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/GroupPropertyHandle.java
{
		assert handle.getModule( ) != null;
		ActivityStack actStack = handle.getModule( ).getActivityStack( );
		actStack.startTrans( );
		try
		{
			for ( Iterator iter = handle.getElements( ).iterator( ); iter
					.hasNext( ); )
			{
				DesignElementHandle elemHandle = (DesignElementHandle) iter
						.next( );
				elemHandle.setProperty( propDefn.getName( ), value );
			}
		}
		catch ( SemanticException e )
		{
			actStack.rollback( );
			throw e;
		}
		actStack.commit( );
	}
	/**
	 * Set the string value on a group of elements. This operation will be
	 * executed within a transaction, it will be rollbacked if any set operation
	 * failed.
	 * 
	 * @param value
	 *            the string value to set
	 * @throws SemanticException
	 *             if the property is undefined on an element or the string