wamblee.org Git - utils/blob

   1 package org.wamblee.support.persistence;
   2
   3 import javax.sql.DataSource;
   4
   5 import org.apache.commons.dbcp.ConnectionFactory;
   6 import org.apache.commons.dbcp.DriverManagerConnectionFactory;
   7 import org.apache.commons.dbcp.PoolableConnectionFactory;
   8 import org.apache.commons.dbcp.PoolingDataSource;
   9 import org.apache.commons.pool.impl.GenericObjectPool;
  10
  11 public abstract class AbstractDatabase implements Database {
  12         private static final int CONNECTION_POOL_SIZE = 16;
  13
  14     private DataSource itsDataSource;
  15
  16         private boolean started;
  17
  18         protected AbstractDatabase() {
  19                 started = false;
  20         }
  21
  22         protected abstract void doStart();
  23
  24         protected abstract void doStop();
  25
  26         /**
  27          * This method must be called from the start method.
  28          */
  29         protected final void createDataSource() {
  30                 GenericObjectPool connectionPool = new GenericObjectPool(null);
  31                 connectionPool.setMaxActive(CONNECTION_POOL_SIZE);
  32                 ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(getJdbcUrl(), getUsername(), getPassword());
  33                 // The following line must be kept in although it does not appear to be used, the constructor regsiters the
  34                 // constructed object at the connection pool.
  35                 PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(connectionFactory,connectionPool,null,null,false,true);
  36                 itsDataSource = new PoolingDataSource(connectionPool);
  37         }
  38
  39
  40         /// BELOW THIS LINE IS NOT OF INTEREST TO SUBCLASSES.
  41
  42         public final DataSource start() {
  43                 if ( started ) {
  44                         throw new RuntimeException("Database already started");
  45                 }
  46                 started = true;
  47                 doStart();
  48                 return getDatasource();
  49         }
  50
  51         public final void stop() {
  52                 if ( ! started ) {
  53                         return; // nothing to do.
  54                 }
  55                 started = false;
  56                 doStop();
  57         }
  58
  59         private final DataSource getDatasource() {
  60                 if ( !started) {
  61                         throw new RuntimeException("Database is not started!");
  62                 }
  63                 return itsDataSource;
  64         }
  65
  66         protected String getProperty(String aName) {
  67                 String value = System.getProperty(aName);
  68                 if ( value != null ) {
  69                         return value;
  70                 }
  71                 value = System.getenv(aName);
  72                 if ( value != null ) {
  73                         return value;
  74                 }
  75                 throw new RuntimeException("This class expects the '" + aName + "' property to be set");
  76         }
  77
  78 }