1 files changed, 60 insertions, 0 deletions
diff --git a/api/src/main/java/io/opencensus/tags/Tag.java b/api/src/main/java/io/opencensus/tags/Tag.java
new file mode 100644
index 00000000..9e0a7a82
--- /dev/null
+++ b/api/src/main/java/io/opencensus/tags/Tag.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2017, 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.tags;
+
+import com.google.auto.value.AutoValue;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * {@link TagKey} paired with a {@link TagValue}.
+ *
+ * @since 0.8
+ */
+@Immutable
+@AutoValue
+public abstract class Tag {
+
+  Tag() {}
+
+  /**
+   * Creates a {@code Tag} from the given key and value.
+   *
+   * @param key the tag key.
+   * @param value the tag value.
+   * @return a {@code Tag} with the given key and value.
+   * @since 0.8
+   */
+  public static Tag create(TagKey key, TagValue value) {
+    return new AutoValue_Tag(key, value);
+  }
+
+  /**
+   * Returns the tag's key.
+   *
+   * @return the tag's key.
+   * @since 0.8
+   */
+  public abstract TagKey getKey();
+
+  /**
+   * Returns the tag's value.
+   *
+   * @return the tag's value.
+   * @since 0.8
+   */
+  public abstract TagValue getValue();
+}