org.apache.hivemind.lib.chain
Interface ChainBuilder

All Known Implementing Classes:

ChainBuilderImpl

public interface ChainBuilder

Service interface for hivemind.lib.ChainBuilder, a service which can assemble an implementation based on a command interface, and an ordered list of objects implementing that interface (the "commands"). This is an implementation of the Gang of Four Chain Of Command pattern.

For each method in the interface, the chain implementation will call the corresponding method on each command object in turn. If any of the command objects return true, then the chain of command stops and the initial method invocation returns true. Otherwise, the chain of command continues to the next command (and will return false if none of the commands returns true).

For methods whose return type is not boolean, the chain stops with the first non-null (for object types), or non-zero (for numeric types). The chain returns the value that was returned by the command. The chain If the method return type is void, all command will be invoked.

Method invocations will also be terminated if an exception is thrown.

Since:

1.1

Author:

Howard M. Lewis Ship

Method Summary

java.lang.Object

buildImplementation(java.lang.Class commandInterface, java.util.List commands, java.lang.String toString) Builds an implementation.

Method Detail

buildImplementation

java.lang.Object buildImplementation(java.lang.Class commandInterface,
                                     java.util.List commands,
                                     java.lang.String toString)

Builds an implementation.

Parameters:

commandInterface - the interface the implementation implements.

commands - a non-null list of command objects implementing the interface.

toString - The value to be returned from the implementation's toString() method (unless toString() is expressly part of the service interface, in which case it is treated as any other method.