|
@@ -0,0 +1,46 @@
|
|
|
+/**
|
|
|
+ * Licensed to the Apache Software Foundation (ASF) under one
|
|
|
+ * or more contributor license agreements. See the NOTICE file
|
|
|
+ * distributed with this work for additional information
|
|
|
+ * regarding copyright ownership. The ASF licenses this file
|
|
|
+ * to you 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 org.apache.hadoop.yarn.util;
|
|
|
+
|
|
|
+import org.apache.hadoop.classification.InterfaceAudience.Public;
|
|
|
+import org.apache.hadoop.classification.InterfaceStability.Evolving;
|
|
|
+import org.apache.hadoop.util.Time;
|
|
|
+
|
|
|
+/**
|
|
|
+ * A monotonic clock from some arbitrary time base in the past, counting in
|
|
|
+ * milliseconds, and not affected by settimeofday or similar system clock
|
|
|
+ * changes.
|
|
|
+ * This is appropriate to use when computing how much longer to wait for an
|
|
|
+ * interval to expire.
|
|
|
+ * This function can return a negative value and it must be handled correctly
|
|
|
+ * by callers. See the documentation of System#nanoTime for caveats.
|
|
|
+ */
|
|
|
+@Public
|
|
|
+@Evolving
|
|
|
+public class MonotonicClock implements Clock {
|
|
|
+
|
|
|
+ /**
|
|
|
+ * Get current time from some arbitrary time base in the past, counting in
|
|
|
+ * milliseconds, and not affected by settimeofday or similar system clock
|
|
|
+ * changes.
|
|
|
+ * @return a monotonic clock that counts in milliseconds.
|
|
|
+ */
|
|
|
+ public long getTime() {
|
|
|
+ return Time.monotonicNow();
|
|
|
+ }
|
|
|
+}
|