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JUCE
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A powerful tree structure that can be used to hold free-form data, and which can handle its own undo and redo behaviour. More...
Classes | |
| class | Listener |
| Listener class for events that happen to a ValueTree. More... | |
Public Member Functions | |
| ValueTree () noexcept | |
| Creates an empty, invalid ValueTree. More... | |
| ValueTree (const Identifier &type) | |
| Creates an empty ValueTree with the given type name. More... | |
| ValueTree (const ValueTree &) noexcept | |
| Creates a reference to another ValueTree. More... | |
| ValueTree & | operator= (const ValueTree &) |
| Makes this object reference another node. More... | |
| ValueTree (ValueTree &&) noexcept | |
| ~ValueTree () | |
| Destructor. More... | |
| bool | operator== (const ValueTree &) const noexcept |
| Returns true if both this and the other tree node refer to the same underlying structure. More... | |
| bool | operator!= (const ValueTree &) const noexcept |
| Returns true if this and the other node refer to different underlying structures. More... | |
| bool | isEquivalentTo (const ValueTree &) const |
| Performs a deep comparison between the properties and children of two trees. More... | |
| bool | isValid () const noexcept |
| Returns true if this node refers to some valid data. More... | |
| ValueTree | createCopy () const |
| Returns a deep copy of this tree and all its sub-nodes. More... | |
| Identifier | getType () const noexcept |
| Returns the type of this node. More... | |
| bool | hasType (const Identifier &typeName) const noexcept |
| Returns true if the node has this type. More... | |
| const var & | getProperty (const Identifier &name) const noexcept |
| Returns the value of a named property. More... | |
| var | getProperty (const Identifier &name, const var &defaultReturnValue) const |
| Returns the value of a named property, or the value of defaultReturnValue if the property doesn't exist. More... | |
| const var * | getPropertyPointer (const Identifier &name) const noexcept |
| Returns a pointer to the value of a named property, or nullptr if the property doesn't exist. More... | |
| const var & | operator[] (const Identifier &name) const noexcept |
| Returns the value of a named property. More... | |
| ValueTree & | setProperty (const Identifier &name, const var &newValue, UndoManager *undoManager) |
| Changes a named property of the node. More... | |
| bool | hasProperty (const Identifier &name) const noexcept |
| Returns true if the node contains a named property. More... | |
| void | removeProperty (const Identifier &name, UndoManager *undoManager) |
| Removes a property from the node. More... | |
| void | removeAllProperties (UndoManager *undoManager) |
| Removes all properties from the node. More... | |
| int | getNumProperties () const noexcept |
| Returns the total number of properties that the node contains. More... | |
| Identifier | getPropertyName (int index) const noexcept |
| Returns the identifier of the property with a given index. More... | |
| Value | getPropertyAsValue (const Identifier &name, UndoManager *undoManager) |
| Returns a Value object that can be used to control and respond to one of the tree's properties. More... | |
| void | copyPropertiesFrom (const ValueTree &source, UndoManager *undoManager) |
| Overwrites all the properties in this tree with the properties of the source tree. More... | |
| int | getNumChildren () const noexcept |
| Returns the number of child nodes belonging to this one. More... | |
| ValueTree | getChild (int index) const |
| Returns one of this node's child nodes. More... | |
| ValueTree | getChildWithName (const Identifier &type) const |
| Returns the first child node with the specified type name. More... | |
| ValueTree | getOrCreateChildWithName (const Identifier &type, UndoManager *undoManager) |
| Returns the first child node with the specified type name, creating and adding a child with this name if there wasn't already one there. More... | |
| ValueTree | getChildWithProperty (const Identifier &propertyName, const var &propertyValue) const |
| Looks for the first child node that has the specified property value. More... | |
| void | addChild (const ValueTree &child, int index, UndoManager *undoManager) |
| Adds a child to this node. More... | |
| void | removeChild (const ValueTree &child, UndoManager *undoManager) |
| Removes the specified child from this node's child-list. More... | |
| void | removeChild (int childIndex, UndoManager *undoManager) |
| Removes a child from this node's child-list. More... | |
| void | removeAllChildren (UndoManager *undoManager) |
| Removes all child-nodes from this node. More... | |
| void | moveChild (int currentIndex, int newIndex, UndoManager *undoManager) |
| Moves one of the children to a different index. More... | |
| bool | isAChildOf (const ValueTree &possibleParent) const noexcept |
| Returns true if this node is anywhere below the specified parent node. More... | |
| int | indexOf (const ValueTree &child) const noexcept |
| Returns the index of a child item in this parent. More... | |
| ValueTree | getParent () const noexcept |
| Returns the parent node that contains this one. More... | |
| ValueTree | getSibling (int delta) const noexcept |
| Returns one of this node's siblings in its parent's child list. More... | |
| XmlElement * | createXml () const |
| Creates an XmlElement that holds a complete image of this node and all its children. More... | |
| String | toXmlString () const |
