Mention that SampledSpanStore.getRegisteredSpanNamesForCollection is for testing.

This commit fixes the last part of #977.  getRegisteredSpanNamesForCollection
was originally public and annotated with VisibleForTesting because it was meant
for testing code that uses OpenCensus.  However, VisibleForTesting is not ideal
because it adds a dependency on Guava and it does not appear in Javadocs.  This
commit instead describes the purpose of the method in the Javadocs.  It also
removes the temporary PublicForTesting annotation.

2 files changed, 5 insertions, 42 deletions

diff --git a/api/src/main/java/io/opencensus/internal/PublicForTesting.java b/api/src/main/java/io/opencensus/internal/PublicForTesting.java
deleted file mode 100644
index cfd37ff2..00000000
--- a/api/src/main/java/io/opencensus/internal/PublicForTesting.java
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright 2018, OpenCensus Authors
- *
- * 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.
- */
-
-package io.opencensus.internal;
-
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
-
-/**
- * Indicates that an element is public instead of package-private only for the purpose of testing.
- * This annotation is only meant to be used as documentation in the source code.
- */
-// TODO(#977): All uses of this annotation should be removed or replaced with @Internal.
-@Retention(RetentionPolicy.SOURCE)
-@Target({
-  ElementType.ANNOTATION_TYPE,
-  ElementType.CONSTRUCTOR,
-  ElementType.FIELD,
-  ElementType.METHOD,
-  ElementType.PACKAGE,
-  ElementType.TYPE
-})
-public @interface PublicForTesting {}
diff --git a/api/src/main/java/io/opencensus/trace/export/SampledSpanStore.java b/api/src/main/java/io/opencensus/trace/export/SampledSpanStore.java
index 99bc5288..2347061b 100644
--- a/api/src/main/java/io/opencensus/trace/export/SampledSpanStore.java
+++ b/api/src/main/java/io/opencensus/trace/export/SampledSpanStore.java
@@ -17,7 +17,6 @@
 package io.opencensus.trace.export;
 
 import com.google.auto.value.AutoValue;
-import io.opencensus.internal.PublicForTesting;
 import io.opencensus.internal.Utils;
 import io.opencensus.trace.Span;
 import io.opencensus.trace.Status;
@@ -123,13 +122,15 @@ public abstract class SampledSpanStore {
   public abstract void unregisterSpanNamesForCollection(Collection<String> spanNames);
 
   /**
-   * Returns the set of unique span names registered to the library. For this set of span names the
-   * library will collect latency based sampled spans and error based sampled spans.
+   * Returns the set of unique span names registered to the library, for use in tests. For this set
+   * of span names the library will collect latency based sampled spans and error based sampled
+   * spans.
+   *
+   * <p>This method is only meant for testing code that uses OpenCensus, and it is not performant.
    *
    * @return the set of unique span names registered to the library.
    * @since 0.7
    */
-  @PublicForTesting
   public abstract Set<String> getRegisteredSpanNamesForCollection();
 
   /**