edu.rice.cs.drjava.ui

Additional Logic

The SingleDisplayModel is a subclass of DefaultGlobalModel, primarily providing the constraint that exactly one document is active at any time. It adds public methods for getting and setting the currently active document to the interface provided by GlobalModel, and fires a corresponding event through the SingleDisplayModelListener class, which is a subclass of GlobalModelListener.

Note that this behavior is not included in the DefaultGlobalModel because the notion of a single active document is specific to this user interface. Alternative GUIs might choose to display multiple documents simultaneously, eliminating the need for this additional constraint. Housing this logic in a subclass of DefaultGlobalModel, rather than in MainFrame itself, allows us to verify through unit tests that only one document can be active.

User Interface

The graphical user interface is implemented in Swing and is coordinated through the MainFrame class. The general layout and primary components of the interface are shown in the image below.

MainFrame

The MainFrame is the JFrame which houses all other components of the GUI. It is solely a means of displaying the state and logic kept within its SingleDisplayModel, and maintains as little state of its own as possible. The MainFrame consists of a JMenuBar containing the menus, current filename, and toolbar buttons, together with a collection of panes for displaying the various components of DrJava. These include a scrollable JList with the OpenDefinitionDocuments, a DefinitionsPane for displaying and editing the source code, and a tabbed pane at the bottom which houses the InteractionsPane, CompilerErrorPanel, and OutputPane.

In addition to setting up the GUI and passing action requests to the model, MainFrame is also responsible for listening to events fired by both the GlobalModel and the document itself, in order to keep the display current.

Other Components

• The primary GUI component outside the MainFrame is the DefinitionsPane, which is a JEditorPane that is tied to a specific OpenDefinitionsDocument in the model. This pane handles all highlighting and text indenting for its document, as well as undoing actions specific to the document.
• The InteractionsPane is held in the tabbed pane at the bottom of the interface and provides the actual interaction with the repl interpreter within the GlobalModel.
• The CompilerErrorPanel is another tab in the tabbed pane, and contains both a JComboBox for selecting the compiler and an ErrorListPane for displaying all the errors from the most recent compilation, sorted by document. The ErrorListPane is an inner class of CompilerErrorPanel, and is responsible for highlighting errors in the list and in the source consistently.
• The OutputPane is the third tab in the tabbed pane, and is simply where System.out and System.err are redirected when DrJava is run.
• The FindReplaceDialog is a separate JDialog which handles the logic and state of finding and replacing text in the code, including highlighting and changing the source position as necessary. Only one FindReplaceDialog exists in the GUI, and it must be notified each time the active document is changed.