Fix a bunch of errorprone warnings. (#1806)

12 files changed, 40 insertions, 71 deletions

diff --git a/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsClientFilterTest.java b/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsClientFilterTest.java
index fa2c1047..eeb4ebc2 100644
--- a/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsClientFilterTest.java
+++ b/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsClientFilterTest.java
@@ -67,7 +67,7 @@ public class JaxrsClientFilterTest {
     filter.filter(requestContext, responseContext);
 
     verify(requestContext).getProperty("opencensus.context");
-    verify(responseContext, times(2)).getStatus();
+    verify(responseContext, times(1)).getStatus();
   }
 
   static HttpRequestContext createHttpRequestContext(Span span, TagContext tagContext)
diff --git a/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsContainerFilterTest.java b/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsContainerFilterTest.java
index e0ee3d94..2c4f748a 100644
--- a/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsContainerFilterTest.java
+++ b/contrib/http_jaxrs/src/test/java/io/opencensus/contrib/http/jaxrs/JaxrsContainerFilterTest.java
@@ -72,6 +72,6 @@ public class JaxrsContainerFilterTest {
     ContainerResponseContext responseContext = mock(ContainerResponseContext.class);
     filter.filter(requestContext, responseContext);
     verify(requestContext).getProperty("opencensus.context");
-    verify(responseContext, times(2)).getStatus();
+    verify(responseContext, times(1)).getStatus();
   }
 }
diff --git a/contrib/http_jetty_client/src/test/java/io/opencensus/contrib/http/jetty/client/HttpRequestListenerTest.java b/contrib/http_jetty_client/src/test/java/io/opencensus/contrib/http/jetty/client/HttpRequestListenerTest.java
index 965efd47..ecb1d0a6 100644
--- a/contrib/http_jetty_client/src/test/java/io/opencensus/contrib/http/jetty/client/HttpRequestListenerTest.java
+++ b/contrib/http_jetty_client/src/test/java/io/opencensus/contrib/http/jetty/client/HttpRequestListenerTest.java
@@ -23,7 +23,6 @@ import static org.mockito.Mockito.when;
 import io.opencensus.contrib.http.HttpClientHandler;
 import io.opencensus.contrib.http.HttpExtractor;
 import io.opencensus.contrib.http.HttpRequestContext;
-import io.opencensus.trace.Span;
 import io.opencensus.trace.Tracing;
 import io.opencensus.trace.propagation.TextFormat.Setter;
 import javax.annotation.Nullable;
@@ -101,22 +100,7 @@ public class HttpRequestListenerTest {
           Tracing.getTracer(),
           extractor,
           Tracing.getPropagationComponent().getTraceContextFormat(),
-          setter) {
-        @Override
-        public HttpRequestContext handleStart(
-            @Nullable Span parent, Object carrier, Object request) {
-          return super.handleStart(parent, carrier, request);
-        }
-
-        @Override
-        public void handleEnd(
-            HttpRequestContext context,
-            @Nullable Object request,
-            @Nullable Object response,
-            @Nullable Throwable error) {
-          super.handleEnd(context, request, response, error);
-        }
-      };
+          setter) {};
   @Mock private HttpClientHandler<Request, Response, Request> mockHandler;
   @Mock private Result mockResult;
 
