Bug 118429 [DataBinding] Validation should use IStatus, not just Strings
In order to use data binding in Workbench or IDE dialogs and preference pages, we need validation in terms of IStatus objects. Using strings is too simplistic. For example, look at the wizard for creating a new class. You will get a warning if the class name does not start with an uppercase letter, or if you don't provide a package name, but you will still be able to click "Finish" to proceed anyway. (Note that IStatus is currently not on the classpath, we need to re-introduce the dependency on org.eclipse.equinox.common, which contains IStatus etc.)
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/BindingEvent.java
* updatable's data type.
	 */
	public static final int PIPELINE_AFTER_VALIDATE = 1;
	/**
	 * A constant indicating that this event is occuring immedately after the
	 * original value has been converted to the other updatable's data type.
	 */
	public static final int PIPELINE_AFTER_CONVERT = 2;
	/**
	 * A constant indicating that this event is occuring immedately after the
	 * business rule validation has occured.
	 */
	public static final int PIPELINE_AFTER_BUSINESS_VALIDATE = 3;
	/**
	 * A constant indicating that this event is occuring immedately after the
	 * converted value has been set/changed on the updatable.
	 */
	public static final int PIPELINE_AFTER_CHANGE = 4;
	
	/**
	 * A constant indicating that this event is occuring due to either a validation
	 * error or warning occuring.
	 */
	public static final int PIPELINE_VALIDATION_ERROR_OR_WARNING = 5;
	/**
	 * A Map of Integer --> String mapping the integer constants for the
	 * pipeline events defined in this class to their String symbols.
	 */
	public final Map pipelineConstants = new HashMap();
	private HashMap eventConstants = new HashMap();