| This returns a string containing an XML representation of the tree. More... | |
| void | writeToStream (OutputStream &output) const |
| Stores this tree (and all its children) in a binary format. More... | |
| void | addListener (Listener *listener) |
| Adds a listener to receive callbacks when this node is changed. More... | |
| void | removeListener (Listener *listener) |
| Removes a listener that was previously added with addListener(). More... | |
| void | sendPropertyChangeMessage (const Identifier &property) |
| Causes a property-change callback to be triggered for the specified property, calling any listeners that are registered. More... | |
| template<typename ElementComparator > | |
| void | sort (ElementComparator &comparator, UndoManager *undoManager, bool retainOrderOfEquivalentItems) |
| This method uses a comparator object to sort the tree's children into order. More... | |
| int | getReferenceCount () const noexcept |
| Returns the total number of references to the shared underlying data structure that this ValueTree is using. More... | |
Static Public Member Functions | |
| static ValueTree | fromXml (const XmlElement &xml) |
| Tries to recreate a node from its XML representation. More... | |
| static ValueTree | readFromStream (InputStream &input) |
| Reloads a tree from a stream that was written with writeToStream(). More... | |
| static ValueTree | readFromData (const void *data, size_t numBytes) |
| Reloads a tree from a data block that was written with writeToStream(). More... | |
| static ValueTree | readFromGZIPData (const void *data, size_t numBytes) |
| Reloads a tree from a data block that was written with writeToStream() and then zipped using GZIPCompressorOutputStream. More... | |
Static Public Attributes | |
| static const ValueTree | invalid |
| An invalid ValueTree that can be used if you need to return one as an error condition, etc. More... | |
A powerful tree structure that can be used to hold free-form data, and which can handle its own undo and redo behaviour.
A ValueTree contains a list of named properties as var objects, and also holds any number of sub-trees.
Create ValueTree objects on the stack, and don't be afraid to copy them around, as they're simply a lightweight reference to a shared data container. Creating a copy of another ValueTree simply creates a new reference to the same underlying object - to make a separate, deep copy of a tree you should explicitly call createCopy().
Each ValueTree has a type name, in much the same way as an XmlElement has a tag name, and much of the structure of a ValueTree is similar to an XmlElement tree. You can convert a ValueTree to and from an XmlElement, and as long as the XML doesn't contain text elements, the conversion works well and makes a good serialisation format. They can also be serialised to a binary format, which is very fast and compact.
All the methods that change data take an optional UndoManager, which will be used to track any changes to the object. For this to work, you have to be careful to consistently always use the same UndoManager for all operations to any node inside the tree.
A ValueTree can only be a child of one parent at a time, so if you're moving one from one tree to another, be careful to always remove it first, before adding it. This could also mess up your undo/redo chain, so be wary! In a debug build you should hit assertions if you try to do anything dangerous, but there are still plenty of ways it could go wrong.
Note that although the children in a tree have a fixed order, the properties are not guaranteed to be stored in any particular order, so don't expect that a property's index will correspond to the order in which the property was added, or that it will remain constant when other properties are added or removed.
Listeners can be added to a ValueTree to be told when properies change and when nodes are added or removed.
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noexcept |
Creates an empty, invalid ValueTree.
A ValueTree that is created with this constructor can't actually be used for anything, it's just a default 'null' ValueTree that can be returned to indicate some sort of failure. To create a real one, use the constructor that takes a string.
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explicit |
Creates an empty ValueTree with the given type name.
Like an XmlElement, each ValueTree node has a type, which you can access with getType() and hasType().
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noexcept |
| ValueTree::~ValueTree | ( | ) |
Destructor.
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noexcept |
Returns true if both this and the other tree node refer to the same underlying structure.
Note that this isn't a value comparison - two independently-created trees which contain identical data are not considered equal.
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noexcept |
Returns true if this and the other node refer to different underlying structures.
Note that this isn't a value comparison - two independently-created trees which contain identical data are not considered equal.
| bool ValueTree::isEquivalentTo | ( | const ValueTree & | ) | const |
Performs a deep comparison between the properties and children of two trees.
If all the properties and children of the two trees are the same (recursively), this returns true. The normal operator==() only checks whether two trees refer to the same shared data structure, so use this method if you need to do a proper value comparison.
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noexcept |
Returns true if this node refers to some valid data.
