Bug 148951 Wrong error msg when set nonexisted col as group key
Description: Wrong error msg when set nonexisted col as group key Steps to reproduce: 1. Insert a table, bind it to dataset 2. Add a group, input abc as group key which is invalid. 3. Preview Expected result: Friendly error msg to tell user the group key is wrong. Actual result: + Group key "abc" in group 1 cannot depend on column bindings defined in the group lower than itself. data.engine.InvalidGroupKey ( 1 time(s) ) detail : org.eclipse.birt.data.engine.core.DataException: Group key "OUNTR" in group 1 cannot depend on column bindings defined in the group lower than itself.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ExprManagerUtil.java
*	Test whether high level group keys are depended on low level group keys.
	 * 
	 * @param exprManager
	 * @return
	 * @throws DataException 
	 */
	private void checkGroupNameValidation( ) throws DataException
	{
		HashMap map = this.getGroupKeys( );
		Iterator it = map.keySet( ).iterator( );
		while ( it.hasNext( ) )
		{
			Integer level = (Integer)it.next( );
			exprManager.setEntryGroupLevel( level.intValue( ) );
			
			if(!ExpressionCompilerUtil.hasColumnRow( map.get( level ).toString( ), exprManager ))
			{
				exprManager.setEntryGroupLevel( ExprManager.OVERALL_GROUP );
				throw new DataException( ResourceConstants.INVALID_GROUP_KEY, new Object[]{ map.get( level ).toString( ), level});
			}
		}
		exprManager.setEntryGroupLevel( ExprManager.OVERALL_GROUP );
	}
	
	/**
	 * Test whether there are dependency cycles in exprManager.
	 * 
	 * @param exprManager
	 * @return
	 * @throws DataException