In Axis2 there are three kinds of configuration files to configure the system. First one configuration file is to configure whole system, second one is to configure a service and the third one is to configure a module.
All the configuration that requires starting axis2 is obtained from axis2.xml. The way of specifying them is very simple and easy. The document is all about the proper way of specifying the configurations in axis2.xml. There are six top level elements that can be seen in the configuration file and those can be listed as follows;
Parameter
In axis2 a parameter is nothing but name value pair, each and every top level
parameter available in the axis2.xml (direct sub elements of root element)
will be transformed into properties in AxisConfiguration. Therefore the top
level parameters in configuration document can be accessed via
AxisConfiguration in the running system. The correct way of defining a
parameter looks like what is shown below;
Transport Receiver
Depending on the underline transport that axis going to be run , need to have
different transport receivers so the way of adding them to the system can be
done as follows;
The above elements shows the way of defining transport receivers in axis2.xml , here name attribute of the 'transportReceiver' element is the name of transport it can be http, tcp , smtp , commonshttp stc , and when the system starts up or when setting transport at the client side one can use these transport names to load the appropriate transport. Class attribute is to specify actual java class which implements required interfaces for the transport. Any transport can have zero or more parameters, and if there are any, then those parameters can be accessed via the corresponding transport receiver.
Transport Senders
As same as transport receivers it is possible to register transport senders
in the system, and latter at the run time those senders can be used to send
the messages. As an example consider Axis2 running under tomcat, then axis
can use TCP transport senders to send message rather than HTTP. The way of
specifying transport senders is as follows:
name: Name of the transport (it is possible to have http and http1 as transport name) Class: Implementation class of the corresponding transport. As same as transport receivers, transport senders can have zero or more parameters, and if there is any then it can be accessed via corresponding transport sender.
Phase Order
The specifying order of phases in execution chain has to be done using phase
order element and it will be look like below;
The most interesting thing is that you can add handlers here as well , if you want to add a handler which should go in to that phase you can directly do that by adding a handler element into it . In addition to that there is no any hard coding stuffs for handler chain in anywhere in Axis2 (at any Axis*) , so all those configuration are also done here in phase order element. The complete configuration will look like as follows; type: the attribute represent type of the flow and which can only be one of the following
In addition to that only child element allowed inside pahseOrder is phase element, which represents available phases in the execution chain. The way of specifying phase inside phaseOrder has to be done as follows;
name: Name of the phase.
There are number of things that one has to keep in mind when changing
pahseOrder,
Module References
If you want to engage a module system wide you can do it by adding top level
module element in axis2.xml. It should be look like following:
ref: the module name which is going to be engage, system wide. Listeners (Observers) In Axis2 AxisConfiguration is observable so that one can register observers into that, and they will be automatically informed whenever a change occurs in AxisConfiuration. In the current implementation the observers are informed of the following events
The description of service is specified using services.xml, each
service archive file need to have services.xml in order to be a valid
service. And which has to be available in META-INF directory of the archive
file.
A very simple services.xml is shown below:
Parameter:
services.xml can have any number of top level parameters and all the
specified parameters will be transformed into service properties in
corresponding ServiceDescrption. There is a compulsory parameter in a
services.xml called ServiceClass which specify the java class which really
does the job and the class will be loaded by MessageReceiver.
Handler
Handler element consists of compulsory and optional attribute and the way of
defining a handler will be look like follows;
Compulsory attributes
name: name of the handler
nlass: handler implementation class
phase: name of the phase that the handler should stay in the execution chain
Optional attributes :
phaseLast: to indicate the handler is last handler of the phase
phaseFirst: to indicate the handler is first handler of the phase.
before : the handler should be invoked before the handler specified by before
handler
after: the handler should be invoked after the handler specified by after
handler
Operations
All the operations you are going to exposeby the service has to be indicated
in the services.xml and the correct way of specifying that should be as
follows:
Only compulsory attribute here is name, which represent the operation name
that is going to be exposed. Any operation can contains module references,
any number of parameters. The most interesting is that one can register
custom message receiver per operation, then the registered message receiver
will be the message receiver for the corresponding operation. If one does not
specify the message receiver then the default message receiver will do the
job.
The description of module is specified using module.xml, each module
archive file need to have module.xml in order to be a valid module. And which
has to be available in META-INF directory of the archive file.
A very simple module.xml is shown below:
name: This is a compulsory attribute and which indicates the name of the
module
class: This is an optional attribute which indicate module implementation
class, a module may or may not contain module implementation class since the
module can also be a collection of handlers. If a module contains an
implementation class which implements the org.apache.axis2.modules.Module
inteface where at the deployment time its init(); method will be called.
parameter: Module can contains any number of parameters and all the listed parameters in the module.xml will be transformed into corresponding ModuleDescription of the module.
Flow :
It is possible to add handlers into a flow directly form services.xml rather
than engaging a modules and the way of doing that is through flow elements.
It is possible to add any number of handlers into a flow and those handlers
will be available in corresponding operations flows in the service (inflow
consist of two parts, one part is up to post dispatch phase and other part is
consisting of operation handlers)
There are four types of valid flows that can be available in services.xml,
and the adding the handles into them can be done by following the above
procedure.
Valid flows:
operations If a module wants to add an operation when it is engaged into a service it can be done by adding operation tag in module.xml and the way of specifying the operation is same as operation in services.xml.