javassist
Class CtMethod

java.lang.Object
  javassist.CtMember
      javassist.CtBehavior
          javassist.CtMethod

public final class CtMethod

extends CtBehavior

An instance of CtMethod represents a method.

See Also:

CtClass.getDeclaredMethods(), CtNewMethod

Nested Class Summary

static class

CtMethod.ConstParameter Instances of this class represent a constant parameter.

Constructor Summary

CtMethod(CtClass returnType, java.lang.String mname, CtClass[] parameters, CtClass declaring)
Creates a public abstract method.

CtMethod(CtMethod src, CtClass declaring, ClassMap map)
Creates a copy of a CtMethod object.

Method Summary

void	addCatch(java.lang.String src, CtClass exceptionType) Adds a catch clause that handles an exception thrown in the method body.
boolean	equals(java.lang.Object obj) Indicates whether obj has the same name and the same signature as this method.
byte[]	getAttribute(java.lang.String name) Obtains an attribute with the given name.
CtClass	getDeclaringClass() Returns the class that declares this method.
CtClass[]	getExceptionTypes() Obtains exceptions that this method may throw.
MethodInfo	getMethodInfo() Returns the MethodInfo representing the method in the class file.
int	getModifiers() Obtains the modifiers of the method.
java.lang.String	getName() Obtains the name of this method.
CtClass[]	getParameterTypes() Obtains parameter types of this method.
CtClass	getReturnType() Obtains the type of the returned value.
java.lang.String	getSignature() Returns the character string representing the parameter types and the return type.
int	hashCode() Returns a hash code value for the method.
void	insertAfter(java.lang.String src) Inserts bytecode at the end of the method body.
void	insertAfter(java.lang.String src, boolean asFinally) Inserts bytecode at the end of the method body.
void	insertBefore(java.lang.String src) Inserts bytecode at the beginning of the method body.
void	instrument(CodeConverter converter) Modifies the method body.
void	instrument(ExprEditor editor) Modifies the method body.
boolean	isEmpty() Returns true if the method body is empty, that is, {}.
void	setAttribute(java.lang.String name, byte[] data) Adds an attribute.
void	setBody(CtMethod src, ClassMap map) Copies a method body from another method.
void	setBody(java.lang.String src) Sets a method body.
void	setExceptionTypes(CtClass[] types) Sets exceptions that this method may throw.
void	setModifiers(int mod) Sets the encoded modifiers of the method.
void	setName(java.lang.String newname) Changes the name of this method.
void	setWrappedBody(CtMethod mbody, CtMethod.ConstParameter constParam) Replace a method body with a new method body wrapping the given method.
void	useCflow(java.lang.String name) Declares to use $cflow for this method.

Methods inherited from class javassist.CtBehavior

addCatch, getMethodInfo2

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CtMethod

public CtMethod(CtClass returnType,
                java.lang.String mname,
                CtClass[] parameters,
                CtClass declaring)

Creates a public abstract method. The created method must be added to a class with CtClass.addMethod().

Parameters:

declaring - the class to which the created method is added.

returnType - the type of the returned value

mname - the method name

parameters - a list of the parameter types

See Also:

CtClass.addMethod(CtMethod)

CtMethod

public CtMethod(CtMethod src,
                CtClass declaring,
                ClassMap map)
         throws CannotCompileException

Creates a copy of a CtMethod object. The created method must be added to a class with CtClass.addMethod().

All occurrences of class names in the created method are replaced with names specified by map if map is not null.

For example, suppose that a method at() is as follows:

public X at(int i) {
     return (X)super.elementAt(i);
 }

(X is a class name.) If map substitutes String for X, then the created method is:

public String at(int i) {
     return (String)super.elementAt(i);
 }

By default, all the occurrences of the names of the class declaring at() and the superclass are replaced with the name of the class and the superclass that the created method is added to. This is done whichever map is null or not. To prevent this replacement, call ClassMap.fix().

Note: if the .class notation (for example, String.class) is included in an expression, the Javac compiler may produce a helper method. Since this constructor never copies this helper method, the programmers have the responsiblity of copying it. Otherwise, use Class.forName() in the expression.

Parameters:

src - the source method.

declaring - the class to which the created method is added.

map - the hashtable associating original class names with substituted names. It can be null.

See Also:

CtClass.addMethod(CtMethod), ClassMap.fix(String)

Method Detail

hashCode

public int hashCode()

Returns a hash code value for the method. If two methods have the same name and signature, then the hash codes for the two methods are equal.

equals

public boolean equals(java.lang.Object obj)

Indicates whether obj has the same name and the same signature as this method.

getMethodInfo

public MethodInfo getMethodInfo()

Returns the MethodInfo representing the method in the class file.

Overrides:

getMethodInfo in class CtBehavior

getModifiers

public int getModifiers()

Obtains the modifiers of the method.

Overrides:

getModifiers in class CtBehavior

Returns:

modifiers encoded with javassist.Modifier.

See Also:

Modifier

setModifiers

public void setModifiers(int mod)

Sets the encoded modifiers of the method.

Changing the modifiers may cause a problem. For example, if a non-static method is changed to static, the method will be rejected by the bytecode verifier.

Overrides:

setModifiers in class CtBehavior

See Also:

Modifier

getName

public java.lang.String getName()

Obtains the name of this method.

Specified by:

getName in class CtBehavior

See Also:

CtConstructor.getName()

setName

public void setName(java.lang.String newname)

Changes the name of this method.

getDeclaringClass

public CtClass getDeclaringClass()

Returns the class that declares this method.

