org.ifeth.sehr.lib
Class DAOJdbc

java.lang.Object
  org.ifeth.sehr.lib.DAOJdbc

All Implemented Interfaces:

DAOJdbcInterface

public class DAOJdbc

extends java.lang.Object

implements DAOJdbcInterface

This is a data access object (DAO) for accessing the SEHR databases by standard JDBC/SQL without using he iBatis layer.

This DAO object implements some often used sql methods and seals them to a single call command. To use this layer first establish a FBDataSource object. After inittialization of this object you can define PreparedStatements or just plain SQL queries to be executed.
Note: This DAO can also use pooled connections for the datasource. To activate a pooled connection use setPooledConnections(boolean). Pooled connections are handy to get more control i.e. on RAS connections!

Version:

$Id: DAOJdbc.java,v 1.1 2005/01/16 12:15:56 hansjhaase Exp $

Author:

hansjhaase

Field Summary

Fields inherited from interface org.ifeth.sehr.lib.DAOJdbcInterface

CON_CANCLOSE, CON_CLOSEDENIED, CON_COMMITREQUIRED, STS_ACTIVE, STS_CLOSED, STS_NOTFOUND, STS_SQLERROR

Constructor Summary

DAOJdbc()
Parameterless constructor.

DAOJdbc(java.sql.Connection con)
Constructor for a single connection DAO object to use it with an already establish connction handle.

DAOJdbc(SEHRDataSource fbds)
Constructor with given FBDataSource object.

Method Summary

void	addPreparedStatement(java.lang.String psname, java.lang.String sql) Add a named and init prepared statement for a single connection (id 0).
void	addPreparedStatement(java.lang.String psname, java.lang.String sql, int cidx) Add a named and init prepared statement for a given connection.
void	canClose(boolean allow) Allow or disallow closing of connection #0 (single connection).
int	checkConnection() Check connection.
int	checkConnection(int idx) Check connection.
void	close() Use this method to close the single connection.
java.sql.Connection	connect() This method established a single connection to the given datasource on instantiation of this object.
int	connectToPool() This method established a new connection using the pool.
int	countConnections() Get number of current handled connections
boolean	executePrepStmnt(java.sql.PreparedStatement stmnt) Execute a prepared statement as SQL query.
boolean	executeQuery(java.lang.String sql) Execute a plain SQL query for single connection.
boolean	executeQuery(java.lang.String sql, int conidx) Execute a plain SQL query using given connection.
void	forceClosePooledConnections() Use this method with care!
void	freeConnection(int cidx) Use this method to put a connection back to the pool
java.sql.Connection	getConnection() get connection handle for a single connection
java.sql.Connection	getConnection(int cidx) get connection handle for a given connection by 'index'
java.sql.PreparedStatement	getPreparedStatement(java.lang.String psname) Retrieve a named statement for single connection from hash to use it by executePrepStmnt(PreparedStatement)
java.sql.PreparedStatement	getPreparedStatement(java.lang.String psname, int idx) Retrieve a named statement for given connection by id to use it by executePrepStmnt(PreparedStatement)
java.sql.ResultSet	getResultSet() Get ResultSet of executed query.
static void	main(java.lang.String[] args) For testing and study purposes...
void	setConnection(java.sql.Connection con) Set a connection handle (The fbds is not required then)
void	setPooledConnections(boolean b) Method to activate or deactivate pooled connections.
void	setSEHRDataSource(SEHRDataSource fbds) Set the FBDataSource handle for which a connection can be initialized.
void	setStatus(int cidx, int statuscode) Set status to handle connection.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DAOJdbc

public DAOJdbc()

Parameterless constructor.

Parameterless constructor. Set the SEHRDataSource by setSEHRDataSource(SEHRDataSource) and check the returncode if a connection is available.

DAOJdbc

public DAOJdbc(SEHRDataSource fbds)

Constructor with given FBDataSource object.

DAOJdbc

public DAOJdbc(java.sql.Connection con)

Constructor for a single connection DAO object to use it with an already establish connction handle.

Method Detail

connect

public java.sql.Connection connect()
                            throws java.sql.SQLException

This method established a single connection to the given datasource on instantiation of this object.

Throws:

java.sql.SQLException

connectToPool

public int connectToPool()
                  throws java.sql.SQLException

This method established a new connection using the pool.

Note: Use setPooledConnections(boolean)first to initiate a pooled connection.

Throws:

java.sql.SQLException

setPooledConnections

public void setPooledConnections(boolean b)
                          throws java.sql.SQLException

Method to activate or deactivate pooled connections.

