/**
* 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.csv;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.camel.Exchange;
import org.apache.camel.spi.DataFormat;
import org.apache.camel.util.ExchangeHelper;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.ObjectHelper;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVStrategy;
import org.apache.commons.csv.writer.CSVConfig;
import org.apache.commons.csv.writer.CSVField;
import org.apache.commons.csv.writer.CSVWriter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* CSV Data format.
* <p/>
* By default, columns are autogenerated in the resulting CSV. Subsequent
* messages use the previously created columns with new fields being added at
* the end of the line. Thus, field order is the same from message to message.
* Autogeneration can be disabled. In this case, only the fields defined in
* csvConfig are written on the output.
*
* @version
*/
public class CsvDataFormat implements DataFormat {
private static final Logger LOGGER = LoggerFactory.getLogger(CsvDataFormat.class);
private CSVStrategy strategy = cloneCSVStrategyIfNecessary(CSVStrategy.DEFAULT_STRATEGY);
private CSVConfig config = new CSVConfig();
private boolean autogenColumns = true;
private String delimiter;
private boolean skipFirstLine;
/**
* Lazy row loading with iterator for big files.
*/
private boolean lazyLoad;
private static CSVStrategy cloneCSVStrategyIfNecessary(CSVStrategy csvStrategy) {
for (Field field : CSVStrategy.class.getFields()) {
try {
if (field.get(null) == csvStrategy) {
// return a safe copy of the declared static constant so that we don't cause any side effect
// by (potentially) other CsvDataFormat objects in use, as we change the properties of the
// strategy itself (e.g. it's set delimiter through the #unmarshal() method below)
LOGGER.debug("Returning a clone of {} as it is the declared constant {} by the CSVStrategy class", csvStrategy, field.getName());
return (CSVStrategy) csvStrategy.clone();
}
} catch (Exception e) {
ObjectHelper.wrapRuntimeCamelException(e);
}
}
// not a declared static constant of CSVStrategy so return it as is
return csvStrategy;
}
public void marshal(Exchange exchange, Object object, OutputStream outputStream) throws Exception {
if (delimiter != null) {
config.setDelimiter(delimiter.charAt(0));
}
OutputStreamWriter out = new OutputStreamWriter(outputStream, IOHelper.getCharsetName(exchange));
CSVWriter csv = new CSVWriter(config);
csv.setWriter(out);
try {
List<?> list = ExchangeHelper.convertToType(exchange, List.class, object);
if (list != null) {
for (Object child : list) {
Map<?, ?> row = ExchangeHelper.convertToMandatoryType(exchange, Map.class, child);
doMarshalRecord(exchange, row, out, csv);
}
} else {
Map<?, ?> row = ExchangeHelper.convertToMandatoryType(exchange, Map.class, object);
doMarshalRecord(exchange, row, out, csv);
}
} finally {
IOHelper.close(out);
}
}
private void doMarshalRecord(Exchange exchange, Map<?, ?> row, Writer out, CSVWriter csv) throws Exception {
if (autogenColumns) {
// no specific config has been set so lets add fields
Set<?> set = row.keySet();
updateFieldsInConfig(set, exchange);
}
csv.writeRecord(row);
}
public Object unmarshal(Exchange exchange, InputStream inputStream) throws Exception {
if (delimiter != null) {
config.setDelimiter(delimiter.charAt(0));
}
strategy.setDelimiter(config.getDelimiter());
Reader reader = null;
boolean error = false;
try {
reader = IOHelper.buffered(new InputStreamReader(inputStream, IOHelper.getCharsetName(exchange)));
CSVParser parser = new CSVParser(reader, strategy);
if (skipFirstLine) {
// read one line ahead and skip it
parser.getLine();
}
CsvIterator csvIterator = new CsvIterator(parser, reader);
return lazyLoad ? csvIterator : loadAllAsList(csvIterator);
} catch (Exception e) {
error = true;
throw e;
} finally {
if (error) {
IOHelper.close(reader);
}
}
}
private List<List<String>> loadAllAsList(CsvIterator iter) {
try {
List<List<String>> list = new ArrayList<List<String>>();
while (iter.hasNext()) {
list.add(iter.next());
}
return list;
} finally {
// close the iterator (which would also close the reader) as we've loaded all the data upfront
IOHelper.close(iter);
}
}
public String getDelimiter() {
return delimiter;
}
public void setDelimiter(String delimiter) {
if (delimiter != null && delimiter.length() > 1) {
throw new IllegalArgumentException("Delimiter must have a length of one!");
}
this.delimiter = delimiter;
}
public CSVConfig getConfig() {
return config;
}
public void setConfig(CSVConfig config) {
this.config = config;
}
public CSVStrategy getStrategy() {
return strategy;
}
public void setStrategy(CSVStrategy strategy) {
this.strategy = cloneCSVStrategyIfNecessary(strategy);
}
public boolean isAutogenColumns() {
return autogenColumns;
}
/**
* Auto generate columns.
*
* @param autogenColumns set to false to disallow column autogeneration (default true)
*/
public void setAutogenColumns(boolean autogenColumns) {
this.autogenColumns = autogenColumns;
}
public boolean isSkipFirstLine() {
return skipFirstLine;
}
public void setSkipFirstLine(boolean skipFirstLine) {
this.skipFirstLine = skipFirstLine;
}
public boolean isLazyLoad() {
return lazyLoad;
}
public void setLazyLoad(boolean lazyLoad) {
this.lazyLoad = lazyLoad;
}
private synchronized void updateFieldsInConfig(Set<?> set, Exchange exchange) {
for (Object value : set) {
if (value != null) {
String text = exchange.getContext().getTypeConverter().convertTo(String.class, value);
// do not add field twice
if (config.getField(text) == null) {
CSVField field = new CSVField(text);
config.addField(field);
}
}
}
}
}