Package org.springframework.util

Class StopWatch

java.lang.Object

org.springframework.util.StopWatch

public class StopWatch
extends Object

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-concept work and in development, rather than as part of production applications.

As of Spring Framework 5.2, running time is tracked and reported in nanoseconds.

Since:

May 2, 2001

Author:

Rod Johnson, Juergen Hoeller, Sam Brannen

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	StopWatch.TaskInfo	Nested class to hold data about one task executed within the StopWatch.

Constructor Summary

Constructors

Constructor	Description
StopWatch()	Construct a new StopWatch.
StopWatch(String id)	Construct a new StopWatch with the given ID.

Method Summary

Modifier and Type	Method	Description
String	currentTaskName()	Get the name of the currently running task, if any.
String	getId()	Get the ID of this StopWatch, as specified on construction.
StopWatch.TaskInfo	getLastTaskInfo()	Get the last task as a StopWatch.TaskInfo object.
String	getLastTaskName()	Get the name of the last task.
long	getLastTaskTimeMillis()	Get the time taken by the last task in milliseconds.
long	getLastTaskTimeNanos()	Get the time taken by the last task in nanoseconds.
int	getTaskCount()	Get the number of tasks timed.
StopWatch.TaskInfo[]	getTaskInfo()	Get an array of the data for tasks performed.
long	getTotalTimeMillis()	Get the total time in milliseconds for all tasks.
long	getTotalTimeNanos()	Get the total time in nanoseconds for all tasks.
double	getTotalTimeSeconds()	Get the total time in seconds for all tasks.
boolean	isRunning()	Determine whether this StopWatch is currently running.
String	prettyPrint()	Generate a string with a table describing all tasks performed.
void	setKeepTaskList(boolean keepTaskList)	Configure whether the StopWatch.TaskInfo array is built over time.
String	shortSummary()	Get a short description of the total running time.
void	start()	Start an unnamed task.
void	start(String taskName)	Start a named task.
void	stop()	Stop the current task.
String	toString()	Generate an informative string describing all tasks performed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

StopWatch

public StopWatch()

Construct a new StopWatch.

Does not start any task.

StopWatch

public StopWatch(String id)

Construct a new StopWatch with the given ID.

The ID is handy when we have output from multiple stop watches and need to distinguish between them.

Does not start any task.

Parameters:

id - identifier for this stop watch

Method Details

getId

public String getId()

Get the ID of this StopWatch, as specified on construction.

Returns:

the ID (empty String by default)

Since:

4.2.2

See Also:

• StopWatch(String)

setKeepTaskList

public void setKeepTaskList(boolean keepTaskList)

Configure whether the StopWatch.TaskInfo array is built over time.

Set this to false when using a StopWatch for millions of intervals; otherwise, the TaskInfo structure will consume excessive memory.

Default is true.

start

public void start()
           throws IllegalStateException

Start an unnamed task.

The results are undefined if stop() or timing methods are called without invoking this method first.

Throws:

IllegalStateException

See Also:

• start(String)
• stop()

start

public void start(String taskName)
           throws IllegalStateException

Start a named task.

The results are undefined if stop() or timing methods are called without invoking this method first.

Parameters:

taskName - the name of the task to start

Throws:

IllegalStateException

See Also:

• start()
• stop()

stop

public void stop()
          throws IllegalStateException

Stop the current task.

The results are undefined if timing methods are called without invoking at least one pair of start() / stop() methods.

Throws:

IllegalStateException

See Also:

• start()
• start(String)

isRunning

public boolean isRunning()

Determine whether this StopWatch is currently running.

See Also:

• currentTaskName()

currentTaskName

@Nullable
public String currentTaskName()

Get the name of the currently running task, if any.

Since:

4.2.2

See Also:

• isRunning()

getLastTaskTimeNanos

public long getLastTaskTimeNanos()
                          throws IllegalStateException

Get the time taken by the last task in nanoseconds.

Throws:

IllegalStateException

Since:

5.2

See Also:

• getLastTaskTimeMillis()

getLastTaskTimeMillis

public long getLastTaskTimeMillis()
                           throws IllegalStateException

Get the time taken by the last task in milliseconds.

Throws:

IllegalStateException

See Also:

• getLastTaskTimeNanos()

getLastTaskName

public String getLastTaskName()
                       throws IllegalStateException

Get the name of the last task.

Throws:

IllegalStateException

getLastTaskInfo

public StopWatch.TaskInfo getLastTaskInfo()
                                   throws IllegalStateException

Get the last task as a StopWatch.TaskInfo object.

Throws:

IllegalStateException

getTotalTimeNanos

public long getTotalTimeNanos()

Get the total time in nanoseconds for all tasks.

Since:

5.2

See Also:

• getTotalTimeMillis()
• getTotalTimeSeconds()

getTotalTimeMillis

public long getTotalTimeMillis()

Get the total time in milliseconds for all tasks.

See Also:

• getTotalTimeNanos()
• getTotalTimeSeconds()

getTotalTimeSeconds

public double getTotalTimeSeconds()

Get the total time in seconds for all tasks.

See Also:

• getTotalTimeNanos()
• getTotalTimeMillis()

getTaskCount

public int getTaskCount()

Get the number of tasks timed.

getTaskInfo

public StopWatch.TaskInfo[] getTaskInfo()

Get an array of the data for tasks performed.

shortSummary

public String shortSummary()

Get a short description of the total running time.

prettyPrint

public String prettyPrint()

Generate a string with a table describing all tasks performed.

For custom reporting, call getTaskInfo() and use the task info directly.

toString

public String toString()

Generate an informative string describing all tasks performed

For custom reporting, call getTaskInfo() and use the task info directly.

Overrides:

toString in class Object