edu.ucsb.nceas.metacat.database

Class DBConnectionPool

java.lang.Object

edu.ucsb.nceas.metacat.database.DBConnectionPool

All Implemented Interfaces:

java.lang.Runnable

public class DBConnectionPool
extends java.lang.Object
implements java.lang.Runnable

A class represent a DBConnection pool. Another user can use the object to initial a connection pool, get db connection or return it. This a singleton class, this means only one instance of this class could be in the program at one time.

Method Summary

Modifier and Type	Method and Description
static DBConnection	getDBConnection(java.lang.String methodName) Method to get a DBConnection in connection pool 1) try to get a DBConnection from DBConnection pool 2) if 1) failed, then check the size of pool.
static DBConnectionPool	getInstance() Returns the single instance, creating one if it's the first time this method is called.
int	getSizeOfDBConnectionPool() Method to get the size of DBConnectionPool
static void	release() Method to shut down all connections
static void	returnDBConnection(DBConnection conn, int serialNumber) Method to return a connection to DBConnection pool.
void	run() periodically to recycle the connection
static boolean	shrinkConnectionPoolSize() Method to decrease dbconnection pool size when all dbconnections are idle If all connections are free and connection pool size greater than initial value, shrink connection pool size to initial value
static void	shrinkDBConnectionPoolSize() Method to decrease dbconnection pool size when all dbconnections are idle If all connections are free and connection pool size greater than initial value, shrink connection pool size to intital value

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static DBConnectionPool getInstance()
                                    throws java.sql.SQLException

Returns the single instance, creating one if it's the first time this method is called.

Throws:

java.sql.SQLException

getSizeOfDBConnectionPool

public int getSizeOfDBConnectionPool()

Method to get the size of DBConnectionPool

getDBConnection

public static DBConnection getDBConnection(java.lang.String methodName)
                                    throws java.sql.SQLException

Method to get a DBConnection in connection pool 1) try to get a DBConnection from DBConnection pool 2) if 1) failed, then check the size of pool. If the size reach the maximum number of connection, throw a exception: couldn't get one 3) If the size is less than the maximum number of connectio, create some new connections and recursive get one

Parameters:

methodName, - the name of method which will check connection out

Throws:

java.sql.SQLException

returnDBConnection

public static void returnDBConnection(DBConnection conn,
                                      int serialNumber)

Method to return a connection to DBConnection pool.

Parameters:

conn, - the Connection object need to check in

release

public static void release()

Method to shut down all connections

run

public void run()

periodically to recycle the connection

Specified by:

run in interface java.lang.Runnable

shrinkConnectionPoolSize

public static boolean shrinkConnectionPoolSize()

Method to decrease dbconnection pool size when all dbconnections are idle If all connections are free and connection pool size greater than initial value, shrink connection pool size to initial value

shrinkDBConnectionPoolSize

public static void shrinkDBConnectionPoolSize()

Method to decrease dbconnection pool size when all dbconnections are idle If all connections are free and connection pool size greater than initial value, shrink connection pool size to intital value