A postoffice object looks after linkages. It can create and destroy them and keeps records of what ones currently exist. It hands out linkage objects that can be used as handles to later unlink (remove) the linkage.
THIS IS AN AXON INTERNAL! If you are writing components you do not need to understand this.
Developers wishing to understand how Axon is implemented should read on with interest!
Every component has its own postoffice. The component's link() and unlink() methods instruct the post office to create and remove linkages.
When a component terminates, it asks its post office to remove any outstanding linkages.
Creating a link from an inbox to an outbox; a passthrough link from an inbox to another inbox; and a passthrough link from an outbox to another outbox:
po = postoffice() c0 = component() c1 = component() c2 = component() c3 = component() link1 = po.link((c1,"outbox"), (c2,"inbox")) link2 = po.link((c2,"inbox"), (c3,"inbox"), passthrough=1) link3 = po.link((c0,"outbox"), (c1,"outbox"), passthrough=2)
Removing one of the linkages; then all linkages involving component c3; then all the rest:
po.unlink(thelinkage=link3) po.unlink(thecomponent=c3) po.unlinkAll()
A postoffice object keeps creates and destroys objects and keeps a record of which ones currently exist.
The linkage object returned when a linkage is created serves only as a handle. It does not form any operation part of the linkage.
Multiple postoffices can (in fact, will) exist in an Axon system. Each looks after its own collection of linkages. A linkage created at one postoffice will not be known to other postoffice objects.
The post office looks after linkages between postboxes, thereby ensuring deliveries along linkages occur as intended.
There is one post office per component.
A Postoffice can have a debug name - this is to help differentiate between postoffices if problems arise.
Methods defined here
Constructor. If a debug name is assigned this will be stored as a debugname attribute.
Provides a string representation of a postoffice, designed for debugging
Stub for legacy
Returns a true value if the linkage given is registered with the postoffie.
link((component,boxname),(component,boxname),**otherargs) -> new linkage
Creates a linkage from a named box on one component to a named box on another. See linkage class for meanings of other arguments. A linkage object is returned as a handle representing the linkage created.
The linkage is registered with this postoffice.
Throws Axon.AxonExceptions.BoxAlreadyLinkedToDestination if the source is already linked to somewhere else (Axon does not permit one-to-many).
unlink([thecomponent][,thelinkage] -> destroys linkage(s).
Destroys the specified linkage, or linkages for the specified component.
Note, it only destroys linkages registered in this postoffice.
Destroys all linkages made with this postoffice.
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-- Automatic documentation generator, 01 Feb 2010 at 04:00:28 UTC/GMT
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