ex7_48.txt

j2ee core design patterns

Example 7.48 ProjectDAO Class

package com.corej2eepatterns.dao;

// imports

public class ProjectDAO {
	final private String tableName = "PROJECT";

	// select statement uses fields
	final private String fields = "project_id, name," +
			"project_manager_id, start_date, end_date, " + 
			" started, completed, accepted, acceptedDate," + 
			" customer_id, description, status";

	// the methods relevant to the ValueListHandler
	// are shown here.
	// See Data Access Object pattern for other details.
	...
	private List findProjects(ProjectTO projCriteria) 
	throws SQLException {

		Statement stmt= null;
		List list = null;
		Connection con = getConnection();
		StringBuffer selectStatement = new StringBuffer();
		selectStatement.append("SELECT " + fields + " FROM " +
			tableName + "where 1=1");

		// append additional conditions to where clause
		// depending on the values specified in 
		// projCriteria

		if (projCriteria.projectId != null) {
			selectStatement.append (" AND PROJECT_ID = '" + 
				projCriteria.projectId + "'");
		}
		// check and add other fields to where clause
		...
		
		try {
			stmt = con.prepareStatement(selectStatement);
			stmt.setString(1, resourceID);
			ResultSet rs = stmt.executeQuery();
			list = createResultsList(rs);
			stmt.close();
		}
		finally {
			con.close();
		}
		return list;
	}

	private List createResultsList(ResultSet rs) 
	throws SQLException {
		ArrayList list = new ArrayList();
		while (rs.next()) {
			int i = 1;
			ProjectTO proj = new ProjectTO(rs.getString(i++));
			proj.projectName = rs.getString(i++);
			proj.managerId = rs.getString(i++);
			proj.startDate = rs.getDate(i++);
			proj.endDate = rs.getDate(i++);
			proj.started = rs.getBoolean(i++);
			proj.completed = rs.getBoolean(i++);
			proj.accepted = rs.getBoolean(i++);
			proj.acceptedDate = rs.getDate(i++);
			proj.customerId = rs.getString(i++);
			proj.projectDescription = rs.getString(i++);
			proj.projectStatus = rs.getString(i++);
			list.add(proj);
		}
		return list;
	}
	...
}