang.String method_name, java.lang.String class_name, InstructionList il, ConstantPool cp) Declare method.
MethodGen(Method m, java.lang.String class_name, ConstantPool cp) Instantiate from existing method.
MethodGen(Method m, java.lang.String class_name, ConstantPool cp, boolean useTags)

Method Summary

Modifier and Type	Method and Description
void	addCodeAttribute(Attribute a) Add an attribute to the code.
void	addException(java.lang.String class_name) Add an exception possibly thrown by this method.
CodeExceptionGen	addExceptionHandler(InstructionHandle start_pc, InstructionHandle end_pc, InstructionHandle handler_pc, ObjectType catch_type) Add an exception handler, i.e., specify region where a handler is active and an instruction where the actual handling is done.
LineNumberGen	addLineNumber(InstructionHandle ih, int src_line) Give an instruction a line number corresponding to the source code line.
LocalVariableGen	addLocalVariable(java.lang.String name, Type type, InstructionHandle start, InstructionHandle end) Adds a local variable to this method and assigns an index automatically.
LocalVariableGen	addLocalVariable(java.lang.String name, Type type, int slot, InstructionHandle start, InstructionHandle end)
void	addParameterAnnotation(int parameterIndex, AnnotationGen annotation)
void	addParameterAnnotationsAsAttribute(ConstantPool cp)
java.util.List	getAnnotationsOnParameter(int i) Return a list of AnnotationGen objects representing parameter annotations
java.lang.String	getArgumentName(int i)
java.lang.String[]	getArgumentNames()
Type	getArgumentType(int i)
Type[]	getArgumentTypes()
java.lang.String	getClassName()
Attribute[]	getCodeAttributes()
CodeExceptionGen[]	getExceptionHandlers()
java.lang.String[]	getExceptions()
int	getHighestlinenumber()
InstructionList	getInstructionList()
LineNumberGen[]	getLineNumbers()
LineNumberTable	getLineNumberTable(ConstantPool cp)
LocalVariableGen[]	getLocalVariables()
LocalVariableTable	getLocalVariableTable(ConstantPool cp)
int	getMaxLocals()
int	getMaxStack()
static int	getMaxStack(ConstantPool cp, InstructionList il, CodeExceptionGen[] et) Computes stack usage of an instruction list by performing control flow analysis.
Method	getMethod() Get method object.
Type	getReturnType()
java.lang.String	getSignature()
void	removeCodeAttribute(Attribute a) Remove a code attribute.
void	removeCodeAttributes() Remove all code attributes.
void	removeException(java.lang.String c) Remove an exception.
void	removeExceptionHandler(CodeExceptionGen c) Remove an exception handler.
void	removeExceptionHandlers() Remove all line numbers.
void	removeExceptions() Remove all exceptions.
void	removeLineNumber(LineNumberGen l) Remove a line number.
void	removeLineNumbers() Remove all line numbers.
void	removeLocalVariable(LocalVariableGen l) Remove a local variable, its slot will not be reused, if you do not use addLocalVariable with an explicit index argument.
void	removeLocalVariables() Remove all local variables.
void	setArgumentName(int i, java.lang.String name)
void	setArgumentNames(java.lang.String[] arg_names)
void	setArgumentType(int i, Type type)
void	setArgumentTypes(Type[] arg_types)
void	setClassName(java.lang.String class_name)
void	setInstructionList(InstructionList il)
void	setMaxLocals() Compute maximum number of local variables.
void	setMaxLocals(int m) Set maximum number of local variables.
void	setMaxStack() Computes max.
void	setMaxStack(int m) Set maximum stack size for this method.
void	setReturnType(Type return_type)
void	stripAttributes(boolean flag)
java.lang.String	toString() Return string representation close to declaration format, `public static void main(String[]) throws IOException', e.g.