It's hard to create an invalid node, but you might get one returned, e.g. by an out-of-range call to getChild().
| ValueTree ValueTree::createCopy | ( | ) | const |
Returns a deep copy of this tree and all its sub-nodes.
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noexcept |
Returns the type of this node.
The type is specified when the ValueTree is created.
Referenced by DrawablePath::ValueTreeWrapper::Element::getType().
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noexcept |
Returns true if the node has this type.
The comparison is case-sensitive.
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noexcept |
Returns the value of a named property.
If no such property has been set, this will return a void variant. You can also use operator[] to get a property.
| var ValueTree::getProperty | ( | const Identifier & | name, |
| const var & | defaultReturnValue | ||
| ) | const |
Returns the value of a named property, or the value of defaultReturnValue if the property doesn't exist.
You can also use operator[] and getProperty to get a property.
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noexcept |
Returns a pointer to the value of a named property, or nullptr if the property doesn't exist.
Referenced by CachedValue< Type >::forceUpdateOfCachedValue().
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noexcept |
Returns the value of a named property.
If no such property has been set, this will return a void variant. This is the same as calling getProperty().
| ValueTree& ValueTree::setProperty | ( | const Identifier & | name, |
| const var & | newValue, | ||
| UndoManager * | undoManager | ||
| ) |
Changes a named property of the node.
The name identifier must not be an empty string. If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
Referenced by CachedValue< Type >::setValue().
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noexcept |
Returns true if the node contains a named property.
Referenced by CachedValue< Type >::isUsingDefault().
| void ValueTree::removeProperty | ( | const Identifier & | name, |
| UndoManager * | undoManager | ||
| ) |
Removes a property from the node.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
Referenced by CachedValue< Type >::resetToDefault().
| void ValueTree::removeAllProperties | ( | UndoManager * | undoManager | ) |
Removes all properties from the node.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
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noexcept |
Returns the total number of properties that the node contains.
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noexcept |
Returns the identifier of the property with a given index.
Note that properties are not guaranteed to be stored in any particular order, so don't expect that the index will correspond to the order in which the property was added, or that it will remain constant when other properties are added or removed.
| Value ValueTree::getPropertyAsValue | ( | const Identifier & | name, |
| UndoManager * | undoManager | ||
| ) |
Returns a Value object that can be used to control and respond to one of the tree's properties.
The Value object will maintain a reference to this tree, and will use the undo manager when it needs to change the value. Attaching a Value::Listener to the value object will provide callbacks whenever the property changes.
Referenced by CachedValue< Type >::getPropertyAsValue().
| void ValueTree::copyPropertiesFrom | ( | const ValueTree & | source, |
| UndoManager * | undoManager | ||
| ) |
Overwrites all the properties in this tree with the properties of the source tree.
Any properties that already exist will be updated; and new ones will be added, and any that are not present in the source tree will be removed.
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noexcept |
Returns the number of child nodes belonging to this one.
| ValueTree ValueTree::getChild | ( | int | index | ) | const |
Returns one of this node's child nodes.
If the index is out of range, it'll return an invalid node. (See isValid() to find out whether a node is valid).
| ValueTree ValueTree::getChildWithName | ( | const Identifier & | type | ) | const |
Returns the first child node with the specified type name.
If no such node is found, it'll return an invalid node. (See isValid() to find out whether a node is valid).
| ValueTree ValueTree::getOrCreateChildWithName | ( | const Identifier & | type, |
| UndoManager * | undoManager | ||
| ) |
Returns the first child node with the specified type name, creating and adding a child with this name if there wasn't already one there.
The only time this will return an invalid object is when the object that you're calling the method on is itself invalid.
| ValueTree ValueTree::getChildWithProperty | ( | const Identifier & | propertyName, |
| const var & | propertyValue | ||
| ) | const |
Looks for the first child node that has the specified property value.
This will scan the child nodes in order, until it finds one that has property that matches the specified value.
If no such node is found, it'll return an invalid node. (See isValid() to find out whether a node is valid).
| void ValueTree::addChild | ( | const ValueTree & | child, |
| int | index, | ||
| UndoManager * | undoManager | ||
| ) |
Adds a child to this node.
Make sure that the child is removed from any former parent node before calling this, or you'll hit an assertion.
If the index is < 0 or greater than the current number of child nodes, the new node will be added at the end of the list.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
| void ValueTree::removeChild | ( | const ValueTree & | child, |
| UndoManager * | undoManager | ||
| ) |
Removes the specified child from this node's child-list.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
| void ValueTree::removeChild | ( | int | childIndex, |
| UndoManager * | undoManager | ||
| ) |
Removes a child from this node's child-list.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
| void ValueTree::removeAllChildren | ( | UndoManager * | undoManager | ) |
Removes all child-nodes from this node.
