Class Traverser


  • public class Traverser
    extends java.lang.Object
    The traverser allows to traverse an object graph deeply. Traversal processors can be used to perform specific actions on traversed object, e.g. object modifications. Does currently not allow transforming objects to other objects of another type (replacements), because objects have to be saved in the graph itself (no extra table for exchanged objects). The traverser can be used as a cloner when processors always return copies of the original objects. todo: introduce classloaders to allows for creating objects with other classloaders (e.g. convert a parameter from a sender to a receiver resource id).
    • Field Detail

      • IGNORE_RESULT

        public static final java.lang.Object IGNORE_RESULT
      • instance

        protected static volatile Traverser instance
        The default cloner.
      • processors

        protected static final java.util.List<ITraverseProcessor> processors
        The default traversal processors with no special actions.
      • processorcache

        protected java.util.Map<java.lang.Class<?>,​ITraverseProcessor> processorcache
    • Constructor Detail

      • Traverser

        public Traverser()
    • Method Detail

      • getDefaultProcessors

        public static java.util.List<ITraverseProcessor> getDefaultProcessors()
        Get the default traversal processors.
        Returns:
        The traversal processors.
      • getInstance

        public static Traverser getInstance()
        Get the default cloner instance.
      • traverseObject

        public static java.lang.Object traverseObject​(java.lang.Object object,
                                                      java.util.List<ITraverseProcessor> conversionprocessors,
                                                      java.util.List<ITraverseProcessor> processors,
                                                      Traverser.MODE mode,
                                                      java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object to traverse.
        processors - The lists of processors.
        Returns:
        The traversed (or modified) object.
      • traverseObject

        public static java.lang.Object traverseObject​(java.lang.Object object,
                                                      java.util.List<ITraverseProcessor> conversionprocessors,
                                                      java.util.List<ITraverseProcessor> processors,
                                                      Traverser.MODE mode,
                                                      java.lang.ClassLoader targetcl,
                                                      java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object to traverse.
        processors - The lists of processors.
        targetcl - If not null, the traverser should make sure that the result object is compatible with the class loader, e.g. by cloning the object using the class loaded from the target class loader.
        Returns:
        The traversed (or modified) object.
      • traverseObject

        public static java.lang.Object traverseObject​(java.lang.Object object,
                                                      java.lang.Class<?> clazz,
                                                      java.util.List<ITraverseProcessor> conversionprocessors,
                                                      java.util.List<ITraverseProcessor> processors,
                                                      Traverser.MODE mode,
                                                      java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object to traverse.
        processors - The lists of processors.
        Returns:
        The traversed (or modified) object.
      • traverseObject

        public static java.lang.Object traverseObject​(java.lang.Object object,
                                                      java.lang.Class<?> clazz,
                                                      java.util.List<ITraverseProcessor> conversionprocessors,
                                                      java.util.List<ITraverseProcessor> processors,
                                                      IStringConverter converter,
                                                      Traverser.MODE mode,
                                                      java.lang.ClassLoader targetcl,
                                                      java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object to traverse.
        processors - The lists of processors.
        targetcl - If not null, the traverser should make sure that the result object is compatible with the class loader, e.g. by cloning the object using the class loaded from the target class loader.
        Returns:
        The traversed (or modified) object.
      • traverse

        public java.lang.Object traverse​(java.lang.Object object,
                                         java.lang.reflect.Type clazz,
                                         java.util.List<ITraverseProcessor> conversionprocessors,
                                         java.util.List<ITraverseProcessor> processors,
                                         IStringConverter converter,
                                         Traverser.MODE mode,
                                         java.lang.ClassLoader targetcl,
                                         java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object.
        targetcl - If not null, the traverser should make sure that the result object is compatible with the class loader, e.g. by cloning the object using the class loaded from the target class loader.
        Returns:
        The processed object.
      • doTraverse

        public java.lang.Object doTraverse​(java.lang.Object object,
                                           java.lang.reflect.Type type,
                                           java.util.List<ITraverseProcessor> conversionprocessors,
                                           java.util.List<ITraverseProcessor> processors,
                                           IStringConverter converter,
                                           Traverser.MODE mode,
                                           java.lang.ClassLoader targetcl,
                                           java.lang.Object context)
        Traverse an object.
        Parameters:
        object - The object.
        targetcl - If not null, the traverser should make sure that the result object is compatible with the class loader, e.g. by cloning the object using the class loaded from the target class loader.
        Returns:
        The processed object.
      • findClazz

        public java.lang.Class<?> findClazz​(java.lang.Object object,
                                            java.lang.ClassLoader cl)
        Find the class of an object.
        Parameters:
        object - The object.
        cl - The classloader.
        Returns:
        The objects class.
      • preemptProcessing

        public java.lang.Object preemptProcessing​(java.lang.Object inputobject,
                                                  java.lang.reflect.Type inputtype,
                                                  java.lang.Object context)
        Allows preemption of processing, if the return value is not null, the returned object is used and processing is skipped.
        Parameters:
        inputobject - The input object
        inputtype - The input class.
        context - The context.
        Returns:
        Null to process as normal, any other object skips normal processing.
      • finalizeProcessing

        public void finalizeProcessing​(java.lang.Object inputobject,
                                       java.lang.Object outputobject,
                                       ITraverseProcessor convproc,
                                       ITraverseProcessor proc,
                                       java.lang.Object context)
        Handle objects after all processing steps have been done before object is returned. Not called for objects returned by preHandle().
        Parameters:
        inputobject - The input object
        outputobject - The object after processing.
        context - The context.
      • convertBasicType

        public static java.lang.Object convertBasicType​(IStringConverter converter,
                                                        java.lang.Object value,
                                                        java.lang.Class<?> targetclazz,
                                                        java.lang.ClassLoader cl,
                                                        java.lang.Object context)
        Convert a basic type.
        Parameters:
        value - The value.
        targetclazz - The target class.
        Returns:
        The converted value.