Bug 143898 [smoke][regression]Chart cannot be extended from library file
Description: Chart cannot be extended from library file Step to reproduce: 1. New a library and insert chart, publish it. 2. New a report, drag data source, dataset and chart to Layout from library 3. Save the report. Result: GUIException: caused by java.lang.reflect. invocation targetexception
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/validators/ExtensionValidator.java
* <h3>Rule</h3>
 * The rule is defined by
 * {@link org.eclipse.birt.report.model.api.extension.IReportItem#validate()}.
 * 
 * <h3>Applicability</h3>
 * This validator is only applied to <code>TableItem</code>.
 */
public class ExtensionValidator extends AbstractElementValidator
{
	/**
	 * Name of this validator.
	 */
	public final static String NAME = "ExtensionValidator"; 
	private final static ExtensionValidator instance = new ExtensionValidator( );
	/**
	 * Returns the singleton validator instance.
	 * 
	 * @return the validator instance
	 */
	public static ExtensionValidator getInstance( )
	{
		return instance;
	}
	/**
	 * Validates whether any cell in the given row overlaps others.
	 * 
	 * @param module
	 *            the module
	 * @param element
	 *            the row to validate