com.yworks.yfiles.server.graphml.flexio.data
Interface INodeHierarchy

All Known Implementing Classes:

DefaultNodeHierarchy

public interface INodeHierarchy

Provides utility functions to query and modify the the node hierarchy of a grouped LayoutGraph.

Internally, the hierarchy is managed using data providers that can be obtained from the graph using the following keys:

• GroupingKeys.NODE_ID_DPKEY - Stores an id for each node. In a yFiles FLEX server component, the NODE_ID_DPKEY data provider is the same instance as the AbstractGraphRoundtripSupport.NODE_2_ID_DPKEY data provider.
• GroupingKeys.PARENT_NODE_ID_DPKEY - Stores the parent node id for each grouped node.
• GroupingKeys.GROUP_DPKEY - Stores whether a node is considered a group node. A group node may have children.

See Also:

LayoutGraph

Method Summary

void	enableGrouping() Adds the DataProviders that are required for working with hierarchic layout graphs and calls transferMapperIDs().
NodeList	getChildren(Node parent) Returns a list of all child nodes of the given parent node.
NodeList	getNeighbors(Node node) Returns a list containing the given node and all it's neighbor nodes.
NodeList	getNodes() Returns a node cursor that allows for breadth-first iteration over the node hierarchy of the provided graph.
Node	getParent(Node child) Gets the parent node of the provided node.
NodeList	getTopLevelNodes() Returns a cursor over all top level nodes of the provided graph, i.e., all nodes for which NodeHierarchy.getParent( node ) yields null.
boolean	isGroupNode(Node node) Whether the given node is considered a group node.
void	setGroupNode(Node node, boolean isGroupNode) Sets whether the provided node should be considered a group node.
void	setParent(NodeList children, Node parent) Adds all nodes contained in the provided NodeList as children of the provided parent node.
void	setParent(Node child, Node parent) Sets the parent node for a given node.
void	transferMapperIDs() Replaces the DataProvider for grouping keys with the id data provider used by yFiles FLEX.

Method Detail

getParent

public Node getParent(Node child)

Gets the parent node of the provided node. If the node is a top-level node, null is returned.

Parameters:

child - The child node.

Returns:

The parent node, or null if child is a top-level node.

setParent

public void setParent(Node child,
                      Node parent)

Sets the parent node for a given node. To make child a top-level node, pass null as the parent.

Calls enableGrouping() to make sure that the graph instance supports hierarchies.

Parameters:

child - The node to assign a new parent.

parent - The parent node to assign to child.

Throws:

java.lang.UnsupportedOperationException - if parent is a child of child, or parent equals child.

setParent

public void setParent(NodeList children,
                      Node parent)

Adds all nodes contained in the provided NodeList as children of the provided parent node.

Parameters:

children - A list of nodes to be added as children of the provided parent node.

parent - The parent node.

setGroupNode

public void setGroupNode(Node node,
                         boolean isGroupNode)

Sets whether the provided node should be considered a group node. A group node may (but doesn't have to) have children.

Parameters:

node - A node.

isGroupNode - Whether to consider the given node a group node.

isGroupNode

public boolean isGroupNode(Node node)

Whether the given node is considered a group node.

This method may return true, even if the given node doesn't have any child nodes.

Parameters:

node - A node.

Returns:

Whether the given node is considered a group node.

getChildren

public NodeList getChildren(Node parent)

Returns a list of all child nodes of the given parent node.

Parameters:

parent - A parent node.

Returns:

A list of all child nodes of the given parent node.

getNeighbors

public NodeList getNeighbors(Node node)

Returns a list containing the given node and all it's neighbor nodes.

If the given node is top-level, all top-level nodes are returned. Otherwise all child nodes of the given node's parent node are returned.

Parameters:

node - The node to get the neighbors for.

Returns:

A list containing the given node and all it's neighbor nodes.

enableGrouping

public void enableGrouping()

Adds the DataProviders that are required for working with hierarchic layout graphs and calls transferMapperIDs().

See Also:

GroupingKeys, transferMapperIDs()

getNodes

public NodeList getNodes()

Returns a node cursor that allows for breadth-first iteration over the node hierarchy of the provided graph.

Returns:

A node cursor that allows to traverse all nodes of the provided graph in in breadth-first manner.

getTopLevelNodes

public NodeList getTopLevelNodes()

Returns a cursor over all top level nodes of the provided graph, i.e., all nodes for which NodeHierarchy.getParent( node ) yields null.

Returns:

A cursor that allows to iterate over all top level nodes of the provided graph.

transferMapperIDs

public void transferMapperIDs()

Replaces the DataProvider for grouping keys with the id data provider used by yFiles FLEX.

After using this function, graph.getDataProvider( GroupingKeys.NODE_ID_DPKEY ) and graph.getDataProvider(AbstractGraphRoundtripSupport.NODE_2_ID_DPKEY ) will yield the same instance. This instance will automatically generate ids for newly created nodes.

Clients should only call this function if the graph is read directly using a GraphML I/O handler instance.

See Also:

AbstractGraphRoundtripSupport.NODE_2_ID_DPKEY, GroupingKeys.NODE_ID_DPKEY, GroupingKeys.PARENT_NODE_ID_DPKEY