Extract a value from a property in camel-context.xml - xpath

Question

The input looks like below,
<book author="ABC" type="Children">
<id>123</id>
<name>XYZ</name>
</book>
I have set the above in property in an xml route as:
<camel:setProperty propertyName="REQUEST">
<camel:xpath>/node()</camel:xpath>
</camel:setProperty>
Then I do some other processing and based on the new response I want to extract the value of an author(i.e. ABC) from this Property and compare it with a element's text string from the response.
I tried a few ways using camel:xpath and camel:simple but am not able to extract the value from property.
What is the correct way to extract this property?

Answer 1

To access the REQUEST property using simple you can do this:
${property.REQUEST}
To access properties using xpath:
<camel:xpath>
function:properties("REQUEST")/[add your xpath expression here]
</camel:xpath>
More info on the properties function can be found here - https://camel.apache.org/xpath.html

Answer 2

I don't know if it's possible using properties, but you should be able to do it with headers.
Firstly:
<setHeader headerName="REQUEST">
<xpath>/node()</xpath>
</setHeader>
Then if you wanted to set another header with just the author value:
<setHeader headerName="REQUEST2">
<xpath headerName="REQUEST" resultType="java.lang.String">/book/#author</xpath>
</setHeader>
Or if you wanted to evaluate the value as a <choice> condition:
<when>
<xpath headerName="REQUEST">/book/#author = 'ABC'</xpath>