OpenShot Audio Library | OpenShotAudio: juce::ListenerList< ListenerClass, ArrayType > Class Template Reference

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juce::ListenerList< ListenerClass, ArrayType > Class Template Reference

`#include <juce_ListenerList.h>`

## Classes
struct | DummyBailOutChecker

## Public Types
using | ThisType = ListenerList<ListenerClass, ArrayType>
using | ListenerType = ListenerClass

## Public Member Functions
| ListenerList ()=default
| ~ListenerList ()
void | add (ListenerClass *listenerToAdd)
void | remove (ListenerClass *listenerToRemove)
ErasedScopeGuard | addScoped (ListenerClass &listenerToAdd)
int | size () const noexcept
bool | isEmpty () const noexcept
void | clear ()
bool | contains (ListenerClass *listener) const noexcept
const ArrayType & | getListeners () const noexcept
template<typename Callback>
void | call (Callback &&callback)
template<typename Callback>
void | callExcluding (ListenerClass *listenerToExclude, Callback &&callback)
template<typename Callback, typename BailOutCheckerType>
void | callChecked (const BailOutCheckerType &bailOutChecker, Callback &&callback)
template<typename Callback, typename BailOutCheckerType>
void | callCheckedExcluding (ListenerClass *listenerToExclude, const BailOutCheckerType &bailOutChecker, Callback &&callback)
template<typename... MethodArgs, typename... Args>
void | call (void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)
template<typename... MethodArgs, typename... Args>
void | callExcluding (ListenerClass *listenerToExclude, void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>
void | callChecked (const BailOutCheckerType &bailOutChecker, void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>
void | callCheckedExcluding (ListenerClass *listenerToExclude, const BailOutCheckerType &bailOutChecker, void(ListenerClass::*callbackFunction)(MethodArgs...), Args &&... args)

## Detailed Description

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
class juce::ListenerList< ListenerClass, ArrayType >

Holds a set of objects and can invoke a member function callback on each object in the set with a single call.

Use a ListenerList to manage a set of objects which need a callback, and you can invoke a member function by simply calling call(), callChecked(), or callExcluding().

E.g.

class MyListenerType
{
public:
void myCallbackMethod (int foo, bool bar);
};
ListenerList<MyListenerType> listeners;
listeners.add (someCallbackObjects...);
// This will invoke myCallbackMethod (1234, true) on each of the objects
// in the list...
listeners.call ([] (MyListenerType& l) { l.myCallbackMethod (1234, true); });
juce::ListenerList
Definition juce_ListenerList.h:81
juce::ListenerList::call
void call(Callback &&callback)
Definition juce_ListenerList.h:182
juce::ListenerList::add
void add(ListenerClass *listenerToAdd)
Definition juce_ListenerList.h:100

It is safe to add listeners, remove listeners, clear the listeners, and delete the ListenerList itself during any listener callback.

If a Listener is added during a callback, it is guaranteed not to be called in the same iteration.

If a Listener is removed during a callback, it is guaranteed not to be called if it hasn't already been called.

If the ListenerList is cleared or deleted during a callback, it is guaranteed that no more listeners will be called.

By default a ListenerList is not thread safe. If thread-safety is required, you can provide a thread-safe Array type as the second type parameter e.g.

using ThreadSafeList = ListenerList<MyListenerType, Array<MyListenerType*, CriticalSection>>;
juce::ListenerList::ListenerList
ListenerList()=default

When calling listeners the iteration can be escaped early by using a "BailOutChecker". A BailOutChecker is a type that has a public member function with the following signature:

bool shouldBailOut() const

This function will be called before making a call to each listener. For an example see the DummyBailOutChecker.

Definition at line 80 of file juce_ListenerList.h.

## Member Typedef Documentation

## ◆ ListenerType

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

using juce::ListenerList< ListenerClass, ArrayType >::ListenerType = ListenerClass

Definition at line 322 of file juce_ListenerList.h.

## ◆ ThisType

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

using juce::ListenerList< ListenerClass, ArrayType >::ThisType = ListenerList<ListenerClass, ArrayType>

Definition at line 321 of file juce_ListenerList.h.

## Constructor & Destructor Documentation

## ◆ ListenerList()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

juce::ListenerList< ListenerClass, ArrayType >::ListenerList | ( |  | ) |
| default

Creates an empty list.

## ◆ ~ListenerList()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

juce::ListenerList< ListenerClass, ArrayType >::~ListenerList | ( |  | ) |
| inline

Destructor.

Definition at line 88 of file juce_ListenerList.h.

## Member Function Documentation

## ◆ add()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::add | ( | ListenerClass * | listenerToAdd | ) |
| inline

Adds a listener to the list. A listener can only be added once, so if the listener is already in the list, this method has no effect.

If a Listener is added during a callback, it is guaranteed not to be called in the same iteration.

See also
  remove

Definition at line 100 of file juce_ListenerList.h.

## ◆ addScoped()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

ErasedScopeGuard juce::ListenerList< ListenerClass, ArrayType >::addScoped | ( | ListenerClass & | listenerToAdd | ) |
| inline

Adds a listener that will be automatically removed again when the Guard is destroyed.

Be very careful to ensure that the ErasedScopeGuard is destroyed or released before the ListenerList is destroyed, otherwise the ErasedScopeGuard may attempt to dereference a dangling pointer when it is destroyed, which will result in a crash.

Definition at line 138 of file juce_ListenerList.h.

