ex7_43.txt

j2ee core design patterns

Example 7.43 	Implementing Value List Handler: ProjectListHandler

package com.corej2eepatterns.vlh;

// imports

public class ProjectListHandler 
extends ValueListHandler {

	private ProjectDAO dao = null;
   . . .

	// Client creates a ProjectTO instance, sets the 
	// values to use for search criteria and passes 
	// the ProjectTO instance as projectCriteria
	// to the constructor and to setCriteria() method
	public ProjectListHandler() 
	throws ProjectException, ListHandlerException {
		try {
			this.dao = PSADAOFactory.getProjectDAO();
		} catch (Exception e) {
			// Handle exception, throw ListHandlerException
		}
	}

	// executes search. Client can invoke this
	// provided that the search criteria has been
	// properly set. Used to perform search to refresh
	// the list with the latest data.
	public void executeSearch(ProjectTO projectCriteria)
	throws ListHandlerException {
		try {
			if (projectCriteria == null) {
				throw new ListHandlerException(
					"Project Criteria required...");
			}
			List resultsList =
				dao.findProjects(projectCriteria);
			setList(resultsList);
		} catch (Exception e) {
			// Handle exception, throw ListHandlerException
		}
	}
}