org.apache.zeppelin.tajo.TajoInterpreter.java Source code

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Here is the source code for org.apache.zeppelin.tajo.TajoInterpreter.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
package org.apache.zeppelin.tajo;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;
import java.util.Properties;

import org.apache.commons.lang.StringUtils;
import org.apache.zeppelin.interpreter.Interpreter;
import org.apache.zeppelin.interpreter.InterpreterContext;
import org.apache.zeppelin.interpreter.InterpreterPropertyBuilder;
import org.apache.zeppelin.interpreter.InterpreterResult;
import org.apache.zeppelin.interpreter.InterpreterResult.Code;
import org.apache.zeppelin.scheduler.Scheduler;
import org.apache.zeppelin.scheduler.SchedulerFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Tajo interpreter for Zeppelin.
 */
public class TajoInterpreter extends Interpreter {
    private Logger logger = LoggerFactory.getLogger(TajoInterpreter.class);

    private Connection connection;
    private Statement statement;
    private Exception exceptionOnConnect;

    public static final String TAJO_JDBC_URI = "tajo.jdbc.uri";
    public static final String TAJO_DRIVER_NAME = "org.apache.tajo.jdbc.TajoDriver";

    static {
        Interpreter.register("tql", "tajo", TajoInterpreter.class.getName(), new InterpreterPropertyBuilder()
                .add(TAJO_JDBC_URI, "jdbc:tajo://localhost:26002/default", "The URL for TajoServer.").build());
    }

    public TajoInterpreter(Properties property) {
        super(property);
    }

    public Connection getJdbcConnection() throws SQLException {
        return DriverManager.getConnection(getProperty(TAJO_JDBC_URI));
    }

    @Override
    public void open() {
        logger.info("Jdbc open connection called!");
        try {
            Class.forName(TAJO_DRIVER_NAME);
        } catch (ClassNotFoundException e) {
            logger.error("Can not open connection", e);
            exceptionOnConnect = e;
            return;
        }
        try {
            connection = getJdbcConnection();
            exceptionOnConnect = null;
            logger.info("Successfully created connection");
        } catch (SQLException e) {
            logger.error("Cannot open connection", e);
            exceptionOnConnect = e;
        }
    }

    @Override
    public void close() {
        try {
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException e) {
            logger.error("Cannot close connection", e);
        } finally {
            connection = null;
            exceptionOnConnect = null;
        }
    }

    private InterpreterResult executeSql(String sql) {
        try {
            if (exceptionOnConnect != null) {
                return new InterpreterResult(Code.ERROR, exceptionOnConnect.getMessage());
            }
            statement = connection.createStatement();
            StringBuilder msg = null;
            if (StringUtils.containsIgnoreCase(sql, "EXPLAIN ")) {
                //return the explain as text, make this visual explain later
                msg = new StringBuilder();
            } else {
                msg = new StringBuilder("%table ");
            }

            ResultSet res = statement.executeQuery(sql);
            try {
                ResultSetMetaData md = res.getMetaData();
                for (int i = 1; i < md.getColumnCount() + 1; i++) {
                    if (i == 1) {
                        msg.append(md.getColumnName(i));
                    } else {
                        msg.append("\t" + md.getColumnName(i));
                    }
                }
                msg.append("\n");
                while (res.next()) {
                    for (int i = 1; i < md.getColumnCount() + 1; i++) {
                        msg.append(res.getString(i) + "\t");
                    }
                    msg.append("\n");
                }
            } finally {
                try {
                    res.close();
                    statement.close();
                } finally {
                    statement = null;
                }
            }

            InterpreterResult interpreterResult = new InterpreterResult(Code.SUCCESS, msg.toString());
            return interpreterResult;
        } catch (SQLException ex) {
            logger.error("Can not run " + sql, ex);
            return new InterpreterResult(Code.ERROR, ex.getMessage());
        }
    }

    @Override
    public InterpreterResult interpret(String cmd, InterpreterContext contextInterpreter) {
        logger.info("Run SQL command '" + cmd + "'");
        return executeSql(cmd);
    }

    @Override
    public void cancel(InterpreterContext context) {
        if (statement != null) {
            try {
                statement.cancel();
            } catch (SQLException ex) {
            } finally {
                statement = null;
            }
        }
    }

    @Override
    public FormType getFormType() {
        return FormType.SIMPLE;
    }

    @Override
    public int getProgress(InterpreterContext context) {
        return 0;
    }

    @Override
    public Scheduler getScheduler() {
        return SchedulerFactory.singleton()
                .createOrGetFIFOScheduler(TajoInterpreter.class.getName() + this.hashCode());
    }

    @Override
    public List<String> completion(String buf, int cursor) {
        return null;
    }
}