Merge pull request #4204 from khatwaniNikhil/BAEL-1657

Bael 1657

spring-rest/src/main/java/com/baeldung/controllers/DeferredResultController.java

@@ -0,0 +1,76 @@
+package com.baeldung.controllers;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.context.request.async.DeferredResult;
+
+import java.util.concurrent.ForkJoinPool;
+
+@RestController
+public class DeferredResultController {
+
+	private final static Logger LOG = LoggerFactory.getLogger(DeferredResultController.class);
+
+	@GetMapping("/async-deferredresult")
+	public DeferredResult<ResponseEntity<?>> handleReqDefResult(Model model) {
+	    LOG.info("Received async-deferredresult request");
+	    DeferredResult<ResponseEntity<?>> output = new DeferredResult<>();
+	    ForkJoinPool.commonPool().submit(() -> {
+	        LOG.info("Processing in separate thread");
+	        try {
+			    Thread.sleep(6000);
+	        } catch (InterruptedException e) {
+	        }
+	        output.setResult(ResponseEntity.ok("ok"));
+	    });
+	    LOG.info("servlet thread freed");
+	    return output;
+	}
+
+	public DeferredResult<ResponseEntity<?>> handleReqWithTimeouts(Model model) {
+		LOG.info("Received async request with a configured timeout");
+		DeferredResult<ResponseEntity<?>> deferredResult = new DeferredResult<>(500l);
+		deferredResult.onTimeout(new Runnable() {
+			@Override
+			public void run() {
+				deferredResult.setErrorResult(
+						ResponseEntity.status(HttpStatus.REQUEST_TIMEOUT).body("Request timeout occurred."));
+			}
+		});
+		ForkJoinPool.commonPool().submit(() -> {
+			LOG.info("Processing in separate thread");
+			try {
+				Thread.sleep(600l);
+				deferredResult.setResult(ResponseEntity.ok("ok"));
+			} catch (InterruptedException e) {
+				LOG.info("Request processing interrupted");
+				deferredResult.setErrorResult(ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
+						.body("INTERNAL_SERVER_ERROR occurred."));
+			}
+
+		});
+		LOG.info("servlet thread freed");
+		return deferredResult;
+	}
+
+	public DeferredResult<ResponseEntity<?>> handleAsyncFailedRequest(Model model) {
+		DeferredResult<ResponseEntity<?>> deferredResult = new DeferredResult<>();
+		ForkJoinPool.commonPool().submit(() -> {
+			try {
+				// Exception occurred in processing
+				throw new Exception();
+			} catch (Exception e) {
+				LOG.info("Request processing failed");
+				deferredResult.setErrorResult(ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
+						.body("INTERNAL_SERVER_ERROR occurred."));
+			}
+		});
+		return deferredResult;
+	}
+
+}