Page History

/** @author Sam Barnum */
public class PersonEditPage {
	private WebPage returnPage;

	/**
	 * Create an edit page
	 * @param businessObject Model which contains the business object to edit.
	 * @param returnPage The page to direct the user to after a successful save operation
	 */
	public PersonEditPage(IModel businessObject, WebPage returnPage) {
		setModel(new CompoundPropertyModel(businessObject));
		this.returnPage = returnPage;
		initComponents();
	}

	void initComponents() {
		// create your form here
	}

	public Person getPerson() {
		return (Person)getModelObject();
	}

	/** Saves the business object to the database */
	void save() {
		EntityManager em = getEntityManager();
		Person person = getPerson();
		if (person.getId() == null) {
			// this is a transient person
			em.persist(person);
		} else {
			// this is a persistent person. There should be no need to call em.merge(),
			// because the person should be in a detachableModel which was loaded at the beginning of the request.
			// just in case, we'll call merge
			person = em.merge(person);
		}
		em.flush(); // if the person was transient, this will assign the primary key value
		// now we set a new Model containing the saved person
		setModelObject(new DetachableEntityModel(person));
		// and take the user to the successful save page
		setResponsePage(returnPage);
	}

	/** Loads the entity manager from the session or other location */
	EntityManager getEntityManager() {
		// implementation omitted
	}



}

/**
 * Model which knows how to fetch a business object by its class and primary key value (id).
 * @author sbarnum
 */
public class DetachableEntityModel extends LoadableDetachableModel implements IModel {
	private final Class entityClass;
	private final Serializable id;

	/**
	 * Create a detatchableEntityModel for a persistent object. The id of object must not be null.
	 * @param object the business object
	 */
	public DetachableEntityModel(MyBusinessObject object) {
		super(object);
		if (object == null) throw new NullPointerException("object must not be null.");
		if (object.getId() == null) throw new NullPointerException("object.getId() must not be null.  " +
			"To create a model for a transient instance, use a LoadableDetachableModel whose " +
			"load() method instantiates a new object.");
		this.entityClass = object.getClass();
		this.id = object.getId();
	}

	/** Loads the business object from the database */	
	protected MyBusinessObject load() {
		return ((Session)Session.get()).getEntityManagerForRequest().find(entityClass, id);
	}
}

add (new Link("addPerson") {
	public void onClick() {
		LoadableDetachableModel businessObjectModel = new LoadableDetachableModel() {
			protected Object load() {
				Person result = new Person();
				result.setType("Administrator"); // or whatever type is being searched on
				return result;
			}
		};
		setResponsePage(new PersonEditPage(businessObjectModel, getWebPage()));
	}
});