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 * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * 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.storm.sql.runtime.serde.csv; import com.google.common.base.Preconditions; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.List; import org.apache.commons.csv.CSVFormat; import org.apache.commons.csv.CSVParser; import org.apache.commons.csv.CSVRecord; import org.apache.storm.spout.Scheme; import org.apache.storm.tuple.Fields; import org.apache.storm.utils.Utils; /** * CsvScheme uses the standard RFC4180 CSV Parser * One of the difference from Tsv format is that fields with embedded commas will be quoted. * eg: a,"b,c",d is allowed. * * @see <a href="https://tools.ietf.org/html/rfc4180">RFC4180</a> */ public class CsvScheme implements Scheme { private final List<String> fieldNames; public CsvScheme(List<String> fieldNames) { this.fieldNames = fieldNames; } @Override public List<Object> deserialize(ByteBuffer ser) { try { String data = new String(Utils.toByteArray(ser), StandardCharsets.UTF_8); CSVParser parser = CSVParser.parse(data, CSVFormat.RFC4180); CSVRecord record = parser.getRecords().get(0); Preconditions.checkArgument(record.size() == fieldNames.size(), "Invalid schema"); ArrayList<Object> list = new ArrayList<>(fieldNames.size()); for (int i = 0; i < record.size(); i++) { list.add(record.get(i)); } return list; } catch (IOException e) { throw new RuntimeException(e); } } @Override public Fields getOutputFields() { return new Fields(fieldNames); } }