org.apache.druid.metadata.storage.derby.DerbyConnector.java Source code

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Here is the source code for org.apache.druid.metadata.storage.derby.DerbyConnector.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.druid.metadata.storage.derby;

import com.google.common.base.Supplier;
import com.google.inject.Inject;
import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.druid.guice.ManageLifecycle;
import org.apache.druid.java.util.common.StringUtils;
import org.apache.druid.java.util.common.lifecycle.LifecycleStart;
import org.apache.druid.java.util.common.lifecycle.LifecycleStop;
import org.apache.druid.java.util.common.logger.Logger;
import org.apache.druid.metadata.MetadataStorage;
import org.apache.druid.metadata.MetadataStorageConnectorConfig;
import org.apache.druid.metadata.MetadataStorageTablesConfig;
import org.apache.druid.metadata.SQLMetadataConnector;
import org.skife.jdbi.v2.DBI;
import org.skife.jdbi.v2.Handle;

@ManageLifecycle
public class DerbyConnector extends SQLMetadataConnector {
    private static final Logger log = new Logger(DerbyConnector.class);
    private static final String SERIAL_TYPE = "BIGINT GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1)";
    private static final String QUOTE_STRING = "\\\"";
    private final DBI dbi;
    private final MetadataStorage storage;

    @Inject
    public DerbyConnector(MetadataStorage storage, Supplier<MetadataStorageConnectorConfig> config,
            Supplier<MetadataStorageTablesConfig> dbTables) {
        super(config, dbTables);

        final BasicDataSource datasource = getDatasource();
        datasource.setDriverClassLoader(getClass().getClassLoader());
        datasource.setDriverClassName("org.apache.derby.jdbc.ClientDriver");

        this.dbi = new DBI(datasource);
        this.storage = storage;
        log.info("Derby connector instantiated with metadata storage [%s].", this.storage.getClass().getName());
    }

    public DerbyConnector(MetadataStorage storage, Supplier<MetadataStorageConnectorConfig> config,
            Supplier<MetadataStorageTablesConfig> dbTables, DBI dbi) {
        super(config, dbTables);
        this.dbi = dbi;
        this.storage = storage;
    }

    @Override
    public boolean tableExists(Handle handle, String tableName) {
        return !handle.createQuery("select * from SYS.SYSTABLES where tablename = :tableName")
                .bind("tableName", StringUtils.toUpperCase(tableName)).list().isEmpty();
    }

    @Override
    protected String getSerialType() {
        return SERIAL_TYPE;
    }

    @Override
    public String getQuoteString() {
        return QUOTE_STRING;
    }

    @Override
    public DBI getDBI() {
        return dbi;
    }

    @Override
    protected int getStreamingFetchSize() {
        // Derby only supports fetch size of 1
        return 1;
    }

    @Override
    public String getValidationQuery() {
        return "VALUES 1";
    }

    @LifecycleStart
    public void start() {
        log.info("Starting DerbyConnector...");
        storage.start();
    }

    @LifecycleStop
    public void stop() {
        log.info("Stopping DerbyConnector...");
        storage.stop();
    }
}