org.javasimon
Class NullSimon

java.lang.Object
  org.javasimon.NullSimon

All Implemented Interfaces:

HasAttributes, Simon

Direct Known Subclasses:

NullCounter, NullStopwatch

 class NullSimon
extends Object
implements Simon

Null Simon implements Simon returned by the disabled Manager.getSimon(String) or Manager.getRootSimon(). Null Simon does nothing, returns null or zeroes wherever return value is expected and has minimal performance impact on the system.

Author:

Richard "Virgo" Richter

Field Summary

(package private) static NullSimon

INSTANCE Internal singleton value of the null Simon.

Constructor Summary

NullSimon()
Used only by the subclasses, otherwise should not be used at all except for a single INSTANCE.

Method Summary

Object	getAttribute(String name) Returns null.
<T> T	getAttribute(String name, Class<T> clazz) Returns null.
Iterator<String>	getAttributeNames() Returns empty iterator.
Map<String,Object>	getCopyAsSortedMap() Returns empty set.
long	getFirstUsage() Returns ms timestamp of the first usage of this Simon.
List<Simon>	getChildren() Returns list of children - direct sub-simons.
long	getLastReset() Returns ms timestamp of the last recent usage of the Simon.reset() method on the Simon.
long	getLastUsage() Returns ms timestamp of the last usage of this Simon.
String	getName() Returns Simon name.
String	getNote() Returns note for the Simon.
Simon	getParent() Returns parent Simon.
SimonState	getState() Returns state of the Simon that can be enabled, disabled or ihnerited.
boolean	isEnabled() Returns true, if the Simon is enabled or if the enabled state is inherited.
void	removeAttribute(String name) Does nothing.
NullSimon	reset() Resets the Simon values related to the measuring, timestamps and so on - usage timestamps, state, attributes are not affected.
Sample	sample() Samples Simon values and returns them in a Java Bean derived from Sample interface.
Sample	sampleAndReset() Samples Simon values and returns them in a Java Bean derived from Sample interface and resets the Simon.
void	setAttribute(String name, Object value) Does nothing.
void	setNote(String note) Sets note for the Simon.
void	setState(SimonState state, boolean overrule) Sets the state of the Simon.
String	toString() Returns string Null Simon.

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

static final NullSimon INSTANCE

Internal singleton value of the null Simon. Null Simon is never directly used in the client code, it is always hidden behind the Simon interface - only its behavior manifests to the client.

Constructor Detail

NullSimon

NullSimon()

Used only by the subclasses, otherwise should not be used at all except for a single INSTANCE.

Method Detail

getParent

public Simon getParent()

Description copied from interface: Simon

Returns parent Simon.

Specified by:

getParent in interface Simon

Returns:

parent Simon

getChildren

public final List<Simon> getChildren()

Description copied from interface: Simon

Returns list of children - direct sub-simons.

Specified by:

getChildren in interface Simon

Returns:

list of children

getName

public String getName()

Description copied from interface: Simon

Returns Simon name. Simon name is always fully qualified and determines also position of the Simon in the monitor hierarchy. Simon name can be null for anonymous Simons.

Specified by:

getName in interface Simon

Returns:

name of the Simon

getState

public SimonState getState()

Description copied from interface: Simon

Returns state of the Simon that can be enabled, disabled or ihnerited.

Specified by:

getState in interface Simon

Returns:

state of the Simon

setState

public void setState(SimonState state,
                     boolean overrule)

Description copied from interface: Simon

Sets the state of the Simon. It must be specified whether to propagate the change and overrule states of all sub-simons which effectively sets the same state to the whole subtree. If subtree is not overruled, some Simons (with their subtrees) may not be affected by this change.

Specified by:

setState in interface Simon

Parameters:

state - a new state.

overrule - specifies whether this change is forced to the whole subtree.

isEnabled

public boolean isEnabled()

Description copied from interface: Simon

Returns true, if the Simon is enabled or if the enabled state is inherited.

Specified by:

isEnabled in interface Simon

Returns:

true, if the Simon is effectively enabled

reset

public NullSimon reset()

Description copied from interface: Simon

Resets the Simon values related to the measuring, timestamps and so on - usage timestamps, state, attributes are not affected. Timestamp of the last reset can be obtained by the method Simon.getLastReset(). Reset is perfomed even for disabled Simons.

Specified by:

reset in interface Simon

Returns:

returns this

getLastReset

public long getLastReset()

Description copied from interface: Simon

Returns ms timestamp of the last recent usage of the Simon.reset() method on the Simon. Returns 0 if reset was not called yet. This timestamp is useful for rate measuring when reset is called on a regular basis - likely via Simon.sampleAndReset(). While client code could store the timestamp too it is not necessary with this method.

Specified by:

getLastReset in interface Simon

Returns:

ms timestamp of the last reset or 0 if reset was not called yet

getFirstUsage

public long getFirstUsage()

Description copied from interface: Simon

Returns ms timestamp of the first usage of this Simon. First and last usage are updated when monitor performs the measuring (start/stop/count/etc). They are not updated when values are obtained from the monitor.

Specified by:

getFirstUsage in interface Simon

Returns:

ms timestamp of the first usage

getLastUsage

public long getLastUsage()

Description copied from interface: Simon

Returns ms timestamp of the last usage of this Simon. First and last usage are updated when monitor performs the measuring (start/stop/count/etc). They are not updated when values are obtained from the monitor.

Specified by:

getLastUsage in interface Simon

Returns:

ms timestamp of the last usage

getNote

public String getNote()

Returns note for the Simon.

Specified by:

getNote in interface Simon

Returns:

note for the Simon.

setNote

public void setNote(String note)

Sets note for the Simon.

Specified by:

setNote in interface Simon

Parameters:

note - note for the Simon.

sample

public Sample sample()

Description copied from interface: Simon

Samples Simon values and returns them in a Java Bean derived from Sample interface.

Specified by:

sample in interface Simon

Returns:

sample containing all Simon values

sampleAndReset

public Sample sampleAndReset()

Description copied from interface: Simon

Samples Simon values and returns them in a Java Bean derived from Sample interface and resets the Simon. Operation is synchronized to assure atomicity.

Specified by:

sampleAndReset in interface Simon

Returns:

sample containing all Simon values

setAttribute

public void setAttribute(String name,
                         Object value)

Does nothing.

Specified by:

setAttribute in interface HasAttributes

Parameters:

name - ignored

value - ignored

getAttribute

public Object getAttribute(String name)

Returns null.

Specified by:

getAttribute in interface HasAttributes

Parameters:

name - ignored

Returns:

null

getAttribute

public <T> T getAttribute(String name,
                          Class<T> clazz)

Returns null.

Specified by:

getAttribute in interface HasAttributes

Parameters:

name - ignored

clazz - ignored

Returns:

null

removeAttribute

public void removeAttribute(String name)

Does nothing.

Specified by:

removeAttribute in interface HasAttributes

Parameters:

name - ignored

getAttributeNames

public Iterator<String> getAttributeNames()

Returns empty iterator.

Specified by:

getAttributeNames in interface HasAttributes

Returns:

empty iterator

getCopyAsSortedMap

public Map<String,Object> getCopyAsSortedMap()

Returns empty set.

Specified by:

getCopyAsSortedMap in interface HasAttributes

Returns:

empty set

toString

public String toString()

Returns string Null Simon.

Overrides:

toString in class Object

Returns:

string Null Simon