javolution.xml

Class XMLFormat<T>

java.lang.Object

javolution.xml.XMLFormat<T>

Direct Known Subclasses:

XMLFormat.Default

public abstract class XMLFormat<T>
extends Object

This class represents the format base class for XML serialization and deserialization.

Instances of this class are typically retrieved from the XMLContext (OSGi service or not).

     @Format(xml=GraphicXML.class) 
     public abstract class Graphic implements XMLSerializable {
         private boolean isVisible;
         private Paint paint; // null if none.
         private Stroke stroke; // null if none.
         private Transform transform; // null if none.
          
         // XML format with positional associations (members identified by their position),
         // see XML package description for examples of name associations.
         public static class GraphicXML extends XMLFormat<Graphic> {
              public void write(Graphic g, OutputElement xml) {
                  xml.setAttribute("isVisible", g.isVisible); 
                  xml.add(g.paint); // First.
                  xml.add(g.stroke); // Second.
                  xml.add(g.transform); // Third.
              }
              public void read(InputElement xml, Graphic g) {
                  g.isVisible = xml.getAttribute("isVisible", true);
                  g.paint = xml.getNext();
                  g.stroke = xml.getNext();
                  g.transform = xml.getNext();
                  return g;
             }
         };
    }
    

Due to the sequential nature of XML serialization/deserialization, formatting/parsing of XML attributes should always be performed before formatting/parsing of the XML content.

The mapping between classes and XML formats can be overriden through XMLBinding instances. Here is an example of serialization/deserialization:

     
     // Creates a list holding diverse objects.
     List list = new ArrayList();
     list.add("John Doe");
     list.add(null);
     Map map = new FastMap();
     map.put("ONE", 1);
     map.put("TWO", 2);
     list.add(map);
     
     // Use of custom binding.
     XMLBinding binding = new XMLBinding();
     binding.setAlias(FastMap.class, "Map");
     binding.setAlias(String.class, "String");
     binding.setAlias(Integer.class, "Integer");
     
     // Formats the list to XML .
     OutputStream out = new FileOutputStream("C:/list.xml");
     XMLObjectWriter writer = new XMLObjectWriter().setOutput(out).setBinding(binding);
     writer.write(list, "MyList", ArrayList.class);
     writer.close();
     

Here is the output list.xml document produced:

     
     <MyList>
         <String value="John Doe"/>
         <Null/>
         <Map>
             <Key class="String" value="ONE"/>
             <Value class="Integer" value="1"/>
             <Key class="String" value="TWO"/>
             <Value class="Integer" value="2"/>
         </Map>
     </MyList>
     

The list can be read back with the following code:

     // Reads back to a FastTable instance.
     InputStream in = new FileInputStream("C:/list.xml");
     XMLObjectReader reader = new XMLObjectReader().setInput(in).setBinding(binding);
     FastTable table = reader.read("MyList", FastTable.class); 
     reader.close();
     

Note: Any type for which a text format is defined can be represented as a XML attribute.

Version:

5.4, December 1, 2009

Author:

Jean-Marie Dautelle

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	XMLFormat.Default Returns the default XML format for any object having a plain text format; this XML representation consists of the plain text representation of the object as a "value" attribute.
static class	XMLFormat.InputElement This class represents an input XML element (unmarshalling).
static class	XMLFormat.OutputElement This class represents an output XML element (marshalling).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	XMLFormat() Default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isReferenceable() Indicates if the object serialized through this format can be referenced to (default true).
T	newInstance(Class<? extends T> cls, XMLFormat.InputElement xml) Allocates a new object of the specified class from the specified XML input element.
abstract void	read(XMLFormat.InputElement xml, T obj) Parses an XML input element into the specified object.
abstract void	write(T obj, XMLFormat.OutputElement xml) Formats an object into the specified XML output element.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

XMLFormat

protected XMLFormat()

Default constructor.

Method Detail

isReferenceable

public boolean isReferenceable()

Indicates if the object serialized through this format can be referenced to (default true). This method can be overriden to return false if serialized objects are manipulated "by value".

Returns:

true if serialized object may hold a reference; false otherwise.

See Also:

XMLReferenceResolver

newInstance

public T newInstance(Class<? extends T> cls,
            XMLFormat.InputElement xml)
              throws XMLStreamException

Allocates a new object of the specified class from the specified XML input element. By default, this method returns an object created using the public no-arg constructor of the specified class. XML formats may override this method in order to use private/multi-arg constructors.

Parameters:

cls - the class of the object to return.

xml - the XML input element.

Returns:

the object corresponding to the specified XML element.

Throws:

XMLStreamException

write

public abstract void write(T obj,
         XMLFormat.OutputElement xml)
                    throws XMLStreamException

Formats an object into the specified XML output element.

Parameters:

obj - the object to format.

xml - the XMLElement destination.

Throws:

XMLStreamException

read

public abstract void read(XMLFormat.InputElement xml,
        T obj)
                   throws XMLStreamException

Parses an XML input element into the specified object.

Parameters:

xml - the XML element to parse.

obj - the object created through newInstance(java.lang.Class<? extends T>, javolution.xml.XMLFormat.InputElement) and to setup from the specified XML element.

Throws:

XMLStreamException