Optimize and refactor EventPublisher class in VES

* Remove need for having sendEvent synchronized by means of using
  Guava LoadingCache. The only thing that made it synchronized was the
  creation of new entries in the map but the synchronization was made
  on each incoming event.
* Split the class to smaller classes which conform to SRP. This makes us
  able to...
* ... write unit tests for affected classes
* TODO: upgrade to Java8 so lambdas will simplify the code even more

Change-Id: I14cf4cfab0570ce5aecc9a5e5dc9f541c499f9d7
Issue-ID: DCAEGEN2-440
Signed-off-by: Piotr Jaszczyk <piotr.jaszczyk@nokia.com>

1 files changed, 143 insertions, 0 deletions

diff --git a/src/test/java/org/onap/dcae/commonFunction/DmaapPublishersTest.java b/src/test/java/org/onap/dcae/commonFunction/DmaapPublishersTest.java
new file mode 100644
index 00000000..782b7c25
--- /dev/null
+++ b/src/test/java/org/onap/dcae/commonFunction/DmaapPublishersTest.java
@@ -0,0 +1,143 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * org.onap.dcaegen2.collectors.ves
+ * ================================================================================
+ * Copyright (C) 2018 Nokia. 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.dcae.commonFunction;
+
+import static org.hamcrest.CoreMatchers.allOf;
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.junit.Assert.assertSame;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import com.att.nsa.cambria.client.CambriaBatchingPublisher;
+import com.att.nsa.cambria.client.CambriaPublisher;
+import com.google.common.collect.ImmutableList;
+import com.google.common.util.concurrent.UncheckedExecutionException;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.security.GeneralSecurityException;
+import java.util.concurrent.TimeUnit;
+import org.hamcrest.BaseMatcher;
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+
+@RunWith(MockitoJUnitRunner.class)
+public class DmaapPublishersTest {
+
+    @Mock
+    private CambriaPublisherFactory publisherFactory;
+    @Mock
+    private CambriaBatchingPublisher cambriaPublisher;
+    private DmaapPublishers cut;
+    @Rule
+    public ExpectedException expectedException = ExpectedException.none();
+
+    @Before
+    public void setUp() throws MalformedURLException, GeneralSecurityException {
+        given(publisherFactory.createCambriaPublisher(anyString())).willReturn(cambriaPublisher);
+        cut = DmaapPublishers.create(publisherFactory);
+    }
+
+    @Test
+    public void getByStreamIdShouldUseCachedItem() throws IOException, GeneralSecurityException {
+        // given
+        String streamId = "sampleStream";
+
+        // when
+        CambriaBatchingPublisher firstPublisher = cut.getByStreamId(streamId);
+        CambriaBatchingPublisher secondPublisher = cut.getByStreamId(streamId);
+
+        // then
+        verify(publisherFactory, times(1)).createCambriaPublisher(streamId);
+        assertSame("should return same instance", firstPublisher, secondPublisher);
+    }
+
+    @Test
+    public void getByStreamIdShouldHandleErrors() throws MalformedURLException, GeneralSecurityException {
+        // given
+        MalformedURLException exception = new MalformedURLException();
+        given(publisherFactory.createCambriaPublisher(anyString())).willThrow(exception);
+        expectedException.expect(allOf(
+                instanceOf(UncheckedExecutionException.class),
+                causeIsInstanceOf(exception.getClass())));
+
+        // when
+        cut.getByStreamId("a stream");
+
+        // then
+        // exception should have been thrown
+    }
+
+    @Test
+    public void closeByStreamIdShouldCloseConnection() throws IOException, InterruptedException {
+        // given
+        String streamId = "sampleStream";
+        given(cambriaPublisher.close(anyLong(), any(TimeUnit.class)))
+                .willReturn(ImmutableList.of(new CambriaPublisher.message("p", "msg")));
+
+        // when
+        CambriaBatchingPublisher cachedPublisher = cut.getByStreamId(streamId);
+        cut.closeByStreamId(streamId);
+
+        // then
+        assertSame("should return proper publisher", cambriaPublisher, cachedPublisher);
+        verify(cambriaPublisher).close(20, TimeUnit.SECONDS);
+    }
+
+    @Test
+    public void closeByStreamIdShouldHandleErrors() throws IOException, InterruptedException {
+        // given
+        String streamId = "sampleStream";
+        given(cambriaPublisher.close(anyLong(), any(TimeUnit.class))).willThrow(IOException.class);
+
+        // when
+        CambriaBatchingPublisher cachedPublisher = cut.getByStreamId(streamId);
+        cut.closeByStreamId(streamId);
+
+        // then
+        assertSame("should return proper publisher", cambriaPublisher, cachedPublisher);
+        verify(cambriaPublisher).close(20, TimeUnit.SECONDS);
+    }
+
+    private Matcher<Exception> causeIsInstanceOf(final Class<?> clazz) {
+        return new BaseMatcher<Exception>() {
+            @Override
+            public boolean matches(Object o) {
+                return o instanceof Throwable && clazz.isInstance(((Throwable) o).getCause());
+            }
+
+            @Override
+            public void describeTo(Description description) {
+                description.appendText("exception cause should be an instance of " + clazz.getName());
+            }
+        };
+    }
+}
\ No newline at end of file