ServerConnPool.java

package com.github.walker.easydb.connection;

import com.github.walker.easydb.assistant.EasyConfig;
import com.github.walker.easydb.exception.DataAccessException;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

/**
 * This class gets the database connection from the connection pool of web
 * server, and maintains it.
 *
 * @author HuQingmiao
 */

class ServerConnPool extends ConnectionPool {

    // Uses Hashtable as the datasource cache, in case of lookuping datasource
    // continually by jndi.
    // private static Hashtable datasourceCache = new Hashtable(2);

    private DataSource dataSource = null;

    private String jndiName = null;

    private String dbType = null;

    protected ServerConnPool(String jndiKey) {
        jndiName = EasyConfig.getProperty(jndiKey);

        String jndiDBTypeKey = jndiKey.substring(0, jndiKey.indexOf('.')) + ".DBType";
        dbType = EasyConfig.getProperty(jndiDBTypeKey);

        log.info("Connection Pool of web server is adopted. ");
    }

    /**
     * Retrieves the database connection
     *
     * @throws SQLException , BaseException
     */
    public Connection getConnection() throws DataAccessException {
        InitialContext initCtx = null;
        Connection conn = null;
        log.debug("jndi.name: " + jndiName);
        try {
            if (dataSource == null) {
                initCtx = new InitialContext();
                dataSource = (DataSource) initCtx.lookup(jndiName);
            }
            conn = dataSource.getConnection();

        } catch (SQLException e) {
            log.error("", e);
            throw new DataAccessException(e.getMessage());
        } catch (NamingException e) {
            log.error("", e);
            throw new DataAccessException(e.getMessage());
        } finally {
            try {
                if (initCtx != null)
                    initCtx.close();
            } catch (NamingException e) {
                log.error("", e);
                throw new DataAccessException(e.getMessage());
            }
        }
        return conn;
    }

    /**
     * Close the connection.
     * <p/>
     * throws SQLException
     */
    public void freeConnection(Connection conn) throws DataAccessException {
        try {
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            log.error("", e);
            throw new DataAccessException(e.getMessage());
        }
    }

    /**
     * 获取数据库类型
     *
     * @return
     */
    public String getDBType() {
        return this.dbType;
    }

}