Java: creating annotation with default value using Codemodel
I am using the Sun CodeModel code generator for my project. During this time, I ended up creating an annotation class. This class will have an array member that accepts an empty array as default values. See next example:
public class Container {
public @interface MyAnnotation {
MyValue[] myValues() default {};
}
}
I used this code to create annotation
JCodeModel codeModel = new JCodeModel();
JDefinedClass myValueClass = codeModel._class(JMod.PUBLIC, "MyValue", ClassType.CLASS);
JDefinedClass containerClass = codeModel._class(JMod.PUBLIC, "Container", ClassType.CLASS);
JDefinedClass annotationClass = containerClass._annotationTypeDeclaration("MyAnnotation");
annotationClass.method(JMod.NONE, myValueClass.array(), "myValues");
but I have no idea how to create a default ad. It only generates the following:
public class Container {
public @interface MyAnnotation {
MyValue[] myValues();
}
}
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JMethod
has a method declareDefaultValue
that allows you to define a default value for the annotation method. The trick after that is to generate an empty array {}
. I haven't been able to figure out how to do this using the existing classes, but you can easily figure it out using JExpressionImpl
:
JCodeModel codeModel = new JCodeModel();
JDefinedClass myValueClass = codeModel._class(JMod.PUBLIC, "MyValue", ClassType.CLASS);
JDefinedClass containerClass = codeModel._class(JMod.PUBLIC, "Container", ClassType.CLASS);
JDefinedClass annotationClass = containerClass._annotationTypeDeclaration("MyAnnotation");
JMethod method = annotationClass.method(JMod.NONE, myValueClass.array(), "myValues");
method.declareDefaultValue(new JExpressionImpl(){
@Override
public void generate(JFormatter f) {
f.p("{}");
}
});
This generates the following:
public @interface MyAnnotation {
MyValue[] myValues() default {};
}
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