Camel bindy marshal to file creates multiple header row - csv

Question

I have the following camel route:
from(inputDirectory)
.unmarshal(jaxb)
.process(jaxb2CSVDataProcessor)
.split(body()) //because there is a list of CSVRecords
.marshal(bindyCsvDataFormat)
.to(outputDirectory); //appending to existing file using "?autoCreate=true&fileExist=Append"
for my CSV model class I am using annotations:
#CsvRecord(separator = ",", generateHeaderColumns = true)
...
and for properties
#DataField(pos = 0)
...
My problem is that the headers are appended every time a new csv record is appended.
Is there a non-dirty way to control this? Am I missing anything here?

Answer 1

I made a work around which is working quite nicely, creating the header by querying the columnames of the #DataField annotation. This is happening once the first time the file is written. I wrote down the whole solution here:
How to generate a Flat file with header and footer using Camel Bindy

Answer 2

I ended up adding a processor that checks if the csv file exists just before the "to" clause. In there I do a manipulation of the byte array and remove the headers.

Answer 3

Hope this helps anyone else. I needed to do something similar where after my first split message I wanted to supress the header output. Here is a complete class (the 'FieldUtils' is part of the apache commons lib)
package com.routes;
import java.io.OutputStream;
import org.apache.camel.Exchange;
import org.apache.camel.dataformat.bindy.BindyAbstractFactory;
import org.apache.camel.dataformat.bindy.BindyCsvFactory;
import org.apache.camel.dataformat.bindy.BindyFactory;
import org.apache.camel.dataformat.bindy.FormatFactory;
import org.apache.camel.dataformat.bindy.csv.BindyCsvDataFormat;
import org.apache.commons.lang3.reflect.FieldUtils;
public class StreamingBindyCsvDataFormat extends BindyCsvDataFormat {
public StreamingBindyCsvDataFormat(Class<?> type) {
super(type);
}
#Override
public void marshal(Exchange exchange, Object body, OutputStream outputStream) throws Exception {
final StreamingBindyModelFactory factory = (StreamingBindyModelFactory) super.getFactory();
final int splitIndex = exchange.getProperty(Exchange.SPLIT_INDEX, -1, int.class);
final boolean splitComplete = exchange.getProperty(Exchange.SPLIT_COMPLETE, false, boolean.class);
super.marshal(exchange, body, outputStream);
if (splitIndex == 0) {
factory.setGenerateHeaderColumnNames(false); // turn off header generate after first exchange
} else if(splitComplete) {
factory.setGenerateHeaderColumnNames(true); // turn on header generate when split complete
}
}
#Override
protected BindyAbstractFactory createModelFactory(FormatFactory formatFactory) throws Exception {
BindyCsvFactory bindyCsvFactory = new StreamingBindyModelFactory(getClassType());
bindyCsvFactory.setFormatFactory(formatFactory);
return bindyCsvFactory;
}
public class StreamingBindyModelFactory extends BindyCsvFactory implements BindyFactory {
public StreamingBindyModelFactory(Class<?> type) throws Exception {
super(type);
}
public void setGenerateHeaderColumnNames(boolean generateHeaderColumnNames) throws IllegalAccessException {
FieldUtils.writeField(this, "generateHeaderColumnNames", generateHeaderColumnNames, true);
}
}
}