Bug 123406 Add geLocaltStringProperty in GroupElementHandle and GroupPropertyHandle
Please refer to 123405. GUI need a way to get the local setting of given property because current getStringPropery method will return inherited value if there are no local value.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/GroupElementHandle.java
/**
	 * Returns <code>true</code> if each of the given collection of element
	 * extends has a parent. Returns <code>false</code> otherwise. If the
	 * collection has no elements, also return <code>false</code>
	 * 
	 * @return <code>true</code> if each of the given collection of element
	 *         extends has a parent. Returns <code>false</code> otherwise. If
	 *         the collection has no elements, also return <code>false</code>
	 */
	abstract public boolean isExtendedElements( );
	
	/**
	 * This method returnt <code>true</code> in following condition:
	 * <p>
	 * 1. The multi selected elements are same type.
	 * <p>
	 * 2. And the multi selected elements have extends.
	 * <p>
	 * 3. If any of the given elements has local properties.
	 * <p>
	 * 
	 * @return <code>true</code> if the conditions is met.
	 */
	public final boolean hasLocalPropertiesForExtendedElements( )
	{
		if ( !isSameType( ) )
			return false;
		if ( !isExtendedElements( ) )
			return false;
		List elements = getElements( );