Package javassist

Class 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 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

      • 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)