javolution.xml

Class XMLBinding

Object

XMLBinding

All Implemented Interfaces:

Serializable, Reusable, XMLSerializable

public class XMLBinding
extends Object
implements Reusable, XMLSerializable

This class represents the binding between Java classes and their XML representation (XMLFormat).

Custom XML bindings can also be used to alias class names and ensure that the XML representation is:

• Impervious to obfuscation.
• Unaffected by any class refactoring.
• Can be mapped to multiple implementations. For example:

       
       // Creates a binding to serialize Swing components into high-level XML
       // and deserialize the same XML into SWT components.
       XMLBinding swingBinding = new XMLBinding();
       swingBinding.setAlias(javax.swing.JButton.class, "Button");
       swingBinding.setAlias(javax.swing.JTable.class, "Table");
       ...
       XMLBinding swtBinding = new XMLBinding();
       swtBinding.setAlias(org.eclipse.swt.widgets.Button.class, "Button");
       swtBinding.setAlias(org.eclipse.swt.widgets.Table.class, "Table");
       ...
       
       // Writes Swing Desktop to XML.
       XMLObjectWriter writer = new XMLObjectWriter().setBinding(swingBinding);
       writer.setOutput(new FileOutputStream("C:/desktop.xml"));
       writer.write(swingDesktop, "Desktop", SwingDesktop.class);
       writer.close();
  
       // Reads back high-level XML to a SWT implementation!    
       XMLObjectReader reader = new XMLObjectReader().setXMLBinding(swtBinding);
       reader.setInput(new FileInputStream("C:/desktop.xml"));
       SWTDesktop swtDesktop = reader.read("Desktop", SWTDesktop.class);
       reader.close();
       

More advanced bindings can also be created through sub-classing.

 
     // XML binding using reflection.
     public ReflectionBinding extends XMLBinding {
         protected XMLFormat getFormat(Class forClass) {
             Field[] fields = forClass.getDeclaredFields();
             return new XMLReflectionFormat(fields);
         }
     }
     
     // XML binding read from DTD input source.
     public DTDBinding extends XMLBinding {
         public DTDBinding(InputStream dtd) {
             ...
         }
     }
     
     // XML binding overriding default formats.
     public MyBinding extends XMLBinding {
         // Non-static formats use unmapped XMLFormat instances.
         XMLFormat<String> myStringFormat = new XMLFormat<String>(null) {...}
         XMLFormat<Collection> myCollectionFormat = new XMLFormat<Collection>(null) {...}
         protected XMLFormat getFormat(Class forClass) throws XMLStreamException {
             if (String.class.equals(forClass))
                  return myStringFormat;
             if (Collection.class.isAssignableFrom(forClass))
                  return myCollectionFormat;
             return super.getFormat(cls);
         }
     }
     

The default XML binding implementation supports all static XML formats (static members of the classes being mapped) as well as the following types:

• java.lang.Object (empty element)
• java.lang.Class
• java.lang.String
• java.lang.Appendable
• java.util.Collection
• java.util.Map
• java.lang.Object[]
• all primitive types wrappers (e.g. Boolean, Integer ...)

Version:

5.4, December 1, 2009

Author:

Jean-Marie Dautelle

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
XMLBinding() Default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
protected XMLFormat	getFormat(Class forClass) Returns the XML format for the specified class/interface.
protected Class	readClass(XMLStreamReader reader, boolean useAttributes) Reads the class corresponding to the current XML element.
void	reset() Resets the internal state of this object to its default values.
void	setAlias(Class cls, QName qName) Sets the qualified alias for the specified class.
void	setAlias(Class cls, String alias) Convenient method equivalent to setAlias(cls, QName.valueOf(alias)).
void	setClassAttribute(QName classAttribute) Sets the qualified name of the attribute holding the class identifier.
void	setClassAttribute(String name) Convenience method equivalent to setClassAttribute(QName.valueOf(name)).
protected void	writeClass(Class cls, XMLStreamWriter writer, boolean useAttributes) Writes the specified class to the current XML element attributes or to a new element if the element attributes cannot be used.

Methods inherited from class Object

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

Constructor Detail

XMLBinding

public XMLBinding()

Default constructor.

Method Detail

setAlias

public void setAlias(Class cls,
            QName qName)

Sets the qualified alias for the specified class.

Parameters:

cls - the class being aliased.

qName - the qualified name.

setAlias

public final void setAlias(Class cls,
            String alias)

Convenient method equivalent to setAlias(cls, QName.valueOf(alias)).

Parameters:

cls - the class being aliased.

alias - the alias for the specified class.

setClassAttribute

public void setClassAttribute(QName classAttribute)

Sets the qualified name of the attribute holding the class identifier. If the local name is null the class attribute is never read/written (which may prevent unmarshalling).

Parameters:

classAttribute - the qualified name of the class attribute or null.

setClassAttribute

public final void setClassAttribute(String name)

Convenience method equivalent to setClassAttribute(QName.valueOf(name)).

Parameters:

name - the name of the class attribute or null.

getFormat

protected XMLFormat getFormat(Class forClass)
                       throws XMLStreamException

Returns the XML format for the specified class/interface. The default implementation returns the XMLFormat.getInstance(java.lang.Class<? extends T>) for the specified class.

Parameters:

forClass - the class for which the XML format is returned.

Returns:

the XML format for the specified class (never null).

Throws:

XMLStreamException - if there is no format for the specified class.

readClass

protected Class readClass(XMLStreamReader reader,
              boolean useAttributes)
                   throws XMLStreamException

Reads the class corresponding to the current XML element. This method is called by XMLFormat.InputElement.getNext() XMLFormat.InputElement.get(String) and XMLFormat.InputElement.get(String, String) to retrieve the Java class corresponding to the current XML element. If useAttributes is set, the default implementation reads the class name from the class attribute; otherwise the class name (or alias) is read from the current element qualified name.

Parameters:

reader - the XML stream reader.

useAttributes - indicates if the element's attributes should be used to identify the class (e.g. when the element name is specified by the user then attributes have to be used).

Returns:

the corresponding class.

Throws:

XMLStreamException

writeClass

protected void writeClass(Class cls,
              XMLStreamWriter writer,
              boolean useAttributes)
                   throws XMLStreamException

Writes the specified class to the current XML element attributes or to a new element if the element attributes cannot be used. This method is called by XMLFormat.OutputElement.add(Object) and XMLFormat.OutputElement.add(Object, String) and XMLFormat.OutputElement.add(Object, String, String) to identify the Java class corresponding to the XML element.

Parameters:

cls - the class to be written.

writer - the XML stream writer.

useAttributes - indicates if the element's attributes should be used to identify the class (e.g. when the element name is specified by the user then attributes have to be used).

Throws:

XMLStreamException

reset

public void reset()

Description copied from interface: Reusable

Resets the internal state of this object to its default values.

Specified by:

reset in interface Reusable