Continue migration to reactive

src/main/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMapping.java

@@ -5,6 +5,8 @@ import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
 import java.util.function.Predicate;
 
 import org.springframework.cloud.gateway.api.RouteLocator;
@@ -25,23 +27,25 @@ import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.G
  */
 public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 
-	private Map<String, RoutePredicate> predicates = new LinkedHashMap<>();
-	private RouteLocator routeLocator;
-	private WebHandler webHandler;
+	private final RouteLocator routeLocator;
+	private final WebHandler webHandler;
+	private final Map<String, RoutePredicate> routePredicates = new LinkedHashMap<>();
+	//TODO: define semeantics for refresh (ie clearing and recalculating combinedPredicates)
+	private final Map<String, Predicate<ServerWebExchange>> combinedPredicates = new ConcurrentHashMap<>();
 
-	public RoutePredicateHandlerMapping(WebHandler webHandler, Map<String, RoutePredicate> predicates,
+	public RoutePredicateHandlerMapping(WebHandler webHandler, Map<String, RoutePredicate> routePredicates,
 										RouteLocator routeLocator) {
 		this.webHandler = webHandler;
 		this.routeLocator = routeLocator;
 
-		predicates.forEach((name, factory) -> {
+		routePredicates.forEach((name, factory) -> {
 			String key = normalizeName(name);
-			if (this.predicates.containsKey(key)) {
+			if (this.routePredicates.containsKey(key)) {
 				this.logger.warn("A RoutePredicate named "+ key
-						+ " already exists, class: " + this.predicates.get(key)
+						+ " already exists, class: " + this.routePredicates.get(key)
 						+ ". It will be overwritten.");
 			}
-			this.predicates.put(key, factory);
+			this.routePredicates.put(key, factory);
 			if (logger.isInfoEnabled()) {
 				logger.info("Loaded RoutePredicate [" + key + "]");
 			}
@@ -58,27 +62,21 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	protected Mono<?> getHandlerInternal(ServerWebExchange exchange) {
 		exchange.getAttributes().put(GATEWAY_HANDLER_MAPPER_ATTR, getClass().getSimpleName());
 
-		Route route;
-		try {
-			route = lookupRoute(exchange);
-		}
-		catch (Exception ex) {
-			return Mono.error(ex);
-		}
-
-		if (route != null) {
-			if (this.logger.isDebugEnabled()) {
-				this.logger.debug("Mapping [" + getExchangeDesc(exchange) + "] to " + route);
+		return lookupRoute(exchange)
+				.log("TRACE")
+				.then((Function<Route, Mono<?>>) r -> {
+					if (logger.isDebugEnabled()) {
+						logger.debug("Mapping [" + getExchangeDesc(exchange) + "] to " + r);
 					}
 
-			exchange.getAttributes().put(GATEWAY_ROUTE_ATTR, route);
-			return Mono.just(this.webHandler);
-		}
-		else if (this.logger.isTraceEnabled()) {
-			this.logger.trace("No Route found for [" + getExchangeDesc(exchange) + "]");
+					exchange.getAttributes().put(GATEWAY_ROUTE_ATTR, r);
+					return Mono.just(webHandler);
+				}).otherwiseIfEmpty(Mono.empty().then(() -> {
+					if (logger.isTraceEnabled()) {
+						logger.trace("No Route found for [" + getExchangeDesc(exchange) + "]");
 					}
-
 					return Mono.empty();
+				}));
 	}
 
 	//TODO: get desc from factory?
@@ -92,28 +90,43 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	}
 
 
-	protected Route lookupRoute(ServerWebExchange exchange) throws Exception {
-		List<Route> routes = this.routeLocator.getRoutes().collectList().block(); //TODO: convert rest of class to Reactive
-
-		for (Route route : routes) {
-			if (!route.getPredicates().isEmpty()) {
+	protected Mono<Route> lookupRoute(ServerWebExchange exchange) {
+		return this.routeLocator.getRoutes()
 				//TODO: cache predicate
-				Predicate<ServerWebExchange> predicate = combinePredicates(route);
-				if (predicate.test(exchange)) {
+				.map(route -> getRouteCombinedPredicates(route))
+				.filter(rcp -> rcp.combinedPredicate.test(exchange))
+				.next()
+				//TODO: error handling
+				.map(rcp -> {
 					if (logger.isDebugEnabled()) {
-						logger.debug("Route matched: " + route.getId());
+						logger.debug("Route matched: " + rcp.route.getId());
 					}
-					validateRoute(route, exchange);
-					return route;
-				} else {
+					validateRoute(rcp.route, exchange);
+					return rcp.route;
+				});
+
+		/* TODO: trace logging
 			if (logger.isTraceEnabled()) {
 				logger.trace("Route did not match: " + route.getId());
+			}*/
 	}
+
+	private RouteCombinedPredicates getRouteCombinedPredicates(Route route) {
+		Predicate<ServerWebExchange> predicate = this.combinedPredicates
+				.computeIfAbsent(route.getId(), k -> combinePredicates(route));
+
+		return new RouteCombinedPredicates(route, predicate);
 	}
+
+	private class RouteCombinedPredicates {
+		private Route route;
+		private Predicate<ServerWebExchange> combinedPredicate;
+
+		public RouteCombinedPredicates(Route route, Predicate<ServerWebExchange> combinedPredicate) {
+			this.route = route;
+			this.combinedPredicate = combinedPredicate;
 		}
 	}
-		return null;
-	}
 
 
 	private Predicate<ServerWebExchange> combinePredicates(Route route) {
@@ -129,7 +142,7 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	}
 
 	private Predicate<ServerWebExchange> lookup(Route route, PredicateDefinition predicate) {
-		RoutePredicate found = this.predicates.get(predicate.getName());
+		RoutePredicate found = this.routePredicates.get(predicate.getName());
 		if (found == null) {
 			throw new IllegalArgumentException("Unable to find RoutePredicate with name " + predicate.getName());
 		}
@@ -155,7 +168,7 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	 * @throws Exception if validation failed
 	 */
 	@SuppressWarnings("UnusedParameters")
-	protected void validateRoute(Route route, ServerWebExchange exchange) throws Exception {
+	protected void validateRoute(Route route, ServerWebExchange exchange) {
 	}
 
 }