diff --git a/contrib/http_servlet/src/main/java/io/opencensus/contrib/http/servlet/OcHttpServletUtil.java b/contrib/http_servlet/src/main/java/io/opencensus/contrib/http/servlet/OcHttpServletUtil.java
index 616b9c27..b1247ba3 100644
--- a/contrib/http_servlet/src/main/java/io/opencensus/contrib/http/servlet/OcHttpServletUtil.java
+++ b/contrib/http_servlet/src/main/java/io/opencensus/contrib/http/servlet/OcHttpServletUtil.java
@@ -92,7 +92,7 @@ public class OcHttpServletUtil {
    * @since 0.20.0
    */
   @MustBeClosed
-  public static Scope withScope(ServletRequest request) throws NullPointerException {
+  public static Scope withScope(ServletRequest request) {
     checkNotNull(request, "request");
     OcHttpServletListener listener =
         (OcHttpServletListener) request.getAttribute(OPENCENSUS_SERVLET_LISTENER);
diff --git a/contrib/http_servlet/src/test/java/io/opencensus/contrib/http/servlet/OcHttpServletListenerTest.java b/contrib/http_servlet/src/test/java/io/opencensus/contrib/http/servlet/OcHttpServletListenerTest.java
index d3ce580a..bd751589 100644
--- a/contrib/http_servlet/src/test/java/io/opencensus/contrib/http/servlet/OcHttpServletListenerTest.java
+++ b/contrib/http_servlet/src/test/java/io/opencensus/contrib/http/servlet/OcHttpServletListenerTest.java
@@ -105,21 +105,7 @@ public class OcHttpServletListenerTest {
           extractor,
           Tracing.getPropagationComponent().getTraceContextFormat(),
           getter,
-          true) {
-        @Override
-        public HttpRequestContext handleStart(Object carrier, Object request) {
-          return super.handleStart(carrier, request);
-        }
-
-        @Override
-        public void handleEnd(
-            HttpRequestContext context,
-            Object request,
-            @Nullable Object response,
-            @Nullable Throwable error) {
-          super.handleEnd(context, request, response, error);
-        }
-      };
+          true) {};
   @Mock HttpRequestContext mockContext;
   @Mock HttpServletResponse mockResponse;
   @Mock HttpServletRequest mockRequest;
diff --git a/contrib/http_util/src/main/java/io/opencensus/contrib/http/AbstractHttpHandler.java b/contrib/http_util/src/main/java/io/opencensus/contrib/http/AbstractHttpHandler.java
index 8c500eb6..dc5ad4d1 100644
--- a/contrib/http_util/src/main/java/io/opencensus/contrib/http/AbstractHttpHandler.java
+++ b/contrib/http_util/src/main/java/io/opencensus/contrib/http/AbstractHttpHandler.java
@@ -101,14 +101,13 @@ abstract class AbstractHttpHandler<Q, P> {
     }
   }
 
-  void spanEnd(Span span, @Nullable P response, @Nullable Throwable error) {
-    int statusCode = extractor.getStatusCode(response);
+  void spanEnd(Span span, int httpStatus, @Nullable Throwable error) {
     if (span.getOptions().contains(Options.RECORD_EVENTS)) {
       span.putAttribute(
           HttpTraceAttributeConstants.HTTP_STATUS_CODE,
-          AttributeValue.longAttributeValue(statusCode));
+          AttributeValue.longAttributeValue(httpStatus));
+      span.setStatus(HttpTraceUtil.parseResponseStatus(httpStatus, error));
     }
-    span.setStatus(HttpTraceUtil.parseResponseStatus(statusCode, error));
     span.end();
   }
 
diff --git a/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpClientHandler.java b/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpClientHandler.java
index 0dcdeec8..0d540d30 100644
--- a/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpClientHandler.java
+++ b/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpClientHandler.java
@@ -147,19 +147,15 @@ public class HttpClientHandler<
       @Nullable P response,
       @Nullable Throwable error) {
     checkNotNull(context, "context");
-    recordStats(context, request, response, error);
-    spanEnd(context.span, response, error);
+    int httpCode = extractor.getStatusCode(response);
+    recordStats(context, request, httpCode);
+    spanEnd(context.span, httpCode, error);
   }
 
-  private void recordStats(
-      HttpRequestContext context,
-      @Nullable Q request,
-      @Nullable P response,
-      @Nullable Throwable error) {
+  private void recordStats(HttpRequestContext context, @Nullable Q request, int httpCode) {
     double requestLatency = NANOSECONDS.toMillis(System.nanoTime() - context.requestStartTime);
 
