public static Element addColumn(Element parent,
    String name,
    Integer length) 
{
        Element column_mapping = parent.addElement("column");
        column_mapping.addAttribute("name", name);
        if (length != null) {
            column_mapping.addAttribute("length", length.toString());
        }
        return column_mapping;
}

 public static  void addColumns(Element any_mapping,
    Iterator columns) 
{
        while (columns.hasNext()) {
            Column column = columns.next();
            addColumn(any_mapping, column.getName(), column.getLength());
        }
}

 public static Element addNativelyGeneratedId(Element parent,
    String name,
    String type) 
{
        Element id_mapping = parent.addElement("id");
        id_mapping.addAttribute("name", name).addAttribute("type", type);
        Element generator_mapping = id_mapping.addElement("generator");
        generator_mapping.addAttribute("class", "native");
        /*generator_mapping.addAttribute("class", "sequence");
        generator_mapping.addElement("param").addAttribute("name", "sequence").setText("custom");*/
        return id_mapping;
}

 public static Element addProperty(Element parent,
    String name,
    String type,
    boolean insertable,
    boolean key) 
{
        Element prop_mapping;
        if (key) {
            prop_mapping = parent.addElement("key-property");
        } else {
            prop_mapping = parent.addElement("property");
        }
        prop_mapping.addAttribute("name", name);
        prop_mapping.addAttribute("insert", Boolean.toString(insertable));
        prop_mapping.addAttribute("update", "false");
        if (type != null) {
            prop_mapping.addAttribute("type", type);
        }
        return prop_mapping;
}

 public static Element createEntity(Document document,
    String entityName,
    String tableName,
    String schema,
    String catalog,
    String discriminatorValue) 
{
        return createEntityCommon(document, "class", entityName, tableName, schema, catalog, discriminatorValue);
}

 public static Element createJoin(Element parent,
    String tableName,
    String schema,
    String catalog) 
{
        Element join_mapping = parent.addElement("join");
        join_mapping.addAttribute("table", tableName);
        if (!StringTools.isEmpty(schema)) {
            join_mapping.addAttribute("schema", schema);
        }
        if (!StringTools.isEmpty(catalog)) {
            join_mapping.addAttribute("catalog", catalog);
        }
        return join_mapping;
}

 public static Element createSubclassEntity(Document document,
    String entityName,
    String tableName,
    String schema,
    String catalog,
    String extendsEntityName,
    String discriminatorValue) 
{
        Element class_mapping = createEntityCommon(document, "subclass", entityName, tableName, schema, catalog,
                discriminatorValue);
        class_mapping.addAttribute("extends", extendsEntityName);
        return class_mapping;
}

 public static MetadataTools.ColumnNameIterator getColumnNameIterator(Iterator columnIterator) 
{
        return new ColumnNameIterator() {
            public boolean hasNext() { return columnIterator.hasNext(); }
            public String next() { return columnIterator.next().getName(); }
            public void remove() { columnIterator.remove(); }
        };
}

 public static MetadataTools.ColumnNameIterator getColumnNameIterator(JoinColumn[] joinColumns) 
{
        return new ColumnNameIterator() {
            int counter = 0;
            public boolean hasNext() { return counter <  joinColumns.length; }
            public String next() { return joinColumns[counter++].name(); }
            public void remove() { throw new UnsupportedOperationException(); }
        };
}

 public static  void prefixNamesInPropertyElement(Element element,
    String prefix,
    MetadataTools.ColumnNameIterator columnNameIterator,
    boolean changeToKey) 
{
        Iterator< Element > properties = element.elementIterator();
        while (properties.hasNext()) {
            Element property = properties.next();
            if ("property".equals(property.getName())) {
                Attribute nameAttr = property.attribute("name");
                if (nameAttr != null) {
                    nameAttr.setText(prefix + nameAttr.getText());
                }
                changeNamesInColumnElement(property, columnNameIterator);
                if (changeToKey) {
                    property.setName("key-property");
                }
            }
        }
}