com.bazaarvoice.jolt.traversr.traversal

Interface TraversalStep<T>

All Known Implementing Classes:

ArrayTraversalStep, AutoExpandArrayTraversalStep, BaseTraversalStep, MapTraversalStep

public interface TraversalStep<T>

A step in a JSON tree traversal.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	TraversalStep.Operation The three things you can do with a Traversal.

Method Summary

Methods

Modifier and Type	Method and Description
Object	get(T tree, String key) Return the data for the key from the provided tree object.
TraversalStep	getChild()
Class<?>	getStepType() Return the Class of the Generic T, so that it can be used in an "instanceof" style check.
Object	newContainer() Create a new mutable Map or List, suitable for this PathElement to traverse.
Object	overwriteSet(T tree, String key, Object data) Insert the data into the tree, overwriting any data that is there.
Object	remove(T tree, String key) Remove and return the data for the key from the provided tree object.
Object	traverse(Object tree, TraversalStep.Operation op, Iterator<String> keys, Object data) The meat of the Traversal.

Method Detail

get

Object get(T tree,
         String key)

Return the data for the key from the provided tree object.

Returns:

data object if available, or null.

remove

Object remove(T tree,
            String key)

Remove and return the data for the key from the provided tree object.

Returns:

data object if available, or null.

overwriteSet

Object overwriteSet(T tree,
                  String key,
                  Object data)

Insert the data into the tree, overwriting any data that is there.

Returns:

returns the data object if successful or null if it could not

getChild

TraversalStep getChild()

Returns:

the child Traversal or null if this Traversal has no child

newContainer

Object newContainer()

Create a new mutable Map or List, suitable for this PathElement to traverse.

Returns:

new List or Map, depending on the type of the Traversal

getStepType

Class<?> getStepType()

Return the Class of the Generic T, so that it can be used in an "instanceof" style check.

Returns:

Class that matches Generic parameter T

traverse

Object traverse(Object tree,
              TraversalStep.Operation op,
              Iterator<String> keys,
              Object data)

The meat of the Traversal. Pull a key from the iterator, use it to make the traversal, and then call traverse on your child Traversal.

Parameters:

tree - tree of data to walk

op - the Operation to perform is this is the last node of the Traversal

keys - keys to use

data - the data to place if the operation is SET

Returns:

if SET, null for fail or the "data" object for ok. if GET, PANTS