Adds http method based predicate helper

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/handler/predicate/RoutePredicates.java

@@ -17,10 +17,11 @@
 
 package org.springframework.cloud.gateway.handler.predicate;
 
-import java.util.function.Predicate;
-
 import org.springframework.web.server.ServerWebExchange;
 
+import java.util.function.Predicate;
+
+import static org.springframework.cloud.gateway.handler.predicate.MethodRoutePredicateFactory.METHOD_KEY;
 import static org.springframework.cloud.gateway.handler.predicate.RoutePredicateFactory.PATTERN_KEY;
 import static org.springframework.tuple.TupleBuilder.tuple;
 
@@ -45,7 +46,9 @@ public class RoutePredicates {
 		return new HostRoutePredicateFactory().apply(tuple().of(PATTERN_KEY, pattern));
 	}
 
-	//TODO: add support for MethodRoutePredicateFactory
+	public static Predicate<ServerWebExchange> method(String method) {
+		return new MethodRoutePredicateFactory().apply(tuple().of(METHOD_KEY, method));
+	}
 
 	public static Predicate<ServerWebExchange> path(String pattern) {
 		return new PathRoutePredicateFactory().apply(tuple().of(PATTERN_KEY, pattern));

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/handler/predicate/RoutePredicatesTest.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 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.cloud.gateway.handler.predicate;
+
+import org.junit.Test;
+import org.springframework.http.HttpMethod;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.cloud.gateway.handler.predicate.RoutePredicates.host;
+import static org.springframework.cloud.gateway.handler.predicate.RoutePredicates.method;
+import static org.springframework.cloud.gateway.handler.predicate.RoutePredicates.path;
+
+/**
+ * @author Biju Kunjummen
+ */
+public class RoutePredicatesTest {
+
+	@Test
+	public void testHostPredicates() {
+		assertThat(host("**").test(mockHostExchange("test.abc.com"))).isTrue();
+		assertThat(host("**.abc.**").test(mockHostExchange("test.abc.com"))).isTrue();
+		assertThat(host("**.co?").test(mockHostExchange("test.abc.com"))).isTrue();
+		assertThat(host("**.co").test(mockHostExchange("test.abc.com"))).isFalse();
+
+	}
+
+	@Test
+	public void testPathPredicates() {
+		assertThat(path("/**").test(mockPathExchange("/path1/path2"))).isTrue();
+		assertThat(path("/path1/*").test(mockPathExchange("/path1/path2"))).isTrue();
+		assertThat(path("/path1/path?").test(mockPathExchange("/path1/path2"))).isTrue();
+	}
+
+	@Test
+	public void testMethodPredicates() {
+		assertThat(method("GET").test(mockMethodExchange("GET"))).isTrue();
+		assertThat(method("POST").test(mockMethodExchange("POST"))).isTrue();
+		assertThat(method("PUT").test(mockMethodExchange("PUT"))).isTrue();
+	}
+
+	private ServerWebExchange mockHostExchange(String host) {
+		MockServerHttpRequest mockRequest = MockServerHttpRequest.get("/")
+				.header("Host", host).build();
+		return mockRequest.toExchange();
+	}
+
+	private ServerWebExchange mockPathExchange(String path) {
+		MockServerHttpRequest mockRequest = MockServerHttpRequest.get(path).build();
+		return mockRequest.toExchange();
+	}
+
+	private ServerWebExchange mockMethodExchange(String method) {
+		MockServerHttpRequest mockRequest = MockServerHttpRequest
+				.method(HttpMethod.resolve(method), "/").build();
+		return mockRequest.toExchange();
+	}
+}