* View implementation of PoolTester *
*
* Create the pool TestAMPool. Since PoolMgr is a singleton object, * use PoolMgr.getInstance to get it. Use createPool * to create the pool. Notice that createPool requires the * name of the pool, * the name of the package that contains the Application Module, the * connect string to the database, and env, the hashtable. The * createPool method is overloaded—an alternative version * takes an additional parameter that lets you override the default * implementation of Application Module Pooling and specify your own. *
* Create a second pool, SecondAMPool that connects with * the same environment variables, but to an Application Module * in a different package. *
* PoolMgr.getInstance().getPool("TestAMPool") gets a * handle to the pool to work with it. *
* Checkout three instances. Note that the classes * ApplicationPoolImpl and PoolMgr contain other * functions that you can use to traverse the pool content. The * ampool package also contains a PoolAdministrator * Web Bean that you can use to dump the contents of the pool. *
* Get a handle to the second pool, check out two instances, * then check in one. *
* Use removePool to remove the Application Module Pool. * This function calls remove() on all of the Application * Module instances, including ones that are currently checked out * and in use, and causes them to disconnect from the database and * remove all of their View Objects. *
* The next part of the program defines a class, CustomPool, * that ensures that no more than three instances are checked out * of the pool at any time. In this case, the definition of the * checkout method is overridden to check that no more than three * instances are checked out. If more than three are checked out, * an exception is thrown. *
* This custom pool class is then used in a program which attempts * to create more than three instances. The try-catch loop is set up to * start checking out instances and to catch exceptions. When an * attempt is made to create the fourth * instance, an exception is thrown. * */ public class PoolTester extends Object { /** * Constructor */ public PoolTester() { } public void doTest() throws Exception { Hashtable info = new Hashtable(); info.put(JboContext.INITIAL_CONTEXT_FACTORY, JboContext.JBO_CONTEXT_FACTORY); info.put(JboContext.DEPLOY_PLATFORM, "LOCAL"); PoolMgr.getInstance().createPool("TestAMPool", "package2.Package2Module" , "jdbc:oracle:thin:scott/tiger@localhost:1521:orcl", info); ApplicationPool pool = PoolMgr.getInstance().getPool("TestAMPool"); ApplicationModule instance = pool.checkout(); ApplicationModule instance2 = pool.checkout(); pool.checkin(instance2); ApplicationModule instance3 = pool.checkout(); PoolMgr.getInstance().removePool("TestAMPool"); // create a pool with a custom application pool class PoolMgr.getInstance().createPool("CustomTestAMPool", "oracle.jbo.common.ampool.CustomPool" , "package2.Package2Module" , "jdbc:oracle:thin:scott/tiger@localhost:1521:orcl", info); pool = PoolMgr.getInstance().getPool("CustomTestAMPool"); try { instance = pool.checkout(); instance = pool.checkout(); instance = pool.checkout(); instance = pool.checkout(); instance = pool.checkout(); } catch(Exception ex) { ex.printStackTrace(); } } /** * Provides a main for the PoolTester * sample implementation of Application Module Pooling. * @param args arguments to the PoolTester sample implementation. */ public static void main(String[] args) { PoolTester poolTester = new PoolTester(); try { poolTester.doTest(); } catch(Exception ex) { ex.printStackTrace(); } } } /** ** This is a simple application pool class that only allows checkout of 3 instances **/ class CustomPool extends ApplicationPoolImpl { public CustomPool() { } /** * checkout * @return oracle.jbo.ApplicationModule */ public synchronized ApplicationModule checkout() throws Exception { // if the instance count > 3 throw an exception int nCount = getInstanceCount(); if(nCount > 3) { throw new RuntimeException("You have exceeded the number of instances for this pool"); } return super.checkout(); } }