I have just released the code for Catwalk a Java Annotation Processor for automatically generating derived domain model classes.

Supposing you have a JPA Entity which you want to pass to a servlet stripped of certain private / internal properties, adding a few annotations to the getters you want to expose allows Catwalk to generate a new class with only those properties and convenience methods for converting between the two types of objects.

The project is still missing a few essentials before being useful, such as documentation, proper examples and being uploaded to a Maven repo.

In the following example, a TestModel class is converted to a WebTestModel class:

TestModel.java

package net.dataforte.test.model;

@Model(pattern = "Web#", classPackage = "net.dataforte.test.webmodel")
public class TestModel {
	String s;
	int i;

	@ModelAttribute
	public String getS() {
		return s;
	}

	public void setS(String s) {
		this.s = s;
	}

	public int getI() {
		return i;
	}

	public void setI(int i) {
		this.i = i;
	}
}

WebTestModel.java

package net.dataforte.test.webmodel;

public class WebTestModel {

	private java.lang.String s;

	public WebTestModel() {}

	public WebTestModel(net.dataforte.test.model.TestModel src) {
		this.fromTestModel(src);
	}

	java.lang.String getS() {
		return s;
	}

	void setS(java.lang.String s) {
		this.s = s;
	}

	public WebTestModel fromTestModel(net.dataforte.test.model.TestModel src) {
		this.s = src.getS();
		return this;
	}

	public net.dataforte.test.model.TestModel toTestModel() {
		net.dataforte.test.model.TestModel that = new net.dataforte.test.model.TestModel();
		that.setS(this.s);
		return that;
	}

}