IFoldingView (yFiles-for-JavaFX-Complete-3.0 API)

All Superinterfaces:

ILookup
```
public interface IFoldingView
extends ILookup
```
Interface that is used for manipulating a managed view of an IGraph that supports folding operations like expanding and collapsing of nodes.
The FoldingManager creates views of a MasterGraph which is created using copies of the original "master" entities. The views are being synchronized via the MasterGraph, but may contain additional view state. Typically nodes and edges are being copied from the MasterGraph and they share many of their properties by reference (e.g. Style). However if group nodes are being represented by collapsed group nodes in this view, they maintain a separate set of labels, ports, bends, and geometry. This view-local state is shared between all views that have been created by the same Manager and can be obtained and modified via the FoldingManager's GetFoldingEdgeState methods for folding edges and folder nodes in the absence of a corresponding IFoldingView view instance. Developers typically don't need to implement this interface themselves, rather an implementation is provided by the framework and can be obtained from the FoldingManager. Use FoldingManager.createFoldingView(INode, java.util.function.Predicate) to obtain an IGraph implementation that contains an implementation of this class in its ILookup.lookup(java.lang.Class) method:

This interface supports the PropertyChanged event. This can be used to easily monitor the validity of this view. Also changes to the LocalRoot property will be published via this event.

A brief description of the interface's API and some usage aspects is given in the section Working with Folding. Class FoldingManager's central role for folding support in general is discussed in the section Folding Revisited.

See Also:

FoldingManager

Field Summary
- Fields inherited from interface com.yworks.yfiles.graph.ILookup
  EMPTY

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`void`	`addGroupCollapsedListener(IEventHandler<ItemEventArgs<INode>> groupCollapsedEvent)` Adds the given listener for the `GroupCollapsed` event that occurs whenever a group has been `collapse(INode)`d.
`void`	`addGroupExpandedListener(IEventHandler<ItemEventArgs<INode>> groupExpandedEvent)` Adds the given listener for the `GroupExpanded` event that occurs whenever a group has been `expand(INode)`ed.
`void`	`addPropertyChangedListener(IEventHandler<PropertyChangedEventArgs> propertyChangedEvent)` Adds the given listener for the `PropertyChanged` event that occurs whenever the view becomes invalid or the `LocalRoot` property changes.
`void`	`collapse(INode groupNode)` This method will collapse the `children` of a group node into the group node.
`default INode`	`createFolderNode()` Directly creates a collapsed node on this instance with the given parameters.
`default INode`	`createFolderNode(INode parent)` Directly creates a collapsed node on this instance with the given parameters.
`default INode`	`createFolderNode(INode parent, RectD layout)` Directly creates a collapsed node on this instance with the given parameters.
`default INode`	`createFolderNode(INode parent, RectD layout, INodeStyle style)` Directly creates a collapsed node on this instance with the given parameters.
`INode`	`createFolderNode(INode parent, RectD layout, INodeStyle style, Object tag)` Directly creates a collapsed node on this instance with the given parameters.
`void`	`dispose()` Disposes of this view explicitly.
`void`	`expand(INode groupNode)` This method will expand a previously `collapsed` group node to make its contents appear in this view.
`IGraph`	`getGraph()` Provides a reference to the `IGraph` implementation that provides the actual view data.
`INode`	`getLocalRoot()` Gets an entity of the `MasterGraph` hierarchy to serve as the virtual root for the view's local hierarchy.
`FoldingManager`	`getManager()` Provides access to the manager that created this view and that contains a reference to the `MasterGraph`.
`IEnumerable<IEdge>`	`getMasterEdges(IEdge foldingEdge)` Helper method that corresponds to the `getMasterItem(IModelItem)` method, but is used for folding edges, only.
`<T extends IModelItem> T`	`getMasterItem(T item)` Helper method that can be used to retrieve the original "master" items in the `MasterGraph` that is managed by the `Manager` associated with this view.
`<T extends IModelItem> T`	`getViewItem(T item)` Helper method that can be used to retrieve the items in this `Graph`-view for all items that are part of the `MasterGraph` that is associated with the `Manager` of this instance.
`boolean`	`isAutoSwitchingToAncestorEnabled()` Determines whether this instance should automatically switch the `LocalRoot` to an ancestor of the current root, if this view becomes `Invalid`.
`boolean`	`isExpanded(INode groupNode)` Determines whether the provided node is currently expanded or will be displayed in `expand(INode)`ed state the next time it will be included in this view.
`boolean`	`isInFoldingState(IModelItem item)` Determines whether the specified item is a folding state in this view.
`boolean`	`isInvalid()` Determines if this view is currently valid and can be edited.
`boolean`	`isNavigationalUndoUnitsEnqueuingEnabled()` Determines whether changes to the `LocalRoot` property and calls to `collapse(INode)` and `expand(INode)` should be recorded in undo history.
`void`	`removeGroupCollapsedListener(IEventHandler<ItemEventArgs<INode>> groupCollapsedEvent)` Removes the given listener for the `GroupCollapsed` event that occurs whenever a group has been `collapse(INode)`d.
`void`	`removeGroupExpandedListener(IEventHandler<ItemEventArgs<INode>> groupExpandedEvent)` Removes the given listener for the `GroupExpanded` event that occurs whenever a group has been `expand(INode)`ed.
`void`	`removePropertyChangedListener(IEventHandler<PropertyChangedEventArgs> propertyChangedEvent)` Removes the given listener for the `PropertyChanged` event that occurs whenever the view becomes invalid or the `LocalRoot` property changes.
`void`	`setAutoSwitchingToAncestorEnabled(boolean value)` Determines whether this instance should automatically switch the `LocalRoot` to an ancestor of the current root, if this view becomes `Invalid`.
`void`	`setLocalRoot(INode value)` Sets an entity of the `MasterGraph` hierarchy to serve as the virtual root for the view's local hierarchy.
`void`	`setNavigationalUndoUnitsEnqueuingEnabled(boolean value)` Determines whether changes to the `LocalRoot` property and calls to `collapse(INode)` and `expand(INode)` should be recorded in undo history.

