dbpool.java

java开源的企业总线.xmlBlaster

   * Create a new JDBC connection, the driver must be registered already.
   * @param instanceId A unique identifier
   * @return The JDBC connection
   */
   public Object toCreate(String instanceId) {
      try {
         return DriverManager.getConnection (this.dbUrl, this.dbUser, this.dbPasswd);
      }
      catch(Exception e) {
         throw new IllegalArgumentException(this.getClass().getName() + ": Couldn't open database connection dbUrl=" + this.dbUrl + " dbUser=" + this.dbUser + ": " + e.toString());
      }
   }

   /**
   * Destroy the JDBC connection.
   * The driver remains.
   * @param resource The Connection object
   */
   public void toErased(Object resource) {
      Connection con = (Connection)resource;
      try {
         con.close();
         log.info("JDBC connection closed for '" + this.dbUrl + "', '" + this.dbUser + "'");
      }
      catch (Exception e) {
         log.severe("System Exception in close JDBC connection: " + e.toString());
         // For example Oracle throws this if you have shutdown Oracle in the mean time:
         // System Exception in close JDBC connection: java.sql.SQLException: Io exception: End of TNS data channel
      }
   }

   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#update(String)
    */
   public int update(String command) throws Exception {
      Connection  conn = null;
      Statement   stmt = null;
      try {
         conn =  reserve();
         conn.setAutoCommit(true);
         stmt = conn.createStatement();
         if (log.isLoggable(Level.FINE)) log.fine("Running update command '" + command + "'");
         int rowsAffected = stmt.executeUpdate(command);
         return rowsAffected;
      }
      catch (SQLException e) {
         String str = "SQLException in query '" + command + "' : " + e;
         log.warning(str + ": sqlSTATE=" + e.getSQLState() + " we destroy the connection in case it's stale");
         //String sqlState = e.getSQLState(); // DatabaseMetaData method getSQLStateType can be used to discover whether the driver returns the XOPEN type or the SQL 99 type
         // To be on the save side we always destroy the connection:
         erase(conn);
         conn = null;
         throw e;
      }
      catch (Throwable e) {
         e.printStackTrace();
         String str = "Unexpected exception in query '" + command + "' : " + e;
         log.severe(str + ": We destroy the connection in case it's stale");
         erase(conn);
         conn = null;
         throw new Exception(e);
      }
      finally {
         try {
            if (stmt!=null) stmt.close();
         }
         catch (SQLException e) {
            log.warning("Closing of stmt failed: " + e.toString());
         }
         if (conn!=null) release(conn);
      }
   }

   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#update(String)
    */
   public int update(Connection conn, String command) throws Exception {
      if (conn == null)
         return update(command);
      
      Statement   stmt = null;
      try {
         stmt = conn.createStatement();
         if (log.isLoggable(Level.FINE)) log.fine("Running update command '" + command + "'");
         int rowsAffected = stmt.executeUpdate(command);
         return rowsAffected;
      }
      catch (SQLException e) {
         String str = "SQLException in query '" + command + "' : " + e;
         log.warning(str + ": sqlSTATE=" + e.getSQLState());
         throw e;
      }
      catch (Throwable e) {
         e.printStackTrace();
         String str = "Unexpected exception in query '" + command + "' : " + e;
         log.severe(str);
         throw new Exception(e);
      }
      finally {
         try {
            if (stmt!=null) stmt.close();
         }
         catch (SQLException e) {
            log.warning("Closing of stmt failed: " + e.toString());
         }
      }
   }

   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#select(String, I_ResultCb)
    */
   public void select(String command, I_ResultCb cb) throws Exception {
      select(null, command, true, cb);
   }

   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#select(java.sql.Connection, String, I_ResultCb)
    */
   public Connection select(Connection connection, String command, I_ResultCb cb) throws Exception {
      return select(connection, command, false, cb);
   }
   
   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#select(java.sql.Connection, String, I_ResultCb, boolean)
    */
   public Connection select(Connection connection, String command, boolean autoCommit, I_ResultCb cb) throws Exception {
      Statement stmt = null;
      ResultSet rs = null;
      Connection conn = null;
      try {
         conn = (connection == null) ? reserve() : connection;
         conn.setAutoCommit(autoCommit);
         stmt = conn.createStatement();
         if (log.isLoggable(Level.FINE)) log.fine("Running " + (autoCommit?"autoCommit":"in "+((connection==null)?"new ":"")+"open transaction") + " command '" + command + "'");
         rs = stmt.executeQuery(command);
         cb.result(conn, rs);
      }
      catch (SQLException e) {
         if (e.getSQLState() != null && e.getSQLState().indexOf("42000") != -1
             && e.toString().indexOf("ORA-00942") != -1) { // ORA-00942: table or view does not exist TODO: How to make this portable???
            // sqlStateXOpen=1, sqlStateSQL99=2 (Oracle 10g returns 0)
            //log.fine("SQLStateType=" + conn.getMetaData().getSQLStateType());
            log.fine("No db change detected, the table does not exist: " + e.toString());
            cb.result(conn, null);
            return conn;
         }
         String str = "SQLException in query '" + command + "' : " + e;
         log.warning(str + ": sqlSTATE=" + e.getSQLState() + " we destroy the connection in case it's stale");
         // To be on the save side we always destroy the connection:
         if (connection == null && conn != null && !conn.getAutoCommit()) conn.rollback();
         erase(conn);
         conn = null;
         throw e;
      }
      catch (Throwable e) {
         if (e instanceof NullPointerException) {
            e.printStackTrace();
         }
         String str = "Unexpected exception in query '" + command + "' : " + e;
         log.severe(str + ": We destroy the connection in case it's stale");
         if (connection == null && conn != null && !conn.getAutoCommit()) conn.rollback();
         erase(conn);
         conn = null;
         throw new Exception(e);
      }
      finally {
         try {
            if (stmt!=null) stmt.close();
         }
         catch (SQLException e) {
            log.warning("Closing of stmt failed: " + e.toString());
         }
      }
      
      if (autoCommit) {
         if (conn!=null) release(conn);
         conn = null;
      }
            
      return conn;
   }

   /**
    * @see org.xmlBlaster.contrib.dbwatcher.db.I_DbPool#shutdown
    */
   public synchronized void shutdown() {
      this.initCount--;
      if (this.initCount > 0)
         return;
      destroy();
   }

   /**
    * may be empty and just contains db.* properties
    * @return
    */
   private I_Info getInfo() {
      return this.info;
   }
   
   public static void main(String[] args) {
      try {
         I_DbPool pool = new DbPool();
         I_Info info = new PropertiesInfo(System.getProperties());
         String filename = info.get("file", null);
         if (filename == null) {
            System.out.println("usage: java -Dfile=someFile org.xmlBlaster.contrib.db.DbPool");
            System.exit(-1);
         }
            
         pool.init(info);
         
         BufferedReader br = new BufferedReader(new FileReader(filename));
         String line = null;
         StringBuffer buf = new StringBuffer();
         while (  (line = br.readLine()) != null)
            buf.append(line).append("\n");
         br.close();
         String cmd = buf.toString();
         System.out.println(cmd);
         pool.update(buf.toString());
         pool.shutdown();
      }
      catch (Exception ex) {
         
      }
   }
   
}