To keep data integrity on open transactions there is a small workaraound to be shure we can deactive our pooled cons
Note: To force closing first use 'forceClosePooledConnections()' first (at your own risc!!) then call this method.

Throws:

java.sql.SQLException

forceClosePooledConnections

public void forceClosePooledConnections()

Use this method with care! Beware of running transactions

close

public void close()
           throws java.sql.SQLException

Use this method to close the single connection.

Use freeConnection(int)to close a pooled connection.

Throws:

java.sql.SQLException

freeConnection

public void freeConnection(int cidx)
                    throws java.sql.SQLException

Use this method to put a connection back to the pool

Throws:

java.sql.SQLException

canClose

public void canClose(boolean allow)

Allow or disallow closing of connection #0 (single connection).

This is a helper method to indicate if a connection is in use or not, e.g. for a period of time, and an application is allowed to close RAS connections.

addPreparedStatement

public void addPreparedStatement(java.lang.String psname,
                                 java.lang.String sql)
                          throws java.sql.SQLException

Add a named and init prepared statement for a single connection (id 0).

Throws:

java.sql.SQLException

See Also:

addPreparedStatement(String, String, int)

addPreparedStatement

public void addPreparedStatement(java.lang.String psname,
                                 java.lang.String sql,
                                 int cidx)
                          throws java.sql.SQLException

Add a named and init prepared statement for a given connection.

Use PreparedStatements for frequently used SQL queries. These statements are first prepared by the engine and then stored as objects. To assign parameters just extract the statement from hash by getPreparedStatement(String, int), assign the parameter and call method executePrepStmnt(PreparedStatement)

Throws:

java.sql.SQLException

getPreparedStatement

public java.sql.PreparedStatement getPreparedStatement(java.lang.String psname)
                                                throws java.lang.Exception

Retrieve a named statement for single connection from hash to use it by executePrepStmnt(PreparedStatement)

Throws:

java.lang.Exception

getPreparedStatement

public java.sql.PreparedStatement getPreparedStatement(java.lang.String psname,
                                                       int idx)
                                                throws java.lang.Exception

Retrieve a named statement for given connection by id to use it by executePrepStmnt(PreparedStatement)

Throws:

java.lang.Exception

executePrepStmnt

public boolean executePrepStmnt(java.sql.PreparedStatement stmnt)
                         throws java.lang.Exception

Execute a prepared statement as SQL query.

If a recordset is available the method returns 'true'. To access the resultset use getResultSet().

Throws:

java.lang.Exception

executeQuery

public boolean executeQuery(java.lang.String sql)
                     throws java.lang.Exception

Execute a plain SQL query for single connection.

Throws:

java.lang.Exception

executeQuery

public boolean executeQuery(java.lang.String sql,
                            int conidx)
                     throws java.lang.Exception

Execute a plain SQL query using given connection.

If a recordset is available the method returns 'true'. To access the resultset use getResultSet().

Throws:

java.lang.Exception

setStatus

public void setStatus(int cidx,
                      int statuscode)
               throws java.sql.SQLException

Set status to handle connection.

Statuscodes (use DAOJdbcInterface):

  0 = can close
  1 = don't close/not allowed
  2 = commit required (manupulated records)
      (if using autocommit this code has no effect)
 

Throws:

java.sql.SQLException

getResultSet

public java.sql.ResultSet getResultSet()

Get ResultSet of executed query.

setConnection

public void setConnection(java.sql.Connection con)

Set a connection handle (The fbds is not required then)

getConnection

public java.sql.Connection getConnection()

get connection handle for a single connection

getConnection

public java.sql.Connection getConnection(int cidx)

get connection handle for a given connection by 'index'

countConnections

public int countConnections()

Get number of current handled connections

checkConnection

public int checkConnection()

Check connection.

See Also:

checkConnection(int)

checkConnection

public int checkConnection(int idx)

Check connection.

Use this together with a timer/thread to check connection periodically.

Returns:

statuscode

Statuscodes:

     -1 = SQL Exception(broken?)
      0 = ok
      1 = closed
      2 = none found for id (already closed/pool out of sync?)
  
 

setSEHRDataSource

public void setSEHRDataSource(SEHRDataSource fbds)
                       throws java.lang.Exception

Set the FBDataSource handle for which a connection can be initialized.

Parameters:

fbds - FBDataSource object

Throws:

java.lang.Exception

main

public static void main(java.lang.String[] args)

For testing and study purposes...