Methods inherited from interface com.yworks.yfiles.graph.ILookup
createDictionaryLookup, createDynamic, createSingle, createSingle, createWrapped, lookup, lookup, lookup, safeLookup

- Method Detail
  - addGroupCollapsedListener
```
void addGroupCollapsedListener(IEventHandler<ItemEventArgs<INode>> groupCollapsedEvent)
```
    Adds the given listener for the GroupCollapsed event that occurs whenever a group has been collapse(INode)d.
    
    Parameters:
    
    groupCollapsedEvent - The listener to add.
    
    See Also:
    
    removeGroupCollapsedListener(IEventHandler)
  - addGroupExpandedListener
```
void addGroupExpandedListener(IEventHandler<ItemEventArgs<INode>> groupExpandedEvent)
```
    Adds the given listener for the GroupExpanded event that occurs whenever a group has been expand(INode)ed.
    
    Parameters:
    
    groupExpandedEvent - The listener to add.
    
    See Also:
    
    removeGroupExpandedListener(IEventHandler)
  - addPropertyChangedListener
```
void addPropertyChangedListener(IEventHandler<PropertyChangedEventArgs> propertyChangedEvent)
```
    Adds the given listener for the PropertyChanged event that occurs whenever the view becomes invalid or the LocalRoot property changes.
    
    Parameters:
    
    propertyChangedEvent - The listener to add.
    
    See Also:
    
    removePropertyChangedListener(IEventHandler)
  - collapse
```
void collapse(INode groupNode)
```
    This method will collapse the children of a group node into the group node.
    If a group node that belongs to this view's hierarchy is in expanded state, calling this method will remove the children from this view. This method will do nothing if the node is already collapsed. Note that collapsing a group node will make it a non-group node in the hierarchy. The collapsed group node has its own separate set of attributes, which can be obtained using the FoldingManager.getFolderNodeState(INode) method. Therefore it may appear that the node changes its location during a collapse operation. This behavior ensures that collapsing a node does not modify the state of the model (only the state in the view is changed), but depending on the application this may confuse the user because he might loose his mental map of the diagram. In order to customize the behavior custom code can register with the GroupCollapsed event to perform the necessary modifications, like adjusting the view port or moving the node to the desired location.
    
