Package com.yahoo.messagebus.routing

Interface RoutingPolicy

All Known Implementing Classes:
CustomPolicy
public interface RoutingPolicy
Decides how to choose between candidate recipients of a hop template point.

The routing policy will be given an address and a set of recipients matching this address. It is responsible for choosing one of the given recipients each time select(com.yahoo.messagebus.routing.RoutingContext) is called. The routing policy chooses which recipient to return each time at its sole discretion, using information in the RoutingContext argument to choose or not as required to implement the policy.

Example:

  • The given address is a/b/?
  • The given recipients are a/b/c, a/b/d and a/b/e - one of these three must be returned on every call to choose

This class is pluggable per template point in the address of a hop.

Author:
bratseth, Simon Thoresen Hult

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    destroy()
    Destroys this factory and frees up any resources it has held.
    void
    merge(RoutingContext context)
    This function is called when all replies have arrived for some message.
    void
    select(RoutingContext context)
    This function must choose a set of services that is to receive the given message from a list of possible recipients.

  • Method Details

    • select

      void select(RoutingContext context)
      This function must choose a set of services that is to receive the given message from a list of possible recipients. This is done by adding child routing contexts to the argument object. These children can then be iterated and manipulated even before selection pass is concluded.
      Parameters:
      context - the complete context for the invocation of this policy. Contains all available data.

    • merge

      void merge(RoutingContext context)
      This function is called when all replies have arrived for some message. The implementation is responsible for merging multiple replies into a single sensible reply. The replies is contained in the child context objects of the argument context, and then response must be set in that context.
      Parameters:
      context - the complete context for the invocation of this policy. Contains all available data.

    • destroy

      void destroy()
      Destroys this factory and frees up any resources it has held. Making further calls on a destroyed factory causes a runtime exception.