com.bazaarvoice.jolt.traversr.traversal

Interface TraversalStep<StepType,DataType>

All Known Implementing Classes:

ArrayTraversalStep, AutoExpandArrayTraversalStep, BaseTraversalStep, MapTraversalStep

public interface TraversalStep<StepType,DataType>

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

Modifier and Type	Method and Description
Optional<DataType>	get(StepType 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.
StepType	newContainer() Create a new mutable Map or List, suitable for this PathElement to traverse.
Optional<DataType>	overwriteSet(StepType tree, String key, DataType data) Insert the data into the tree, overwriting any data that is there.
Optional<DataType>	remove(StepType tree, String key) Remove and return the data for the key from the provided tree object.
Optional<DataType>	traverse(StepType tree, TraversalStep.Operation op, Iterator<String> keys, DataType data) The meat of the Traversal.

Method Detail

get

Optional<DataType> get(StepType tree,
                       String key)

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

Returns:

data object if available, or null.

remove

Optional<DataType> remove(StepType tree,
                          String key)

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

Returns:

data object if available, or null.

overwriteSet

Optional<DataType> overwriteSet(StepType tree,
                                String key,
                                DataType 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

StepType 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

Optional<DataType> traverse(StepType tree,
                            TraversalStep.Operation op,
                            Iterator<String> keys,
                            DataType 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