org.springframework.messaging.handler.MessageCondition Maven / Gradle / Ivy
/*
* Copyright 2002-2015 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.springframework.messaging.handler;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
/**
* Contract for mapping conditions to messages.
*
* Message conditions can be combined (e.g. type + method-level conditions),
* matched to a specific Message, as well as compared to each other in the
* context of a Message to determine which one matches a request more closely.
*
* @author Rossen Stoyanchev
* @since 4.0
* @param the kind of condition that this condition can be combined with or compared to
*/
public interface MessageCondition {
/**
* Define the rules for combining this condition with another.
* For example combining type- and method-level conditions.
* @param other the condition to combine with
* @return the resulting message condition
*/
T combine(T other);
/**
* Check if this condition matches the given Message and returns a
* potentially new condition with content tailored to the current message.
* For example a condition with destination patterns might return a new
* condition with sorted, matching patterns only.
* @return a condition instance in case of a match; or {@code null} if there is no match.
*/
@Nullable
T getMatchingCondition(Message message);
/**
* Compare this condition to another in the context of a specific message.
* It is assumed both instances have been obtained via
* {@link #getMatchingCondition(Message)} to ensure they have content
* relevant to current message only.
*/
int compareTo(T other, Message message);
}