PCM Development/EDP2/Visualization/Create Custom View

This guide describes how a new JFreeChart-view can be created and added to the list of visualizations available in EDP2.

Important information

• The extension point for registering new charts is: de.uka.ipd.sdq.edp2.visualization.datasink
• All charts using the JFreeChart library must subclass JFreeChartEditorInput
• The existing implementation of HistogramEditorInput can be used as a guideline
• In addition to the input element itself, a factory for the element is required, see also step 2 in the #Step-by-step guide below.
• A JFreeChartEditorInput should not be confused with a DefaultSequence.

Thus, if you wish to create a particular type of chart, e.g. utilisation, you should first consider using an existing chart (e.g. PieChart) and setting title and properties in a way to represent the desired measure graphically.

Step-by-step guide

Guide for creating a new chart, using the PieChartEditorInput-class as an example:

1. Create the class "PieChartEditorInput<PieDataset>", subclassing JFreeChartEditorInput.
   • Note that the class is typed, the type must be the dataset required by this JFreeChart
   1. Add required constants for persisting PieChart-elements and its properties
      • the ELEMENT_NAME"-constant is required to identify the element itself:
        • private static final String ELEMENT_NAME = "PieChartEditorInput";
      • other constants are keys for storing different options of the chart, for example for showing values on the chart:
        • public final static String SHOW_RELATIVE_AMOUNT_KEY = "showRelativeAmount";
        • public final static String SHOW_ABSOLUTE_AMOUNT_KEY = "showAbsoluteAmount";
   2. Add fields for the properties and corresponding getters/setters, as well as field(s) containing the data to be displayed by this chart:
      • private double[][] data;
   3. Create two constructors, one default-constructor, which is required for persistence, and one setting default values and the source of the input:

      public PieChartEditorInput() {

      this(null);

      }

      public PieChartEditorInput(AbstractDataSource source) {

      super();

      setShowAbsoluteAmount(false);

      setShowRelativeAmount(true);

      }
      

   4. Implement public void updateInputData() - This method is central. It should contain appropriate code to accomplish the following:
      • Create a new instance of the data which is used by this JFreeChartEditorInput's chart
      • Unwrap the data provided in the DataSource and use them to fill the data-field
      • Finally, add the following to make sure changes to this element are propagated to the JFreeChartEditorInputHandle and the JFreeChartEditor classes.

      setChanged();

      notifyObservers();
      

   5. Implement the remaining inherited methods. Their purpose is documented in the respective interfaces / super-classes. Let's take a look at a few special ones:
      • public boolean canAccept(AbstractDataSource source)
        • Method to check if a specified source contains valid data for this IDataSink-instance
      • public PieChartEditorInput createCopyForSource(AbstractDataSource source)
        • Return a new instance of this class for a provided source
      • public HashMap<String, Object> getProperties()
        • Add all properties and their current values to the inherited properties field here
      • public void setProperties(HashMap<String, Object> newProperties)
        • Check which properties are contained in newProperties, parse the values and use setters to change field values
      • public JFreeChart getChart()
        • Return a JFreeChart using the appropriate plot and/or renderer. If multiple inputs are supported by the encapsulated Chart, they must be retrieved from the JFreeChartEditorInputHandle and added here.

1. Create a factory class for the input, subclassing ElementFactory
   1. You can basically copy an existing Factory-class, e.g. HistogramEditorInputFactory
      • change the type of the "restoredElement" to the type of the class this factory is for, i.e. PieChartEditorInput