org.simpleframework.xml.strategy
Class TreeStrategy

java.lang.Object
  org.simpleframework.xml.strategy.TreeStrategy

All Implemented Interfaces:

Strategy

public class TreeStrategy
extends java.lang.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(java.lang.String label, java.lang.String length)
Constructor for the TreeStrategy object.

Method Summary

Value	read(Type type, NodeMap node, java.util.Map map) This is used to resolve and load a class for the given element.
boolean	write(Type type, java.lang.Object value, NodeMap node, java.util.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(java.lang.String label,
                    java.lang.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,
                  java.util.Map map)
           throws java.lang.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:

java.lang.Exception - thrown if the class cannot be resolved

write

public boolean write(Type type,
                     java.lang.Object value,
                     NodeMap node,
                     java.util.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