Camel: Splitting a collection and writing to files - apache-camel

Question

I´m trying to split an ArrayList and writing each element to it´s own file using Apache Camel like in this simplified example:
from("timer://poll?period=10000").process(new Processor(){
public void process(Exchange exchange){
ArrayList<String> list = new ArrayList<String>();
list.add("one");
list.add("two");
list.add("three");
exchange.getIn().setBody(list, ArrayList.class);
}
}).split(body()).log(body().toString()).to("file:some/dir");
The log prints each item but only "three" is saved to a file. What am I doing wrong?
Jan

Answer 1

After you called split function, your route is divided in 3 ways, each method or route executed after that is applied on each process way.
In each process way, split method add CamelSplitIndex property.
So this code should work
from("timer://poll?period=10000").process(new Processor(){
public void process(Exchange exchange){
ArrayList<String> list = new ArrayList<String>();
list.add("one");
list.add("two");
list.add("three");
exchange.getIn().setBody(list, ArrayList.class);
}
}).split(body()).log(body().toString()).to("file:some/dir?fileName=${header.CamelSplitIndex}");
This is second example with xml file and xpath.
We suppose that you want to explose xml for each node order with an element name inside:
<orders>
<order>
<name>Order 1</name>
</order>
<order>
<name>Order 2</name>
</order>
</order>
We suppose that we want to explode this xml file in 2 files
from("file://repo-source").split(xpath("//orders/order")).setHeader("orderName", xpath("/order/name").stringResult()).to("file://repo?fileName=${header.orderName}.xml");

Answer 2

The file producer will by default "override" if a file already exists.
See the fileExist option at its documentation page
http://camel.apache.org/file2
Since the input to this route is also a file, then the producer will "inherit" the file name from the input.
So in your case if you want to save each splitted message in a new file, then you would need to set a target file name, using the fileName option
"file:some/dir?fileName=splitted-${id}"
The fileName option supports the simple and file language
http://camel.apache.org/simple.html
http://camel.apache.org/file-language.html
That means the file name can be dynamic computed, such as above, where ${id} is an unique message id.