Java tutorial
/** * 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.metamodel.mongodb.mongo3; import java.io.File; import java.sql.Connection; import java.sql.DriverManager; import org.apache.metamodel.DataContext; import org.apache.metamodel.UpdateCallback; import org.apache.metamodel.UpdateScript; import org.apache.metamodel.data.DataSet; import org.apache.metamodel.data.Row; import org.apache.metamodel.insert.RowInsertionBuilder; import org.apache.metamodel.jdbc.JdbcDataContext; import org.apache.metamodel.schema.Column; import org.apache.metamodel.schema.Schema; import org.apache.metamodel.schema.Table; import org.apache.metamodel.util.FileHelper; import com.mongodb.MongoClient; import com.mongodb.client.MongoDatabase; /** * Simple example program that can copy data to a MongoDB collection */ public class MongoDbDataCopyer { private final DataContext _sourceDataContext; private final MongoDatabase _mongoDb; private final String _collectionName; private final String _sourceSchemaName; private final String _sourceTableName; // example copy job that will populate the mongodb with Derby data public static void main(String[] args) throws Exception { System.setProperty("derby.storage.tempDirector", FileHelper.getTempDir().getAbsolutePath()); System.setProperty("derby.stream.error.file", File.createTempFile("metamodel-derby", ".log").getAbsolutePath()); File dbFile = new File("../jdbc/src/test/resources/derby_testdb.jar"); dbFile = dbFile.getCanonicalFile(); if (!dbFile.exists()) { throw new IllegalStateException("File does not exist: " + dbFile); } Class.forName("org.apache.derby.jdbc.EmbeddedDriver"); Connection connection = DriverManager .getConnection("jdbc:derby:jar:(" + dbFile.getAbsolutePath() + ")derby_testdb;territory=en"); connection.setReadOnly(true); MongoClient client = new MongoClient(); MongoDatabase mongoDb = client.getDatabase("orderdb_copy"); DataContext sourceDataContext = new JdbcDataContext(connection); new MongoDbDataCopyer(mongoDb, "orders", sourceDataContext, "APP", "orders").copy(); new MongoDbDataCopyer(mongoDb, "offices", sourceDataContext, "APP", "offices").copy(); new MongoDbDataCopyer(mongoDb, "payments", sourceDataContext, "APP", "payments").copy(); new MongoDbDataCopyer(mongoDb, "orderfact", sourceDataContext, "APP", "orderfact").copy(); new MongoDbDataCopyer(mongoDb, "products", sourceDataContext, "APP", "products").copy(); connection.close(); client.close(); } public MongoDbDataCopyer(MongoDatabase mongoDb, String collectionName, DataContext sourceDataContext, String sourceSchemaName, String sourceTableName) { _mongoDb = mongoDb; _collectionName = collectionName; _sourceDataContext = sourceDataContext; _sourceSchemaName = sourceSchemaName; _sourceTableName = sourceTableName; } public void copy() { final MongoDbDataContext targetDataContext = new MongoDbDataContext(_mongoDb); targetDataContext.executeUpdate(new UpdateScript() { @Override public void run(UpdateCallback callback) { final Table sourceTable = getSourceTable(); final Table targetTable = callback .createTable(targetDataContext.getDefaultSchema(), _collectionName).like(sourceTable) .execute(); final Column[] sourceColumns = sourceTable.getColumns(); final DataSet dataSet = _sourceDataContext.query().from(sourceTable).select(sourceColumns) .execute(); while (dataSet.next()) { final Row row = dataSet.getRow(); RowInsertionBuilder insertBuilder = callback.insertInto(targetTable); for (Column column : sourceColumns) { insertBuilder = insertBuilder.value(column.getName(), row.getValue(column)); } insertBuilder.execute(); } dataSet.close(); } }); } private Table getSourceTable() { final Schema schema; if (_sourceSchemaName != null) { schema = _sourceDataContext.getSchemaByName(_sourceSchemaName); } else { schema = _sourceDataContext.getDefaultSchema(); } return schema.getTableByName(_sourceTableName); } }