protected synchronized DataSource createDataSource()

in commons-dbcp-1.3/src/main/java/org/apache/commons/dbcp/BasicDataSource.java [1120:1255]
114 lines of code
20 McCabe index (conditional complexity)

    protected synchronized DataSource createDataSource()
        throws SQLException {

        // Return the pool if we have already created it
        if (dataSource != null) {
            return (dataSource);
        }

        // Load the JDBC driver class
        Class driverFromCCL = null;        
        if (driverClassName != null) {
            try {
                try {
                    Class.forName(driverClassName);
                } catch (ClassNotFoundException e) {
                    driverFromCCL = Thread.currentThread().getContextClassLoader().loadClass(driverClassName);
                }
            } catch (Throwable t) {
                String message = "Cannot load JDBC driver class '" +
                    driverClassName + "'";
                logWriter.println(message);
                t.printStackTrace(logWriter);
                throw new SQLNestedException(message, t);
            }
        }

        // Create a JDBC driver instance
        Driver driver = null;
        try {
            if (driverFromCCL != null) {
                driver = (Driver) driverFromCCL.newInstance();
                if (!driver.acceptsURL(url)) {
                    new SQLException("No suitable driver", "08001");                    
                }
            } else {
                driver = DriverManager.getDriver(url);
            }
        } catch (Throwable t) {
            String message = "Cannot create JDBC driver of class '" +
                (driverClassName != null ? driverClassName : "") + 
                "' for connect URL '" + url + "'";
            logWriter.println(message);
            t.printStackTrace(logWriter);
            throw new SQLNestedException(message, t);
        }

        // Can't test without a validationQuery
        if (validationQuery == null) {
            setTestOnBorrow(false);
            setTestOnReturn(false);
            setTestWhileIdle(false);
        }

        // Create an object pool to contain our active connections
        if ((abandonedConfig != null) && (abandonedConfig.getRemoveAbandoned())) {
            connectionPool = new AbandonedObjectPool(null,abandonedConfig);
        }
        else {
            connectionPool = new GenericObjectPool();
        }
        connectionPool.setMaxActive(maxActive);
        connectionPool.setMaxIdle(maxIdle);
        connectionPool.setMinIdle(minIdle);
        connectionPool.setMaxWait(maxWait);
        connectionPool.setTestOnBorrow(testOnBorrow);
        connectionPool.setTestOnReturn(testOnReturn);
        connectionPool.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        connectionPool.setNumTestsPerEvictionRun(numTestsPerEvictionRun);
        connectionPool.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        connectionPool.setTestWhileIdle(testWhileIdle);
        
        // Set up statement pool, if desired
        GenericKeyedObjectPoolFactory statementPoolFactory = null;
        if (isPoolPreparedStatements()) {
            statementPoolFactory = new GenericKeyedObjectPoolFactory(null, 
                        -1, // unlimited maxActive (per key)
                        GenericKeyedObjectPool.WHEN_EXHAUSTED_FAIL, 
                        0, // maxWait
                        1, // maxIdle (per key) 
                        maxOpenPreparedStatements); 
        }

        // Set up the driver connection factory we will use
        if (username != null) {
            connectionProperties.put("user", username);
        } else {
            log("DBCP DataSource configured without a 'username'");
        }
        
        if (password != null) {
            connectionProperties.put("password", password);
        } else {
            log("DBCP DataSource configured without a 'password'");
        }
        
        DriverConnectionFactory driverConnectionFactory =
            new DriverConnectionFactory(driver, url, connectionProperties);

        // Set up the poolable connection factory we will use
        PoolableConnectionFactory connectionFactory = null;
        try {
            connectionFactory =
                new PoolableConnectionFactory(driverConnectionFactory,
                                              connectionPool,
                                              statementPoolFactory,
                                              validationQuery,
                                              defaultReadOnly,
                                              defaultAutoCommit,
                                              defaultTransactionIsolation,
                                              defaultCatalog,
                                              abandonedConfig);
            if (connectionFactory == null) {
                throw new SQLException("Cannot create PoolableConnectionFactory");
            }
            validateConnectionFactory(connectionFactory);
        } catch (RuntimeException e) {
            throw e;
        } catch (Exception e) {
            throw new SQLNestedException("Cannot create PoolableConnectionFactory (" + e.getMessage() + ")", e);
        }

        // Create and return the pooling data source to manage the connections
        dataSource = new PoolingDataSource(connectionPool);
        ((PoolingDataSource) dataSource).setAccessToUnderlyingConnectionAllowed(isAccessToUnderlyingConnectionAllowed());
        dataSource.setLogWriter(logWriter);

        try {
            for (int i = 0 ; i < initialSize ; i++) {
                connectionPool.addObject();
            }
        } catch (Exception e) {
            throw new SQLNestedException("Error preloading the connection pool", e);
        }
        
        return dataSource;
    }