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/*
* Copyright 2011-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.util;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import org.apache.http.annotation.NotThreadSafe;
/**
* Used both as a base class and a minimal support of timing info.
*
* In contrast to {@link TimingInfoFullSupport}, which is intended to be a full
* support of the timing info, this class only provides a minimal support of
* start and end time (ie with no-ops for sub-event measurements) for backward
* compatiblity reasons.
*
* This class is instantiated instead of {@link TimingInfoFullSupport} when
* request metric collection is not required during a particular service
* request/response cycle.
*/
@NotThreadSafe
public class TimingInfo {
static final int UNKNOWN = -1;
/**
* The wall clock time (as the number of milliseconds since Epoch)
* of when the timing measurement starts; or null if unknown.
* This field is not meant to be used for timing measurement.
* For more info, see:
* https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks
*/
private final Long startEpochTimeMilli;
/**
* Start time in nanosecond used for timing measurement.
* Note the value in this field may have nothing to do with
* the wall clock time.
* The wall clock time of when the timing measurement starts
* can optionally be captured in {@link #startEpochTimeMilli}.
* For more info, see:
* https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks
*
* Note System.nanoTime() can return negative values.
*/
private final long startTimeNano;
/**
* End time in nanosecond used for timing measurement or null if unknown.
* Note the value in this field is only meant to be used for timing
* measurement, and is not directly related to the wall clock time.
* For more info, see:
* https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks
*
* Note System.nanoTime() can return negative values.
*/
private Long endTimeNano;
/**
* Captures the current wall clock time (since epoch in millisecond)
* and the current time (in nanosecond) used for timing measurement.
* For more info, see:
* https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks
*/
public static TimingInfo startTiming() {
return new TimingInfo(Long.valueOf(System.currentTimeMillis()), System.nanoTime(), null);
}
/**
* Captures the current wall clock time (since epoch in millisecond)
* and the current time (in nanosecond) used for timing measurement.
* For more info, see:
* https://blogs.oracle.com/dholmes/entry/inside_the_hotspot_vm_clocks
*/
public static TimingInfo startTimingFullSupport() {
return new TimingInfoFullSupport(Long.valueOf(System.currentTimeMillis()), System.nanoTime(), null);
}
/**
* Captures the given start time in nanosecond, ignoring the wall clock time.
*
* @param startTimeNano start time in nanosecond
*/
public static TimingInfo startTimingFullSupport(long startTimeNano) {
return new TimingInfoFullSupport(null, startTimeNano, null);
}
/**
* Returns a {@link TimingInfoFullSupport} based on the given
* start and end time in nanosecond, ignoring the wall clock time.
*
* @param startTimeNano start time in nanosecond
* @param endTimeNano end time in nanosecond
*/
public static TimingInfo newTimingInfoFullSupport(long startTimeNano, long endTimeNano) {
return new TimingInfoFullSupport(null, startTimeNano, Long.valueOf(endTimeNano));
}
/**
* Returns a {@link TimingInfoFullSupport} based on the given
* start time since epoch in millisecond,
* and the given start and end time in nanosecond.
*
* @param startEpochTimeMilli start time since epoch in millisecond
* @param startTimeNano start time in nanosecond
* @param endTimeNano end time in nanosecond
*/
public static TimingInfo newTimingInfoFullSupport(
long startEpochTimeMilli, long startTimeNano, long endTimeNano) {
return new TimingInfoFullSupport(Long.valueOf(startEpochTimeMilli), startTimeNano, Long.valueOf(endTimeNano));
}
/**
* Returns an instance of {@link TimingInfo} that is not modifiable, given
* the start and end nano times.
*/
public static TimingInfo unmodifiableTimingInfo(long startTimeNano, Long endTimeNano) {
return new TimingInfoUnmodifiable(null, startTimeNano, endTimeNano);
}
/**
* Returns an instance of {@link TimingInfo} that is not modifiable.
*
* @param startEpochTimeMilli start time since epoch in millisecond
* @param startTimeNano start time in nanosecond
* @param endTimeNano end time in nanosecond; or null if not known
*/
public static TimingInfo unmodifiableTimingInfo(long startEpochTimeMilli, long startTimeNano, Long endTimeNano) {
return new TimingInfoUnmodifiable(startEpochTimeMilli, startTimeNano, endTimeNano);
}
/**
* A private ctor to facilitate the deprecation of using millisecond and
* migration to using nanosecond for timing measurement.
