org.grouplens.grapht.solver

Class RuleBasedBindingFunction

java.lang.Object

org.grouplens.grapht.solver.RuleBasedBindingFunction

All Implemented Interfaces:

BindingFunction

public class RuleBasedBindingFunction
extends Object
implements BindingFunction

BindingFunction that uses BindRules created by the fluent API to bind desires to other desires or satisfactions.

For more details on context management, see ContextPattern, ContextElementMatcher, and QualifierMatcher. This function uses the context to activate and select BindRules. A number of rules are used to order applicable BindRules and choose the best. When any of these rules rely on the current dependency context, the deepest node in the context has the most influence. Put another way, if contexts were strings, they could be ordered lexicographically from the right to the left.

When selecting BindRules to apply to a Desire, BindRules are ordered first by context match, then by the ordering defined by the bind rule itself.

A summary of these rules is that the best specified BindRule is applied, where the context that the BindRule is activated in has more priority than the type of the BindRule. If multiple rules tie for best, then the solver fails with a checked exception.

Author:

GroupLens Research

Constructor Summary

Constructors

Constructor and Description
RuleBasedBindingFunction(com.google.common.collect.Multimap<ContextMatcher,BindRule> rules)

Method Summary

Modifier and Type	Method and Description
BindingResult	bind(InjectionContext context, DesireChain desire) Find the applicable binding, if any, for a desire in a particular context.
com.google.common.collect.ListMultimap<ContextMatcher,BindRule>	getRules() Get the rules underlying this binding function.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RuleBasedBindingFunction

public RuleBasedBindingFunction(com.google.common.collect.Multimap<ContextMatcher,BindRule> rules)

Method Detail

getRules

public com.google.common.collect.ListMultimap<ContextMatcher,BindRule> getRules()

Get the rules underlying this binding function.

Returns:

The rules used by this BindingFunction

bind

public BindingResult bind(InjectionContext context,
                          DesireChain desire)
                   throws ResolutionException

Description copied from interface: BindingFunction

Find the applicable binding, if any, for a desire in a particular context.

Specified by:

bind in interface BindingFunction

Parameters:

context - The context.

desire - The desire.

Returns:

The result of binding desire, or null if there is no binding.

Throws:

ResolutionException - If there is an error (such as ambiguous bindings).