Merge pull request #30028 from yuzawa-san:request-predicate-commit

* gh-30028:
  Polishing external contribution
  Improve attribute handling in RequestPredicates

Author: poutsma

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RequestPredicates.java

@@ -21,7 +21,6 @@
 import java.security.Principal;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
@@ -296,11 +295,6 @@ private static void traceMatch(String prefix, Object desired, @Nullable Object a
 		}
 	}
 
-	private static void restoreAttributes(ServerRequest request, Map<String, Object> attributes) {
-		request.attributes().clear();
-		request.attributes().putAll(attributes);
-	}
-
 	private static Map<String, String> mergePathVariables(Map<String, String> oldVariables,
 			Map<String, String> newVariables) {
 
@@ -432,13 +426,94 @@ public interface Visitor {
 	}
 
 
+	/**
+	 * Extension of {@code RequestPredicate} that can modify the {@code ServerRequest}.
+	 */
+	static abstract class RequestModifyingPredicate implements RequestPredicate {
+
+
+		public static RequestModifyingPredicate of(RequestPredicate requestPredicate) {
+			if (requestPredicate instanceof RequestModifyingPredicate modifyingPredicate) {
+				return modifyingPredicate;
+			}
+			else {
+				return new RequestModifyingPredicate() {
+					@Override
+					protected Result testInternal(ServerRequest request) {
+						return Result.of(requestPredicate.test(request));
+					}
+				};
+			}
+		}
+
+
+		@Override
+		public final boolean test(ServerRequest request) {
+			Result result = testInternal(request);
+			boolean value = result.value();
+			if (value) {
+				result.modify(request);
+			}
+			return value;
+		}
+
+		protected abstract Result testInternal(ServerRequest request);
+
+
+		protected static final class Result {
+
+			private static final Result TRUE = new Result(true, null);
+
+			private static final Result FALSE = new Result(false, null);
+
+
+			private final boolean value;
+
+			@Nullable
+			private final Consumer<ServerRequest> modify;
+
+
+			private Result(boolean value, @Nullable Consumer<ServerRequest> modify) {
+				this.value = value;
+				this.modify = modify;
+			}
+
+
+			public static Result of(boolean value) {
+				return of(value, null);
+			}
+
+			public static Result of(boolean value, @Nullable Consumer<ServerRequest> commit) {
+				if (commit == null) {
+					return value ? TRUE : FALSE;
+				}
+				else {
+					return new Result(value, commit);
+				}
+			}
+
+
+			public boolean value() {
+				return this.value;
+			}
+
+			public void modify(ServerRequest request) {
+				if (this.modify != null) {
+					this.modify.accept(request);
+				}
+			}
+		}
+
+	}
+
+
 	private static class HttpMethodPredicate implements RequestPredicate {
 
 		private final Set<HttpMethod> httpMethods;
 
 		public HttpMethodPredicate(HttpMethod httpMethod) {
 			Assert.notNull(httpMethod, "HttpMethod must not be null");
-			this.httpMethods = Collections.singleton(httpMethod);
+			this.httpMethods = Set.of(httpMethod);
 		}
 
 		public HttpMethodPredicate(HttpMethod... httpMethods) {
@@ -482,39 +557,41 @@ public String toString() {
 	}
 
 
-	private static class PathPatternPredicate implements RequestPredicate, ChangePathPatternParserVisitor.Target {
+	private static class PathPatternPredicate extends RequestModifyingPredicate
+			implements ChangePathPatternParserVisitor.Target {
 
 		private PathPattern pattern;
 
+
 		public PathPatternPredicate(PathPattern pattern) {
 			Assert.notNull(pattern, "'pattern' must not be null");
 			this.pattern = pattern;
 		}
 
+
 		@Override
-		public boolean test(ServerRequest request) {
+		protected Result testInternal(ServerRequest request) {
 			PathContainer pathContainer = request.requestPath().pathWithinApplication();
 			PathPattern.PathMatchInfo info = this.pattern.matchAndExtract(pathContainer);
 			traceMatch("Pattern", this.pattern.getPatternString(), request.path(), info != null);
 			if (info != null) {
-				mergeAttributes(request, info.getUriVariables(), this.pattern);
-				return true;
+				return Result.of(true, serverRequest -> mergeAttributes(serverRequest, info.getUriVariables()));
 			}
 			else {
-				return false;
+				return Result.of(false);
 			}
 		}
 
