Add Scope as interface for NonThrowingCloseables that work with current context.

This interface allows users to write a shorter, more descriptive type name when
using scoped tags or spans.

3 files changed, 10 insertions, 11 deletions

diff --git a/core/src/main/java/io/opencensus/stats/CurrentTagsUtils.java b/core/src/main/java/io/opencensus/stats/CurrentTagsUtils.java
index e22f372b..96022561 100644
--- a/core/src/main/java/io/opencensus/stats/CurrentTagsUtils.java
+++ b/core/src/main/java/io/opencensus/stats/CurrentTagsUtils.java
@@ -14,8 +14,7 @@
 package io.opencensus.stats;
 
 import io.grpc.Context;
-
-import io.opencensus.common.NonThrowingCloseable;
+import io.opencensus.common.Scope;
 import io.opencensus.tags.unsafe.ContextUtils;
 
 /**
@@ -48,12 +47,12 @@ final class CurrentTagsUtils {
    * @return An object that defines a scope where the given {@code StatsContext} is set to the
    *     current context.
    */
-  static NonThrowingCloseable withStatsContext(StatsContext statsContext) {
+  static Scope withStatsContext(StatsContext statsContext) {
     return new WithStatsContext(statsContext, ContextUtils.TAG_CONTEXT_KEY);
   }
 
   // Supports try-with-resources idiom.
-  private static final class WithStatsContext implements NonThrowingCloseable {
+  private static final class WithStatsContext implements Scope {
 
     private final Context origContext;
 
diff --git a/core/src/main/java/io/opencensus/stats/StatsContextFactory.java b/core/src/main/java/io/opencensus/stats/StatsContextFactory.java
index cee9f253..833d6d3d 100644
--- a/core/src/main/java/io/opencensus/stats/StatsContextFactory.java
+++ b/core/src/main/java/io/opencensus/stats/StatsContextFactory.java
@@ -15,7 +15,7 @@ package io.opencensus.stats;
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import io.opencensus.common.NonThrowingCloseable;
+import io.opencensus.common.Scope;
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -67,7 +67,7 @@ public abstract class StatsContextFactory {
    * void doWork() {
    *   // Construct a new StatsContext with required tags to be set into current context.
    *   StatsContext statsCtx = statsCtxFactory.getCurrentStatsContext().with(tagKey, tagValue);
-   *   try (NonThrowingCloseable scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx)) {
+   *   try (Scope scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx)) {
    *     doSomeOtherWork();  // Here "scopedStatsCtx" is the current StatsContext.
    *   }
    * }
@@ -84,7 +84,7 @@ public abstract class StatsContextFactory {
    * void doWork() {
    *   // Construct a new StatsContext with required tags to be set into current context.
    *   StatsContext statsCtx = statsCtxFactory.getCurrentStatsContext().with(tagKey, tagValue);
-   *   NonThrowingCloseable scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx);
+   *   Scope scopedStatsCtx = statsCtxFactory.withStatsContext(statsCtx);
    *   try {
    *     doSomeOtherWork();  // Here "scopedStatsCtx" is the current StatsContext.
    *   } finally {
@@ -98,7 +98,7 @@ public abstract class StatsContextFactory {
    *     current Context.
    * @throws NullPointerException if statsContext is null.
    */
-  public final NonThrowingCloseable withStatsContext(StatsContext statsContext) {
+  public final Scope withStatsContext(StatsContext statsContext) {
     return CurrentTagsUtils.withStatsContext(checkNotNull(statsContext, "statsContext"));
   }
 }
diff --git a/core/src/test/java/io/opencensus/stats/CurrentTagsUtilsTest.java b/core/src/test/java/io/opencensus/stats/CurrentTagsUtilsTest.java
index 46e5675b..0e3060d9 100644
--- a/core/src/test/java/io/opencensus/stats/CurrentTagsUtilsTest.java
+++ b/core/src/test/java/io/opencensus/stats/CurrentTagsUtilsTest.java
@@ -16,7 +16,7 @@ package io.opencensus.stats;
 import static com.google.common.truth.Truth.assertThat;
 
 import io.grpc.Context;
-import io.opencensus.common.NonThrowingCloseable;
+import io.opencensus.common.Scope;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -46,7 +46,7 @@ public class CurrentTagsUtilsTest {
   @Test
   public void testWithStatsContext() {
     assertThat(CurrentTagsUtils.getCurrentStatsContext()).isNull();
-    NonThrowingCloseable scopedStatsCtx = CurrentTagsUtils.withStatsContext(statsContext);
+    Scope scopedStatsCtx = CurrentTagsUtils.withStatsContext(statsContext);
     try {
       assertThat(CurrentTagsUtils.getCurrentStatsContext()).isSameAs(statsContext);
     } finally {
@@ -58,7 +58,7 @@ public class CurrentTagsUtilsTest {
   @Test
   public void testWithStatsContextUsingWrap() {
     Runnable runnable;
-    NonThrowingCloseable scopedStatsCtx = CurrentTagsUtils.withStatsContext(statsContext);
+    Scope scopedStatsCtx = CurrentTagsUtils.withStatsContext(statsContext);
     try {
       assertThat(CurrentTagsUtils.getCurrentStatsContext()).isSameAs(statsContext);
       runnable = Context.current().wrap(