io.cdap.directives.parser

Class JsParser

java.lang.Object

io.cdap.directives.parser.JsParser

All Implemented Interfaces:

Directive, EntityMetrics, Executor<List<Row>,List<Row>>, Lineage, Serializable

@Categories(categories={"parser","json"})
public class JsParser
extends Object
implements Directive, Lineage

This class is a JSON Parser directive with optional argument specifying the depth to which the JSON needs to be parsed.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME

Fields inherited from interface io.cdap.wrangler.api.Directive

TYPE

Constructor Summary

Constructors

Constructor and Description
JsParser()

Method Summary

Modifier and Type	Method and Description
UsageDefinition	define()
void	destroy()
List<Row>	execute(List<Row> rows, ExecutorContext context)
static Object	getValue(com.google.gson.JsonElement element) Gets a single value from the JsonElement.
static Object	getValue(com.google.gson.JsonPrimitive primitive) Extracts a value from the JsonPrimitive.
void	initialize(Arguments args)
static void	jsonFlatten(com.google.gson.JsonObject root, String field, int depth, int maxDepth, Row row) Recursively flattens JSON until the 'depth' is reached.
Mutation	lineage()

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.cdap.wrangler.api.Directive

getCountMetrics

Methods inherited from interface io.cdap.wrangler.api.Executor

getOutputSchema

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

Constructor Detail

JsParser

public JsParser()

Method Detail

define

public UsageDefinition define()

Specified by:

define in interface Directive

initialize

public void initialize(Arguments args)
                throws DirectiveParseException

Specified by:

initialize in interface Executor<List<Row>,List<Row>>

Throws:

DirectiveParseException

destroy

public void destroy()

Specified by:

destroy in interface Executor<List<Row>,List<Row>>

execute

public List<Row> execute(List<Row> rows,
                         ExecutorContext context)
                  throws DirectiveExecutionException,
                         ErrorRowException

Specified by:

execute in interface Executor<List<Row>,List<Row>>

Throws:

DirectiveExecutionException

ErrorRowException

lineage

public Mutation lineage()

Specified by:

lineage in interface Lineage

jsonFlatten

public static void jsonFlatten(com.google.gson.JsonObject root,
                               String field,
                               int depth,
                               int maxDepth,
                               Row row)

Recursively flattens JSON until the 'depth' is reached.

Parameters:

root - of the JSONObject

field - name to be used to be stored in the row.

depth - current depth into JSON structure.

maxDepth - maximum depth to reach

row - to which the flatten fields need to be added.

getValue

public static Object getValue(com.google.gson.JsonElement element)

Gets a single value from the JsonElement. The value could be JsonObject or JsonArray or JsonPrimitive.

Parameters:

element - value to be extracted.

Returns:

the sub-element, else JsonNull.

getValue

public static Object getValue(com.google.gson.JsonPrimitive primitive)

Extracts a value from the JsonPrimitive.

Parameters:

primitive - object to extract real value.

Returns:

java type extracted from the JsonPrimitive