*
* @param startEpochTimeMilli start time since epoch in millisecond
* @param startTimeNano start time in nanosecond
* @param endTimeNano end time in nanosecond; or null if not known
*/
protected TimingInfo(Long startEpochTimeMilli, long startTimeNano, Long endTimeNano) {
this.startEpochTimeMilli = startEpochTimeMilli;
this.startTimeNano = startTimeNano;
this.endTimeNano = endTimeNano;
}
@Deprecated
public final long getStartTime() {
return isStartEpochTimeMilliKnown()
? startEpochTimeMilli
// best effort even though technically this is incorrect
: TimeUnit.NANOSECONDS.toMillis(startTimeNano)
;
}
@Deprecated
public final long getStartEpochTimeMilli() {
Long v = getStartEpochTimeMilliIfKnown();
return v == null ? UNKNOWN : v.longValue();
}
public final Long getStartEpochTimeMilliIfKnown() {
return startEpochTimeMilli;
}
public final long getStartTimeNano() {
return startTimeNano;
}
@Deprecated
public final long getEndTime() {
return getEndEpochTimeMilli();
}
@Deprecated
public final long getEndEpochTimeMilli() {
Long v = getEndEpochTimeMilliIfKnown();
return v == null ? UNKNOWN : v.longValue();
}
public final Long getEndEpochTimeMilliIfKnown() {
return isStartEpochTimeMilliKnown() && isEndTimeKnown()
// make use of the wall clock time and elpased time
? startEpochTimeMilli.longValue()
+ TimeUnit.NANOSECONDS.toMillis(endTimeNano.longValue() - startTimeNano)
: null;
}
public final long getEndTimeNano() {
return endTimeNano == null ? UNKNOWN : endTimeNano;
}
public final Long getEndTimeNanoIfKnown() {
return endTimeNano;
}
@Deprecated
public final double getTimeTakenMillis() {
Double v = getTimeTakenMillisIfKnown();
return v == null ? UNKNOWN : v.doubleValue();
}
public final Double getTimeTakenMillisIfKnown() {
return isEndTimeKnown()
? durationMilliOf(startTimeNano, endTimeNano)
: null
;
}
/**
* Returns the duration in milliseconds as double, preserving the decimal
* precision as necessary, for the given start and end time in nanoseconds.
*/
public static double durationMilliOf(long startTimeNano, long endTimeNano) {
double micros = (double)TimeUnit.NANOSECONDS.toMicros(endTimeNano - startTimeNano);
return micros / 1000.0; // convert microseconds to milliseconds in double rather than long, preserving the precision
}
@Deprecated
public final long getElapsedTimeMillis() {
Double v = getTimeTakenMillisIfKnown();
return v == null ? UNKNOWN : v.longValue();
}
public final boolean isEndTimeKnown() {
return endTimeNano != null;
}
public final boolean isStartEpochTimeMilliKnown() {
return startEpochTimeMilli != null;
}
public final String toString() {
return String.valueOf(getTimeTakenMillis());
}
@Deprecated
public void setEndTime(long endTimeMilli) {
this.endTimeNano = Long.valueOf(TimeUnit.MILLISECONDS.toNanos(endTimeMilli));
}
public void setEndTimeNano(long endTimeNano) {
this.endTimeNano = endTimeNano;
}
public TimingInfo endTiming() {
this.endTimeNano = Long.valueOf(System.nanoTime());
return this;
}
public void addSubMeasurement(String subMeasurementName, TimingInfo timingInfo) {}
public TimingInfo getSubMeasurement(String subMeasurementName) { return null; }
public TimingInfo getSubMeasurement(String subMesurementName, int index) { return null; }
public TimingInfo getLastSubMeasurement(String subMeasurementName) { return null; }
public List getAllSubMeasurements(String subMeasurementName) { return null; }
public Map> getSubMeasurementsByName() { return Collections.emptyMap(); }
public Number getCounter(String key) { return null; }
public Map getAllCounters() { return Collections.emptyMap(); }
public void setCounter(String key, long count) {}
public void incrementCounter(String key) {}
}