| /* |
| 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 quarks.samples.connectors.jdbc; |
| |
| import java.io.File; |
| import java.nio.file.Files; |
| import java.util.List; |
| import java.util.Properties; |
| |
| import quarks.connectors.jdbc.JdbcStreams; |
| import quarks.providers.direct.DirectProvider; |
| import quarks.topology.TStream; |
| import quarks.topology.Topology; |
| |
| /** |
| * A simple JDBC connector sample demonstrating streaming read access |
| * of a dbms table and creating stream tuples from the results. |
| */ |
| public class SimpleReaderApp { |
| private final Properties props; |
| |
| public static void main(String[] args) throws Exception { |
| if (args.length != 1) |
| throw new Exception("missing pathname to jdbc.properties file"); |
| SimpleReaderApp reader = new SimpleReaderApp(args[0]); |
| reader.run(); |
| } |
| |
| /** |
| * @param jdbcPropsPath pathname to properties file |
| */ |
| SimpleReaderApp(String jdbcPropsPath) throws Exception { |
| props = new Properties(); |
| props.load(Files.newBufferedReader(new File(jdbcPropsPath).toPath())); |
| } |
| |
| /** |
| * Create a topology for the writer application and run it. |
| */ |
| private void run() throws Exception { |
| DirectProvider tp = new DirectProvider(); |
| |
| // build the application/topology |
| |
| Topology t = tp.newTopology("jdbcSampleWriter"); |
| |
| // Create the JDBC connector |
| JdbcStreams myDb = new JdbcStreams(t, |
| () -> DbUtils.getDataSource(props), |
| dataSource -> dataSource.getConnection()); |
| |
| // Create a sample stream of tuples containing a person id |
| List<PersonId> personIdList = PersonData.toPersonIds(PersonData.loadPersonData(props)); |
| personIdList.add(new PersonId(99999)); |
| TStream<PersonId> personIds = t.collection(personIdList); |
| |
| // For each tuple on the stream, read info from the db table |
| // using the "id", and create a Person tuple on the result stream. |
| TStream<Person> persons = myDb.executeStatement(personIds, |
| () -> "SELECT id, firstname, lastname FROM persons WHERE id = ?", |
| (personId,stmt) -> stmt.setInt(1, personId.id), |
| (personId,rSet,exc,resultStream) -> { |
| if (exc != null) { |
| // some failure processing this tuple. an error was logged. |
| System.err.println("Unable to process id="+personId+": "+exc); |
| return; |
| } |
| if (rSet.next()) { |
| resultStream.accept( |
| new Person(rSet.getInt("id"), |
| rSet.getString("firstname"), |
| rSet.getString("lastname"))); |
| } |
| else { |
| System.err.println("Unknown person id="+personId.id); |
| } |
| } |
| ); |
| |
| // print out Person tuples as they are retrieved |
| persons.sink(person -> System.out.println("retrieved person: "+person)); |
| |
| // run the application / topology |
| tp.submit(t); |
| } |
| } |