Index: base/android/java/src/org/chromium/base/metrics/RecordHistogram.java |
diff --git a/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java b/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java |
new file mode 100644 |
index 0000000000000000000000000000000000000000..8295a850c0aabaf1b0cd60bd80faf565c70b081e |
--- /dev/null |
+++ b/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java |
@@ -0,0 +1,62 @@ |
+// Copyright 2014 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+package org.chromium.base.metrics; |
+ |
+import org.chromium.base.JNINamespace; |
+import org.chromium.base.VisibleForTesting; |
+ |
+/** |
+ * Java API for recording UMA histograms. As opposed to macros used in native code, these calls are |
+ * not caching the histogram pointer; also, the JNI calls are relatively costly - avoid calling |
+ * these methods in performance-critical code. |
+ */ |
+@JNINamespace("base::android") |
+public class RecordHistogram { |
+ /** |
+ * Records a sample in a boolean UMA histogram of the given name. Boolean histogram has two |
+ * buckets, corresponding to success (true) and failure (false). |
+ * @param name name of the histogram |
+ * @param sample sample to be recorded, either true or false |
+ */ |
+ public static void recordBooleanHistogram(String name, boolean sample) { |
+ nativeRecordBooleanHistogram(name, sample); |
+ } |
+ |
+ /** |
+ * Records a sample in an enumerated histogram of the given name and boundary. Note that |
+ * |boundary| identifies the histogram - it should be the same at every invocation. |
+ * @param name name of the histogram |
+ * @param sample sample to be recorded, at least 0 and at most |boundary| - 1 |
+ * @param boundary upper bound for legal sample values - all sample values has to be strictly |
+ * lower than |boundary| |
+ */ |
+ public static void recordEnumeratedHistogram(String name, int sample, int boundary) { |
+ nativeRecordEnumeratedHistogram(name, sample, boundary); |
+ } |
+ |
+ /** |
+ * Returns the number of samples recorded in the given bucket of the given histogram. |
+ * @param name name of the histogram to look up |
+ * @param sample the bucket containing this sample value will be looked up |
+ */ |
+ @VisibleForTesting |
+ public static int getHistogramValueCountForTesting(String name, int sample) { |
+ return nativeGetHistogramValueCountForTesting(name, sample); |
+ } |
+ |
+ /** |
+ * Initializes the metrics system. |
+ */ |
+ public static void initialize() { |
+ nativeInitialize(); |
+ } |
+ |
+ private static native void nativeRecordBooleanHistogram(String name, boolean sample); |
+ private static native void nativeRecordEnumeratedHistogram( |
+ String name, int sample, int boundary); |
+ |
+ private static native int nativeGetHistogramValueCountForTesting(String name, int sample); |
+ private static native void nativeInitialize(); |
+} |