Java Doc for JGraph.java in  » Graphic-Library » jgraph » org » jgraph » Java Source Code / Java DocumentationJava Source Code and Java Documentation

A JGraph object doesn't actually contain your data; it simply provides a view of the data. Like any non-trivial Swing component, the graph gets data by querying its data model.

JGraph displays its data by drawing individual elements. Each element displayed by the graph contains exactly one item of data, which is called a cell. A cell may either be a vertex or an edge. Vertices may have neighbours or not, and edges may have source and target vertices or not, depending on whether they are connected.

Creating a Graph

The following code creates a JGraph object:

JGraph graph = new JGraph();
...
JScrollPane graphLayoutCache = new JScrollPane(graph)

The code creates an instance of JGraph and puts it in a scroll pane. JGraphs constructor is called with no arguments in this example, which causes the constructor to create a sample model.

Editing

Outmoved, cloned, resized, and shaped, or connected/disconnected to or from other cells.

Keyboard Bindings

JGraph defines the following set of keyboard bindings:

• Alt-Click forces marquee selection if over a cell.
• Shift- or Ctrl-Select extends or toggles the selection.
• Shift-Drag constrains the offset to one direction.
• Ctrl-Drag clones the selection.
• Doubleclick/F2 starts editing a cell.

Customization

There are a number of additional methods that customize JGraph. For example, setMinimumMove() defines the minimum amount of pixels before a move operation is initiated. setSnapSize() defines the maximum distance for a cell to be selected. setFloatEnabled() enables/disables port floating.

With setDisconnectOnMove() you can indicate if the selected subgraph should be disconnected from the unselected rest when a move operation is initiated. setDragEnabled() enables/disables the use of Drag And Drop, and setDropEnabled() sets if the graph accepts Drops from external sources.

Customizing a graphs display

JGraph performs some look-and-feel specific painting. You can customize this painting in a limited way. For example, you can modify the grid using setGridColor() and setGridSize(), and you can change the handle colors using setHandleColor() and setLockedHandleColor().

If you want finer control over the rendering, you can subclass one of the default renderers, and extend its paint()-method. A renderer is a Component-extension that paints a cell based on its attributes. Thus, neither the JGraph nor its look-and-feel-specific implementation actually contain the code that paints the cell. Instead, the graph uses the cell renderers painting code.

Selection

Apart from the single-cell and marquee-selection, JGraphs selection model also allows to "step-into" groups, and select children. This feature can be disabled using the setAllowsChildSelection() method of the selection model instance.

If you are interested in knowing when the selection changes implement the GraphSelectionListener interface and add the instance using the method addGraphSelectionListener. valueChanged will be invoked when the selection changes, that is if the user clicks twice on the same vertex valueChanged will only be invoked once.

Change Notification

For detection of double-clicks or when a user clicks on a cell, regardless of whether or not it was selected, I recommend you implement a MouseListener and use getFirstCellForLocation.

Undo Support

To enable Undo-Support, a GraphUndoManager must be added using addGraphSelectionListener. The GraphUndoManager is an extension of Swing's GraphUndoManager that maintains a command history in the context of multiple views. In this setup, a cell may have a set of attributes in each view attached to the model.

For example, consider a position that is stored separately in each view. If a node is inserted, the change will be visible in all attached views, resulting in a new node that pops-up at the initial position. If the node is subsequently moved, say, in view1, this does not constitute a change in view2. If view2 does an "undo", the move and the insertion must be undone, whereas an "undo" in view1 will only undo the previous move operation.

Like all JComponent classes, you can use javax.swing.InputMap and javax.swing.ActionMap to associate an javax.swing.Action object with a javax.swing.KeyStroke and execute the action under specified conditions.
author:
   Gaudenz Alder
version:
   2.1 16/03/03

NOTE: For JGraph to properly display tooltips of its renderers, JGraph must be a registered component with the ToolTipManager. This can be done by invoking ToolTipManager.sharedInstance().registerComponent(graph). This is not done automatically!
Parameters:
  e - the MouseEvent that initiated theToolTip display a string containing the tooltip or null ifevent is null

Fires a property change for the ANTIALIASED_PROPERTY.
Parameters:
  newValue - whether to turn antialiasing on or off

Note: Editable determines whether the graph allows editing. This is not to be confused with enabled, which allows the graph to handle mouse events (including editing).
Parameters:
  flag - a boolean value, true if the graph is editable

Note: Updates the graphs's model using using the model from the layout cache.

Fires a property change for the GRAPH_LAYOUT_CACHE_PROPERTY.
Parameters:
  newLayoutCache - the GraphLayoutCache that is to provide theview-data