Methods inherited from class org.aspectj.apache.bcel.generic.FieldGenOrMethodGen

addAnnotation, addAnnotationsAsAttribute, addAttribute, getAnnotations, getAttributes, getAttributesImmutable, getConstantPool, getName, getType, removeAnnotation, removeAnnotations, removeAttribute, removeAttributes, setConstantPool, setName, setType

Methods inherited from class org.aspectj.apache.bcel.classfile.Modifiers

getModifiers, isAbstract, isBridge, isFinal, isInterface, isNative, isPrivate, isProtected, isPublic, isStatic, isStrictfp, isSynchronized, isTransient, isVarargs, isVolatile, setModifiers

Methods inherited from class java.lang.Object

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

Constructor Detail

MethodGen

public MethodGen(int access_flags,
                 Type return_type,
                 Type[] arg_types,
                 java.lang.String[] arg_names,
                 java.lang.String method_name,
                 java.lang.String class_name,
                 InstructionList il,
                 ConstantPool cp)

Declare method. If the method is non-static the constructor automatically declares a local variable `$this' in slot 0. The actual code is contained in the `il' parameter, which may further manipulated by the user. But he must take care not to remove any instruction (handles) that are still referenced from this object. For example one may not add a local variable and later remove the instructions it refers to without causing havoc. It is safe however if you remove that local variable, too.

Parameters:

access_flags - access qualifiers

return_type - method type

arg_types - argument types

arg_names - argument names (if this is null, default names will be provided for them)

method_name - name of method

class_name - class name containing this method (may be null, if you don't care)

il - instruction list associated with this method, may be null only for abstract or native methods

cp - constant pool

MethodGen

public MethodGen(Method m,
                 java.lang.String class_name,
                 ConstantPool cp)

Instantiate from existing method.

Parameters:

m - method

class_name - class name containing this method

cp - constant pool

MethodGen

public MethodGen(Method m,
                 java.lang.String class_name,
                 ConstantPool cp,
                 boolean useTags)

Method Detail

getHighestlinenumber

public int getHighestlinenumber()

addLocalVariable

public LocalVariableGen addLocalVariable(java.lang.String name,
                                         Type type,
                                         int slot,
                                         InstructionHandle start,
                                         InstructionHandle end)

addLocalVariable

public LocalVariableGen addLocalVariable(java.lang.String name,
                                         Type type,
                                         InstructionHandle start,
                                         InstructionHandle end)

Adds a local variable to this method and assigns an index automatically.

Parameters:

name - variable name

type - variable type

start - from where the variable is valid, if this is null, it is valid from the start

end - until where the variable is valid, if this is null, it is valid to the end

Returns:

new local variable object

See Also:

LocalVariable

removeLocalVariable

public void removeLocalVariable(LocalVariableGen l)

Remove a local variable, its slot will not be reused, if you do not use addLocalVariable with an explicit index argument.

removeLocalVariables

public void removeLocalVariables()

Remove all local variables.

getLocalVariables

public LocalVariableGen[] getLocalVariables()

getLocalVariableTable

public LocalVariableTable getLocalVariableTable(ConstantPool cp)

Returns:

`LocalVariableTable' attribute of all the local variables of this method.

addLineNumber

public LineNumberGen addLineNumber(InstructionHandle ih,
                                   int src_line)

Give an instruction a line number corresponding to the source code line.

Parameters:

ih - instruction to tag

Returns:

new line number object

See Also:

LineNumber

removeLineNumber

public void removeLineNumber(LineNumberGen l)

Remove a line number.

removeLineNumbers

public void removeLineNumbers()

Remove all line numbers.

getLineNumbers

public LineNumberGen[] getLineNumbers()

getLineNumberTable

public LineNumberTable getLineNumberTable(ConstantPool cp)

Returns:

'LineNumberTable' attribute for all the local variables of this method.

addExceptionHandler

public CodeExceptionGen addExceptionHandler(InstructionHandle start_pc,
                                            InstructionHandle end_pc,
                                            InstructionHandle handler_pc,
                                            ObjectType catch_type)

Add an exception handler, i.e., specify region where a handler is active and an instruction where the actual handling is done.