     String methodStr = request == null ? "" : extractor.getMethod(request);
-    int status = extractor.getStatusCode(response);
     TagContext startCtx =
         tagger
             .toBuilder(context.tagContext)
@@ -169,7 +165,7 @@ public class HttpClientHandler<
                 METADATA_NO_PROPAGATION)
             .put(
                 HTTP_CLIENT_STATUS,
-                TagValue.create(status == 0 ? "error" : Integer.toString(status)),
+                TagValue.create(httpCode == 0 ? "error" : Integer.toString(httpCode)),
                 METADATA_NO_PROPAGATION)
             .build();
 
diff --git a/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpServerHandler.java b/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpServerHandler.java
index 46fb1b36..c179eec3 100644
--- a/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpServerHandler.java
+++ b/contrib/http_util/src/main/java/io/opencensus/contrib/http/HttpServerHandler.java
@@ -163,17 +163,16 @@ public class HttpServerHandler<
       HttpRequestContext context, Q request, @Nullable P response, @Nullable Throwable error) {
     checkNotNull(context, "context");
     checkNotNull(request, "request");
-    recordStats(context, request, response, error);
-    spanEnd(context.span, response, error);
+    int httpCode = extractor.getStatusCode(response);
+    recordStats(context, request, httpCode);
+    spanEnd(context.span, httpCode, error);
   }
 
-  private void recordStats(
-      HttpRequestContext context, Q request, @Nullable P response, @Nullable Throwable error) {
+  private void recordStats(HttpRequestContext context, Q request, int httpCode) {
     double requestLatency = NANOSECONDS.toMillis(System.nanoTime() - context.requestStartTime);
 
     String methodStr = extractor.getMethod(request);
     String routeStr = extractor.getRoute(request);
-    int status = extractor.getStatusCode(response);
     TagContext startCtx =
         tagger
             .toBuilder(context.tagContext)
@@ -187,7 +186,7 @@ public class HttpServerHandler<
                 METADATA_NO_PROPAGATION)
             .put(
                 HTTP_SERVER_STATUS,
-                TagValue.create(status == 0 ? "error" : Integer.toString(status)),
+                TagValue.create(httpCode == 0 ? "error" : Integer.toString(httpCode)),
                 METADATA_NO_PROPAGATION)
             .build();
 
diff --git a/contrib/http_util/src/test/java/io/opencensus/contrib/http/AbstractHttpHandlerTest.java b/contrib/http_util/src/test/java/io/opencensus/contrib/http/AbstractHttpHandlerTest.java
index c275eba3..6da9884d 100644
--- a/contrib/http_util/src/test/java/io/opencensus/contrib/http/AbstractHttpHandlerTest.java
+++ b/contrib/http_util/src/test/java/io/opencensus/contrib/http/AbstractHttpHandlerTest.java
@@ -34,6 +34,7 @@ import io.opencensus.trace.Span;
 import io.opencensus.trace.Span.Options;
 import io.opencensus.trace.SpanContext;
 import io.opencensus.trace.SpanId;
+import io.opencensus.trace.Status;
 import io.opencensus.trace.TraceId;
 import io.opencensus.trace.TraceOptions;
 import java.util.EnumSet;
@@ -59,7 +60,6 @@ public class AbstractHttpHandlerTest {
 
   @Rule public final ExpectedException thrown = ExpectedException.none();
   private final Object request = new Object();
-  private final Object response = new Object();
   private final Exception error = new Exception("test");
   private final Random random = new Random();
   private final SpanContext spanContext =
@@ -74,6 +74,7 @@ public class AbstractHttpHandlerTest {
   private AbstractHttpHandler<Object, Object> handler;
   @Captor private ArgumentCaptor<MessageEvent> captor;
   @Captor private ArgumentCaptor<AttributeValue> attributeCaptor;
+  @Captor private ArgumentCaptor<Status> statusCaptor;
   @Captor private ArgumentCaptor<EndSpanOptions> optionsCaptor;
 
   @Spy private FakeSpan fakeSpan = new FakeSpan(spanContext, EnumSet.of(Options.RECORD_EVENTS));
@@ -130,32 +131,39 @@ public class AbstractHttpHandlerTest {
   @Test
   public void handleEndDisallowNullSpan() {
     thrown.expect(NullPointerException.class);
-    handler.spanEnd(null, response, error);
+    handler.spanEnd(null, 0, error);
   }
 
   @Test
-  public void handleEndAllowNullResponseAndError() {
-    handler.spanEnd(fakeSpan, /*response=*/ null, /*error=*/ null);
+  public void handleEndAllowZeroCodeAndNullError() {
+    handler.spanEnd(fakeSpan, 0, null);
+    verify(fakeSpan).setStatus(statusCaptor.capture());
+    assertThat(statusCaptor.getValue()).isEqualTo(Status.UNKNOWN);
+  }
+
+  @Test
+  public void handleEndAllowNonZeroCodeAndNullError() {
+    handler.spanEnd(fakeSpan, 200, null);
+    verify(fakeSpan).setStatus(statusCaptor.capture());
+    assertThat(statusCaptor.getValue()).isEqualTo(Status.OK);
   }
 
