Add getResult/hasResult methods to DeferredResult

Issue: SPR-10603

spring-web/src/main/java/org/springframework/web/context/request/async/DeferredResult.java

@@ -107,6 +107,22 @@ public class DeferredResult<T> {
 		return ((this.result != RESULT_NONE) || this.expired);
 	}
 
+	/**
+	 * @return {@code true} if the DeferredResult has been set.
+	 */
+	public boolean hasResult() {
+		return this.result != RESULT_NONE;
+	}
+
+	/**
+	 * @return the result or {@code null} if the result wasn't set; since the result can
+	 *         also be {@code null}, it is recommended to use {@link #hasResult()} first
+	 *         to check if there is a result prior to calling this method.
+	 */
+	public Object getResult() {
+		return hasResult() ? this.result : null;
+	}
+
 	/**
 	 * Return the configured timeout value in milliseconds.
 	 */

spring-web/src/test/java/org/springframework/web/context/request/async/DeferredResultTests.java

@@ -20,7 +20,7 @@ import org.junit.Test;
 import org.springframework.web.context.request.async.DeferredResult.DeferredResultHandler;
 
 import static org.junit.Assert.*;
-import static org.mockito.BDDMockito.*;
+import static org.mockito.Mockito.*;
 
 /**
  * DeferredResult tests.
@@ -69,6 +69,21 @@ public class DeferredResultTests {
 		verify(handler).handleResult("hello");
 	}
 
+	@Test
+	public void hasResult() {
+		DeferredResultHandler handler = mock(DeferredResultHandler.class);
+
+		DeferredResult<String> result = new DeferredResult<String>();
+		result.setResultHandler(handler);
+
+		assertFalse(result.hasResult());
+		assertNull(result.getResult());
+
+		result.setResult("hello");
+
+		assertEquals("hello", result.getResult());
+	}
+
 	@Test
 	public void onCompletion() throws Exception {
 		final StringBuilder sb = new StringBuilder();