Group nodes

A group node is an instance of the GraphMLGroupNode.

Creating a group node

To create a group node in the main diagram, you must use the GraphMLDiagram.addGroupNode() method. The method return the group node which you will be able to customize (for example, to add a label).

You can also create a group node and sets its label at the same time with the GraphMLDiagram.addGroupNodeWithLabel(String) method

Group node states

A group node has two states:

• The opened state where the children nodes are shown in the group node. To access this state, you can perform GraphMLGroupNode.getOpenedStateNode()
• The closed state where the children nodes are not shown in the group node. To access this state, you can perform GraphMLGroupNode.getClosedStateNode()

Adding a node in a group node

You can add a node as a child of the group node by GraphMLGroupNode.addNode(), or by GraphMLGroupNode.addNodeWithLabel(String)

You can also create a group node as child of a group node by GraphMLGroupNode.addGroupNode(), or by GraphMLGroupNode.addGroupNodeWithLabel(String)

Computing the node size

It is possible to compute the group node size using the children nodes using AbstractGraphMLNode.computeSize(boolean) or GraphMLGroupNode.computeSize(float, boolean). The way the size is computed depends on the GraphMLGroupNode.getGroupOpenedNodeSizeType():

• GroupNodeSizeType.MANUAL: The with and height of the group node will be computed using the DiagramDefaults.groupNodeOpenedWidth and DiagramDefaults.groupNodeOpenedHeight values
• GroupNodeSizeType.CHILDREN_WIDTH: The with and height of the group node will be computed considering that all the children of the group node are layout on one line.
  
  
• GroupNodeSizeType.CHILDREN_HEIGHT: The with and height of the group node will be computed considering that all the children of the group node are layout on one column.
  
  
• GroupNodeSizeType.CHILDREN_DISTRIBUTED: The with and height of the group node will be computed considering that all the children of the group node are layout on a grid

Customizing the node

As for the GraphMLNode, you can access the properties of ShapeNode class allows to set various properties of the ShapeNode through one of the following methods:

• The GraphMLGroupNode.getClosedStateNode() method return the ShapeNode associated with the closed state
• The GraphMLGroupNode.getOpenedStateNode() method return the ShapeNode associated with the opened state

Most of the methods of the ShapeNode class are available on the GraphMLGroupNode. These methods will set the properties on the two node states. For example:

      GraphMLNode node = diagram.addNode();
      node.setFillColor("red"); // will fill the two states of the group node

Example

In this example, we create a diagram with two group nodes, and two nodes in each of the groups:

      GraphMLFactory factory = GraphMLFactory.getInstance();
      GraphMLDiagram diagram = factory.newDiagram();

      // create first group
      GraphMLGroupNode gnode1 = diagram.addGroupNode();
      gnode1.setLabel("Group 1");
      GraphMLNode node1 = gnode1.addNode();
      node1.setLabel("Node 1");
      GraphMLNode node2 = gnode1.addNode();
      node2.setLabel("Node 2");

      // create second group
      GraphMLGroupNode gnode2 = diagram.addGroupNode();
      gnode2.setLabel("Group 2");
      GraphMLNode node3 = gnode2.addNode();
      node3.setLabel("Node 3");
      GraphMLNode node4 = gnode2.addNode();
      node4.setLabel("Node 4");

      // create edges
      GraphMLEdge edge = node1.addEdgeTo(node2);
      GraphMLEdge edge2 = node3.addEdgeTo(node4);
      GraphMLEdge edge3 = node1.addEdgeTo(node4);