com.cloudera.sqoop.metastore.hsqldb.HsqldbMetaStore.java Source code

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Here is the source code for com.cloudera.sqoop.metastore.hsqldb.HsqldbMetaStore.java

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/**
 * Licensed to Cloudera, Inc. under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  Cloudera, Inc. 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 com.cloudera.sqoop.metastore.hsqldb;

import java.io.File;

import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.util.StringUtils;

import org.hsqldb.Server;
import org.hsqldb.ServerConstants;

import com.cloudera.sqoop.SqoopOptions;

import com.cloudera.sqoop.manager.HsqldbManager;

/**
 * Container for an HSQLDB-backed metastore.
 */
public class HsqldbMetaStore {

    public static final Log LOG = LogFactory.getLog(HsqldbMetaStore.class.getName());

    /** Where on the local fs does the metastore put files? */
    public static final String META_STORAGE_LOCATION_KEY = "sqoop.metastore.server.location";

    /**
     * What port does the metastore listen on?
     */
    public static final String META_SERVER_PORT_KEY = "sqoop.metastore.server.port";

    /** Default to this port if unset. */
    public static final int DEFAULT_PORT = 16000;

    private int port;
    private String fileLocation;
    private Server server;
    private Configuration conf;

    public HsqldbMetaStore(Configuration config) {
        this.conf = config;
        init();
    }

    /**
     * Determine the user's home directory and return a file path
     * under this root where the shared metastore can be placed.
     */
    private String getHomeDirFilePath() {
        String homeDir = System.getProperty("user.home");

        File homeDirObj = new File(homeDir);
        File sqoopDataDirObj = new File(homeDirObj, ".sqoop");
        File databaseFileObj = new File(sqoopDataDirObj, "shared-metastore.db");

        return databaseFileObj.toString();
    }

    private void init() {
        if (null != server) {
            LOG.debug("init(): server already exists.");
            return;
        }

        fileLocation = conf.get(META_STORAGE_LOCATION_KEY, null);
        if (null == fileLocation) {
            fileLocation = getHomeDirFilePath();
            LOG.warn("The location for metastore data has not been explicitly set. "
                    + "Placing shared metastore files in " + fileLocation);
        }

        this.port = conf.getInt(META_SERVER_PORT_KEY, DEFAULT_PORT);
    }

    public void start() {
        try {
            if (server != null) {
                server.checkRunning(false);
            }
        } catch (RuntimeException re) {
            LOG.info("Server is already started.");
            return;
        }

        server = new Server();
        server.setDatabasePath(0, "file:" + fileLocation);
        server.setDatabaseName(0, "sqoop");
        server.putPropertiesFromString("hsqldb.write_delay=false");
        server.setPort(port);
        server.setSilent(true);
        server.setNoSystemExit(true);

        server.start();
        LOG.info("Server started on port " + port + " with protocol " + server.getProtocol());
    }

    /**
     * Blocks the current thread until the server is shut down.
     */
    public void waitForServer() {
        while (true) {
            int curState = server.getState();
            if (curState == ServerConstants.SERVER_STATE_SHUTDOWN) {
                LOG.info("Got shutdown notification");
                break;
            }

            try {
                Thread.sleep(100);
            } catch (InterruptedException ie) {
                LOG.info("Interrupted while blocking for server:" + StringUtils.stringifyException(ie));
            }
        }
    }

    /**
     * Connects to the server and instructs it to shutdown.
     */
    public void shutdown() {
        // Send the SHUTDOWN command to the server via SQL.
        SqoopOptions options = new SqoopOptions(conf);
        options.setConnectString("jdbc:hsqldb:hsql://localhost:" + port + "/sqoop");
        options.setUsername("SA");
        options.setPassword("");
        HsqldbManager manager = new HsqldbManager(options);
        Statement s = null;
        try {
            Connection c = manager.getConnection();
            s = c.createStatement();
            s.execute("SHUTDOWN");
        } catch (SQLException sqlE) {
            LOG.warn("Exception shutting down database: " + StringUtils.stringifyException(sqlE));
        } finally {
            if (null != s) {
                try {
                    s.close();
                } catch (SQLException sqlE) {
                    LOG.warn("Error closing statement: " + sqlE);
                }
            }

            try {
                manager.close();
            } catch (SQLException sqlE) {
                LOG.warn("Error closing manager: " + sqlE);
            }
        }
    }
}