/*
* Copyright 2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.gradle.api.attributes;
import org.gradle.api.Action;
import org.gradle.api.ActionConfiguration;
import org.gradle.api.Incubating;
import org.gradle.internal.HasInternalProtocol;
import java.util.Comparator;
/**
* <p>A chain of disambiguation rules. By default the chain is empty and will not do any disambiguation.</p>
*
* <p>For a given set of rules, the execution is done <i>in order</i>, and interrupts as soon as a rule
* selected at least one candidate (through {@link MultipleCandidatesDetails#closestMatch(Object)}).
* </p>
*
* <p>If the end of the rule chain is reached and that no rule selected a candidate then the candidate list is returned
* unmodified, meaning we still have an ambiguous match.</p>
*
* @param <T> the concrete type of the attribute
*/
@Incubating
@HasInternalProtocol
public interface DisambiguationRuleChain<T> {
/**
* <p>Adds an arbitrary disambiguation rule to the chain.</p>
* <p>A disambiguation rule can select the best match from a list of candidates.</p>
*
* <p>A rule <i>can</i> express an preference by calling the @{link {@link MultipleCandidatesDetails#closestMatch(Object)}
* method to tell that a candidate is the best one.</p>
*
* <p>It is not mandatory for a rule to choose, and it is not an error to select multiple candidates.</p>
*
* @param rule the rule to add
*/
void add(Class<? extends AttributeDisambiguationRule<T>> rule);
/**
* <p>Adds an arbitrary disambiguation rule to the chain, possibly configuring the rule as well.</p>
*
* @param rule the rule to add
* @param configureAction the action to use to configure the rule
*/
void add(Class<? extends AttributeDisambiguationRule<T>> rule, Action<? super ActionConfiguration> configureAction);
/**
* Adds an ordered disambiguation rule. Values will be compared using the
* provided comparator, and the rule will automatically select the first
* value (if multiple candidates have the same attribute value, there will
* still be an ambiguity).
*
* @param comparator the comparator to use
*/
void pickFirst(Comparator<? super T> comparator);
/**
* Adds an ordered disambiguation rule. Values will be compared using the
* provided comparator, and the rule will automatically select the last
* value (if multiple candidates have the same attribute value, there will
* still be an ambiguity).
*
* @param comparator the comparator to use
*/
void pickLast(Comparator<? super T> comparator);
}