javassist

Class CtNewConstructor

java.lang.Object

javassist.CtNewConstructor

public class CtNewConstructor
extends java.lang.Object

A collection of static methods for creating a CtConstructor. An instance of this class does not make any sense.

A class initializer (static constructor) cannot be created by the methods in this class. Call makeClassInitializer() in CtClass and append code snippet to the body of the class initializer obtained by makeClassInitializer().

See Also:

CtClass.addConstructor(CtConstructor), CtClass.makeClassInitializer()

Field Summary

Fields

Modifier and Type	Field and Description
static int	PASS_ARRAY Specifies that parameters are converted into an array of Object and passed to a super-class' constructor.
static int	PASS_NONE Specifies that no parameters are passed to a super-class' constructor.
static int	PASS_PARAMS Specifies that parameters are passed as is to a super-class' constructor.

Constructor Summary

Constructors

Constructor and Description
CtNewConstructor()

Method Summary

Modifier and Type	Method and Description
static CtConstructor	copy(CtConstructor c, CtClass declaring, ClassMap map) Creates a copy of a constructor.
static CtConstructor	defaultConstructor(CtClass declaring) Creates a default (public) constructor.
static CtConstructor	make(CtClass[] parameters, CtClass[] exceptions, CtClass declaring) Creates a public constructor that only calls a constructor in the super class.
static CtConstructor	make(CtClass[] parameters, CtClass[] exceptions, int howto, CtMethod body, CtMethod.ConstParameter cparam, CtClass declaring) Creates a public constructor.
static CtConstructor	make(CtClass[] parameters, CtClass[] exceptions, java.lang.String body, CtClass declaring) Creates a public constructor.
static CtConstructor	make(java.lang.String src, CtClass declaring) Compiles the given source code and creates a constructor.
static CtConstructor	skeleton(CtClass[] parameters, CtClass[] exceptions, CtClass declaring) Creates a public constructor that only calls a constructor in the super class.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PASS_NONE

public static final int PASS_NONE

Specifies that no parameters are passed to a super-class' constructor. That is, the default constructor is invoked.

See Also:

Constant Field Values

PASS_ARRAY

public static final int PASS_ARRAY

Specifies that parameters are converted into an array of Object and passed to a super-class' constructor.

See Also:

Constant Field Values

PASS_PARAMS

public static final int PASS_PARAMS

Specifies that parameters are passed as is to a super-class' constructor. The signature of that constructor must be the same as that of the created constructor.

See Also:

Constant Field Values

Constructor Detail

CtNewConstructor

public CtNewConstructor()

Method Detail

make

public static CtConstructor make(java.lang.String src,
                                 CtClass declaring)
                          throws CannotCompileException

Compiles the given source code and creates a constructor. The source code must include not only the constructor body but the whole declaration.

Parameters:

src - the source text.

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

Throws:

CannotCompileException

make

public static CtConstructor make(CtClass[] parameters,
                                 CtClass[] exceptions,
                                 java.lang.String body,
                                 CtClass declaring)
                          throws CannotCompileException

Creates a public constructor.

Parameters:

parameters - a list of the parameter types.

exceptions - a list of the exception types.

body - the source text of the constructor body. It must be a block surrounded by {}. If it is null, the substituted constructor body does nothing except calling super().

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

Throws:

CannotCompileException

copy

public static CtConstructor copy(CtConstructor c,
                                 CtClass declaring,
                                 ClassMap map)
                          throws CannotCompileException

Creates a copy of a constructor. This is a convenience method for calling this constructor. See the description of the constructor for particular behavior of the copying.

Parameters:

c - the copied constructor.

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:

CtConstructor.CtConstructor(CtConstructor,CtClass,ClassMap)

defaultConstructor

public static CtConstructor defaultConstructor(CtClass declaring)
                                        throws CannotCompileException

Creates a default (public) constructor.

The created constructor takes no parameter. It calls super().

Throws:

CannotCompileException

skeleton

public static CtConstructor skeleton(CtClass[] parameters,
                                     CtClass[] exceptions,
                                     CtClass declaring)
                              throws CannotCompileException

Creates a public constructor that only calls a constructor in the super class. The created constructor receives parameters specified by parameters but calls the super's constructor without those parameters (that is, it calls the default constructor).

The parameters passed to the created constructor should be used for field initialization. CtField.Initializer objects implicitly insert initialization code in constructor bodies.

Parameters:

parameters - parameter types

exceptions - exception types

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

Throws:

CannotCompileException

See Also:

CtField.Initializer.byParameter(int)

make

public static CtConstructor make(CtClass[] parameters,
                                 CtClass[] exceptions,
                                 CtClass declaring)
                          throws CannotCompileException

Creates a public constructor that only calls a constructor in the super class. The created constructor receives parameters specified by parameters and calls the super's constructor with those parameters.

Parameters:

parameters - parameter types

exceptions - exception types

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

Throws:

CannotCompileException

make

public static CtConstructor make(CtClass[] parameters,
                                 CtClass[] exceptions,
                                 int howto,
                                 CtMethod body,
                                 CtMethod.ConstParameter cparam,
                                 CtClass declaring)
                          throws CannotCompileException

Creates a public constructor.

If howto is PASS_PARAMS, the created constructor calls the super's constructor with the same signature. The superclass must contain a constructor taking the same set of parameters as the created one.

If howto is PASS_NONE, the created constructor calls the super's default constructor. The superclass must contain a constructor taking no parameters.

If howto is PASS_ARRAY, the created constructor calls the super's constructor with the given parameters in the form of an array of Object. The signature of the super's constructor must be:

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

Here, cvalue is the constant value specified by cparam.

If cparam is null, the signature must be:

constructor(Object[] params)

If body is not null, a copy of that method is embedded in the body of the created constructor. The embedded method is executed after the super's constructor is called and the values of fields are initialized. Note that body must not be a constructor but a method.

Since the embedded method is wrapped in parameter-conversion code as in CtNewMethod.wrapped(), the constructor parameters are passed in the form of an array of Object. The method specified by body must have the signature shown below:

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

If cparam is null, the signature must be:

Object method(Object[] params)

Although the type of the returned value is Object, the value must be always null.

Example:

 ClassPool pool = ... ;
 CtClass xclass = pool.makeClass("X");
 CtMethod method = pool.getMethod("Sample", "m");
 xclass.setSuperclass(pool.get("Y"));
 CtClass[] argTypes = { CtClass.intType };
 ConstParameter cparam = ConstParameter.string("test");
 CtConstructor c = CtNewConstructor.make(argTypes, null,
                                  PASS_PARAMS, method, cparam, xclass);
 xclass.addConstructor(c);

where the class Sample is as follows:

 public class Sample {
     public Object m(Object[] args, String msg) {
         System.out.println(msg);
         return null;
     }
 }

This program produces the following class:

 public class X extends Y {
     public X(int p0) {
         super(p0);
         String msg = "test";
         Object[] args = new Object[] { p0 };
         // begin of copied body
         System.out.println(msg);
         Object result = null;
         // end
     }
 }

Parameters:

parameters - a list of the parameter types

exceptions - a list of the exceptions

howto - how to pass parameters to the super-class' constructor (PASS_NONE, PASS_ARRAY, or PASS_PARAMS)

body - appended body (may be null). It must be not a constructor but a method.

cparam - constant parameter (may be null.)

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

Throws:

CannotCompileException

See Also:

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