    In addition to that this method can also be used for master nodes which are currently not represented in this view. In this case these nodes will be displayed as collapsed the next time they will be included in this view.
    
    Parameters:
    
    groupNode - A group node that is part of the Graph or the master graph.
    
    See Also:
    
    isExpanded(INode)
  - createFolderNode
```
default INode createFolderNode()
```
    Directly creates a collapsed node on this instance with the given parameters.
    This will implicitly create a new empty group node on the MasterGraph with the defaults for such a group node. The parent must be part of the Folded Graph View or null to create a folder at the root of the current hierarchy. It will be converted into a group node if necessary. The returned INode is also part of the Folded Graph View.
    
    Returns:
    
    A collapsed (folder) node that lives in Graph
  - createFolderNode
```
default INode createFolderNode(INode parent)
```
    Directly creates a collapsed node on this instance with the given parameters.
    This will implicitly create a new empty group node on the MasterGraph with the defaults for such a group node. The parent must be part of the Folded Graph View or null to create a folder at the root of the current hierarchy. It will be converted into a group node if necessary. The returned INode is also part of the Folded Graph View.
    
    Parameters:
    
    parent - The parent node in the Graph, or null
    
    Returns:
    
    A collapsed (folder) node that lives in Graph
  - createFolderNode
```
default INode createFolderNode(INode parent,
                               RectD layout)
```
    Directly creates a collapsed node on this instance with the given parameters.
    This will implicitly create a new empty group node on the MasterGraph with the defaults for such a group node. The parent must be part of the Folded Graph View or null to create a folder at the root of the current hierarchy. It will be converted into a group node if necessary. The returned INode is also part of the Folded Graph View.
    
    Parameters:
    
    parent - The parent node in the Graph, or null
    
    layout - The layout for the collapsed node.
    
    Returns:
    
    A collapsed (folder) node that lives in Graph
  - createFolderNode
```
default INode createFolderNode(INode parent,
                               RectD layout,
                               INodeStyle style)
```
    Directly creates a collapsed node on this instance with the given parameters.
    This will implicitly create a new empty group node on the MasterGraph with the defaults for such a group node. The parent must be part of the Folded Graph View or null to create a folder at the root of the current hierarchy. It will be converted into a group node if necessary. The returned INode is also part of the Folded Graph View.
    
    Parameters:
    
    parent - The parent node in the Graph, or null
    
    layout - The layout for the collapsed node.
    
    style - The style for the collapsed node
    
    Returns:
    
    A collapsed (folder) node that lives in Graph
  - createFolderNode
```
INode createFolderNode(INode parent,
                       RectD layout,
                       INodeStyle style,
                       Object tag)
```
    Directly creates a collapsed node on this instance with the given parameters.
    This will implicitly create a new empty group node on the MasterGraph with the defaults for such a group node. The parent must be part of the Folded Graph View or null to create a folder at the root of the current hierarchy. It will be converted into a group node if necessary. The returned INode is also part of the Folded Graph View.
    
    Parameters:
    
    parent - The parent node in the Graph, or null
    
    layout - The layout for the collapsed node.
    
    style - The style for the collapsed node
    
    tag - The tag of the node.
    
