Class VisitorStrategy

  • All Implemented Interfaces:
    Strategy

    public class VisitorStrategy
    extends java.lang.Object
    implements Strategy
    The VisitorStrategy object is a simplification of a strategy, which allows manipulation of the serialization process. Typically implementing a Strategy is impractical as it requires the implementation to determine the type a node represents. Instead it is often easier to visit each node that is being serialized or deserialized and manipulate it so that the resulting XML can be customized.

    To perform customization in this way a Visitor can be implemented. This can be passed to this strategy which will ensure the visitor is given each XML element as it is either being serialized or deserialized. Such an inversion of control allows the nodes to be manipulated with little effort. By default this used TreeStrategy object as a default strategy to delegate to. However, any strategy can be used.

    Author:
    Niall Gallagher
    See Also:
    Visitor
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      Value read​(Type type, NodeMap<InputNode> node, java.util.Map map)
      This method will read with an internal strategy after it has been intercepted by the visitor.
      boolean write​(Type type, java.lang.Object value, NodeMap<OutputNode> node, java.util.Map map)
      This method will write with an internal strategy before it has been intercepted by the visitor.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • VisitorStrategy

        public VisitorStrategy​(Visitor visitor)
        Constructor for the VisitorStrategy object. This strategy requires a visitor implementation that can be used to intercept the serialization and deserialization process.
        Parameters:
        visitor - this is the visitor used for interception
      • VisitorStrategy

        public VisitorStrategy​(Visitor visitor,
                               Strategy strategy)
        Constructor for the VisitorStrategy object. This strategy requires a visitor implementation that can be used to intercept the serialization and deserialization process.
        Parameters:
        visitor - this is the visitor used for interception
        strategy - this is the strategy to be delegated to
    • Method Detail

      • read

        public Value read​(Type type,
                          NodeMap<InputNode> node,
                          java.util.Map map)
                   throws java.lang.Exception
        This method will read with an internal strategy after it has been intercepted by the visitor. Interception of the XML node before it is delegated to the internal strategy allows the visitor to change some attributes or details before the node is interpreted by the strategy.
        Specified by:
        read in interface Strategy
        Parameters:
        type - this is the type of the root element expected
        node - this is the node map used to resolve an override
        map - this is used to maintain contextual information
        Returns:
        the value that should be used to describe the instance
        Throws:
        java.lang.Exception - thrown if the class cannot be resolved
      • write

        public boolean write​(Type type,
                             java.lang.Object value,
                             NodeMap<OutputNode> node,
                             java.util.Map map)
                      throws java.lang.Exception
        This method will write with an internal strategy before it has been intercepted by the visitor. Interception of the XML node before it is delegated to the internal strategy allows the visitor to change some attributes or details before the node is interpreted by the strategy.
        Specified by:
        write in interface Strategy
        Parameters:
        type - this is the type of the root element expected
        node - this is the node map used to resolve an override
        map - this is used to maintain contextual information
        value - this is the instance variable being serialized
        Returns:
        the value that should be used to describe the instance
        Throws:
        java.lang.Exception - thrown if the details cannot be set