com.splout.db.engine.JDBCManager.java Source code

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Here is the source code for com.splout.db.engine.JDBCManager.java

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package com.splout.db.engine;

/*
 * #%L
 * Splout SQL commons
 * %%
 * Copyright (C) 2012 - 2013 Datasalt Systems S.L.
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */

import com.jolbox.bonecp.BoneCP;
import com.jolbox.bonecp.BoneCPConfig;
import com.splout.db.common.QueryResult;
import com.splout.db.engine.EngineManager.EngineException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

/**
 * Generic JDBC Manager which can be reused by any engine which is
 * JDBC-compliant.
 */
public class JDBCManager {

    private final static Log log = LogFactory.getLog(JDBCManager.class);
    BoneCP connectionPool = null;

    public JDBCManager(String driver, String connectionUri, int nConnectionsPool, String userName, String password)
            throws SQLException, ClassNotFoundException {

        Class.forName(driver);

        BoneCPConfig config = new BoneCPConfig();
        config.setJdbcUrl(connectionUri);
        config.setMinConnectionsPerPartition(nConnectionsPool);
        config.setMaxConnectionsPerPartition(nConnectionsPool);
        config.setUsername(userName);
        config.setPassword(password);
        config.setPartitionCount(1);
        config.setDefaultAutoCommit(false);

        connectionPool = new BoneCP(config); // setup the connection pool
    }

    public QueryResult query(String query, int maxResults) throws EngineException {
        long start = System.currentTimeMillis();
        Connection connection = null;
        ResultSet rs = null;
        Statement stmt = null;
        try {
            connection = connectionPool.getConnection(); // fetch a connection
            stmt = connection.createStatement();
            QueryResult result = null;
            if (stmt.execute(query)) {
                rs = stmt.getResultSet();
                result = convertResultSetToQueryResult(rs, maxResults);
            } else {
                result = QueryResult.emptyQueryResult();
            }
            long end = System.currentTimeMillis();
            log.info(Thread.currentThread().getName() + ": Query [" + query + "] handled in [" + (end - start)
                    + "] ms.");
            return result;
        } catch (SQLException e) {
            throw convertException(e);
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                connection.close();
            } catch (SQLException e) {
                throw convertException(e);
            }
        }
    }

    public static QueryResult convertResultSetToQueryResult(ResultSet rs, int maxResults) throws SQLException {
        ResultSetMetaData md = rs.getMetaData();
        int columns = md.getColumnCount();
        String[] columnNames = new String[columns];
        for (int i = 0; i < columns; i++) {
            columnNames[i] = md.getColumnName(i);
        }

        List<Object[]> list = new ArrayList<Object[]>();
        while (rs.next() && list.size() < maxResults) {
            Object[] row = new Object[columns];
            for (int i = 1; i <= columns; ++i) {
                row[i] = rs.getObject(i);
            }
            list.add(row);
        }

        if (list.size() == maxResults) {
            throw new SQLException("Hard limit on number of results reached (" + maxResults
                    + "), please use a LIMIT for this query.");
        }

        return new QueryResult(columnNames, list);
    }

    public void close() {
        connectionPool.shutdown();
    }

    public QueryResult exec(String query) throws EngineException {
        return query(query, 1);
    }

    public Connection getConnectionFromPool() throws SQLException {
        return connectionPool.getConnection();
    }

    protected static EngineException convertException(SQLException e) {
        if (e instanceof SQLSyntaxErrorException) {
            return new EngineManager.SyntaxErrorException(e.getMessage());
        } else if (e instanceof SQLTimeoutException) {
            return new EngineManager.QueryInterruptedException(e.getMessage());
        } else {
            return new EngineManager.ShouldNotRetryInReplicaException(e.getMessage(), e);
        }
    }

}