    Returns:
    
    A collapsed (folder) node that lives in Graph
  - dispose
```
void dispose()
```
    Disposes of this view explicitly.
    Normally it is not necessary to do so, because the view will be garbage collected automatically. However if the view still displays contents, this might have unwanted negative side effects (group node sizes being calculated, etc.) A disposed of instance is not synchronized with the FoldingManager anymore and should not be used anymore.
  - expand
```
void expand(INode groupNode)
```
    This method will expand a previously collapsed group node to make its contents appear in this view.
    If a node that belongs to this view is in collapsed state, calling this method will make the children appear in this view. This method will do nothing if the node is already expanded. Note that expanding a collapsed group node will make the node a group node, whereas a collapsed group node is no group node in this hierarchy and thus cannot have visible children. The expanded group node has its own separate set of attributes, which may be different from the collapsed state that can be obtained using the FoldingManager.getFolderNodeState(INode) method. The expanded state is always the same as the state of the master node. Because of these differences it may appear that the node changes its location during an expand operation. This behavior ensures that expanding a node does not modify the state of the model by moving the node or its descendants (only the state in the view is changed), but depending on the application this may confuse the user because he might loose his mental map of the diagram. In order to customize the behavior custom code can register with the GroupExpanded event to perform the necessary modifications, like adjusting the view port or moving the node and its descendants to the desired location.
    
    In addition to that this method can also be used for master nodes which are currently not represented in this view. In this case these nodes will be displayed as expanded the next time they will be included in this view.
    
    Parameters:
    
    groupNode - A group node that is part of the Graph or the master graph.
    
    See Also:
    
    isExpanded(INode), collapse(INode)
  - getGraph
```
IGraph getGraph()
```
    Provides a reference to the IGraph implementation that provides the actual view data.
    The instance has an implementation of this interface in its ILookup that has been obtained from the FoldingManager's FoldingManager.createFoldingView(INode, java.util.function.Predicate) set of methods. The instance holds the elements in the view only, which in general is a subset of the MasterGraph. Also note that the elements are not the same references as their masters, they are copies that may share the same attributes.
    
    Returns:
    
    The Graph.
  - getLocalRoot
```
INode getLocalRoot()
```
    Gets an entity of the MasterGraph hierarchy to serve as the virtual root for the view's local hierarchy.
    This property can be set to any group node in the MasterGraph's hierarchy whose contents will then be represented in this view. Note that the root of the view's local hierarchy is not set to the same instance.
    
    Returns:
    
    The LocalRoot.
    
    See Also:
    
    setLocalRoot(INode)
  - getManager
```
FoldingManager getManager()
```
    Provides access to the manager that created this view and that contains a reference to the MasterGraph.
    
    Returns:
    
    The Manager.
  - getMasterEdges
```
IEnumerable<IEdge> getMasterEdges(IEdge foldingEdge)
```
    Helper method that corresponds to the getMasterItem(IModelItem) method, but is used for folding edges, only.
    Since folding edges can represent more than one master edge, this method can be used to query all of the master edges that the provided folding edge represents. If the folding edge corresponds to a single master edge, the result will enumerate that edge, only.
    
    Parameters:
    
    foldingEdge - The folding edge for which the master edges should be returned.
    
    Returns:
    
    An enumerable that can enumerate all of the edges in the MasterGraph that are being represented by the folding edge in this view.
    
    See Also:
    
    IFoldingEdgeFactory.addToExistingFoldingEdge(IEdge), getViewItem(IModelItem)
  - getMasterItem
```
<T extends IModelItem> T getMasterItem(T item)
```
    Helper method that can be used to retrieve the original "master" items in the MasterGraph that is managed by the Manager associated with this view.
    Since the Graph view that is associated with this instance maintains a copy of the entities in the Manager's MasterGraph, there is a mapping between elements that belong to this view's Graph and the elements in the master graph. This method can be called for the elements contained in this IGraph and will return the corresponding item in the master graph that the element corresponds to, if any. Note that for some items in the Graph, there is no master item in the MasterGraph, e.g. the IPort instances to which folding edges connect have no corresponding ports in the master graph. The same holds true for the bends and labels of folding edges and folder nodes. For folding edges, this method will yield the main representing edge in the master, if the folding edge represents more than one master edge. For nodes, the master node will be returned, no matter whether the node is currently collapsed or not.
    
    Type Parameters:
    
    T - The type of the argument, which is typically INode, IEdge, ILabel, IBend, or IPort.
    
    Parameters:
    
    item - The item that is part of this Graph for which the original "master" item in the MasterGraph will be returned.
    