   @Test
   public void handleEndShouldEndSpan() {
     when(extractor.getStatusCode(any(Object.class))).thenReturn(0);
 
-    handler.spanEnd(fakeSpan, response, error);
+    handler.spanEnd(fakeSpan, 0, error);
     verify(fakeSpan).end(optionsCaptor.capture());
-    EndSpanOptions options = optionsCaptor.getValue();
-    assertThat(options).isEqualTo(EndSpanOptions.DEFAULT);
+    assertThat(optionsCaptor.getValue()).isEqualTo(EndSpanOptions.DEFAULT);
   }
 
   @Test
   public void handleEndWithRecordEvents() {
     when(extractor.getStatusCode(any(Object.class))).thenReturn(0);
-    handler.spanEnd(fakeSpan, response, error);
+    handler.spanEnd(fakeSpan, 0, error);
     verify(fakeSpan)
         .putAttribute(eq(HttpTraceAttributeConstants.HTTP_STATUS_CODE), attributeCaptor.capture());
-    AttributeValue attribute = attributeCaptor.getValue();
-    assertThat(attribute).isEqualTo(AttributeValue.longAttributeValue(0));
+    assertThat(attributeCaptor.getValue()).isEqualTo(AttributeValue.longAttributeValue(0));
   }
 
   @Test
@@ -166,8 +174,7 @@ public class AbstractHttpHandlerTest {
 
   private void verifyAttributes(String key) {
     verify(span).putAttribute(eq(key), attributeCaptor.capture());
-    AttributeValue attribute = attributeCaptor.getValue();
-    assertThat(attribute.toString()).contains(attributeMap.get(key));
+    assertThat(attributeCaptor.getValue().toString()).contains(attributeMap.get(key));
   }
 
   @Test
diff --git a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/ZPageHttpHandler.java b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/ZPageHttpHandler.java
index c2c46ce8..68812055 100644
--- a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/ZPageHttpHandler.java
+++ b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/ZPageHttpHandler.java
@@ -83,6 +83,6 @@ final class ZPageHttpHandler implements HttpHandler {
         result.put(splits.get(0), "");
       }
     }
-    return result;
+    return Collections.unmodifiableMap(result);
   }
 }
diff --git a/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/RpczZPageHandlerTest.java b/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/RpczZPageHandlerTest.java
index 2a75fe8b..6031f628 100644
--- a/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/RpczZPageHandlerTest.java
+++ b/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/RpczZPageHandlerTest.java
@@ -38,14 +38,13 @@ import java.util.Arrays;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
-import org.mockito.Mock;
 import org.mockito.Mockito;
 
 /** Unit tests for {@link RpczZPageHandler}. */
 @RunWith(JUnit4.class)
 public class RpczZPageHandlerTest {
 
-  @Mock private final ViewManager mockViewManager = Mockito.mock(ViewManager.class);
+  private final ViewManager mockViewManager = Mockito.mock(ViewManager.class);
 
   private static final TagValue METHOD_1 = TagValue.create("method1");
   private static final TagValue METHOD_2 = TagValue.create("method2");
diff --git a/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/StatszZPageHandlerTest.java b/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/StatszZPageHandlerTest.java
index 32fd92f0..50e5f420 100644
--- a/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/StatszZPageHandlerTest.java
+++ b/contrib/zpages/src/test/java/io/opencensus/contrib/zpages/StatszZPageHandlerTest.java
@@ -54,14 +54,13 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
-import org.mockito.Mock;
 import org.mockito.Mockito;
 
 /** Unit tests for {@link StatszZPageHandler}. */
 @RunWith(JUnit4.class)
 public class StatszZPageHandlerTest {
 
-  @Mock private final ViewManager mockViewManager = Mockito.mock(ViewManager.class);
+  private final ViewManager mockViewManager = Mockito.mock(ViewManager.class);
 
   private static final View MY_VIEW =
       View.create(