This commit updates AbstractHeaderMapper in a number of ways:
* The 'userDefinedHeaderPrefix' property has been removed as some
advanced tests revealed that the feature is actually broken right
now and there is no easy way to fix it. A new richer hook point
that indicates if the property comes from the target object or the
standard MessageHeaders has been added.
* A HeaderMatcher interface has been introduced to replace the
lengthy checks in shouldMapHeader. Several implementations
of that interface are provided
* An additional pattern has been added that maps any header that is
*not* a standard header. It uses the standardHeaderPrefix property
for that purpose
* A number of protected method that were only used to create the
instance have been removed in favour of a non default constructor.
Subclasses should provide those *static* values in their own default
constructor.
* The list of transient headers can now be customized. Transient
headers are headers that should never be mapped. The standard
ErrorChannel and ReplyChannel headers have also been removed from
the default transient headers list as they no longer need to be
transient
header-mapper: Polishing
463c185b38