juce::Value::ValueSource Class Reference

Used internally by the Value class as the base class for its shared value objects. More...

#include <juce_Value.h>

Inheritance diagram for juce::Value::ValueSource:

Collaboration diagram for juce::Value::ValueSource:

Public Member Functions
	ValueSource ()
	~ValueSource () override
void	decReferenceCount () noexcept
	Decreases the object's reference count. More...
bool	decReferenceCountWithoutDeleting () noexcept
	Decreases the object's reference count. More...
int	getReferenceCount () const noexcept
	Returns the object's current reference count. More...
virtual var	getValue () const =0
	Returns the current value of this object. More...
void	incReferenceCount () noexcept
	Increments the object's reference count. More...
void	sendChangeMessage (bool dispatchSynchronously)
	Delivers a change message to all the listeners that are registered with this value. More...
virtual void	setValue (const var &newValue)=0
	Changes the current value. More...

Protected Member Functions
void	resetReferenceCount () noexcept
	Resets the reference count to zero without deleting the object. More...

Protected Attributes
SortedSet< Value * >	valuesWithListeners

Private Member Functions
void	cancelPendingUpdate () noexcept
	This will stop any pending updates from happening. More...
void	handleAsyncUpdate () override
	Called back to do whatever your class needs to do. More...
void	handleUpdateNowIfNeeded ()
	If an update has been triggered and is pending, this will invoke it synchronously. More...
bool	isUpdatePending () const noexcept
	Returns true if there's an update callback in the pipeline. More...
void	triggerAsyncUpdate ()
	Causes the callback to be triggered at a later time. More...

Friends
class	Value

Detailed Description

Used internally by the Value class as the base class for its shared value objects.

The Value class is essentially a reference-counted pointer to a shared instance of a ValueSource object. If you're feeling adventurous, you can create your own custom ValueSource classes to allow Value objects to represent your own custom data items.

Constructor & Destructor Documentation

ValueSource()

juce::Value::ValueSource::ValueSource

(

)

~ValueSource()

juce::Value::ValueSource::~ValueSource ( )

override

Member Function Documentation

cancelPendingUpdate()

void juce::AsyncUpdater::cancelPendingUpdate ( )

noexceptinherited

This will stop any pending updates from happening.

If called after triggerAsyncUpdate() and before the handleAsyncUpdate() callback happens, this will cancel the handleAsyncUpdate() callback.

Note that this method simply cancels the next callback - if a callback is already in progress on a different thread, this won't block until the callback finishes, so there's no guarantee that the callback isn't still running when the method returns.

decReferenceCount()

void juce::ReferenceCountedObject::decReferenceCount ( )

inlinenoexceptinherited

Decreases the object's reference count.

If the count gets to zero, the object will be deleted.

References jassert.

decReferenceCountWithoutDeleting()

bool juce::ReferenceCountedObject::decReferenceCountWithoutDeleting ( )

inlinenoexceptinherited

Decreases the object's reference count.

If the count gets to zero, the object will not be deleted, but this method will return true, allowing the caller to take care of deletion.

References jassert.

getReferenceCount()

int juce::ReferenceCountedObject::getReferenceCount ( ) const

inlinenoexceptinherited

Returns the object's current reference count.

getValue()

virtual var juce::Value::ValueSource::getValue ( ) const

pure virtual

Returns the current value of this object.

handleAsyncUpdate()

void juce::Value::ValueSource::handleAsyncUpdate ( )

overrideprivatevirtual

Called back to do whatever your class needs to do.

This method is called by the message thread at the next convenient time after the triggerAsyncUpdate() method has been called.

Implements juce::AsyncUpdater.

handleUpdateNowIfNeeded()

void juce::AsyncUpdater::handleUpdateNowIfNeeded ( )

inherited

If an update has been triggered and is pending, this will invoke it synchronously.

Use this as a kind of "flush" operation - if an update is pending, the handleAsyncUpdate() method will be called immediately; if no update is pending, then nothing will be done.

Because this may invoke the callback, this method must only be called on the main event thread.

incReferenceCount()

void juce::ReferenceCountedObject::incReferenceCount ( )

inlinenoexceptinherited

Increments the object's reference count.

This is done automatically by the smart pointer, but is public just in case it's needed for nefarious purposes.

isUpdatePending()

bool juce::AsyncUpdater::isUpdatePending ( ) const

noexceptinherited

Returns true if there's an update callback in the pipeline.

resetReferenceCount()

void juce::ReferenceCountedObject::resetReferenceCount ( )

inlineprotectednoexceptinherited

Resets the reference count to zero without deleting the object.

You should probably never need to use this!

sendChangeMessage()

void juce::Value::ValueSource::sendChangeMessage

(

bool

dispatchSynchronously

)

Delivers a change message to all the listeners that are registered with this value.

If dispatchSynchronously is true, the method will call all the listeners before returning; otherwise it'll dispatch a message and make the call later.

setValue()

virtual void juce::Value::ValueSource::setValue ( const var &  newValue )

pure virtual

Changes the current value.

This must also trigger a change message if the value actually changes.

triggerAsyncUpdate()

void juce::AsyncUpdater::triggerAsyncUpdate ( )

inherited

Causes the callback to be triggered at a later time.

This method returns immediately, after which a callback to the handleAsyncUpdate() method will be made by the message thread as soon as possible.

If an update callback is already pending but hasn't happened yet, calling this method will have no effect.

It's thread-safe to call this method from any thread, BUT beware of calling it from a real-time (e.g. audio) thread, because it involves posting a message to the system queue, which means it may block (and in general will do on most OSes).

Friends And Related Function Documentation

Value

friend class Value

friend

Member Data Documentation

valuesWithListeners

SortedSet<Value*> juce::Value::ValueSource::valuesWithListeners

protected

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The documentation for this class was generated from the following file:

• juce_Value.h