DATAREST-1193 - DelegatingHandlerMapping is now a MatchableHandlerMapping.

DelegatingHandlerMapping now implements MatchableHandlerMapping by selecting the a delegate based on the already implemented algorithm and then invoking the ….match(…) method in case the selected one is a MatchableHandlerMapping in turn.

Refactored the internals a bit to be able to reuse the selection algorithm from both ….getHandler(…) and ….match(…).

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/support/DelegatingHandlerMappingUnitTests.java

@@ -17,6 +17,7 @@ package org.springframework.data.rest.webmvc.support;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
+import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.Mockito.*;
 
 import java.util.Arrays;
@@ -25,12 +26,15 @@ import javax.servlet.http.HttpServletRequest;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Answers;
 import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.HttpRequestMethodNotSupportedException;
 import org.springframework.web.bind.UnsatisfiedServletRequestParameterException;
 import org.springframework.web.servlet.HandlerMapping;
+import org.springframework.web.servlet.handler.MatchableHandlerMapping;
+import org.springframework.web.servlet.handler.RequestMatchResult;
 
 /**
  * Unit tests for {@link DelegatingHandlerMapping}.
@@ -38,7 +42,7 @@ import org.springframework.web.servlet.HandlerMapping;
  * @author Oliver Gierke
  * @soundtrack Benny Greb - Stabila (Moving Parts)
  */
-@RunWith(MockitoJUnitRunner.class)
+@RunWith(MockitoJUnitRunner.Silent.class)
 public class DelegatingHandlerMappingUnitTests {
 
 	@Mock HandlerMapping first, second;
@@ -54,6 +58,24 @@ public class DelegatingHandlerMappingUnitTests {
 		assertHandlerTriedButExceptionThrown(mapping, UnsatisfiedServletRequestParameterException.class);
 	}
 
+	@Test // DATAREST-1193
+	public void exposesMatchabilityOfSelectedMapping() {
+
+		// Given:
+		// A matching mapping that doesn't get selected
+		MatchableHandlerMapping third = mock(MatchableHandlerMapping.class);
+		doReturn(mock(RequestMatchResult.class)).when(third).match(any(), any());
+
+		// A matching mapping that gets selected
+		RequestMatchResult result = mock(RequestMatchResult.class);
+		MatchableHandlerMapping fourth = mock(MatchableHandlerMapping.class, Answers.RETURNS_MOCKS);
+		doReturn(result).when(fourth).match(any(), any());
+
+		DelegatingHandlerMapping mapping = new DelegatingHandlerMapping(Arrays.asList(first, second, third, fourth));
+
+		assertThat(mapping.match(request, "somePattern")).isEqualTo(result);
+	}
+
 	private final void assertHandlerTriedButExceptionThrown(HandlerMapping mapping, Class<? extends Exception> type)
 			throws Exception {