A bus destination is a virtual location within a service
integration bus, to which applications attach as producers, consumers,
or both to exchange messages.
This topic provides a brief description of general destination
concepts. For more detailed descriptions of specific types of destinations,
see Learning about bus destinations.
Bus destinations can be either
"permanent" or
"temporary":
- A permanent destination is defined by an administrator for use
by one or more applications over an indeterminate period of time.
Such destinations remain until explicitly deleted by the administrator
or by some administrative command or script.
- A temporary destination is created and deleted by an application,
or the messaging provider, for use by that application during a session
with a service integration bus. The destination is assigned a unique
name.
The following are the main types of destination:
- Queue
- A destination for point-to-point messaging.
- Topic space
- A destination for publish/subscribe messaging.
- Alias
- An alias destination makes a destination available by another name and, optionally, overrides the parameters of the destination. Applications
can use an alias destination to route messages to another destination
in the same bus or in another (foreign) bus.
- Foreign
- A foreign destination provides a mapping to a destination of the
same name on a different bus and enables applications on one bus
to access directly the destination on another bus. You can set its
own destination properties which will override the destination defaults.
You can configure queue, topic space, and alias destinations with
one or more mediations that refine how messages are handled
by the destination.
You can configure queue, topic space, and alias destinations with
routing paths.
- The default forward routing path defines a sequential list of
intermediary destinations that messages must pass through to reach
the target destination, before consumers can retrieve the messages
from that destination. Each intermediary destination applies its mediations
to the messages.
- The reply destination is the next destination to which reply messages
are sent.
Applications use API-specific artifacts like a JMS queue, which
is associated with a queue destination.
The mediations, default forward routing path, and reply destination
are all mechanisms that the administrator can use to modify the flow
of messages through the service integration bus. The administrator
can create and modify these mechanisms without the sending and receiving
applications having to be aware or without any need for the applications
to be modified.