How to use the excludePattern in camel for the remove headers? - apache-camel

Question

I tried to work with the camel's remove header which works for some and does not work for other patterns
It works for the below patterns
<removeHeaders pattern="*" />
<removeHeaders pattern="CamelFile*" />
It does not work for
<removeHeaders pattern="*File*" />
Is the above expected?
Also in the exclude pattern I observe that the wildcard patterns * is not recognised at all.
<setHeader headerName="firstCustomHeader">
<constant>firstCustomHeader</constant>
</setHeader>
<setHeader headerName="secondCustomHeader">
<constant>secondCustomHeader</constant>
</setHeader>
<setHeader headerName="thirdCustomHeader">
<constant>thirdCustomHeader</constant>
</setHeader>
<setHeader headerName="fourthCustomHeader">
<constant>fourthCustomHeader</constant>
</setHeader>
<removeHeaders pattern="*" excludePattern="fourth*|third*" />
the above removes all the header but does excludes the excludePattern value
How do I achieve the relevant above mentioned pattern?
Camel Version 2.13.1

Answer 1

You could accomplish the removeHeaders **File** using the following pattern:
pattern="\w+File\w+"
Similarly, your excludePattern can also be achieved using:
excludePattern="fourth\w+|third\w+"
These are basically regular expressions that can be tested here.

Answer 2

Yes either use a regular expression or use a single * in the end as
wildcard. So *File* is not valid, as it has two *, and therefore Camel assumes its a regular expression.
So you should do a regular expression
pattern=".*File.*"
Where as if you have only one * its a shorthand for matching wildcards, but the * must be only once and at the end of the line, such as
pattern="File*"
The syntax is documented here
http://camel.apache.org/intercept