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juce::CachedValue< Type > Class Template Reference

## Detailed Description

template<typename Type>
class juce::CachedValue< Type >

This class acts as a typed wrapper around a property inside a ValueTree.

A CachedValue provides an easy way to read and write a ValueTree property with a chosen type. So for example a CachedValue<int> allows you to read or write the property as an int, and a CachedValue<String> lets you work with it as a String.

It also allows efficient access to the value, by caching a copy of it in the type that is being used.

You can give the CachedValue an optional UndoManager which it will use when writing to the underlying ValueTree.

If the property inside the ValueTree is missing, the CachedValue will automatically return an optional default value, which can be specified when initialising the CachedValue.

To create one, you can either use the constructor to attach the CachedValue to a ValueTree, or can create an uninitialised CachedValue with its default constructor and then attach it later with the referTo() methods.

Common types like String, int, double which can be easily converted to a var should work out-of-the-box, but if you want to use more complex custom types, you may need to implement some template specialisations of VariantConverter which this class uses to convert between the type and the ValueTree's internal var.

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

- juce_data_structures/values/juce_CachedValue.h

Inheritance diagram for juce::CachedValue< Type >:

## Public Member Functions

| CachedValue ()
| Default constructor.
| CachedValue (ValueTree &tree, const Identifier &propertyID, UndoManager *undoManager)
| Constructor.
| CachedValue (ValueTree &tree, const Identifier &propertyID, UndoManager *undoManager, const Type &defaultToUse)
| Constructor.
| operator Type () const noexcept
| Returns the current value of the property.
Type | get () const noexcept
| Returns the current value of the property.
const Type & | operator* () const noexcept
| Dereference operator.
const Type * | operator-> () const noexcept
| Dereference operator.
template<typename OtherType>
bool | operator== (const OtherType &other) const
| Returns true if the current value of the property (or the fallback value) is equal to other.
template<typename OtherType>
bool | operator!= (const OtherType &other) const
| Returns true if the current value of the property (or the fallback value) is not equal to other.
Value | getPropertyAsValue ()
| Returns the current property as a Value object.
bool | isUsingDefault () const
| Returns true if the current property does not exist and the CachedValue is using the fallback default value instead.
Type | getDefault () const
| Returns the current fallback default value.
CachedValue & | operator= (const Type &newValue)
| Sets the property.
void | setValue (const Type &newValue, UndoManager *undoManagerToUse)
| Sets the property.
void | resetToDefault ()
| Removes the property from the referenced ValueTree and makes the CachedValue return the fallback default value instead.
void | resetToDefault (UndoManager *undoManagerToUse)
| Removes the property from the referenced ValueTree and makes the CachedValue return the fallback default value instead.
void | setDefault (const Type &value)
| Resets the fallback default value.
void | referTo (ValueTree &tree, const Identifier &property, UndoManager *um)
| Makes the CachedValue refer to the specified property inside the given ValueTree.
void | referTo (ValueTree &tree, const Identifier &property, UndoManager *um, const Type &defaultVal)
| Makes the CachedValue refer to the specified property inside the given ValueTree, and specifies a fallback value to use if the property does not exist.
void | forceUpdateOfCachedValue ()
| Force an update in case the referenced property has been changed from elsewhere.
ValueTree & | getValueTree () noexcept
| Returns a reference to the ValueTree containing the referenced property.
const Identifier & | getPropertyID () const noexcept
| Returns the property ID of the referenced property.
UndoManager * | getUndoManager () noexcept
| Returns the UndoManager that is being used.

## Constructors and Destructors

## CachedValue() [1/3]

template<typename Type>

juce::CachedValue< Type >::CachedValue | ( |  | ) |

inline default

Default constructor.

Creates a default CachedValue not referring to any property. To initialise the object, call one of the referTo() methods.

Referenced by operator=().

## CachedValue() [2/3]

template<typename Type>

juce::CachedValue< Type >::CachedValue | ( | ValueTree & | tree,
|  | const Identifier & | propertyID,
|  | UndoManager * | undoManager )

inline

Constructor.

Creates a CachedValue referring to a Value property inside a ValueTree. If you use this constructor, the fallback value will be a default-constructed instance of Type.

Parameters

  tree | The ValueTree containing the property
  propertyID | The identifier of the property
  undoManager | The UndoManager to use when writing to the property

## CachedValue() [3/3]

template<typename Type>

juce::CachedValue< Type >::CachedValue | ( | ValueTree & | tree,
|  | const Identifier & | propertyID,
|  | UndoManager * | undoManager,
|  | const Type & | defaultToUse )

inline

Constructor.

Creates a default Cached Value referring to a Value property inside a ValueTree, and specifies a fallback value to use if the property does not exist.

Parameters

  tree | The ValueTree containing the property
  propertyID | The identifier of the property
  undoManager | The UndoManager to use when writing to the property
  defaultToUse | The fallback default value to use.