Overrides:

getDeclaringClass in class CtMember

getParameterTypes

public CtClass[] getParameterTypes()
                            throws NotFoundException

Obtains parameter types of this method.

Overrides:

getParameterTypes in class CtBehavior

Throws:

NotFoundException

getReturnType

public CtClass getReturnType()
                      throws NotFoundException

Obtains the type of the returned value.

Throws:

NotFoundException

getSignature

public java.lang.String getSignature()

Returns the character string representing the parameter types and the return type. If two methods have the same parameter types and the return type, getSignature() returns the same string.

Overrides:

getSignature in class CtBehavior

getExceptionTypes

public CtClass[] getExceptionTypes()
                            throws NotFoundException

Obtains exceptions that this method may throw.

Overrides:

getExceptionTypes in class CtBehavior

Throws:

NotFoundException

setExceptionTypes

public void setExceptionTypes(CtClass[] types)
                       throws NotFoundException

Sets exceptions that this method may throw.

Overrides:

setExceptionTypes in class CtBehavior

Parameters:

types - exception types (or null)

Throws:

NotFoundException

isEmpty

public boolean isEmpty()

Returns true if the method body is empty, that is, {}. It also returns true if the method is an abstract method.

Specified by:

isEmpty in class CtBehavior

setBody

public void setBody(java.lang.String src)
             throws CannotCompileException

Sets a method body.

Overrides:

setBody in class CtBehavior

Parameters:

src - the source code representing the method body. It must be a single statement or block. If it is null, the substituted method body does nothing except returning zero or null.

Throws:

CannotCompileException

setBody

public void setBody(CtMethod src,
                    ClassMap map)
             throws CannotCompileException

Copies a method body from another method. If this method is abstract, the abstract modifier is removed after the method body is copied.

All occurrences of the class names in the copied method body are replaced with the names specified by map if map is not null.

Parameters:

src - the method that the body is copied from.

map - the hashtable associating original class names with substituted names. It can be null.

Throws:

CannotCompileException

setWrappedBody

public void setWrappedBody(CtMethod mbody,
                           CtMethod.ConstParameter constParam)
                    throws CannotCompileException

Replace a method body with a new method body wrapping the given method.

Parameters:

mbody - the wrapped method

constParam - the constant parameter given to the wrapped method (maybe null).

Throws:

CannotCompileException

See Also:

CtNewMethod.wrapped(CtClass,String,CtClass[],CtClass[],CtMethod,CtMethod.ConstParameter,CtClass)

getAttribute

public byte[] getAttribute(java.lang.String name)

Obtains an attribute with the given name. If that attribute is not found in the class file, this method returns null.

Overrides:

getAttribute in class CtBehavior

Parameters:

name - attribute name

setAttribute

public void setAttribute(java.lang.String name,
                         byte[] data)

Adds an attribute. The attribute is saved in the class file.

Overrides:

setAttribute in class CtBehavior

Parameters:

name - attribute name

data - attribute value

useCflow

public void useCflow(java.lang.String name)
              throws CannotCompileException

Declares to use $cflow for this method. If $cflow is used, the class files modified with Javassist requires a support class javassist.runtime.Cflow at runtime (other Javassist classes are not required at runtime).

Every $cflow variable is given a unique name. For example, if the given name is "Point.paint", then the variable is indicated by $cflow(Point.paint).

Overrides:

useCflow in class CtBehavior

Parameters:

name - $cflow name. It can include alphabets, numbers, _, $, and . (dot).

Throws:

CannotCompileException

See Also:

Cflow

instrument

public void instrument(CodeConverter converter)
                throws CannotCompileException

Modifies the method body.

Overrides:

instrument in class CtBehavior

Parameters:

converter - specifies how to modify.

Throws:

CannotCompileException

instrument

public void instrument(ExprEditor editor)
                throws CannotCompileException

Modifies the method body.

Overrides:

instrument in class CtBehavior

Parameters:

editor - specifies how to modify.

Throws:

CannotCompileException

insertBefore

public void insertBefore(java.lang.String src)
                  throws CannotCompileException

Inserts bytecode at the beginning of the method body.

Overrides:

insertBefore in class CtBehavior

Parameters:

src - the source code representing the inserted bytecode. It must be a single statement or block.

Throws:

CannotCompileException

insertAfter

public void insertAfter(java.lang.String src)
                 throws CannotCompileException

Inserts bytecode at the end of the method body. The bytecode is inserted just before every return insturction. It is not executed when an exception is thrown.

Overrides:

insertAfter in class CtBehavior

Parameters:

src - the source code representing the inserted bytecode. It must be a single statement or block.

Throws:

CannotCompileException

insertAfter

public void insertAfter(java.lang.String src,
                        boolean asFinally)
                 throws CannotCompileException

Inserts bytecode at the end of the method body. The bytecode is inserted just before every return insturction.

Overrides:

insertAfter in class CtBehavior

Parameters:

src - the source code representing the inserted bytecode. It must be a single statement or block.

asFinally - true if the inserted bytecode is executed not only when the transfer normally returns but also when an exception is thrown.

Throws:

CannotCompileException

addCatch

public void addCatch(java.lang.String src,
                     CtClass exceptionType)
              throws CannotCompileException

Adds a catch clause that handles an exception thrown in the method body. The catch clause must end with a return or throw statement.

Overrides:

addCatch in class CtBehavior

Parameters:

src - the source code representing the catch clause. It must be a single statement or block.

exceptionType - the type of the exception handled by the catch clause.

Throws:

CannotCompileException