Bug 116223 [refactoring] ProcessorBasedRefactoring does not handle exceptions thrown by participants
I20051108-1011 ProcessorBasedRefactoring protects itself against participants that throw an exception in createChange(..). However, it does not catch execptions thrown in initialize(..) or in checkConditions(..). We had a case where initialize(..) threw a ClassCastException, which generated a wrong error message (participant does not extend required type). I think we should protect all call backs and disable participants that throw a RuntimeException.
org.eclipse.ltk.core.refactoring/src/org/eclipse/ltk/core/refactoring/participants/ProcessorBasedRefactoring.java
*   <li>its processor is checked whether it is an instance of the
	 *       requested type.</li>
	 *   <li>the request is delegated to the super class.</li>
	 * </ol>
	 * 
	 * @param clazz the adapter class to look up
	 * 
	 * @return the requested adapter or <code>null</code>if no adapter
	 *  exists. 
	 */
	public Object getAdapter(Class clazz) {
		if (clazz.isInstance(this))
			return this;
		if (clazz.isInstance(getProcessor()))
			return getProcessor();
		return super.getAdapter(clazz);
	}
	
	/* non java-doc
	 * for debugging only
	 */
	public String toString() {
		return getName();
	}
	
	
	
	private CheckConditionsContext createCheckConditionsContext() throws CoreException {
		CheckConditionsContext result= new CheckConditionsContext();
		IConditionChecker checker= new ValidateEditChecker(getValidationContext());