Package smile.io

Class JSON

java.lang.Object

smile.io.JSON

public class JSON
extends Object

Reads JSON datasets. No nested objects are currently allowed.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	JSON.Mode	JSON files in single-line or multi-line mode.

Constructor Summary

Constructors

Constructor	Description
JSON()	Constructor.

Method Summary

Modifier and Type	Method	Description
JSON	charset(Charset charset)	Sets the charset.
StructType	inferSchema(BufferedReader reader, int limit)	Infer the schema from the top n rows.
JSON	mode(JSON.Mode mode)	Sets the file mode (single-line or multi-line).
DataFrame	read(BufferedReader reader, int limit)	Reads a limited number of records from a JSON file.
DataFrame	read(String path)	Reads a JSON file.
DataFrame	read(String path, int limit)	Reads a JSON file.
DataFrame	read(Path path)	Reads a JSON file.
DataFrame	read(Path path, int limit)	Reads a JSON file.
JSON	schema(StructType schema)	Sets the schema.

Methods inherited from class java.lang.Object

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

Constructor Details

JSON

public JSON()

Constructor.

Method Details

schema

public JSON schema(StructType schema)

Sets the schema.

Parameters:

schema - the data schema.

Returns:

this object.

charset

public JSON charset(Charset charset)

Sets the charset.

Parameters:

charset - the charset of file.

Returns:

this object.

mode

public JSON mode(JSON.Mode mode)

Sets the file mode (single-line or multi-line).

Parameters:

mode - the file mode.

Returns:

this object.

read

public DataFrame read(Path path)
               throws IOException

Reads a JSON file.

Parameters:

path - the input file path.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.

read

public DataFrame read(Path path,
 int limit)
               throws IOException

Reads a JSON file.

Parameters:

path - the input file path.

limit - the number of records to read.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.

read

public DataFrame read(String path)
               throws IOException,
URISyntaxException

Reads a JSON file.

Parameters:

path - the input file path.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.

URISyntaxException - when the file path syntax is wrong.

read

public DataFrame read(String path,
 int limit)
               throws IOException,
URISyntaxException

Reads a JSON file.

Parameters:

path - the input file path.

limit - the number of records to read.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.

URISyntaxException - when the file path syntax is wrong.

read

public DataFrame read(BufferedReader reader,
 int limit)
               throws IOException

Reads a limited number of records from a JSON file.

Parameters:

reader - the file reader.

limit - the number of records to read.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.

inferSchema

public StructType inferSchema(BufferedReader reader,
 int limit)
                       throws IOException

Infer the schema from the top n rows.

1. Infer type of each row.
2. Merge row types to find common type
3. String type by default.

Parameters:

reader - the file reader.

limit - the number of records to read.

Returns:

the data frame.

Throws:

IOException - when fails to read the file.