columnMap = new HashMap<String, AttributeColumnImpl>();
rows = new ArrayList<AttributeRowImpl>();
AttributeColumnImpl co1 = nodeClass.addColumn("col1", "Column 1", AttributeType.STRING, AttributeOrigin.DATA, "nil");
AttributeColumnImpl co2 = nodeClass.addColumn("col2", "Column 2", AttributeType.INT, AttributeOrigin.PROPERTY, 0);
AttributeColumnImpl co3 = nodeClass.addColumn("col3", "Column 3", AttributeType.LIST_STRING, AttributeOrigin.DATA, new StringList("nothing", ","));
AttributeColumnImpl co4 = nodeClass.addColumn("col4", "Column 4", AttributeType.STRING, AttributeOrigin.COMPUTED, "zero");
AttributeColumnImpl co5 = nodeClass.addColumn("col5", "Column 5", AttributeType.BOOLEAN, AttributeOrigin.DATA, true);
AttributeColumnImpl co6 = nodeClass.addColumn("col6", "Column 6", AttributeType.STRING, AttributeOrigin.DATA, "default");
columnMap.put("col1", co1);