-		private static void mergeAttributes(ServerRequest request, Map<String, String> variables,
-				PathPattern pattern) {
+		private void mergeAttributes(ServerRequest request, Map<String, String> variables) {
+			Map<String, Object> attributes = request.attributes();
 			Map<String, String> pathVariables = mergePathVariables(request.pathVariables(), variables);
-			request.attributes().put(RouterFunctions.URI_TEMPLATE_VARIABLES_ATTRIBUTE,
-						Collections.unmodifiableMap(pathVariables));
+			attributes.put(RouterFunctions.URI_TEMPLATE_VARIABLES_ATTRIBUTE,
+					Collections.unmodifiableMap(pathVariables));
 
-			pattern = mergePatterns(
-					(PathPattern) request.attributes().get(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE),
-					pattern);
-			request.attributes().put(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE, pattern);
+			PathPattern pattern = mergePatterns(
+					(PathPattern) attributes.get(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE),
+					this.pattern);
+			attributes.put(RouterFunctions.MATCHING_PATTERN_ATTRIBUTE, pattern);
 		}
 
 		@Override
@@ -756,28 +833,42 @@ public String toString() {
 	 * {@link RequestPredicate} for where both {@code left} and {@code right} predicates
 	 * must match.
 	 */
-	static class AndRequestPredicate implements RequestPredicate, ChangePathPatternParserVisitor.Target {
+	static class AndRequestPredicate extends RequestModifyingPredicate
+			implements ChangePathPatternParserVisitor.Target {
 
 		private final RequestPredicate left;
 
+		private final RequestModifyingPredicate leftModifying;
+
 		private final RequestPredicate right;
 
+		private final RequestModifyingPredicate rightModifying;
+
+
 		public AndRequestPredicate(RequestPredicate left, RequestPredicate right) {
 			Assert.notNull(left, "Left RequestPredicate must not be null");
 			Assert.notNull(right, "Right RequestPredicate must not be null");
 			this.left = left;
+			this.leftModifying = of(left);
 			this.right = right;
+			this.rightModifying = of(right);
 		}
 
-		@Override
-		public boolean test(ServerRequest request) {
-			Map<String, Object> oldAttributes = new HashMap<>(request.attributes());
 
-			if (this.left.test(request) && this.right.test(request)) {
-				return true;
+		@Override
+		protected Result testInternal(ServerRequest request) {
+			Result leftResult = this.leftModifying.testInternal(request);
+			if (!leftResult.value()) {
+				return leftResult;
+			}
+			Result rightResult = this.rightModifying.testInternal(request);
+			if (!rightResult.value()) {
+				return rightResult;
 			}
-			restoreAttributes(request, oldAttributes);
-			return false;
+			return Result.of(true, serverRequest -> {
+				leftResult.modify(serverRequest);
+				rightResult.modify(serverRequest);
+			});
 		}
 
 		@Override
@@ -796,11 +887,11 @@ public void accept(Visitor visitor) {
 
 		@Override
 		public void changeParser(PathPatternParser parser) {
-			if (this.left instanceof ChangePathPatternParserVisitor.Target leftTarget) {
-				leftTarget.changeParser(parser);
+			if (this.left instanceof ChangePathPatternParserVisitor.Target target) {
+				target.changeParser(parser);
 			}
-			if (this.right instanceof ChangePathPatternParserVisitor.Target rightTarget) {
-				rightTarget.changeParser(parser);
+			if (this.right instanceof ChangePathPatternParserVisitor.Target target) {
+				target.changeParser(parser);
 			}
 		}
 
@@ -814,23 +905,25 @@ public String toString() {
 	/**
 	 * {@link RequestPredicate} that negates a delegate predicate.
 	 */
-	static class NegateRequestPredicate implements RequestPredicate, ChangePathPatternParserVisitor.Target {
+	static class NegateRequestPredicate extends RequestModifyingPredicate
+			implements ChangePathPatternParserVisitor.Target {
 
 		private final RequestPredicate delegate;
 