## Member Functions

## operator Type()

template<typename Type>

juce::CachedValue< Type >::operator Type | ( |  | ) | const

inline noexcept

Returns the current value of the property.

If the property does not exist, returns the fallback default value.

This is the same as calling get().

## get()

template<typename Type>

Type juce::CachedValue< Type >::get | ( |  | ) | const

inline noexcept

Returns the current value of the property.

If the property does not exist, returns the fallback default value.

## operator*()

template<typename Type>

const Type & juce::CachedValue< Type >::operator* | ( |  | ) | const

inline noexcept

Dereference operator.

Provides direct access to the property.

## operator->()

template<typename Type>

const Type * juce::CachedValue< Type >::operator-> | ( |  | ) | const

inline noexcept

Dereference operator.

Provides direct access to members of the property if it is of object type.

## operator==()

template<typename Type>
template<typename OtherType>

bool juce::CachedValue< Type >::operator== | ( | const OtherType & | other | ) | const

inline

Returns true if the current value of the property (or the fallback value) is equal to other.

Referenced by operator!=().

## operator!=()

template<typename Type>
template<typename OtherType>

bool juce::CachedValue< Type >::operator!= | ( | const OtherType & | other | ) | const

inline

Returns true if the current value of the property (or the fallback value) is not equal to other.

References operator==().

## getPropertyAsValue()

template<typename Type>

Value juce::CachedValue< Type >::getPropertyAsValue | ( |  | ) |

inline

Returns the current property as a Value object.

## isUsingDefault()

template<typename Type>

bool juce::CachedValue< Type >::isUsingDefault | ( |  | ) | const

inline

Returns true if the current property does not exist and the CachedValue is using the fallback default value instead.

Referenced by setValue().

## getDefault()

template<typename Type>

Type juce::CachedValue< Type >::getDefault | ( |  | ) | const

inline

Returns the current fallback default value.

## operator=()

template<typename Type>

CachedValue< Type > & juce::CachedValue< Type >::operator= | ( | const Type & | newValue | ) |

inline

Sets the property.

This will actually modify the property in the referenced ValueTree.

References CachedValue(), and setValue().

## setValue()

template<typename Type>

void juce::CachedValue< Type >::setValue | ( | const Type & | newValue,
|  | UndoManager * | undoManagerToUse )

inline

Sets the property.

This will actually modify the property in the referenced ValueTree.

References juce::exactlyEqual(), isUsingDefault(), and juce::VariantConverter< Type >::toVar().

Referenced by operator=().

## resetToDefault() [1/2]

template<typename Type>

void juce::CachedValue< Type >::resetToDefault | ( |  | ) |

inline

Removes the property from the referenced ValueTree and makes the CachedValue return the fallback default value instead.

References resetToDefault().

Referenced by resetToDefault().

## resetToDefault() [2/2]

template<typename Type>

void juce::CachedValue< Type >::resetToDefault | ( | UndoManager * | undoManagerToUse | ) |

inline

Removes the property from the referenced ValueTree and makes the CachedValue return the fallback default value instead.

References forceUpdateOfCachedValue().

## setDefault()

template<typename Type>

void juce::CachedValue< Type >::setDefault | ( | const Type & | value | ) |

inline

Resets the fallback default value.

## referTo() [1/2]

template<typename Type>

void juce::CachedValue< Type >::referTo | ( | ValueTree & | tree,
|  | const Identifier & | property,
|  | UndoManager * | um )

inline

Makes the CachedValue refer to the specified property inside the given ValueTree.

## referTo() [2/2]

template<typename Type>

void juce::CachedValue< Type >::referTo | ( | ValueTree & | tree,
|  | const Identifier & | property,
|  | UndoManager * | um,
|  | const Type & | defaultVal )

inline

Makes the CachedValue refer to the specified property inside the given ValueTree, and specifies a fallback value to use if the property does not exist.

## forceUpdateOfCachedValue()

template<typename Type>

void juce::CachedValue< Type >::forceUpdateOfCachedValue | ( |  | ) |

inline

Force an update in case the referenced property has been changed from elsewhere.

Note: The CachedValue is a ValueTree::Listener and therefore will be informed of changes of the referenced property anyway (and update itself). But this may happen asynchronously. forceUpdateOfCachedValue() forces an update immediately.

Referenced by resetToDefault().

## getValueTree()

template<typename Type>

ValueTree & juce::CachedValue< Type >::getValueTree | ( |  | ) |

inline noexcept

Returns a reference to the ValueTree containing the referenced property.

## getPropertyID()

template<typename Type>

const Identifier & juce::CachedValue< Type >::getPropertyID | ( |  | ) | const

inline noexcept

Returns the property ID of the referenced property.

## getUndoManager()

template<typename Type>

UndoManager * juce::CachedValue< Type >::getUndoManager | ( |  | ) |

inline noexcept

Returns the UndoManager that is being used.

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