Parameters:

start_pc - Start of region (inclusive)

end_pc - End of region (inclusive)

handler_pc - Where handling is done

catch_type - class type of handled exception or null if any exception is handled

Returns:

new exception handler object

removeExceptionHandler

public void removeExceptionHandler(CodeExceptionGen c)

Remove an exception handler.

removeExceptionHandlers

public void removeExceptionHandlers()

Remove all line numbers.

getExceptionHandlers

public CodeExceptionGen[] getExceptionHandlers()

addException

public void addException(java.lang.String class_name)

Add an exception possibly thrown by this method.

Parameters:

class_name - (fully qualified) name of exception

removeException

public void removeException(java.lang.String c)

Remove an exception.

removeExceptions

public void removeExceptions()

Remove all exceptions.

getExceptions

public java.lang.String[] getExceptions()

addCodeAttribute

public void addCodeAttribute(Attribute a)

Add an attribute to the code. Currently, the JVM knows about the LineNumberTable, LocalVariableTable and StackMap attributes, where the former two will be generated automatically and the latter is used for the MIDP only. Other attributes will be ignored by the JVM but do no harm.

Parameters:

a - attribute to be added

addParameterAnnotationsAsAttribute

public void addParameterAnnotationsAsAttribute(ConstantPool cp)

removeCodeAttribute

public void removeCodeAttribute(Attribute a)

Remove a code attribute.

removeCodeAttributes

public void removeCodeAttributes()

Remove all code attributes.

getCodeAttributes

public Attribute[] getCodeAttributes()

Returns:

all attributes of this method.

getMethod

public Method getMethod()

Get method object. Never forget to call setMaxStack() or setMaxStack(max), respectively, before calling this method (the same applies for max locals).

Returns:

method object

setMaxLocals

public void setMaxLocals(int m)

Set maximum number of local variables.

getMaxLocals

public int getMaxLocals()

setMaxStack

public void setMaxStack(int m)

Set maximum stack size for this method.

getMaxStack

public int getMaxStack()

getClassName

public java.lang.String getClassName()

Returns:

class that contains this method

setClassName

public void setClassName(java.lang.String class_name)

setReturnType

public void setReturnType(Type return_type)

getReturnType

public Type getReturnType()

setArgumentTypes

public void setArgumentTypes(Type[] arg_types)

getArgumentTypes

public Type[] getArgumentTypes()

setArgumentType

public void setArgumentType(int i,
                            Type type)

getArgumentType

public Type getArgumentType(int i)

setArgumentNames

public void setArgumentNames(java.lang.String[] arg_names)

getArgumentNames

public java.lang.String[] getArgumentNames()

setArgumentName

public void setArgumentName(int i,
                            java.lang.String name)

getArgumentName

public java.lang.String getArgumentName(int i)

getInstructionList

public InstructionList getInstructionList()

setInstructionList

public void setInstructionList(InstructionList il)

getSignature

public java.lang.String getSignature()

Specified by:

getSignature in class FieldGenOrMethodGen

setMaxStack

public void setMaxStack()

Computes max. stack size by performing control flow analysis.

setMaxLocals

public void setMaxLocals()

Compute maximum number of local variables.

stripAttributes

public void stripAttributes(boolean flag)

getMaxStack

public static int getMaxStack(ConstantPool cp,
                              InstructionList il,
                              CodeExceptionGen[] et)

Computes stack usage of an instruction list by performing control flow analysis.

Returns:

maximum stack depth used by method

toString

public final java.lang.String toString()

Return string representation close to declaration format, `public static void main(String[]) throws IOException', e.g.

Overrides:

toString in class java.lang.Object

Returns:

String representation of the method.

getAnnotationsOnParameter

public java.util.List getAnnotationsOnParameter(int i)

Return a list of AnnotationGen objects representing parameter annotations

addParameterAnnotation

public void addParameterAnnotation(int parameterIndex,
                                   AnnotationGen annotation)