If the undoManager parameter is non-null, its UndoManager::perform() method will be used, so that this change can be undone.
| void ValueTree::moveChild | ( | int | currentIndex, |
| int | newIndex, | ||
| UndoManager * | undoManager | ||
| ) |
Moves one of the children to a different index.
This will move the child to a specified index, shuffling along any intervening items as required. So for example, if you have a list of { 0, 1, 2, 3, 4, 5 }, then calling move (2, 4) would result in { 0, 1, 3, 4, 2, 5 }.
| currentIndex | the index of the item to be moved. If this isn't a valid index, then nothing will be done |
| newIndex | the index at which you'd like this item to end up. If this is less than zero, the value will be moved to the end of the list |
| undoManager | the optional UndoManager to use to store this transaction |
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noexcept |
Returns true if this node is anywhere below the specified parent node.
This returns true if the node is a child-of-a-child, as well as a direct child.
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noexcept |
Returns the index of a child item in this parent.
If the child isn't found, this returns -1.
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noexcept |
Returns the parent node that contains this one.
If the node has no parent, this will return an invalid node. (See isValid() to find out whether a node is valid).
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noexcept |
Returns one of this node's siblings in its parent's child list.
The delta specifies how far to move through the list, so a value of 1 would return the node that follows this one, -1 would return the node before it, 0 will return this node itself, etc. If the requested position is beyond the range of available nodes, this will return ValueTree::invalid.
| XmlElement* ValueTree::createXml | ( | ) | const |
Creates an XmlElement that holds a complete image of this node and all its children.
If this node is invalid, this may return nullptr. Otherwise, the XML that is produced can be used to recreate a similar node by calling fromXml().
The caller must delete the object that is returned.
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static |
Tries to recreate a node from its XML representation.
This isn't designed to cope with random XML data - for a sensible result, it should only be fed XML that was created by the createXml() method.
| String ValueTree::toXmlString | ( | ) | const |
This returns a string containing an XML representation of the tree.
This is quite handy for debugging purposes, as it provides a quick way to view a tree.
| void ValueTree::writeToStream | ( | OutputStream & | output | ) | const |
Stores this tree (and all its children) in a binary format.
Once written, the data can be read back with readFromStream().
It's much faster to load/save your tree in binary form than as XML, but obviously isn't human-readable.
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static |
Reloads a tree from a stream that was written with writeToStream().
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static |
Reloads a tree from a data block that was written with writeToStream().
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static |
Reloads a tree from a data block that was written with writeToStream() and then zipped using GZIPCompressorOutputStream.
| void ValueTree::addListener | ( | Listener * | listener | ) |
Adds a listener to receive callbacks when this node is changed.
The listener is added to this specific ValueTree object, and not to the shared object that it refers to. When this object is deleted, all the listeners will be lost, even if other references to the same ValueTree still exist. And if you use the operator= to make this refer to a different ValueTree, any listeners will begin listening to changes to the new tree instead of the old one.
When you're adding a listener, make sure that you add it to a ValueTree instance that will last for as long as you need the listener. In general, you'd never want to add a listener to a local stack-based ValueTree, and would usually add one to a member variable.
Referenced by CachedValue< Type >::CachedValue(), and CachedValue< Type >::forceUpdateOfCachedValue().
| void ValueTree::removeListener | ( | Listener * | listener | ) |
Removes a listener that was previously added with addListener().
Referenced by CachedValue< Type >::forceUpdateOfCachedValue().
| void ValueTree::sendPropertyChangeMessage | ( | const Identifier & | property | ) |
Causes a property-change callback to be triggered for the specified property, calling any listeners that are registered.
| void ValueTree::sort | ( | ElementComparator & | comparator, |
| UndoManager * | undoManager, | ||
| bool | retainOrderOfEquivalentItems | ||
| ) |
This method uses a comparator object to sort the tree's children into order.
The object provided must have a method of the form:
..and this method must return:
To improve performance, the compareElements() method can be declared as static or const.
| comparator | the comparator to use for comparing elements. |
| undoManager | optional UndoManager for storing the changes |
| retainOrderOfEquivalentItems | if this is true, then items which the comparator says are equivalent will be kept in the order in which they currently appear in the array. This is slower to perform, but may be important in some cases. If it's false, a faster algorithm is used, but equivalent elements may be rearranged. |
References OwnedArray< ObjectClass, TypeOfCriticalSectionToUse >::sort().
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noexcept |
Returns the total number of references to the shared underlying data structure that this ValueTree is using.
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static |
