XML Naming Conventions

Here is great page summarizing various XML related naming specifications.
* Use of Camel Case for Naming XML and XML-Related Components
* FEDERAL XML NAMING AND DESIGN RULES
* Global Justice XML Data Model Naming and Design Rules

Filed under: xml | |No Comments

XML Schema: Use elementFormDefault to Hide/Expose Namespaces

Use elementFormDefault to Hide/Expose Namespaces

* 'elementFormDefault' is a binary switch attribute in the schema to control if the origin (i.e. namespace) of each element should be
- hidden (elementFormDefault="unqualified")
- or exposed ("elementFormDefault="qualified").
* elementFormDefault defaults to "unqualified"
* All schemas must have a consistent value for 'elementFormDefault' in order to hide/expose all elements.

Hide Namespaces

* Advantages:
- Simplicity
- Flexibility to change the schema without impact of instance documents.
* Howto:
- Set elementFormDefault="unqualified" in all schemas.
- The element must not be globally declared.

Best Practices

* Make two identical copies of a schema:
- One with elementFormDefault="qualified"
- One with elementFormDefault="unqualified"
* Minimize the use of global elements and attributes.

Notes

* Global elements and attribute must always be qualified.
* Use <include> to include schema with same namespace.
* Use <import> to include schema with different namespace.

References

* Hide (Localize) Namespaces Versus Expose Namespaces or PDF version

Filed under: xml | |Comments off

XML Schema: Create Variable Content Container Using Abstract Type

Implementation

* Define an abstract base type (PublicationType) to include common elements:

 
<xsd:complexType name="PublicationType" abstract="true">
  <xsd:sequence>
    <xsd:element name="Title" type="xsd:string"/>
    <xsd:element name="Author" type="xsd:string"
      minOccurs="0" maxOccurs="unbounded"/>
    <xsd:element name="Date" type="xsd:gYear"/>
  </xsd:sequence>
</xsd:complexType>
 

* Define concrete types(BookType, MagazineType) to extend abstract type

 
<xsd:complexType name="BookType">
  <xsd:complexContent>
    <xsd:extension base="PublicationType">
      <xsd:sequence>
        <xsd:element name="ISBN" type="xsd:string"/>
        <xsd:element name="Publisher" type="xsd:string"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>
 

 
<xsd:complexType name="MagazineType">
  <xsd:complexContent>
    <xsd:restriction base="PublicationType">
      <xsd:sequence>
        <xsd:element name="Title" type="xsd:string"/>
        <xsd:element name="Author" type="xsd:string"
          minOccurs="0" maxOccurs="0"/>
        <xsd:element name="Date" type="xsd:gYear"/>
      </xsd:sequence>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>
 

* Define container element (Catalogue) to contain an element (Publication) of the abstract type (PublicationType):

 
<xsd:element name="Catalogue">
  <xsd:complexType>
    <xsd:sequence>
      <xsd:element name="Publication"
        type="PublicationType"
        maxOccurs="unbounded"/>
    </xsd:sequence>
  </xsd:complexType>
</xsd:element>
 

* Example

 
<?xml version="1.0"?>
<Catalogue xmlns="http://www.catalogue.org"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation=
  "http://www.catalogue.org
  Catalogue.xsd">
  <Book>
    <Title>Illusions The Adventures of a Reluctant Messiah</Title>
    <Author>Richard Bach</Author>
    <Date>1977</Date>
    <ISBN>0-440-34319-4</ISBN>
    <Publisher>Dell Publishing Co.</Publisher>
  </Book>
  <Magazine>
    <Title>Natural Health</Title>
    <Date>1999</Date>
  </Magazine>
  <Book>
    <Title>The First and Last Freedom</Title>
    <Author>J. Krishnamurti</Author>
    <Date>1954</Date>
    <ISBN>0-06-064831-7</ISBN>
    <Publisher>Harper &amp; Row</Publisher>
  </Book>
</Catalogue>

Extend the schema

* Add a new concrete type (CDType)

 
<include schemaLocation="Catalogue.xsd"/>
<complexType name="CDType">
  <complexContent>
    <extension base="PublicationType" >
      <sequence>
        <element name="RecordingCompany" type="string"/>
      </sequence>
    </extension>
  </complexContent>
</complexType>
 

* Example

 
<?xml version="1.0"?>
<Catalogue xmlns="http://www.catalogue.org"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation=
  "http://www.catalogue.org
  Catalogue.xsd">
  <Book>
    <Title>Illusions The Adventures of a Reluctant Messiah</Title>
    <Author>Richard Bach</Author>
    <Date>1977</Date>
    <ISBN>0-440-34319-4</ISBN>
    <Publisher>Dell Publishing Co.</Publisher>
  </Book>
  <Magazine>
    <Title>Natural Health</Title>
    <Date>1999</Date>
  </Magazine>
  <Book>
    <Title>The First and Last Freedom</Title>
    <Author>J. Krishnamurti</Author>
    <Date>1954</Date>
    <ISBN>0-06-064831-7</ISBN>
    <Publisher>Harper &amp; Row</Publisher>
  </Book>
  <CD>
    <Title>Timeless Serenity</Title>
    <Author>Dyveke Spino</Author>
    <Date>1984</Date>
    <RecordingCompany>Dyveke Spino Productions</RecordingCompany>
  </CD>
</Catalogue>

Reference

* http://www.xfront.com/VariableContentContainers.pdf

Filed under: xml | |Comments off

XML Util

Convert XML document to String

protected String docToString(Document doc){
  String xmlStr = null;
  try {
    Transformer transformer = TransformerFactory.newInstance().newTransformer();
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    StreamResult streamResult = new StreamResult(new StringWriter());
    DOMSource domSrc = new DOMSource(doc);
    transformer.transform(domSrc,streamResult);
    xmlStr = streamResult.getWriter().toString();
  } catch (TransformerConfigurationException e) {
    log.error(e);
  } catch (TransformerFactoryConfigurationError e) {
    log.error(e);
  } catch (TransformerException e) {
    log.error(e);
  }
  return xmlStr;
}
 

Filed under: xml | |No Comments