## ◆ call() [1/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename Callback>

void juce::ListenerList< ListenerClass, ArrayType >::call | ( | Callback && | callback | ) |
| inline

Calls an invokable object for each listener in the list.

Definition at line 182 of file juce_ListenerList.h.

## ◆ call() [2/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename... MethodArgs, typename... Args>

void juce::ListenerList< ListenerClass, ArrayType >::call | ( | void(ListenerClass::* | callbackFunction )(MethodArgs...),
|  | Args &&... | args )
| inline

Calls a specific listener method for each listener in the list.

Definition at line 255 of file juce_ListenerList.h.

## ◆ callChecked() [1/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename Callback, typename BailOutCheckerType>

void juce::ListenerList< ListenerClass, ArrayType >::callChecked | ( | const BailOutCheckerType & | bailOutChecker,
|  | Callback && | callback )
| inline

Calls an invokable object for each listener in the list, additionally checking the bail-out checker before each call.

See the class description for info about writing a bail-out checker.

Definition at line 207 of file juce_ListenerList.h.

## ◆ callChecked() [2/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>

void juce::ListenerList< ListenerClass, ArrayType >::callChecked | ( | const BailOutCheckerType & | bailOutChecker,
|  | void(ListenerClass::* | callbackFunction )(MethodArgs...),
|  | Args &&... | args )
| inline

Calls a specific listener method for each listener in the list, additionally checking the bail-out checker before each call.

See the class description for info about writing a bail-out checker.

Definition at line 283 of file juce_ListenerList.h.

## ◆ callCheckedExcluding() [1/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename Callback, typename BailOutCheckerType>

void juce::ListenerList< ListenerClass, ArrayType >::callCheckedExcluding | ( | ListenerClass * | listenerToExclude,
|  | const BailOutCheckerType & | bailOutChecker,
|  | Callback && | callback )
| inline

Calls an invokable object for each listener in the list, except for the listener specified by listenerToExclude, additionally checking the bail-out checker before each call.

See the class description for info about writing a bail-out checker.

Definition at line 221 of file juce_ListenerList.h.

## ◆ callCheckedExcluding() [2/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename BailOutCheckerType, typename... MethodArgs, typename... Args>

void juce::ListenerList< ListenerClass, ArrayType >::callCheckedExcluding | ( | ListenerClass * | listenerToExclude,
|  | const BailOutCheckerType & | bailOutChecker,
|  | void(ListenerClass::* | callbackFunction )(MethodArgs...),
|  | Args &&... | args )
| inline

Calls a specific listener method for each listener in the list, except for the listener specified by listenerToExclude, additionally checking the bail-out checker before each call.

See the class description for info about writing a bail-out checker.

Definition at line 300 of file juce_ListenerList.h.

## ◆ callExcluding() [1/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename Callback>

void juce::ListenerList< ListenerClass, ArrayType >::callExcluding | ( | ListenerClass * | listenerToExclude,
|  | Callback && | callback )
| inline

Calls an invokable object for each listener in the list, except for the listener specified by listenerToExclude.

Definition at line 193 of file juce_ListenerList.h.

## ◆ callExcluding() [2/2]

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>
template<typename... MethodArgs, typename... Args>

void juce::ListenerList< ListenerClass, ArrayType >::callExcluding | ( | ListenerClass * | listenerToExclude,
|  | void(ListenerClass::* | callbackFunction )(MethodArgs...),
|  | Args &&... | args )
| inline

Calls a specific listener method for each listener in the list, except for the listener specified by listenerToExclude.

Definition at line 267 of file juce_ListenerList.h.

## ◆ clear()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::clear | ( |  | ) |
| inline

Clears the list.

If the ListenerList is cleared during a callback, it is guaranteed that no more listeners will be called.

Definition at line 155 of file juce_ListenerList.h.

## ◆ contains()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

bool juce::ListenerList< ListenerClass, ArrayType >::contains | ( | ListenerClass * | listener | ) | const
| inlinenoexcept

Returns true if the specified listener has been added to the list.

Definition at line 166 of file juce_ListenerList.h.

## ◆ getListeners()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

const ArrayType & juce::ListenerList< ListenerClass, ArrayType >::getListeners | ( |  | ) | const
| inlinenoexcept

Returns the raw array of listeners.

Any attempt to mutate the array may result in undefined behaviour.

If the array uses a mutex/CriticalSection, reading from the array without first obtaining the lock may potentially result in undefined behaviour.

See also
  add, remove, clear, contains

Definition at line 177 of file juce_ListenerList.h.

## ◆ isEmpty()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

bool juce::ListenerList< ListenerClass, ArrayType >::isEmpty | ( |  | ) | const
| inlinenoexcept

Returns true if no listeners are registered, false otherwise.

Definition at line 148 of file juce_ListenerList.h.

## ◆ remove()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

void juce::ListenerList< ListenerClass, ArrayType >::remove | ( | ListenerClass * | listenerToRemove | ) |
| inline

Removes a listener from the list. If the listener wasn't in the list, this has no effect.

If a Listener is removed during a callback, it is guaranteed not to be called if it hasn't already been called.

Definition at line 114 of file juce_ListenerList.h.

## ◆ size()

template<class ListenerClass, class ArrayType = Array<ListenerClass*>>

int juce::ListenerList< ListenerClass, ArrayType >::size | ( |  | ) | const
| inlinenoexcept

Returns the number of registered listeners.

Definition at line 145 of file juce_ListenerList.h.

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

- juce_ListenerList.h