Package org.apache.druid.data.input.impl

Class JsonNodeReader

java.lang.Object

org.apache.druid.data.input.IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

org.apache.druid.data.input.impl.JsonNodeReader

All Implemented Interfaces:

InputEntityReader

public class JsonNodeReader
extends IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

In contrast to JsonLineReader which processes input text line by line independently, this class tries to split the input into a list of JsonNode objects, and then parses each JsonNode independently into an InputRow.

The input text can be: 1. a JSON string of an object in a line or multiple lines(such as pretty-printed JSON text) 2. multiple JSON object strings concatenated by white space character(s)

If an input string contains invalid JSON syntax, any valid JSON objects found prior to encountering the invalid syntax will be successfully parsed, but parsing will not continue after the invalid syntax.

Method Summary

Modifier and Type	Method	Description
protected CloseableIterator<com.fasterxml.jackson.databind.JsonNode>	intermediateRowIterator()	Creates an iterator of intermediate rows.
protected List<InputRow>	parseInputRows(com.fasterxml.jackson.databind.JsonNode intermediateRow)	Parses the given intermediate row into a list of InputRows.
protected InputEntity	source()
protected List<Map<String,Object>>	toMap(com.fasterxml.jackson.databind.JsonNode intermediateRow)	Converts the given intermediate row into a Map.

Methods inherited from class org.apache.druid.data.input.IntermediateRowParsingReader

intermediateRowAsString, intermediateRowIteratorWithMetadata, read, sample

Methods inherited from class java.lang.Object

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

Method Details

intermediateRowIterator

protected CloseableIterator<com.fasterxml.jackson.databind.JsonNode> intermediateRowIterator()
                                                                                      throws IOException

Description copied from class: IntermediateRowParsingReader

Creates an iterator of intermediate rows. The returned rows will be consumed by IntermediateRowParsingReader.parseInputRows(T) and IntermediateRowParsingReader.toMap(T). Either this or IntermediateRowParsingReader.intermediateRowIteratorWithMetadata() should be implemented

Overrides:

intermediateRowIterator in class IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

Throws:

IOException

source

protected InputEntity source()

Overrides:

source in class IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

Returns:

InputEntity which the implementation is reading from. Useful in generating informative ParseExceptions. For example, in case of FileEntity, file name containing erroneous records or in case of HttpEntity, the endpoint containing the erroneous data can be attached to the error message

parseInputRows

protected List<InputRow> parseInputRows(com.fasterxml.jackson.databind.JsonNode intermediateRow)
                                 throws ParseException

Description copied from class: IntermediateRowParsingReader

Parses the given intermediate row into a list of InputRows. This should return a non-empty list.

Specified by:

parseInputRows in class IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

Throws:

ParseException - if it cannot parse the given intermediateRow properly

toMap

protected List<Map<String,Object>> toMap(com.fasterxml.jackson.databind.JsonNode intermediateRow)
                                  throws IOException

Description copied from class: IntermediateRowParsingReader

Converts the given intermediate row into a Map. The returned JSON will be used by InputSourceSampler. Implementations can use any method to convert the given row into a Map. This should return a non-empty list with the same size of the list returned by IntermediateRowParsingReader.parseInputRows(T) or the returned objects will be discarded

Specified by:

toMap in class IntermediateRowParsingReader<com.fasterxml.jackson.databind.JsonNode>

Throws:

IOException