org.simpleframework.xml.strategy
Class TreeStrategy

java.lang.Object
  extended by org.simpleframework.xml.strategy.TreeStrategy
All Implemented Interfaces:
Strategy

public class TreeStrategy
extends Object
implements Strategy

The TreeStrategy object is used to provide a simple strategy for handling object graphs in a tree structure. This does not resolve cycles in the object graph. This will make use of the specified class attribute to resolve the class to use for a given element during the deserialization process. For the serialization process the "class" attribute will be added to the element specified. If there is a need to use an attribute name other than "class" then the name of the attribute to use can be specified.

Author:
Niall Gallagher
See Also:
CycleStrategy

Constructor Summary
TreeStrategy()
          Constructor for the TreeStrategy object.
TreeStrategy(String label, String length)
          Constructor for the TreeStrategy object.
 
Method Summary
 Value read(Type type, NodeMap node, Map map)
          This is used to resolve and load a class for the given element.
 boolean write(Type type, Object value, NodeMap node, Map map)
          This is used to attach a attribute to the provided element that is used to identify the class.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

TreeStrategy

public TreeStrategy()
Constructor for the TreeStrategy object. This is used to create a strategy that can resolve and load class objects for deserialization using a "class" attribute. Also for serialization this will add the appropriate "class" value.


TreeStrategy

public TreeStrategy(String label,
                    String length)
Constructor for the TreeStrategy object. This is used to create a strategy that can resolve and load class objects for deserialization using the specified attribute. The attribute value can be any legal XML attribute name.

Parameters:
label - this is the name of the attribute to use
length - this is used to determine the array length
Method Detail

read

public Value read(Type type,
                  NodeMap node,
                  Map map)
           throws Exception
This is used to resolve and load a class for the given element. Resolution of the class to used is done by inspecting the XML element provided. If there is a "class" attribute on the element then its value is used to resolve the class to use. If no such attribute exists on the element this returns null.

Specified by:
read in interface Strategy
Parameters:
type - this is the type of the XML element expected
node - this is the element used to resolve an override
map - this is used to maintain contextual information
Returns:
returns the class that should be used for the object
Throws:
Exception - thrown if the class cannot be resolved

write

public boolean write(Type type,
                     Object value,
                     NodeMap node,
                     Map map)
This is used to attach a attribute to the provided element that is used to identify the class. The attribute name is "class" and has the value of the fully qualified class name for the object provided. This will only be invoked if the object class is different from the field class.

Specified by:
write in interface Strategy
Parameters:
type - this is the declared class for the field used
value - this is the instance variable being serialized
node - this is the element used to represent the value
map - this is used to maintain contextual information
Returns:
this returns true if serialization is complete