Add a DMaaP simulator

Added a DMaaP simulator for testing applications.  One current
limitation is that the simulator does not support multiple "subscribers"
on the same topic; if someone gets a message, that message cannot be
subsequently retrieved by anyone else.  The simulator has also not been
tested for concurrent getting and posting.

Also added a way to set the response code DMaaP would return for a get
to test that policy can gracefully handle errors.

It may need some work to become truely its own "feature"

Issue-ID: POLICY-489
Change-Id: I524981bdf5e4e825f13e6197dda11d9498e4f4bf
Signed-off-by: Charles Cole <cc847m@att.com>

1 files changed, 123 insertions, 0 deletions

diff --git a/feature-simulators/src/main/java/org/onap/policy/drools/simulators/DMaaPSimulatorJaxRs.java b/feature-simulators/src/main/java/org/onap/policy/drools/simulators/DMaaPSimulatorJaxRs.java
new file mode 100644
index 00000000..bdabc6ee
--- /dev/null
+++ b/feature-simulators/src/main/java/org/onap/policy/drools/simulators/DMaaPSimulatorJaxRs.java
@@ -0,0 +1,123 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * feature-simulators
+ * ================================================================================
+ * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.drools.simulators;
+
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.BlockingQueue;
+
+import javax.servlet.http.HttpServletResponse;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.DefaultValue;
+import javax.ws.rs.GET;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.MediaType;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Path("/events")
+public class DMaaPSimulatorJaxRs {
+	
+	private static final Map<String, BlockingQueue<String>> queues = new ConcurrentHashMap<>();
+	private static final Logger logger = LoggerFactory.getLogger(DMaaPSimulatorJaxRs.class);
+	private static int responseCode = 200;
+	
+	@GET
+	@Path("/{topicName}/{consumeGroup}/{consumerId}")
+	public String subscribe(@DefaultValue("0") @QueryParam("timeout") int timeout, @PathParam("topicName") String topicName,
+	        @Context final HttpServletResponse httpResponse) {
+	    int currentRespCode = responseCode;
+        httpResponse.setStatus(currentRespCode);
+        try {
+            httpResponse.flushBuffer();
+        } catch (IOException e) {
+            final Logger logger = LoggerFactory.getLogger(DMaaPSimulatorJaxRs.class);
+            logger.error("flushBuffer threw: ", e);
+            return "Got an error";
+        }
+        
+	    if (currentRespCode < 200 || currentRespCode >= 300)
+	    {
+	        return "You got response code: " + currentRespCode;
+	    }
+		if (queues.containsKey(topicName)) {
+			BlockingQueue<String> queue = queues.get(topicName);
+			String response = "No Data";
+			try {
+				response = queue.poll(timeout, TimeUnit.MILLISECONDS);
+			} catch (InterruptedException e) {
+				logger.debug("error in DMaaP simulator", e);
+			}
+			if (response == null) {
+			    response = "No Data";
+			}
+			return response;
+		}
+		else if (timeout > 0) {
+			try {
+				Thread.sleep(timeout);
+				if (queues.containsKey(topicName)) {
+					BlockingQueue<String> queue = queues.get(topicName);
+					String response = queue.poll();
+					if (response == null) {
+					    response = "No Data";
+					}
+					return response;
+				}
+			} catch (InterruptedException e) {
+				logger.debug("error in DMaaP simulator", e);
+			}
+		}
+		return "No topic";
+	}
+	
+	@POST
+	@Path("/{topicName}")
+	@Consumes(MediaType.TEXT_PLAIN)
+	public String publish(@PathParam("topicName") String topicName, String body) { 
+		if (queues.containsKey(topicName)) {
+			BlockingQueue<String> queue = queues.get(topicName);
+			queue.offer(body);
+		}
+		else {
+			BlockingQueue<String> queue = new LinkedBlockingQueue<>();
+			queue.offer(body);
+			queues.put(topicName, queue);
+		}
+		
+		return "";
+	}
+	
+	@POST
+	@Path("/setStatus")
+	public String setStatus(@QueryParam("statusCode") int statusCode) {
+	    responseCode = statusCode;
+	    return "Status code set";
+	}
+}