EMF Compare/How To Open Compare Dialog With Comparison

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This is only valid for the 2.0 release stream.

In this page you will learn how to open a dialog displaying the result of a comparison.

Preparing the input

The first thing to do is to implement your own class of CompareEditorInput.

You must override two methods :

  • prepareInput(IProgressMonitor), that must return the Comparison object (result from the EMFCompare computation) adapted as an IDiffElement
  • createDiffViewer(Composite), that must return a new instance of EMFCompareStructureMergeViewer.

Here is a sample implementation that you can reuse as is :

/**
 * A custom implementation of the editor input.
 */
class EMFCompareEditorInput extends CompareEditorInput {

	private final Comparison comparison;

	private final AdapterFactory adapterFactory;

	/**
	 * Constructor.
	 * 
	 * @param configuration
	 *            the compare configuration
	 * @param comparison
	 *            the comparison
	 */
	public CustomCompareEditorInput(CompareConfiguration configuration) {
		super(configuration);
		this.comparison = (Comparison)configuration.getProperty(EMFCompareConstants.COMPARE_RESULT);
		this.adapterFactory = new ComposedAdapterFactory(ComposedAdapterFactory.Descriptor.Registry.INSTANCE); 
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.compare.CompareEditorInput#prepareInput(org.eclipse.core.runtime.IProgressMonitor)
	 */
	@Override
	protected Object prepareInput(IProgressMonitor monitor) throws InvocationTargetException,
			InterruptedException {
		return adapterFactory.adapt(this.comparison, IDiffElement.class);
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.compare.CompareEditorInput#createDiffViewer(org.eclipse.swt.widgets.Composite)
	 */
	@Override
	public Viewer createDiffViewer(Composite parent) {
		return new EMFCompareStructureMergeViewer(parent, getCompareConfiguration());
	};
}

Preparing the configuration

When instantiating an EMFCompareEditorInput, you have to give him a CompareConfiguration. This is a standard CompareConfiguration (no specific implementation needed). But you need to fill two EMFCompare specific properties:

  • EMFCompareConstants.COMPARE_RESULT, the comparison itself.
  • EMFCompareConstants.EDITING_DOMAIN, an EMFCompareEditingDomain. It is not an implementation of EditingDomain from EMF. It shares similar concepts (it has a command stack, it can create some commands) but is much more simpler.

Here is a code sample on how to create a CompareConfiguration suitable for EMFCompareEditorInput.

final CompareConfiguration configuration = new CompareConfiguration();
configuration.setProperty(EMFCompareConstants.COMPARE_RESULT, comparison);
configuration.setProperty(EMFCompareConstants.EDITING_DOMAIN, new EMFCompareEditingDomain(comparison, left, right, ancestor));