/*
* Copyright (C) 2009 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.android.quicksearchbox;
import android.os.SystemClock;
/**
* Tracks latency in wall-clock time. Since {@link #getLatency} returns an {@code int},
* latencies over 2^31 ms (~ 25 days) cannot be measured.
* This class uses {@link SystemClock#uptimeMillis} which does not advance during deep sleep.
*/
public class LatencyTracker {
/**
* Start time, in milliseconds as returned by {@link SystemClock#uptimeMillis}.
*/
private long mStartTime;
/**
* Creates a new latency tracker and sets the start time.
*/
public LatencyTracker() {
mStartTime = SystemClock.uptimeMillis();
}
/**
* Resets the start time.
*/
public void reset() {
mStartTime = SystemClock.uptimeMillis();
}
/**
* Gets the number of milliseconds since the object was created, or {@link #reset} was called.
*/
public int getLatency() {
long now = SystemClock.uptimeMillis();
return (int) (now - mStartTime);
}
}