io.cdap.functions

Class DDL

java.lang.Object

io.cdap.functions.DDL

public final class DDL
extends Object

Structured Row and Schema DDL.

Constructor Summary

Constructors

Constructor and Description
DDL()

Method Summary

Modifier and Type	Method and Description
static io.cdap.cdap.api.data.schema.Schema	drop(io.cdap.cdap.api.data.schema.Schema schema, String path) Drops a path from the schema to generate a new Schema.
static io.cdap.cdap.api.data.schema.Schema	drop(io.cdap.cdap.api.data.schema.Schema schema, String path, String... paths)
static io.cdap.cdap.api.data.format.StructuredRecord	drop(io.cdap.cdap.api.data.format.StructuredRecord record, String path)
static io.cdap.cdap.api.data.format.StructuredRecord	drop(io.cdap.cdap.api.data.format.StructuredRecord record, String path, String... paths)
static boolean	hasField(io.cdap.cdap.api.data.format.StructuredRecord record, String name) Given a StructuredRecord and the name of the field, it checks, if the field exists in the StructuredRecord.
static io.cdap.cdap.api.data.schema.Schema	parse(io.cdap.cdap.api.data.schema.Schema schema) Identity parse method to extract Schema.
static io.cdap.cdap.api.data.schema.Schema	parse(String json) Given a JSON representation of schema, returns a Schema object.
static io.cdap.cdap.api.data.format.StructuredRecord	parse(io.cdap.cdap.api.data.format.StructuredRecord record) Given a StructuredRecord returns the same StructuredRecord.
static io.cdap.cdap.api.data.schema.Schema	parsesql(String sql) Given a SQL DDL, returns the Schema representation of the SQL.
static io.cdap.cdap.api.data.schema.Schema	select(io.cdap.cdap.api.data.schema.Schema schema, String path) Selects the sub-record based on the path specified.
static <T> T	select(io.cdap.cdap.api.data.format.StructuredRecord record, String path) Select a sub-stucture of a StructuredRecord.
static com.google.gson.JsonElement	toJson(io.cdap.cdap.api.data.format.StructuredRecord record) Converts a StructuredRecord to JSON string.

Methods inherited from class java.lang.Object

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

Constructor Detail

DDL

public DDL()

Method Detail

parse

public static io.cdap.cdap.api.data.schema.Schema parse(String json)
                                                 throws IOException

Given a JSON representation of schema, returns a Schema object.

Parameters:

json - string representation of schema.

Returns:

instance of Schema representing JSON string.

Throws:

IOException - thrown when there is issue parsing the data.

parsesql

public static io.cdap.cdap.api.data.schema.Schema parsesql(String sql)
                                                    throws IOException

Given a SQL DDL, returns the Schema representation of the SQL.

Parameters:

sql - to be converted to Schema.

Returns:

instance of Schema.

Throws:

IOException - throw when there is issue parsing the sql.

parse

public static io.cdap.cdap.api.data.schema.Schema parse(io.cdap.cdap.api.data.schema.Schema schema)

Identity parse method to extract Schema. This method is added if a user makes a mistake of parsing the schema again.

Parameters:

schema - to be returned.

Returns:

above schema object.

parse

public static io.cdap.cdap.api.data.format.StructuredRecord parse(io.cdap.cdap.api.data.format.StructuredRecord record)

Given a StructuredRecord returns the same StructuredRecord.

toJson

public static com.google.gson.JsonElement toJson(io.cdap.cdap.api.data.format.StructuredRecord record)
                                          throws IOException

Converts a StructuredRecord to JSON string.

Parameters:

record - to be converted to JSON

Returns:

JSON string representation of structured record.

Throws:

IOException - thrown if there are any issues with parsing.

hasField

public static boolean hasField(io.cdap.cdap.api.data.format.StructuredRecord record,
                               String name)

Given a StructuredRecord and the name of the field, it checks, if the field exists in the StructuredRecord.

Parameters:

record - in which the field needs to be checked.

name - of the field to be checked.

Returns:

true if present and it's a record, else false.

drop

public static io.cdap.cdap.api.data.schema.Schema drop(io.cdap.cdap.api.data.schema.Schema schema,
                                                       String path)

Drops a path from the schema to generate a new Schema.

Parameters:

schema - to be modified.

path - to be removed from Schema.

Returns:

modified Schema

drop

public static io.cdap.cdap.api.data.schema.Schema drop(io.cdap.cdap.api.data.schema.Schema schema,
                                                       String path,
                                                       String... paths)

select

public static io.cdap.cdap.api.data.schema.Schema select(io.cdap.cdap.api.data.schema.Schema schema,
                                                         String path)

Selects the sub-record based on the path specified.

Parameters:

schema - to be used as source to apply the path to.

path - to be applied on the Schema to select.

Returns:

sub-selected Schema

drop

public static io.cdap.cdap.api.data.format.StructuredRecord drop(io.cdap.cdap.api.data.format.StructuredRecord record,
                                                                 String path)

drop

public static io.cdap.cdap.api.data.format.StructuredRecord drop(io.cdap.cdap.api.data.format.StructuredRecord record,
                                                                 String path,
                                                                 String... paths)

select

public static <T> T select(io.cdap.cdap.api.data.format.StructuredRecord record,
                           String path)

Select a sub-stucture of a StructuredRecord.

Type Parameters:

T - type of object returned.

Parameters:

record - to be operated on

path - to applied to the StructuredRecord

Returns:

sub-structure of the StructuredRecord