Module org.apache.arrow.vector

Package org.apache.arrow.vector.ipc

Class JsonFileReader

java.lang.Object

org.apache.arrow.vector.ipc.JsonFileReader

All Implemented Interfaces:

AutoCloseable, DictionaryProvider

public class JsonFileReader
extends Object
implements AutoCloseable, DictionaryProvider

A reader for JSON files that translates them into vectors. This reader is used for integration tests.

This class uses a streaming parser API, method naming tends to reflect this implementation detail.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.arrow.vector.dictionary.DictionaryProvider

DictionaryProvider.MapDictionaryProvider

Constructor Summary

Constructors

Constructor	Description
JsonFileReader(File inputFile, BufferAllocator allocator)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
void	close()
Set<Long>	getDictionaryIds()	Get all dictionary IDs.
Dictionary	lookup(long id)	Return the dictionary for the given ID.
VectorSchemaRoot	read()	Returns the next record batch from the file.
boolean	read(VectorSchemaRoot root)	Reads the next record batch from the file into root.
int	skip(int numBatches)	Skips a number of record batches in the file.
Schema	start()	Reads the beginning (schema section) of the json file and returns it.

Methods inherited from class java.lang.Object

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

Constructor Details

JsonFileReader

public JsonFileReader(File inputFile,
 BufferAllocator allocator)
               throws com.fasterxml.jackson.core.JsonParseException,
IOException

Constructs a new instance.

Parameters:

inputFile - The file to read.

allocator - The allocator to use for allocating buffers.

Throws:

com.fasterxml.jackson.core.JsonParseException

IOException

Method Details

lookup

public Dictionary lookup(long id)

Description copied from interface: DictionaryProvider

Return the dictionary for the given ID.

Specified by:

lookup in interface DictionaryProvider

getDictionaryIds

public Set<Long> getDictionaryIds()

Description copied from interface: DictionaryProvider

Get all dictionary IDs.

Specified by:

getDictionaryIds in interface DictionaryProvider

start

public Schema start()
             throws com.fasterxml.jackson.core.JsonParseException,
IOException

Reads the beginning (schema section) of the json file and returns it.

Throws:

com.fasterxml.jackson.core.JsonParseException

IOException

read

public boolean read(VectorSchemaRoot root)
             throws IOException

Reads the next record batch from the file into root.

Throws:

IOException

read

public VectorSchemaRoot read()
                      throws IOException

Returns the next record batch from the file.

Throws:

IOException

skip

public int skip(int numBatches)
         throws IOException

Skips a number of record batches in the file.

Parameters:

numBatches - the number of batches to skip

Returns:

the actual number of skipped batches.

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Throws:

IOException