    Returns:
    
    An item in the MasterGraph that corresponds to the item or null, if there is no such item.
    
    See Also:
    
    getViewItem(IModelItem)
  - getViewItem
```
<T extends IModelItem> T getViewItem(T item)
```
    Helper method that can be used to retrieve the items in this Graph-view for all items that are part of the MasterGraph that is associated with the Manager of this instance.
    Since the Graph view that is associated with this instance maintains a copy of the entities in the Manager's MasterGraph, there is a mapping between elements that belong to master graph and the elements in the Graph of this view. This method can be called for the elements contained in this master graph's items and will return the corresponding item in this view's Graph if the element is represented by an item in this view. Note that for some items in the MasterGraph, there may be no item in the Graph instance, e.g. those elements which are part of a collapsed subtree in the MasterGraph hierarchy or those items that do not belong to the subtree that is induced by the LocalRoot of this view. Also, for nodes and edges that are being represented by dummies in this view, labels, ports, and bends are not being represented directly by corresponding entities in this graph. If more than one edge is represented by a folding edge in this view, this method will yield the same folding edge instance for each of them.
    
    Type Parameters:
    
    T - The type of the argument, which is typically INode, IEdge, ILabel, IBend, or IPort.
    
    Parameters:
    
    item - An item that is part of the MasterGraph that is associated with the Manager of this instance.
    
    Returns:
    
    An item in the local graph view that corresponds to the item or null, if the item is not currently being represented in this view.
    
    See Also:
    
    getMasterItem(IModelItem), getMasterEdges(IEdge)
  - isAutoSwitchingToAncestorEnabled
```
boolean isAutoSwitchingToAncestorEnabled()
```
    Determines whether this instance should automatically switch the LocalRoot to an ancestor of the current root, if this view becomes Invalid.
    By default this property is set to true which assures that this view will never become Invalid. It is the responsibility of the client code to check for the validity of this view before trying to modify it if this feature is disabled.
    
    Returns:
    
    The AutoSwitchingToAncestorEnabled.
    
    See Also:
    
    setAutoSwitchingToAncestorEnabled(boolean)
  - isExpanded
```
boolean isExpanded(INode groupNode)
```
    Determines whether the provided node is currently expanded or will be displayed in expand(INode)ed state the next time it will be included in this view.
    Expanded group nodes will have all of their children visible in this view.
    
    The groupNode can be either a node of the view or the master graph. If the node is from the master graph and is currently not represented in this view, this method will return the expand(INode)ed state it will have the next time it will be included in this view.
    
    Parameters:
    
    groupNode - The group node for which the expanded state will be returned.
    
    Returns:
    
    true, if the group node can be collapsed.
  - isInFoldingState
```
boolean isInFoldingState(IModelItem item)
```
    Determines whether the specified item is a folding state in this view.
    This method can be used to determine if an INode, IEdge, IPort, ILabel, or IBend has a view local state and is not a direct copy of the master item, if any. Note that collapsed group nodes are in folding state, even though they do have a master item in the master graph and folding edges always have at least one master edge, while all other folding items don't have a corresponding master item in the master graph.
    
    Parameters:
    
    item - One of the items that are contained in the Graph.
    
    Returns:
    
    Whether the item is in folding state and is not an exact copy of an item in the MasterGraph.
  - isInvalid
```
boolean isInvalid()
```
    Determines if this view is currently valid and can be edited.
    A view is invalid if the LocalRoot is not currently part of the MasterGraph hierarchy. This can happen if the root node is removed from the MasterGraph. Note that the view can become valid again if the removal is undone.
    
    Returns:
    
    The Invalid.
    
    See Also:
    
    isAutoSwitchingToAncestorEnabled()
  - isNavigationalUndoUnitsEnqueuingEnabled
```
boolean isNavigationalUndoUnitsEnqueuingEnabled()
```
    Determines whether changes to the LocalRoot property and calls to collapse(INode) and expand(INode) should be recorded in undo history.
    By default this property is set to false, however depending on the use case it may make sense to enqueue IUndoUnits for this type of operations.
    
