org.apache.kafka.connect.data

Interface Schema

All Known Implementing Classes:

ConnectSchema, SchemaBuilder

public interface Schema

Definition of an abstract data type. Data types can be primitive types (integer types, floating point types, boolean, strings, and bytes) or complex types (typed arrays, maps with one key schema and value schema, and structs that have a fixed set of field names each with an associated value schema). Any type can be specified as optional, allowing it to be omitted (resulting in null values when it is missing) and can specify a default value.

All schemas may have some associated metadata: a name, version, and documentation. These are all considered part of the schema itself and included when comparing schemas. Besides adding important metadata, these fields enable the specification of logical types that specify additional constraints and semantics (e.g. UNIX timestamps are just an int64, but the user needs the know about the additional semantics to interpret it properly).

Schemas can be created directly, but in most cases using SchemaBuilder will be simpler.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Schema.Type The type of a schema.

Field Summary

Fields

Modifier and Type	Field and Description
static Schema	BOOLEAN_SCHEMA
static Schema	BYTES_SCHEMA
static Schema	FLOAT32_SCHEMA
static Schema	FLOAT64_SCHEMA
static Schema	INT16_SCHEMA
static Schema	INT32_SCHEMA
static Schema	INT64_SCHEMA
static Schema	INT8_SCHEMA
static Schema	OPTIONAL_BOOLEAN_SCHEMA
static Schema	OPTIONAL_BYTES_SCHEMA
static Schema	OPTIONAL_FLOAT32_SCHEMA
static Schema	OPTIONAL_FLOAT64_SCHEMA
static Schema	OPTIONAL_INT16_SCHEMA
static Schema	OPTIONAL_INT32_SCHEMA
static Schema	OPTIONAL_INT64_SCHEMA
static Schema	OPTIONAL_INT8_SCHEMA
static Schema	OPTIONAL_STRING_SCHEMA
static Schema	STRING_SCHEMA

Method Summary

Modifier and Type	Method and Description
java.lang.Object	defaultValue()
java.lang.String	doc()
Field	field(java.lang.String fieldName) Get a field for this Schema by name.
java.util.List<Field>	fields() Get the list of fields for this Schema.
boolean	isOptional()
Schema	keySchema() Get the key schema for this map schema.
java.lang.String	name()
java.util.Map<java.lang.String,java.lang.String>	parameters() Get a map of schema parameters.
Schema	schema() Return a concrete instance of the Schema
Schema.Type	type()
Schema	valueSchema() Get the value schema for this map or array schema.
java.lang.Integer	version() Get the optional version of the schema.

Field Detail

INT8_SCHEMA

static final Schema INT8_SCHEMA

INT16_SCHEMA

static final Schema INT16_SCHEMA

INT32_SCHEMA

static final Schema INT32_SCHEMA

INT64_SCHEMA

static final Schema INT64_SCHEMA

FLOAT32_SCHEMA

static final Schema FLOAT32_SCHEMA

FLOAT64_SCHEMA

static final Schema FLOAT64_SCHEMA

BOOLEAN_SCHEMA

static final Schema BOOLEAN_SCHEMA

STRING_SCHEMA

static final Schema STRING_SCHEMA

BYTES_SCHEMA

static final Schema BYTES_SCHEMA

OPTIONAL_INT8_SCHEMA

static final Schema OPTIONAL_INT8_SCHEMA

OPTIONAL_INT16_SCHEMA

static final Schema OPTIONAL_INT16_SCHEMA

OPTIONAL_INT32_SCHEMA

static final Schema OPTIONAL_INT32_SCHEMA

OPTIONAL_INT64_SCHEMA

static final Schema OPTIONAL_INT64_SCHEMA

OPTIONAL_FLOAT32_SCHEMA

static final Schema OPTIONAL_FLOAT32_SCHEMA

OPTIONAL_FLOAT64_SCHEMA

static final Schema OPTIONAL_FLOAT64_SCHEMA

OPTIONAL_BOOLEAN_SCHEMA

static final Schema OPTIONAL_BOOLEAN_SCHEMA

OPTIONAL_STRING_SCHEMA

static final Schema OPTIONAL_STRING_SCHEMA

OPTIONAL_BYTES_SCHEMA

static final Schema OPTIONAL_BYTES_SCHEMA

Method Detail

type

Schema.Type type()

Returns:

the type of this schema

isOptional

boolean isOptional()

Returns:

true if this field is optional, false otherwise

defaultValue

java.lang.Object defaultValue()

Returns:

the default value for this schema

name

java.lang.String name()

Returns:

the name of this schema

version

java.lang.Integer version()

Get the optional version of the schema. If a version is included, newer versions *must* be larger than older ones.

Returns:

the version of this schema

doc

java.lang.String doc()

Returns:

the documentation for this schema

parameters

java.util.Map<java.lang.String,java.lang.String> parameters()

Get a map of schema parameters.

Returns:

Map containing parameters for this schema, or null if there are no parameters

keySchema

Schema keySchema()

Get the key schema for this map schema. Throws a DataException if this schema is not a map.

Returns:

the key schema

valueSchema

Schema valueSchema()

Get the value schema for this map or array schema. Throws a DataException if this schema is not a map or array.

Returns:

the value schema

fields

java.util.List<Field> fields()

Get the list of fields for this Schema. Throws a DataException if this schema is not a struct.

Returns:

the list of fields for this Schema

field

Field field(java.lang.String fieldName)

Get a field for this Schema by name. Throws a DataException if this schema is not a struct.

Parameters:

fieldName - the name of the field to look up

Returns:

the Field object for the specified field, or null if there is no field with the given name

schema

Schema schema()

Return a concrete instance of the Schema

Returns:

the Schema