Add latch mechanism to pause/resume in inmemory source

modules/siddhi-core/src/main/java/io/siddhi/core/stream/input/source/InMemorySource.java

@@ -33,6 +33,9 @@
 import io.siddhi.core.util.transport.OptionHolder;
 import org.apache.log4j.Logger;
 
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
 /**
  * Implementation of {@link Source} to receive events through in-memory transport.
  */
@@ -62,6 +65,9 @@ public class InMemorySource extends Source {
     private static final String TOPIC_KEY = "topic";
     private SourceEventListener sourceEventListener;
     private InMemoryBroker.Subscriber subscriber;
+    private ReentrantLock pauseLock = new ReentrantLock();
+    private Condition unpaused = pauseLock.newCondition();
+    private volatile boolean paused = false;
 
     @Override
     protected ServiceDeploymentInfo exposeServiceDeploymentInfo() {
@@ -77,6 +83,18 @@ public StateFactory<State> init(SourceEventListener sourceEventListener, OptionH
         this.subscriber = new InMemoryBroker.Subscriber() {
             @Override
             public void onMessage(Object event) {
+                if (paused) {
+                    pauseLock.lock();
+                    try {
+                        while (paused) {
+                            unpaused.await();
+                        }
+                    } catch (InterruptedException ie) {
+                        Thread.currentThread().interrupt();
+                    } finally {
+                        pauseLock.unlock();
+                    }
+                }
                 sourceEventListener.onEvent(event, null);
             }
 
@@ -110,12 +128,17 @@ public void destroy() {
 
     @Override
     public void pause() {
-        InMemoryBroker.unsubscribe(subscriber);
+        paused = true;
     }
 
     @Override
     public void resume() {
-        InMemoryBroker.subscribe(subscriber);
+        paused = false;
+        try {
+            pauseLock.lock();
+            unpaused.signalAll();
+        } finally {
+            pauseLock.unlock();
+        }
     }
-
 }

modules/siddhi-core/src/test/java/io/siddhi/core/query/trigger/TriggerTestCase.java

@@ -194,7 +194,7 @@ public void receive(Event[] events) {
                     count++;
                     if (count > 1) {
                         float triggerTimeDiff = timestamp / 1000 - lastTimeStamp / 1000;
-                        AssertJUnit.assertTrue(1.0f == triggerTimeDiff);
+                        AssertJUnit.assertTrue(1 == Math.round(triggerTimeDiff));
                     }
                     lastTimeStamp = timestamp;
                 }

modules/siddhi-core/src/test/java/io/siddhi/core/transport/InMemoryTransportTestCase.java

@@ -39,6 +39,7 @@
 import java.time.LocalDate;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public class InMemoryTransportTestCase {
@@ -1564,4 +1565,60 @@ public void receive(Event[] events) {
 
     }
 
+    @Test(dependsOnMethods = {"inMemoryTestCase21"})
+    public void inMemoryTestCase22() throws InterruptedException {
+        log.info("Test inMemoryTestCase22");
+        SiddhiManager siddhiManager = new SiddhiManager();
+
+        String publisherApp = "" +
+                "define stream CheckStockStream (symbol1 string, totalPrice double); " +
+                "@sink(type='inMemory', topic='OutputStream', @map(type='passThrough')) " +
+                "define stream OutputStream (symbol1 string, totalPrice double); " +
+                "" +
+                "from CheckStockStream " +
+                "select * " +
+                "insert into OutputStream; ";
+
+        String consumerApp = "" +
+                "@source(type='inMemory', topic='OutputStream', @map(type='passThrough')) " +
+                "define stream InputStream (symbol1 string, totalPrice double); ";
+
+        SiddhiAppRuntime publisherRuntime = siddhiManager.createSiddhiAppRuntime(publisherApp);
+        SiddhiAppRuntime consumerRuntime = siddhiManager.createSiddhiAppRuntime(consumerApp);
+
+        consumerRuntime.addCallback("InputStream", new StreamCallback() {
+            @Override
+            public void receive(Event[] events) {
+                EventPrinter.print(events);
+                wso2Count.incrementAndGet();
+            }
+        });
+        InputHandler stockStream = publisherRuntime.getInputHandler("CheckStockStream");
+
+        publisherRuntime.start();
+        consumerRuntime.start();
+
+        stockStream.send(new Object[]{"WSO2", 50.0f});
+        stockStream.send(new Object[]{"WSO2", 70.0f});
+        Executors.newSingleThreadExecutor().execute(new Runnable() {
+            @Override
+            public void run() {
+                consumerRuntime.getSources().iterator().next().get(0).pause();
+            }
+        });
+        Executors.newSingleThreadExecutor().execute(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    stockStream.send(new Object[]{"WSO2", 90f});
+                } catch (InterruptedException ignored) {
+                }
+            }
+        });
+        Thread.sleep(2000);
+        consumerRuntime.getSources().iterator().next().get(0).resume();
+        Thread.sleep(2000);
+        Assert.assertEquals(wso2Count.get(), 3);
+        siddhiManager.shutdown();
+    }
 }