private BasicDataSource initPool()

in src/protocol/jdbc/src/main/java/org/apache/jmeter/protocol/jdbc/config/DataSourceElement.java [214:321]
94 lines of code
16 McCabe index (conditional complexity)

    private BasicDataSource initPool(String maxPool) {
        BasicDataSource dataSource = new BasicDataSource();

        if (log.isDebugEnabled()) {
            log.debug("MaxPool: {} Timeout: {} TrimInt: {} Auto-Commit: {} Preinit: {} poolPreparedStatements: {}",
                    maxPool, getTimeout(), getTrimInterval(), isAutocommit(), isPreinit(), poolPreparedStatements);
        }
        int poolSize = Integer.parseInt(maxPool);
        dataSource.setMinIdle(0);
        dataSource.setInitialSize(poolSize);
        dataSource.setAutoCommitOnReturn(false);
        if(StringUtils.isNotEmpty(initQuery)) {
            String[] sqls = initQuery.split("\n");
            dataSource.setConnectionInitSqls(Arrays.asList(sqls));
        } else {
            dataSource.setConnectionInitSqls(Collections.emptyList());
        }
        if(StringUtils.isNotEmpty(connectionProperties)) {
            dataSource.setConnectionProperties(connectionProperties);
        }
        if (StringUtils.isNotEmpty(poolPreparedStatements)) {
            int maxPreparedStatements = Integer.parseInt(poolPreparedStatements);
            if (maxPreparedStatements < 0) {
                dataSource.setPoolPreparedStatements(false);
            } else {
                dataSource.setPoolPreparedStatements(true);
                dataSource.setMaxOpenPreparedStatements(10);
            }
        }
        dataSource.setRollbackOnReturn(false);
        dataSource.setMaxIdle(poolSize);
        dataSource.setMaxTotal(poolSize);
        dataSource.setMaxWaitMillis(Long.parseLong(getTimeout()));

        dataSource.setDefaultAutoCommit(isAutocommit());

        if (log.isDebugEnabled()) {
            StringBuilder sb = new StringBuilder(40);
            sb.append("KeepAlive: ");
            sb.append(isKeepAlive());
            sb.append(" Age: ");
            sb.append(getConnectionAge());
            sb.append(" CheckQuery: ");
            sb.append(getCheckQuery());
            log.debug(sb.toString());
        }
        dataSource.setTestOnBorrow(false);
        dataSource.setTestOnReturn(false);
        dataSource.setTestOnCreate(false);
        dataSource.setTestWhileIdle(false);

        if(isKeepAlive()) {
            dataSource.setTestWhileIdle(true);
            String validationQuery = getCheckQuery();
            if (StringUtils.isBlank(validationQuery)) {
                dataSource.setValidationQuery(null);
            } else {
                dataSource.setValidationQuery(validationQuery);
            }
            dataSource.setSoftMinEvictableIdleTimeMillis(Long.parseLong(getConnectionAge()));
            dataSource.setTimeBetweenEvictionRunsMillis(Integer.parseInt(getTrimInterval()));
        }

        int transactionIsolation = DataSourceElementBeanInfo.getTransactionIsolationMode(getTransactionIsolation());
        if (transactionIsolation >= 0) {
            dataSource.setDefaultTransactionIsolation(transactionIsolation);
        }

        String _username = getUsername();
        if (log.isDebugEnabled()) {
            StringBuilder sb = new StringBuilder(40);
            sb.append("Driver: ");
            sb.append(getDriver());
            sb.append(" DbUrl: ");
            sb.append(getDbUrl());
            sb.append(" User: ");
            sb.append(_username);
            log.debug(sb.toString());
        }
        dataSource.setDriverClassName(getDriver());
        dataSource.setUrl(getDbUrl());

        if (_username.length() > 0){
            dataSource.setUsername(_username);
            dataSource.setPassword(getPassword());
        }

        if(isPreinit()) {
            // side effect - connection pool init - that is what we want
            // see also https://commons.apache.org/proper/commons-dbcp/apidocs/org/apache/commons/dbcp2/BasicDataSource.html#setInitialSize-int-
            // it says: "The pool is initialized the first time one of the following methods is invoked:
            // getConnection, setLogwriter, setLoginTimeout, getLoginTimeout, getLogWriter."
            // so we get a connection and close it - which releases it back to the pool (but stays open)
            try {
                dataSource.getConnection().close();
                if (log.isDebugEnabled()) {
                    log.debug("Preinitializing the connection pool: {}@{}", getDataSourceName(), System.identityHashCode(dataSource));
                }
            } catch (SQLException ex) {
                if (log.isErrorEnabled()) {
                    log.error("Error preinitializing the connection pool: {}@{}", getDataSourceName(), System.identityHashCode(dataSource), ex);
                }
            }
        }

        log.debug("PoolConfiguration:{}", this.dataSource);
        return dataSource;
    }