The mediator performs a blocking external service
invocation during mediation. The serviceURL and the optional action
specifies the parameters for this external call. The source element
specifies the payload for the request message using an XPath
expression; or a registry key that will be used. The target element
specifies a node, at which the resulting payload will be attached into
the current message, or the name of a key/property using which the
response would be attached to the current message context as a
property.
As the callout mediator performs a blocking call, it cannot use the
default non-blocking http/s transports based on Java NIO, and thus
defaults to using the samples/axis2Client/client_repo/conf/axis2.xml as
the Axis2 configuration, and samples/axis2Client/client_repo as the
client repository unless these are specified separately
Adding a callout mediator
As shown in figure 1 go to Advanced
and click Callout.
Figure 1: Adding a callout mediator
Configuring Callout options
Figure 2 shows all the Callout specific options that can be tweaked.