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 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

All Methods Instance Methods Concrete Methods
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 Detail
  - 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 Detail
  - 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

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

Class StopWatch

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

StopWatch

StopWatch

Method Detail

getId

setKeepTaskList

start

start

stop

isRunning

currentTaskName

getLastTaskTimeNanos

getLastTaskTimeMillis

getLastTaskName

getLastTaskInfo

getTotalTimeNanos

getTotalTimeMillis

getTotalTimeSeconds

getTaskCount

getTaskInfo

shortSummary

prettyPrint

toString