org.springframework.util

Class StopWatch

java.lang.Object

org.springframework.util.StopWatch

public class StopWatch
extends java.lang.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.currentTimeMillis(), 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.

Since:

May 2, 2001

Author:

Rod Johnson, Juergen Hoeller, Sam Brannen

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StopWatch.TaskInfo Inner class to hold data about one task executed within the stop watch.

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	currentTaskName Name of the current task
private java.lang.String	id Identifier of this stop watch.
private boolean	keepTaskList
private StopWatch.TaskInfo	lastTaskInfo
private boolean	running Is the stop watch currently running?
private long	startTimeMillis Start time of the current task
private int	taskCount
private java.util.List<StopWatch.TaskInfo>	taskList
private long	totalTimeMillis Total running time

Constructor Summary

Constructors

Constructor and Description
StopWatch() Construct a new stop watch.
StopWatch(java.lang.String id) Construct a new stop watch with the given id.

Method Summary

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

Methods inherited from class java.lang.Object

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

Field Detail

id

private final java.lang.String id

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.

keepTaskList

private boolean keepTaskList

taskList

private final java.util.List<StopWatch.TaskInfo> taskList

startTimeMillis

private long startTimeMillis

Start time of the current task

running

private boolean running

Is the stop watch currently running?

currentTaskName

private java.lang.String currentTaskName

Name of the current task

lastTaskInfo

private StopWatch.TaskInfo lastTaskInfo

taskCount

private int taskCount

totalTimeMillis

private long totalTimeMillis

Total running time

Constructor Detail

StopWatch

public StopWatch()

Construct a new stop watch. Does not start any task.

StopWatch

public StopWatch(java.lang.String id)

Construct a new stop watch with the given id. Does not start any task.

Parameters:

id - identifier for this stop watch. Handy when we have output from multiple stop watches and need to distinguish between them.

Method Detail

getId

public java.lang.String getId()

Return the id of this stop watch, 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)

Determine whether the TaskInfo array is built over time. Set this to "false" when using a StopWatch for millions of intervals, or the task info structure will consume excessive memory. Default is "true".

start

public void start()
           throws java.lang.IllegalStateException

Start an unnamed task. The results are undefined if stop() or timing methods are called without invoking this method.

Throws:

java.lang.IllegalStateException

See Also:

stop()

start

public void start(java.lang.String taskName)
           throws java.lang.IllegalStateException

Start a named task. The results are undefined if stop() or timing methods are called without invoking this method.

Parameters:

taskName - the name of the task to start

Throws:

java.lang.IllegalStateException

See Also:

stop()

stop

public void stop()
          throws java.lang.IllegalStateException

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

Throws:

java.lang.IllegalStateException

See Also:

start()

isRunning

public boolean isRunning()

Return whether the stop watch is currently running.

See Also:

currentTaskName()

currentTaskName

@Nullable
public java.lang.String currentTaskName()

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

Since:

4.2.2

See Also:

isRunning()

getLastTaskTimeMillis

public long getLastTaskTimeMillis()
                           throws java.lang.IllegalStateException

Return the time taken by the last task.

Throws:

java.lang.IllegalStateException

getLastTaskName

public java.lang.String getLastTaskName()
                                 throws java.lang.IllegalStateException

Return the name of the last task.

Throws:

java.lang.IllegalStateException

getLastTaskInfo

public StopWatch.TaskInfo getLastTaskInfo()
                                   throws java.lang.IllegalStateException

Return the last task as a TaskInfo object.

Throws:

java.lang.IllegalStateException

getTotalTimeMillis

public long getTotalTimeMillis()

Return the total time in milliseconds for all tasks.

getTotalTimeSeconds

public double getTotalTimeSeconds()

Return the total time in seconds for all tasks.

getTaskCount

public int getTaskCount()

Return the number of tasks timed.

getTaskInfo

public StopWatch.TaskInfo[] getTaskInfo()

Return an array of the data for tasks performed.

shortSummary

public java.lang.String shortSummary()

Return a short description of the total running time.

prettyPrint

public java.lang.String prettyPrint()

Return a string with a table describing all tasks performed. For custom reporting, call getTaskInfo() and use the task info directly.

toString

public java.lang.String toString()

Return an informative string describing all tasks performed For custom reporting, call getTaskInfo() and use the task info directly.

Overrides:

toString in class java.lang.Object