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/*
* Copyright (C) 2018 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.
*/
#ifndef ANDROID_COUNTER_METRIC_H_
#define ANDROID_COUNTER_METRIC_H_
#include <functional>
#include <map>
#include <string>
#include <media/MediaAnalyticsItem.h>
#include <utils/Log.h>
namespace android {
// The CounterMetric class is used to hold counts of operations or events.
// A CounterMetric can break down counts by a dimension specified by the
// application. E.g. an application may want to track counts broken out by
// error code or the size of some parameter.
//
// Example:
//
// CounterMetric<status_t> workCounter;
// workCounter("workCounterName", "result_status");
//
// status_t err = DoWork();
//
// // Increments the number of times called with the given error code.
// workCounter.Increment(err);
//
// std::map<int, int64_t> values;
// metric.ExportValues(
// [&] (int attribute_value, int64_t value) {
// values[attribute_value] = value;
// });
//
// // Do something with the exported stat.
//
template<typename AttributeType>
class CounterMetric {
public:
// Instantiate the counter with the given metric name and
// attribute names. |attribute_names| must not be null.
CounterMetric(
const std::string& metric_name,
const std::string& attribute_name)
: metric_name_(metric_name),
attribute_name_(attribute_name) {}
// Increment the count of times the operation occurred with this
// combination of attributes.
void Increment(AttributeType attribute) {
if (values_.find(attribute) == values_.end()) {
values_[attribute] = 1;
} else {
values_[attribute] = values_[attribute] + 1;
}
};
// Export the metrics to the provided |function|. Each value for Attribute
// has a separate count. As such, |function| will be called once per value
// of Attribute.
void ExportValues(
std::function<void (const AttributeType&,
const int64_t count)> function) const {
for (auto it = values_.begin(); it != values_.end(); it++) {
function(it->first, it->second);
}
}
const std::string& metric_name() const { return metric_name_; };
private:
const std::string metric_name_;
const std::string attribute_name_;
std::map<AttributeType, int64_t> values_;
};
} // namespace android
#endif // ANDROID_COUNTER_METRIC_H_