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.camel.dataformat.bindy.csv; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Scanner; import org.apache.camel.Exchange; import org.apache.camel.dataformat.bindy.BindyAbstractDataFormat; import org.apache.camel.dataformat.bindy.BindyAbstractFactory; import org.apache.camel.dataformat.bindy.BindyCsvFactory; import org.apache.camel.dataformat.bindy.BindyKeyValuePairFactory; import org.apache.camel.dataformat.bindy.util.Converter; import org.apache.camel.spi.DataFormat; import org.apache.camel.spi.PackageScanClassResolver; import org.apache.camel.util.IOHelper; import org.apache.camel.util.ObjectHelper; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * A <a href="http://camel.apache.org/data-format.html">data format</a> ( * {@link DataFormat}) using Bindy to marshal to and from CSV files */ public class BindyCsvDataFormat extends BindyAbstractDataFormat { private static final transient Log LOG = LogFactory.getLog(BindyCsvDataFormat.class); public BindyCsvDataFormat() { } public BindyCsvDataFormat(String... packages) { super(packages); } @SuppressWarnings("unchecked") public void marshal(Exchange exchange, Object body, OutputStream outputStream) throws Exception { BindyCsvFactory factory = (BindyCsvFactory) getFactory(exchange.getContext().getPackageScanClassResolver()); ObjectHelper.notNull(factory, "not instantiated"); // Get CRLF byte[] bytesCRLF = Converter.getByteReturn(factory.getCarriageReturn()); if (factory.getGenerateHeaderColumnNames()) { String result = factory.generateHeader(); byte[] bytes = exchange.getContext().getTypeConverter().convertTo(byte[].class, exchange, result); outputStream.write(bytes); // Add a carriage return outputStream.write(bytesCRLF); } List<Map<String, Object>> models; // the body is not a prepared list so help a bit here and create one for us if (exchange.getContext().getTypeConverter().convertTo(List.class, body) == null) { models = new ArrayList<Map<String, Object>>(); Iterator it = ObjectHelper.createIterator(body); while (it.hasNext()) { Object model = it.next(); String name = model.getClass().getName(); Map<String, Object> row = new HashMap<String, Object>(); row.put(name, body); models.add(row); } } else { // cast to the expected type models = (List<Map<String, Object>>) body; } for (Map<String, Object> model : models) { String result = factory.unbind(model); byte[] bytes = exchange.getContext().getTypeConverter().convertTo(byte[].class, exchange, result); outputStream.write(bytes); // Add a carriage return outputStream.write(bytesCRLF); } } public Object unmarshal(Exchange exchange, InputStream inputStream) throws Exception { BindyCsvFactory factory = (BindyCsvFactory) getFactory(exchange.getContext().getPackageScanClassResolver()); ObjectHelper.notNull(factory, "not instantiated"); // List of Pojos List<Map<String, Object>> models = new ArrayList<Map<String, Object>>(); // Pojos of the model Map<String, Object> model; InputStreamReader in = new InputStreamReader(inputStream); // Scanner is used to read big file Scanner scanner = new Scanner(in); // Retrieve the separator defined to split the record String separator = factory.getSeparator(); ObjectHelper.notNull(separator, "The separator has not been defined in the annotation @CsvRecord or not instantiated during initModel."); int count = 0; try { // If the first line of the CSV file contains columns name, then we // skip this line if (factory.getSkipFirstLine()) { // Check if scanner is empty if (scanner.hasNextLine()) { scanner.nextLine(); } } while (scanner.hasNextLine()) { // Read the line String line = scanner.nextLine().trim(); if (ObjectHelper.isEmpty(line)) { // skip if line is empty continue; } // Increment counter count++; // Create POJO where CSV data will be stored model = factory.factory(); // Split the CSV record according to the separator defined in // annotated class @CSVRecord String[] tokens = line.split(separator, -1); List<String> result = Arrays.asList(tokens); // must unquote tokens before use result = unquoteTokens(result); if (result.size() == 0 || result.isEmpty()) { throw new java.lang.IllegalArgumentException("No records have been defined in the CSV !"); } if (result.size() > 0) { if (LOG.isDebugEnabled()) { LOG.debug("Size of the record splitted : " + result.size()); } // Bind data from CSV record with model classes factory.bind(result, model, count); // Link objects together factory.link(model); // Add objects graph to the list models.add(model); if (LOG.isDebugEnabled()) { LOG.debug("Graph of objects created : " + model); } } } // Test if models list is empty or not // If this is the case (correspond to an empty stream, ...) if (models.size() == 0) { throw new java.lang.IllegalArgumentException("No records have been defined in the CSV !"); } else { return models; } } finally { scanner.close(); IOHelper.close(in, "in", LOG); } } /** * Unquote the tokens, by removing leading and trailing quote chars */ private List<String> unquoteTokens(List<String> result) { List<String> answer = new ArrayList<String>(result.size()); for (String s : result) { if (s.startsWith("\"") || s.startsWith("'")) { s = s.substring(1); } if (s.endsWith("\"") || s.endsWith("'")) { s = s.substring(0, s.length() - 1); } answer.add(s); } return answer; } protected BindyAbstractFactory createModelFactory(PackageScanClassResolver resolver) throws Exception { return new BindyCsvFactory(resolver, getPackages()); } }