+		private final RequestModifyingPredicate delegateModifying;
+
+
 		public NegateRequestPredicate(RequestPredicate delegate) {
 			Assert.notNull(delegate, "Delegate must not be null");
 			this.delegate = delegate;
+			this.delegateModifying = of(delegate);
 		}
 
+
 		@Override
-		public boolean test(ServerRequest request) {
-			Map<String, Object> oldAttributes = new HashMap<>(request.attributes());
-			boolean result = !this.delegate.test(request);
-			if (!result) {
-				restoreAttributes(request, oldAttributes);
-			}
-			return result;
+		protected Result testInternal(ServerRequest request) {
+			Result result = this.delegateModifying.testInternal(request);
+			return Result.of(!result.value(), result::modify);
 		}
 
 		@Override
@@ -858,34 +951,36 @@ public String toString() {
 	 * {@link RequestPredicate} where either {@code left} or {@code right} predicates
 	 * may match.
 	 */
-	static class OrRequestPredicate implements RequestPredicate, ChangePathPatternParserVisitor.Target {
+	static class OrRequestPredicate extends RequestModifyingPredicate
+			implements ChangePathPatternParserVisitor.Target {
 
 		private final RequestPredicate left;
 
+		private final RequestModifyingPredicate leftModifying;
+
 		private final RequestPredicate right;
 
+		private final RequestModifyingPredicate rightModifying;
+
+
 		public OrRequestPredicate(RequestPredicate left, RequestPredicate right) {
 			Assert.notNull(left, "Left RequestPredicate must not be null");
 			Assert.notNull(right, "Right RequestPredicate must not be null");
 			this.left = left;
+			this.leftModifying = of(left);
 			this.right = right;
+			this.rightModifying = of(right);
 		}
 
 		@Override
-		public boolean test(ServerRequest request) {
-			Map<String, Object> oldAttributes = new HashMap<>(request.attributes());
-
-			if (this.left.test(request)) {
-				return true;
+		protected Result testInternal(ServerRequest request) {
+			Result leftResult = this.leftModifying.testInternal(request);
+			if (leftResult.value()) {
+				return leftResult;
 			}
 			else {
-				restoreAttributes(request, oldAttributes);
-				if (this.right.test(request)) {
-					return true;
-				}
+				return this.rightModifying.testInternal(request);
 			}
-			restoreAttributes(request, oldAttributes);
-			return false;
 		}
 
 		@Override
@@ -910,11 +1005,11 @@ public void accept(Visitor visitor) {
 
 		@Override
 		public void changeParser(PathPatternParser parser) {
-			if (this.left instanceof ChangePathPatternParserVisitor.Target leftTarget) {
-				leftTarget.changeParser(parser);
+			if (this.left instanceof ChangePathPatternParserVisitor.Target target) {
+				target.changeParser(parser);
 			}
-			if (this.right instanceof ChangePathPatternParserVisitor.Target rightTarget) {
-				rightTarget.changeParser(parser);
+			if (this.right instanceof ChangePathPatternParserVisitor.Target target) {
+				target.changeParser(parser);
 			}
 		}
 

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/RequestPredicateAttributesTests.java

@@ -182,24 +182,25 @@ public void orBothFail() {
 	}
 
 
-	private static class AddAttributePredicate implements RequestPredicate {
+	private static class AddAttributePredicate extends RequestPredicates.RequestModifyingPredicate {
 
-		private boolean result;
+		private final boolean result;
 
 		private final String key;
 
 		private final String value;
 
-		private AddAttributePredicate(boolean result, String key, String value) {
+
+		public AddAttributePredicate(boolean result, String key, String value) {
 			this.result = result;
 			this.key = key;
 			this.value = value;
 		}
 
+
 		@Override
-		public boolean test(ServerRequest request) {
-			request.attributes().put(key, value);
-			return this.result;
+		protected Result testInternal(ServerRequest request) {
+			return Result.of(this.result, serverRequest -> serverRequest.attributes().put(this.key, this.value));
 		}
 	}