Package javassist

Class CtNewMethod

java.lang.Object
javassist.CtNewMethod
public class CtNewMethod extends Object
A collection of static methods for creating a CtMethod. An instance of this class does not make any sense.
See Also:

  • Constructor Details

    • CtNewMethod

      public CtNewMethod()

  • Method Details

    • make

      public static CtMethod make(String src, CtClass declaring) throws CannotCompileException
      Compiles the given source code and creates a method. The source code must include not only the method body but the whole declaration, for example, 
      "public Object id(Object obj) { return obj; }"
      Parameters:
      src - the source text.
      declaring - the class to which the created method is added.
      Throws:
      CannotCompileException

    • make

      public static CtMethod make(String src, CtClass declaring, String delegateObj, String delegateMethod) throws CannotCompileException
      Compiles the given source code and creates a method. The source code must include not only the method body but the whole declaration, for example, 
      "public Object id(Object obj) { return obj; }"

      If the source code includes $proceed(), then it is compiled into a method call on the specified object.

      Parameters:
      src - the source text.
      declaring - the class to which the created method is added.
      delegateObj - the source text specifying the object that is called on by $proceed().
      delegateMethod - the name of the method that is called by $proceed().
      Throws:
      CannotCompileException

    • make

      public static CtMethod make(CtClass returnType, String mname, CtClass[] parameters, CtClass[] exceptions, String body, CtClass declaring) throws CannotCompileException
      Creates a public (non-static) method. The created method cannot be changed to a static method later.
      Parameters:
      returnType - the type of the returned value.
      mname - the method name.
      parameters - a list of the parameter types.
      exceptions - a list of the exception types.
      body - the source text of the method body. It must be a block surrounded by {}. If it is null, the created method does nothing except returning zero or null.
      declaring - the class to which the created method is added.
      Throws:
      CannotCompileException
      See Also:

    • make

      public static CtMethod make(int modifiers, CtClass returnType, String mname, CtClass[] parameters, CtClass[] exceptions, String body, CtClass declaring) throws CannotCompileException
      Creates a method. modifiers can contain Modifier.STATIC.
      Parameters:
      modifiers - access modifiers.
      returnType - the type of the returned value.
      mname - the method name.
      parameters - a list of the parameter types.
      exceptions - a list of the exception types.
      body - the source text of the method body. It must be a block surrounded by {}. If it is null, the created method does nothing except returning zero or null.
      declaring - the class to which the created method is added.
      Throws:
      CannotCompileException
      See Also:

    • copy

      public static CtMethod copy(CtMethod src, CtClass declaring, ClassMap map) throws CannotCompileException
      Creates a copy of a method. This method is provided for creating a new method based on an existing method. This is a convenience method for calling this constructor. See the description of the constructor for particular behavior of the copying.
      Parameters:
      src - the source method.
      declaring - the class to which the created method is added.
      map - the hash table associating original class names with substituted names. It can be null.
      Throws:
      CannotCompileException
      See Also:

    • copy

      public static CtMethod copy(CtMethod src, String name, CtClass declaring, ClassMap map) throws CannotCompileException
      Creates a copy of a method with a new name. This method is provided for creating a new method based on an existing method. This is a convenience method for calling this constructor. See the description of the constructor for particular behavior of the copying.
      Parameters:
      src - the source method.
      name - the name of the created method.
      declaring - the class to which the created method is added.
      map - the hash table associating original class names with substituted names. It can be null.
      Throws:
      CannotCompileException
      See Also:

    • abstractMethod

      public static CtMethod abstractMethod(CtClass returnType, String mname, CtClass[] parameters, CtClass[] exceptions, CtClass declaring) throws NotFoundException
      Creates a public abstract method.
      Parameters:
      returnType - the type of the returned value
      mname - the method name
      parameters - a list of the parameter types
      exceptions - a list of the exception types
      declaring - the class to which the created method is added.
      Throws:
      NotFoundException
      See Also:

    • getter

      public static CtMethod getter(String methodName, CtField field) throws CannotCompileException
      Creates a public getter method. The getter method returns the value of the specified field in the class to which this method is added. The created method is initially not static even if the field is static. Change the modifiers if the method should be static.
      Parameters:
      methodName - the name of the getter
      field - the field accessed.
      Throws:
      CannotCompileException

    • setter

      public static CtMethod setter(String methodName, CtField field) throws CannotCompileException
      Creates a public setter method. The setter method assigns the value of the first parameter to the specified field in the class to which this method is added. The created method is not static even if the field is static. You may not change it to be static by setModifiers() in CtBehavior.
      Parameters:
      methodName - the name of the setter
      field - the field accessed.
      Throws:
      CannotCompileException

    • delegator

      public static CtMethod delegator(CtMethod delegate, CtClass declaring) throws CannotCompileException
      Creates a method forwarding to a delegate in a super class. The created method calls a method specified by delegate with all the parameters passed to the created method. If the delegate method returns a value, the created method returns that value to the caller. The delegate method must be declared in a super class.

      The following method is an example of the created method. 

       int f(int p, int q) {
     return super.f(p, q);
 }

      The name of the created method can be changed by setName().

      Parameters:
      delegate - the method that the created method forwards to.
      declaring - the class to which the created method is added.
      Throws:
      CannotCompileException

    • wrapped

      public static CtMethod wrapped(CtClass returnType, String mname, CtClass[] parameterTypes, CtClass[] exceptionTypes, CtMethod body, CtMethod.ConstParameter constParam, CtClass declaring) throws CannotCompileException
      Creates a wrapped method. The wrapped method receives parameters in the form of an array of Object.

      The body of the created method is a copy of the body of the method specified by body. However, it is wrapped in parameter-conversion code.

      The method specified by body must have this singature: 

      Object method(Object[] params, <type> cvalue)

      The type of the cvalue depends on constParam. If constParam is null, the signature must be: 

      Object method(Object[] params)

      The method body copied from body is wrapped in parameter-conversion code, which converts parameters specified by parameterTypes into an array of Object. The returned value is also converted from the Object type to the type specified by returnType. Thus, the resulting method body is as follows: 

       Object[] params = new Object[] { p0, p1, ... };
 <type> cvalue = <constant-value>;
  ... copied method body ...
 Object result = <returned value>
 return (<returnType>)result;

      The variables p0, p2, ... represent formal parameters of the created method. The value of cvalue is specified by constParam.

      If the type of a parameter or a returned value is a primitive type, then the value is converted into a wrapper object such as java.lang.Integer. If the type of the returned value is void, the returned value is discarded.

      Example: 

       ClassPool pool = ... ;
 CtClass vec = pool.makeClass("intVector");
 vec.setSuperclass(pool.get("java.util.Vector"));
 CtMethod addMethod = pool.getMethod("Sample", "add0");

 CtClass[] argTypes = { CtClass.intType };
 CtMethod m = CtNewMethod.wrapped(CtClass.voidType, "add", argTypes,
                                  null, addMethod, null, vec);
 vec.addMethod(m);

      where the class Sample is as follows: 

      public class Sample extends java.util.Vector {
     public Object add0(Object[] args) {
         super.addElement(args[0]);
         return null;
     }
 }

      This program produces a class intVector: 

      public class intVector extends java.util.Vector {
     public void add(int p0) {
         Object[] args = new Object[] { p0 };
         // begin of the copied body
         super.addElement(args[0]);
         Object result = null;
         // end
     }
 }

      Note that the type of the parameter to add() depends only on the value of argTypes passed to CtNewMethod.wrapped(). Thus, it is easy to modify this program to produce a StringVector class, which is a vector containing only String objects, and other vector classes.

      Parameters:
      returnType - the type of the returned value.
      mname - the method name.
      parameterTypes - a list of the parameter types.
      exceptionTypes - a list of the exception types.
      body - the method body (must not be a static method).
      constParam - the constant parameter (maybe null).
      declaring - the class to which the created method is added.
      Throws:
      CannotCompileException