CodeModel help needed for right-hand singleton.getinstance() assignment

问题

I've been able to generate 99% of what I need with the CodeModel API, but I am stumped here...

Using the various "directXX" methods does not add import statements to the generated code, and I can work without the "directXXX" type of methods except for one place in a generated class.

Suppose I desire a generated method like:

/**
* Copies data from this Value-Obj instance, to the returned PERSON instance.
* 
* @return PERSON
* 
*/
public PERSON mapVOToPERSON() throws MappingException
{
   Mapper mapper = (com.blah.util.MapperSingleton.getMapperInstance());
   return mapper.map(this, PERSON.class);
}

You can see the right hand of the Mapper assignment in parens. Emitting the entire package+class was the only way I could find to just declare "SomeSingleton.someMethod()" on the right hand side and have the generated code compile. Without the MapperSingleton being added to the object model, there is no import generated...

Questions:

1) Is there a way to force an import to be generated?

2) How to declare an expression that gives me the right side of the Mapper assignment within the object model (so that an import of MapperSingleton gets generated.

Any help appreciated...

回答1:

Maybe I don't understand the question fully but, is code like this OK?

JCodeModel model = new JCodeModel();
JClass mapper = model.directClass("com.another.Mapper");
JClass factory = model.directClass("com.another.MapperSingleton");
JDefinedClass dc = model._class("com.example.Something");
JMethod method = dc.method(JMod.PUBLIC | JMod.STATIC, mapper, "testMethod");
method.body()._return(factory.staticInvoke("getMapperInstance"));
model.build(destinationDirectory);

It will generate

package com.example;

import com.another.Mapper;
import com.another.MapperSingleton;

public class Something {


    public static Mapper testMethod() {
        return MapperSingleton.getMapperInstance();
    }

}

This is with CodeModel 2.4

EDIT! Second try

    JCodeModel model = new JCodeModel();
    JClass mapper = model.directClass("com.blah.util.Mapper");
    JClass factory = model.directClass("com.blah.util.MapperSingleton");
    JDefinedClass dc = model._class("com.example.Something");
    JDefinedClass person = model._class("com.example.PERSON");
    JMethod method = dc.method(JMod.PUBLIC, person, "mapVOToPERSON");
    JBlock block = method.body();
    JVar lhs = block.decl(mapper, "mapper", factory.staticInvoke("getMapperInstance"));
    JInvocation map = lhs.invoke("map");
    map.arg(JExpr._this()); 
    map.arg(person.dotclass());
    method.body()._return(map);
    model.build(destinationDirectory);

Generates

package com.example;

import com.blah.util.Mapper;
import com.blah.util.MapperSingleton;

public class Something {


    public PERSON mapVOToPERSON() {
        Mapper mapper = MapperSingleton.getMapperInstance();
        return mapper.map(this, PERSON.class);
    }

}

回答2:

Peter, I think what you're looking for is JVar#init(JExpression). This is the method you should use to create the RHS initialisation of a variable or field declaration.

So, when you declare mapper and get a JVar, call init on this JVar and pass in the JExpression that represents your call to com.blah.util.MapperSingleton.getMapperInstance().

In order to create the JExpression you need (one that represents a call to MapperSingleton), use myclass.owner().ref(MapperSingleton.class).staticInvoke("getMapperInstance").

来源：https://stackoverflow.com/questions/4851937/codemodel-help-needed-for-right-hand-singleton-getinstance-assignment

标签

java

code-generation

sun-codemodel