    Returns:
    
    The NavigationalUndoUnitsEnqueuingEnabled.
    
    See Also:
    
    isAutoSwitchingToAncestorEnabled(), setNavigationalUndoUnitsEnqueuingEnabled(boolean)
  - removeGroupCollapsedListener
```
void removeGroupCollapsedListener(IEventHandler<ItemEventArgs<INode>> groupCollapsedEvent)
```
    Removes the given listener for the GroupCollapsed event that occurs whenever a group has been collapse(INode)d.
    
    Parameters:
    
    groupCollapsedEvent - The listener to remove.
    
    See Also:
    
    addGroupCollapsedListener(IEventHandler)
  - removeGroupExpandedListener
```
void removeGroupExpandedListener(IEventHandler<ItemEventArgs<INode>> groupExpandedEvent)
```
    Removes the given listener for the GroupExpanded event that occurs whenever a group has been expand(INode)ed.
    
    Parameters:
    
    groupExpandedEvent - The listener to remove.
    
    See Also:
    
    addGroupExpandedListener(IEventHandler)
  - removePropertyChangedListener
```
void removePropertyChangedListener(IEventHandler<PropertyChangedEventArgs> propertyChangedEvent)
```
    Removes the given listener for the PropertyChanged event that occurs whenever the view becomes invalid or the LocalRoot property changes.
    
    Parameters:
    
    propertyChangedEvent - The listener to remove.
    
    See Also:
    
    addPropertyChangedListener(IEventHandler)
  - setAutoSwitchingToAncestorEnabled
```
void setAutoSwitchingToAncestorEnabled(boolean value)
```
    Determines whether this instance should automatically switch the LocalRoot to an ancestor of the current root, if this view becomes Invalid.
    By default this property is set to true which assures that this view will never become Invalid. It is the responsibility of the client code to check for the validity of this view before trying to modify it if this feature is disabled.
    
    Parameters:
    
    value - The AutoSwitchingToAncestorEnabled to set.
    
    See Also:
    
    isAutoSwitchingToAncestorEnabled()
  - setLocalRoot
```
void setLocalRoot(INode value)
```
    Sets an entity of the MasterGraph hierarchy to serve as the virtual root for the view's local hierarchy.
    This property can be set to any group node in the MasterGraph's hierarchy whose contents will then be represented in this view. Note that the root of the view's local hierarchy is not set to the same instance.
    
    Parameters:
    
    value - The LocalRoot to set.
    
    See Also:
    
    getLocalRoot()
  - setNavigationalUndoUnitsEnqueuingEnabled
```
void setNavigationalUndoUnitsEnqueuingEnabled(boolean value)
```
    Determines whether changes to the LocalRoot property and calls to collapse(INode) and expand(INode) should be recorded in undo history.
    By default this property is set to false, however depending on the use case it may make sense to enqueue IUndoUnits for this type of operations.
    
    Parameters:
    
    value - The NavigationalUndoUnitsEnqueuingEnabled to set.
    
    See Also:
    
    isAutoSwitchingToAncestorEnabled(), isNavigationalUndoUnitsEnqueuingEnabled()

Interface IFoldingView

Field Summary

Fields inherited from interface com.yworks.yfiles.graph.ILookup

Method Summary

Methods inherited from interface com.yworks.yfiles.graph.ILookup

Method Detail

addGroupCollapsedListener

addGroupExpandedListener

addPropertyChangedListener

collapse

createFolderNode

createFolderNode

createFolderNode

createFolderNode

createFolderNode

dispose

expand

getGraph

getLocalRoot

getManager

getMasterEdges

getMasterItem

getViewItem

isAutoSwitchingToAncestorEnabled

isExpanded

isInFoldingState

isInvalid

isNavigationalUndoUnitsEnqueuingEnabled

removeGroupCollapsedListener

removeGroupExpandedListener

removePropertyChangedListener

setAutoSwitchingToAncestorEnabled

setLocalRoot

setNavigationalUndoUnitsEnqueuingEnabled