com.bazaarvoice.jolt.shiftr.spec

Class ShiftrSpec

java.lang.Object

com.bazaarvoice.jolt.shiftr.spec.ShiftrSpec

Direct Known Subclasses:

ShiftrCompositeSpec, ShiftrLeafSpec

public abstract class ShiftrSpec
extends Object

A Spec Object represents a single line from the JSON Shiftr Spec. At a minimum a single Spec has : Raw LHS spec value Some kind of PathElement (based off that raw LHS value) Additionally there are 2 distinct subclasses of the base Spec LeafSpec : where the RHS is a String or Array of Strings, that specify an write path for the data from this level in the tree CompositeSpec : where the RHS is a map of children Specs Mapping of JSON Shiftr Spec to Spec objects : { rating-*" : { // CompositeSpec with one child and a Star PathElement "&(1)" : { // CompositeSpec with one child and a Reference PathElement "foo: { // CompositeSpec with one child and a Literal PathElement "value" : "Rating-&1.value" // OutputtingSpec with a Literal PathElement and one write path } } } } The tree structure of formed by the CompositeSpecs is what is used during Shiftr transforms to do the parallel tree walk with the input data tree. During the parallel tree walk a stack of data (a WalkedPath) is maintained, and used when a tree walk encounters an Outputting spec to evaluate the wildcards in the write DotNotationPath.

Field Summary

Fields

Modifier and Type	Field and Description
protected MatchablePathElement	pathElement

Constructor Summary

Constructors

Constructor and Description
ShiftrSpec(String rawJsonKey)

Method Summary

Methods

Modifier and Type	Method and Description
abstract boolean	apply(String inputKey, Object input, WalkedPath walkedPath, Map<String,Object> output) This is the main recursive method of the Shiftr parallel "spec" and "input" tree walk.
static List<String>	parseDotNotation(List<String> pathStrings, Iterator<Character> iter, String dotNotationRef) Method that recursively parses a dotNotation String based on an iterator.
static List<PathElement>	parseDotNotationRHS(String dotNotation) Parse the dotNotation of the RHS.
static PathElement	parseSingleKeyLHS(String key) Visible for Testing.
static Iterator<Character>	stringIterator(String string) Helper method to turn a String into an Iterator

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pathElement

protected final MatchablePathElement pathElement

Constructor Detail

ShiftrSpec

public ShiftrSpec(String rawJsonKey)

Method Detail

parseSingleKeyLHS

public static PathElement parseSingleKeyLHS(String key)

Visible for Testing. Inspects the key in a particular order to determine the correct sublass of PathElement to create.

Parameters:

key - String that should represent a single PathElement

Returns:

a concrete implementation of PathElement

stringIterator

public static Iterator<Character> stringIterator(String string)

Helper method to turn a String into an Iterator

parseDotNotation

public static List<String> parseDotNotation(List<String> pathStrings,
                            Iterator<Character> iter,
                            String dotNotationRef)

Method that recursively parses a dotNotation String based on an iterator. This method will call out to parseAtPathElement

Parameters:

pathStrings - List to store parsed Strings that each represent a PathElement

iter - the iterator to pull characters from

dotNotationRef - the original dotNotation string used for error messages

Returns:

parseDotNotationRHS

public static List<PathElement> parseDotNotationRHS(String dotNotation)

Parse the dotNotation of the RHS.

apply

public abstract boolean apply(String inputKey,
            Object input,
            WalkedPath walkedPath,
            Map<String,Object> output)

This is the main recursive method of the Shiftr parallel "spec" and "input" tree walk. It should return true if this Spec object was able to successfully apply itself given the inputKey and input object. In the context of the Shiftr parallel treewalk, if this method returns true, the assumption is that no other sibling Shiftr specs need to look at this particular input key.

Returns:

true if this this spec "handles" the inputkey such that no sibling specs need to see it