/*
* Copyright 2002-2017 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.web.reactive.function.server;
import java.util.Optional;
import org.springframework.util.Assert;
/**
* Represents a function that evaluates on a given {@link ServerRequest}.
* Instances of this function that evaluate on common request properties can be found in {@link RequestPredicates}.
*
* @author Arjen Poutsma
* @since 5.0
* @see RequestPredicates
* @see RouterFunctions#route(RequestPredicate, HandlerFunction)
* @see RouterFunctions#nest(RequestPredicate, RouterFunction)
*/
@FunctionalInterface
public interface RequestPredicate {
/**
* Evaluate this predicate on the given request.
* @param request the request to match against
* @return {@code true} if the request matches the predicate; {@code false} otherwise
*/
boolean test(ServerRequest request);
/**
* Return a composed request predicate that tests against both this predicate AND
* the {@code other} predicate. When evaluating the composed predicate, if this
* predicate is {@code false}, then the {@code other} predicate is not evaluated.
* @param other a predicate that will be logically-ANDed with this predicate
* @return a predicate composed of this predicate AND the {@code other} predicate
*/
default RequestPredicate and(RequestPredicate other) {
Assert.notNull(other, "'other' must not be null");
return new RequestPredicates.AndRequestPredicate(this, other);
}
/**
* Return a predicate that represents the logical negation of this predicate.
* @return a predicate that represents the logical negation of this predicate
*/
default RequestPredicate negate() {
return (t) -> !test(t);
}
/**
* Return a composed request predicate that tests against both this predicate OR
* the {@code other} predicate. When evaluating the composed predicate, if this
* predicate is {@code true}, then the {@code other} predicate is not evaluated.
* @param other a predicate that will be logically-ORed with this predicate
* @return a predicate composed of this predicate OR the {@code other} predicate
*/
default RequestPredicate or(RequestPredicate other) {
Assert.notNull(other, "'other' must not be null");
return new RequestPredicates.OrRequestPredicate(this, other);
}
/**
* Transform the given request into a request used for a nested route. For instance,
* a path-based predicate can return a {@code ServerRequest} with a the path remaining after a
* match.
* <p>The default implementation returns an {@code Optional} wrapping the given path if
* {@link #test(ServerRequest)} evaluates to {@code true}; or {@link Optional#empty()} if it
* evaluates to {@code false}.
* @param request the request to be nested
* @return the nested request
* @see RouterFunctions#nest(RequestPredicate, RouterFunction)
*/
default Optional<ServerRequest> nest(ServerRequest request) {
return test(request) ? Optional.of(request) : Optional.empty();
}
}