1 files changed, 96 insertions, 0 deletions
diff --git a/java/com/google/gerrit/metrics/Timer2.java b/java/com/google/gerrit/metrics/Timer2.java
new file mode 100644
index 0000000000..bf19448d70
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+++ b/java/com/google/gerrit/metrics/Timer2.java
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+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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 com.google.gerrit.metrics;
+
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.extensions.registration.RegistrationHandle;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Records elapsed time for an operation or span.
+ *
+ * <p>Typical usage in a try-with-resources block:
+ *
+ * <pre>
+ * try (Timer2.Context ctx = timer.start(field)) {
+ * }
+ * </pre>
+ *
+ * @param <F1> type of the field.
+ * @param <F2> type of the field.
+ */
+public abstract class Timer2<F1, F2> implements RegistrationHandle {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  public static class Context extends TimerContext {
+    private final Timer2<Object, Object> timer;
+    private final Object field1;
+    private final Object field2;
+
+    @SuppressWarnings("unchecked")
+    <F1, F2> Context(Timer2<F1, F2> timer, F1 field1, F2 field2) {
+      this.timer = (Timer2<Object, Object>) timer;
+      this.field1 = field1;
+      this.field2 = field2;
+    }
+
+    @Override
+    public void record(long elapsed) {
+      timer.record(field1, field2, elapsed, NANOSECONDS);
+    }
+  }
+
+  protected final String name;
+
+  public Timer2(String name) {
+    this.name = name;
+  }
+
+  /**
+   * Begin a timer for the current block, value will be recorded when closed.
+   *
+   * @param field1 bucket to record the timer
+   * @param field2 bucket to record the timer
+   * @return timer context
+   */
+  public Context start(F1 field1, F2 field2) {
+    return new Context(this, field1, field2);
+  }
+
+  /**
+   * Record a value in the distribution.
+   *
+   * @param field1 bucket to record the timer
+   * @param field2 bucket to record the timer
+   * @param value value to record
+   * @param unit time unit of the value
+   */
+  public final void record(F1 field1, F2 field2, long value, TimeUnit unit) {
+    logger.atFinest().log("%s (%s, %s) took %dms", name, field1, field2, unit.toMillis(value));
+    doRecord(field1, field2, value, unit);
+  }
+
+  /**
+   * Record a value in the distribution.
+   *
+   * @param field1 bucket to record the timer
+   * @param field2 bucket to record the timer
+   * @param value value to record
+   * @param unit time unit of the value
+   */
+  protected abstract void doRecord(F1 field1, F2 field2, long value, TimeUnit unit);
+}