# Header

## Overview

The header language provides a convenient way of accessing header values in the current message. When you supply a header name, the header language performs a case-insensitive lookup and returns the corresponding header value.

## Example

Example 6, “Using the header language” shows a route that resequences incoming exchanges according to the value of a `SequenceNumber` header (where the sequence number must be a positive integer).

Example 6. Using the header language

    <camelContext xmlns="http://camel.apache.org/schema/spring">
      <route>
        <from uri="SourceURL"/>
        <resequence>
          <language language="header">SequenceNumber</language>
        </resequence>
        <to uri="TargetURL"/>
      </route>
    </camelContext>