org.elasticsearch.common.StopWatch Maven / Gradle / Ivy
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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.common;
import org.elasticsearch.common.lease.Releasable;
import org.elasticsearch.common.unit.TimeValue;
import java.text.NumberFormat;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
/**
* Simple stop watch, allowing for timing of a number of tasks,
* exposing total running time and running time for each named task.
*
* Conceals use of System.nanoTime(), improving the
* readability of application code and reducing the likelihood of calculation errors.
*
* Note that this object is not designed to be thread-safe and does not
* use synchronization.
*
* This class is normally used to verify performance during proof-of-concepts
* and in development, rather than as part of production applications.
*
*
*/
public class StopWatch {
/**
* Identifier of this stop watch.
* Handy when we have output from multiple stop watches
* and need to distinguish between them in log or console output.
*/
private final String id;
private final List taskList = new LinkedList<>();
/**
* Start time of the current task
*/
private long startTimeNS;
/**
* Is the stop watch currently running?
*/
private boolean running;
/**
* Name of the current task
*/
private String currentTaskName;
private TaskInfo lastTaskInfo;
/**
* Total running time
*/
private long totalTimeNS;
/**
* Construct a new stop watch. Does not start any task.
*/
public StopWatch() {
this.id = "";
}
/**
* Construct a new stop watch with the given id.
* Does not start any task.
*
* @param id identifier for this stop watch.
* Handy when we have output from multiple stop watches
* and need to distinguish between them.
*/
public StopWatch(String id) {
this.id = id;
}
/**
* Start an unnamed task. The results are undefined if {@link #stop()}
* or timing methods are called without invoking this method.
*
* @see #stop()
*/
public StopWatch start() throws IllegalStateException {
return start("");
}
/**
* Start a named task. The results are undefined if {@link #stop()}
* or timing methods are called without invoking this method.
*
* @param taskName the name of the task to start
* @see #stop()
*/
public StopWatch start(String taskName) throws IllegalStateException {
if (this.running) {
throw new IllegalStateException("Can't start StopWatch: it's already running");
}
this.startTimeNS = System.nanoTime();
this.running = true;
this.currentTaskName = taskName;
return this;
}
/**
* Stop the current task. The results are undefined if timing
* methods are called without invoking at least one pair
* {@link #start()} / {@code #stop()} methods.
*
* @see #start()
*/
public StopWatch stop() throws IllegalStateException {
if (!this.running) {
throw new IllegalStateException("Can't stop StopWatch: it's not running");
}
long lastTimeNS = System.nanoTime() - this.startTimeNS;
this.totalTimeNS += lastTimeNS;
this.lastTaskInfo = new TaskInfo(this.currentTaskName, TimeValue.nsecToMSec(lastTimeNS));
this.taskList.add(lastTaskInfo);
this.running = false;
this.currentTaskName = null;
return this;
}
public Releasable timing(String taskName) {
start(taskName);
return this::stop;
}
/**
* Return whether the stop watch is currently running.
*/
public boolean isRunning() {
return this.running;
}
/**
* Return the time taken by the last task.
*/
public TimeValue lastTaskTime() throws IllegalStateException {
if (this.lastTaskInfo == null) {
throw new IllegalStateException("No tests run: can't get last interval");
}
return this.lastTaskInfo.getTime();
}
/**
* Return the total time for all tasks.
*/
public TimeValue totalTime() {
return new TimeValue(totalTimeNS, TimeUnit.NANOSECONDS);
}
/**
* Return an array of the data for tasks performed.
*/
public TaskInfo[] taskInfo() {
return this.taskList.toArray(new TaskInfo[0]);
}
/**
* Return a short description of the total running time.
*/
public String shortSummary() {
return "StopWatch '" + this.id + "': running time = " + totalTime();
}
/**
* Return a string with a table describing all tasks performed.
* For custom reporting, call getTaskInfo() and use the task info directly.
*/
public String prettyPrint() {
StringBuilder sb = new StringBuilder(shortSummary());
sb.append('\n');
sb.append("-----------------------------------------\n");
sb.append("ms % Task name\n");
sb.append("-----------------------------------------\n");
NumberFormat nf = NumberFormat.getNumberInstance(Locale.ROOT);
nf.setMinimumIntegerDigits(5);
nf.setGroupingUsed(false);
NumberFormat pf = NumberFormat.getPercentInstance(Locale.ROOT);
pf.setMinimumIntegerDigits(3);
pf.setGroupingUsed(false);
for (TaskInfo task : taskInfo()) {
sb.append(nf.format(task.getTime().millis())).append(" ");
sb.append(pf.format(task.getTime().secondsFrac() / totalTime().secondsFrac())).append(" ");
sb.append(task.getTaskName()).append("\n");
}
return sb.toString();
}
/**
* Return an informative string describing all tasks performed
* For custom reporting, call getTaskInfo() and use the task info directly.
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder(shortSummary());
for (TaskInfo task : taskInfo()) {
sb.append("; [").append(task.getTaskName()).append("] took ").append(task.getTime());
long percent = Math.round((100.0f * task.getTime().millis()) / totalTime().millis());
sb.append(" = ").append(percent).append("%");
}
return sb.toString();
}
/**
* Inner class to hold data about one task executed within the stop watch.
*/
public static class TaskInfo {
private final String taskName;
private final TimeValue timeValue;
private TaskInfo(String taskName, long timeMillis) {
this.taskName = taskName;
this.timeValue = new TimeValue(timeMillis, TimeUnit.MILLISECONDS);
}
/**
* Return the name of this task.
*/
public String getTaskName() {
return taskName;
}
/**
* Return the time this task took.
*/
public TimeValue getTime() {
return timeValue;
}
}
}