Merge remote-tracking branch 'aosp/upstream-master' into merge am: dd3cabeacc

am: 6fbc3cf5a1

Change-Id: I11b0ec1cf561d2a14da78e444b1594f167787fe6

1 files changed, 51 insertions, 0 deletions

diff --git a/impl_core/src/main/java/io/opencensus/implcore/internal/TimestampConverter.java b/impl_core/src/main/java/io/opencensus/implcore/internal/TimestampConverter.java
new file mode 100644
index 00000000..c70f5860
--- /dev/null
+++ b/impl_core/src/main/java/io/opencensus/implcore/internal/TimestampConverter.java
@@ -0,0 +1,51 @@
+/*
+ * 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.implcore.internal;
+
+import io.opencensus.common.Clock;
+import io.opencensus.common.Timestamp;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * This class provides a mechanism for converting {@link System#nanoTime() nanoTime} values to
+ * {@link Timestamp}.
+ */
+@Immutable
+public final class TimestampConverter {
+  private final Timestamp timestamp;
+  private final long nanoTime;
+
+  // Returns a WallTimeConverter initialized to now.
+  public static TimestampConverter now(Clock clock) {
+    return new TimestampConverter(clock.now(), clock.nowNanos());
+  }
+
+  /**
+   * Converts a {@link System#nanoTime() nanoTime} value to {@link Timestamp}.
+   *
+   * @param nanoTime value to convert.
+   * @return the {@code Timestamp} representation of the {@code time}.
+   */
+  public Timestamp convertNanoTime(long nanoTime) {
+    return timestamp.addNanos(nanoTime - this.nanoTime);
+  }
+
+  private TimestampConverter(Timestamp timestamp, long nanoTime) {
+    this.timestamp = timestamp;
+    this.nanoTime = nanoTime;
+  }
+}