org.apache.drill.exec.store.easy.json.parser

Class SimpleMessageParser

java.lang.Object

org.apache.drill.exec.store.easy.json.parser.SimpleMessageParser

All Implemented Interfaces:

MessageParser

public class SimpleMessageParser
extends Object
implements MessageParser

A message parser which accepts a path to the data encoded as a slash-separated string. Given the following JSON message:

 { status: {
     succeeded: true,
     runTimeMs: 123,
   }
   response: {
     rowCount: 10,
     rows: [
       { ... },
       { ... } ]
     },
   footer: "something interesting"
  }
 

The path to the actual data would be "response/rows".

The message parser will "free-wheel" over all objects not on the data path. Thus, this class will skip over the nested structure within the status member.

If the data path is not found then this class reports EOF of the whole data stream. It may have skipped over the actual payload if the path is mis-configured.

The payload can also be a single JSON object:

   response: {
     field1: "value1",
     field2: "value2",
     ...
     },
 

This parser "ungets" the value token (start object or start array) so that the structure parser can determine which case to handle.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.drill.exec.store.easy.json.parser.MessageParser

MessageParser.MessageContextException

Constructor Summary

Constructors

Constructor and Description
SimpleMessageParser(String dataPath)

Method Summary

Modifier and Type	Method and Description
boolean	parsePrefix(TokenIterator tokenizer)
void	parseSuffix(TokenIterator tokenizer)

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleMessageParser

public SimpleMessageParser(String dataPath)

Method Detail

parsePrefix

public boolean parsePrefix(TokenIterator tokenizer)
                    throws MessageParser.MessageContextException

Specified by:

parsePrefix in interface MessageParser

Throws:

MessageParser.MessageContextException

parseSuffix

public void parseSuffix(TokenIterator tokenizer)

Specified by:

parseSuffix in interface MessageParser