Remove a BOM Character From an Apache Camel Exchange Message (DSL Java)

A BOM character (Byte Order Mark) is an invisible character located at the start of a text file. A machine can identify the BOM character by its hexadecimal byte sequence, but to the user, the BOM character is invisible. 

Apache Camel has a validation component that ignores BOM characters if they appear at the beginning of a file, but the component does not ignore BOM characters if they appear elsewhere. This can cause failures in an application. For example, when we use a splitter and aggregator, the exchange message can be ordered differently after aggregation is completed (i.e. the BOM character is not located at the start of a file, but somewhere else).  

You may also like: How to Transform Any Type of Java Bean With BULL.

To avoid failures based on BOM characters, we create a Java Bean that scans the exchange message for the BOM character by its hexadecimal code and replaces it with an empty string. 

 public void detectBomCharacter(Exchange exchange) { 

   String newBody = ((String)exchange.getIn().getBody()).replaceAll("\\uFEFF", "");

   exchange.getMessage().setBody((newBody)); 

 } 

 
The test using JUnit Jupiter could look as follows:

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import org.apache.camel.Exchange;

import org.apache.camel.support.DefaultExchange;

import org.apache.camel.impl.DefaultCamelContext;

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

class BomProcessor{

    Exchange exchange;

    BomProcessor bomProcessor;

    public void setUp(){

        exchange = new DefaultExchange(new DefaultCamelContext());

        bomProcessor = new BomProcessor ();

    }

    @Test

    public void shouldRemoveBomCharacter() {

        exchange.getIn().setBody("\uFEFFTest\uFEFF to remove\uFEFF BOM.\uFEFF");

        bomProcessor.removeBomCharacter(exchange);

        assertEquals("Test to remove BOM.", exchange.getMessage().getBody());

    }

}

Further Reading

• Open Source Integration With Apache Camel and How Fuse IDE Can Help.
• Microservices With Apache Camel.