databasehelper.java

Sun公司Dream项目

/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * http://www.opensource.org/licenses/cddl1.php
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * http://www.opensource.org/licenses/cddl1.php.  If 
 * applicable, add the following below this CDDL HEADER, 
 * with the fields enclosed by brackets "[]" replaced 
 * with your own identifying information: 
 * Portions Copyright [yyyy]
 * [name of copyright owner]
 */ 

/*
 * $(@)DatabaseHelper.java $Revision: 1.3 $ $Date: 2006/07/24 17:00:52 $
 * 
 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
 */
package com.sun.licenseserver;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import java.util.logging.Logger;

import javax.servlet.ServletContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;


/**
 * The singelton class that encapsulates the JDBC code
 * required to execute SQL statements. To use this class
 * one needs to call the init(...) method that will be used 
 * to initialize the JDBC properties (jdbc driver, url, username and password).
 * The class also checks whether the sunLsLicenses table exists in the database
 * and creates it if it does not exists.
 * 
 * 
 */
public class DatabaseHelper {
    
    /**
     * This is a singleton class and therefore a private constructor.
     */
    private DatabaseHelper() {
    }
    
    /**
     * 
     * This is a singleton class and therefore a private constructor.
     * @param The servlet context used to get a handle to the configuration file.
     */
    private DatabaseHelper(ServletContext sc) {
        m_log.finer("Entering Function...");
        String    confFile = "/WEB-INF/conf/license-server.xml";
        URL       confFileURL = null;
    	try {
	    	confFileURL = sc.getResource(confFile);
	    } catch (MalformedURLException e1) { 
            m_log.severe("License Server configuration file does not exists..");
		    m_initError = true;
		    e1.printStackTrace();
    	}
	    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder        db  = null;
        Document               doc = null;
        try {
            db = dbf.newDocumentBuilder();
            doc = db.parse(confFileURL.openStream());
	    } catch (SAXException e2) {
           m_log.severe("Error in Parsing License Server Configuration File..");
	       e2.printStackTrace();
           m_initError = true;
	    } catch (IOException e2) {
           m_log.severe("Error in Parsing License Server Configuration File..");
           m_log.severe("Probably the file /WEB-INF/conf/license-server.xml does not exists");
           e2.printStackTrace();
           m_initError = true;
        } catch (ParserConfigurationException e) {
            m_log.severe("Error in Parsing License Server Configuration File..");
            e.printStackTrace();
            m_initError = true;
        }
        initializeProperties(doc);
        loadJDBCDriver();
        createTable();
        m_log.finer("Leaving Function...");
    }
    
    /**
     * 
     * This is a singleton class and therefore a private constructor.
     * @param The servlet context used to get a handle to the configuration file.
     */
    private DatabaseHelper(Document doc) {
        m_log.finer("Entering Function...");
        initializeProperties(doc);
        loadJDBCDriver();
        createTable();
        m_log.finer("Leaving Function...");
    }
    
    /**
     * One of the init functions should be called
     * before the database helper object can be used.
     * This init will be called from jsp pages.
     * 
     * @param sc
     * @return
     */
    public static DatabaseHelper init(ServletContext sc) {
        m_log.finer("Entering Function...");
        if (m_databaseHelper != null) {
           m_log.fine("No need to init. an instance already exists");
           return m_databaseHelper;     
        }
        m_log.fine("Creating a new instance");
        m_databaseHelper = new DatabaseHelper(sc);
        m_log.finer("Leaving Function...");
        return m_databaseHelper;
    }
    
    /**
     * One of the init functions should be called
     * before the database helper object can be used.
     * This init will be called by the LicenseServer servlet 
     * that needs to access some conf values.
     * 
     * @param doc
     * @return
     */
    public static DatabaseHelper init(Document doc) {
        m_log.finer("Entering Function...");
        if (m_databaseHelper != null) {
           m_log.fine("No need to init. an instance already exists");
           return m_databaseHelper;     
        }
        m_log.fine("Creating a new instance");
        m_databaseHelper = new DatabaseHelper(doc);
        m_log.finer("Leaving Function...");
        return m_databaseHelper;
    }
    
    /**
     * This class checks for the existence of the tables required for this
     * project and creates them if they do not exist.
     * 
     *
     */
    public void createTable() {
        if (m_initError) {
            m_log.severe("Databasehelper has not been initialized. Skipping table creation..");
            return;
        }
        
        try {
            if (!hasTable("sunLsLicenses")) {
                String sql = "CREATE TABLE sunLsLicenses ("
                             + "id varchar(20),"
                             + "contentId varchar(40), "
                             + "shopId varchar(40),"
                             + "userId varchar(40),"
                             + "license BLOB, " 
                             + "mime varchar(40)"
                             + ")";
                executeStatementWithoutResults(sql);
            }
        } catch (LicenseServerException e) {
            m_log.severe("Error in creating sunLsLicense table, or checking for its existense");
            m_initError = true;
            e.printStackTrace();
        }
        
    }
    
    /**
     * Open a connection to jdbc URL specified in configuration file.
     */
    public Connection getConnection() 
    throws LicenseServerException {
        m_log.finer("Entering Function...");
        Properties  p = new Properties();
        Connection  con = null;
        if ((m_databaseUser != null) && !m_databaseUser.equals("")) {
            p.put("user", m_databaseUser);
        }
        if ((m_databasePassword != null) && !m_databasePassword.equals(" ")) {
            m_log.fine("Using Password");
            p.put("password", m_databasePassword);
        }
        m_log.fine("Using JDBC URL [" + m_databaseURL + "]");
        m_log.fine("Using JDBC Driver [" + m_databaseDriver + "]"); 
        m_log.fine("Connecting to database with user [" + m_databaseUser + "]");
        try {
	        con = DriverManager.getConnection(m_databaseURL, p);
	    } catch (SQLException e) {
	        m_log.severe("Error in establishing a connection to the database [" + e.getMessage() + "]");
            e.printStackTrace();
            if (con != null) {
               try {
				con.close();
			   } catch (SQLException e1) {
				   // TODO Auto-generated catch block
				   e1.printStackTrace();
                   throw new LicenseServerException(LicenseServerException.EC_DATABASE_ERROR,
                            "Error in getting a connection to DB and closing the partial connection" + e.getMessage());
			   }   
            }
            throw new LicenseServerException(LicenseServerException.EC_DATABASE_ERROR,
                    "Error in getting a connection to DB" + e.getMessage()); 
	    }
        m_log.finer("Leaving Function...");
        return con;
     }
    
    /**
     * Release the jdbc connection.
     * @param Connection object to be released
     */
    public void freeConnection(Connection con) 
    throws LicenseServerException {
        m_log.finer("Entering Function...");
        if (con == null) {
        	return;
        }
        try {
			con.close();
		} catch (SQLException e) {
            m_log.severe("Error in closing a connection [" + e.getMessage() + "]");
		    throw new LicenseServerException(LicenseServerException.EC_DATABASE_ERROR,
                    "Error in frreing connection" + e.getMessage()); 
		}   
        m_log.finer("Leaving Function...");
    }

    /**
     * load JDBC driver specified in Configuration file.
     */
    private void loadJDBCDriver() {
        m_log.finer("Entering Function...");