skillbean.java

21天学通J2EE的例子3

package data;

import java.rmi.*;
import java.sql.*;
import java.util.*;
import javax.ejb.*;
import javax.naming.*;
import javax.sql.*;

public class SkillBean implements EntityBean
{
    private DataSource dataSource;
    private String name;
    private String description;

    public String getName () {
        return name;
    }
    
    public String getDescription () {
        return description;
    }
    
    public void setDescription (String description) {
        this.description = description;
    }

    // EJB methods start here

    public void ejbPostCreate (String name, String description) {}

    public String ejbCreate (String name, String description) throws CreateException {
        try {
            ejbFindByPrimaryKey(name);
            throw new CreateException("Duplicate skill name: "+name);
        }
        catch (FinderException ex) {}
        
        Connection con = null;
        PreparedStatement stmt = null;
        try {
            con = dataSource.getConnection();
            stmt = con.prepareStatement(
            "INSERT INTO Skill (name,description) VALUES (?,?)");

            stmt.setString(1, name);
            stmt.setString(2, description);
            stmt.executeUpdate();
        }
        catch (SQLException e) {
            error("Error creating Skill "+name,e);
        }
        finally {
            closeConnection(con, stmt, null);
        }
        this.name = name;
        this.description = description;
        return name;
    }
    
    public String ejbFindByPrimaryKey(String name) throws FinderException {
        Connection con = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            con = dataSource.getConnection();
            stmt = con.prepareStatement(
            "SELECT name FROM Skill WHERE name = ?");

            stmt.setString(1, name);
            rs = stmt.executeQuery();

            if (!rs.next()) {
                throw new FinderException("Unknown Skill: "+name);
            }
            return name;
        }
        catch (SQLException e) {
            error("Error in findByPrimaryKey for "+name,e);
        }
        finally {
            closeConnection(con, stmt, rs);
        }
        return null;
    }

    public List ejbHomeLookup(List names) throws FinderException {
        List res = new ArrayList();
        for(Iterator iter = names.iterator(); iter.hasNext(); ) {
            String name = (String)iter.next();
            SkillLocal skill = ((SkillLocalHome)ctx.getEJBLocalHome()).findByPrimaryKey(name);
            if (skill == null) {
                throw new FinderException("Could not find skill named " + name);
            }
            res.add(skill);
        }
        return res;
    }
    
    public Collection ejbFindAll() throws FinderException {
        Connection con = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            con = dataSource.getConnection();
            stmt = con.prepareStatement(
            "SELECT name FROM Skill ORDER BY name");

            rs = stmt.executeQuery();

            Collection col = new ArrayList();
            while (rs.next()) {
                col.add(rs.getString(1));
            }
            return col;
        }
        catch (SQLException e) {
            error("Error in findAll",e);
        }
        finally {
            closeConnection(con, stmt, rs);
        }
        return null;
    }

    public void ejbLoad(){
        name = (String)ctx.getPrimaryKey();
        Connection con = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            con = dataSource.getConnection();
            stmt = con.prepareStatement(
            "SELECT name,description FROM Skill WHERE name = ?");

            stmt.setString(1, name);
            rs = stmt.executeQuery();

            if (!rs.next()) {
                error("No data found in ejbLoad for "+name,null);
            }
            this.name = rs.getString(1);
            this.description = rs.getString(2);
        }
        catch (SQLException e) {
            error("Error in ejbLoad for "+name,e);
        }
        finally {
            closeConnection(con, stmt, rs);
        }
    }

    public void ejbStore(){
        Connection con = null;
        PreparedStatement stmt = null;
        try {
            con = dataSource.getConnection();
            stmt = con.prepareStatement(
            "UPDATE Skill SET description = ? WHERE name = ?");

            stmt.setString(1, description);
            stmt.setString(2, name);
            stmt.executeUpdate();
        }
        catch (SQLException e) {
            error("Error in ejbStore for "+name,e);
        }
        finally {
            closeConnection(con, stmt, null);
        }
    }

    public void ejbPassivate(){
        name = null;
        description = null;
    }

    public void ejbActivate(){
    }

    public void ejbRemove(){
        name = (String)ctx.getPrimaryKey();
        
        Connection con = null;
        PreparedStatement stmt = null;
        try {
            con = dataSource.getConnection();
          
            stmt = con.prepareStatement(
            "DELETE FROM Skill WHERE name = ?");

            stmt.setString(1, name);
            stmt.executeUpdate();
        }
        catch (SQLException e) {
            error("Error removing location "+name,e);
        }
        finally {
            closeConnection(con, stmt, null);
        }
        name = null;
        description = null;
    }

    private EntityContext ctx;
    
    public void setEntityContext(EntityContext ctx) {
        this.ctx = ctx;
        InitialContext ic = null;
        try {
            ic = new InitialContext();
            dataSource = (DataSource)ic.lookup("java:comp/env/jdbc/Agency");
        }
        catch (NamingException ex) {
            error("Error looking up depended EJB or resource",ex);
            return;
        }
    }   

    public void unsetEntityContext() {
        this.ctx = null;
        dataSource = null;
    }   

    private void closeConnection (Connection con, PreparedStatement stmt, ResultSet rslt) {
        if (rslt != null) {
            try {
                rslt.close();
            }
            catch (SQLException e) {}
        }
        if (stmt != null) {
            try {
                stmt.close();
            }
            catch (SQLException e) {}
        }
        if (con != null) {
            try {
                con.close();
            }
            catch (SQLException e) {}
        }
    }

    private void error (String msg, Exception ex) {
        String s = "SkillBean: "+msg + "\n" + ex;
        System.out.println(s);
        throw new EJBException(s,ex);
    }
    
}