public class SchemaBuilder extends Object
A fluent interface for building Schema
instances. The flow of the API
is designed to mimic the Avro Schema
Specification
{ "type": "record", "name": "HandshakeRequest", "namespace":"org.apache.avro.ipc", "fields": [ {"name": "clientHash", "type": {"type": "fixed", "name": "MD5", "size": 16}}, {"name": "clientProtocol", "type": ["null", "string"]}, {"name": "serverHash", "type": "MD5"}, {"name": "meta", "type": ["null", {"type": "map", "values": "bytes"}]} ] }
Schema schema = SchemaBuilder .record("HandshakeRequest").namespace("org.apache.avro.ipc) .fields() .name("clientHash").type().fixed("MD5").size(16).noDefault() .name("clientProtocol").type().nullable().stringType().noDefault() .name("serverHash").type("MD5") .name("meta").type().nullable().map().values().bytesType().noDefault() .endRecord();
"type":is a
SchemaBuilder.TypeBuilder
, SchemaBuilder.FieldTypeBuilder
, or
SchemaBuilder.UnionFieldTypeBuilder
, depending on the context. These types all
share a similar API for selecting and building types.
{"type":"int"} {"type":{"name":"int"}} {"type":{"name":"int", "customProp":"val"}}The analogous code form for the above three JSON lines are the below three lines:
.intType() .intBuilder().endInt() .intBuilder().prop("customProp", "val").endInt()Every primitive type has a shortcut to create the trivial type, and a builder when custom properties are required. The first line above is a shortcut for the second, analogous to the JSON case.
SchemaBuilder.NamespacedBuilder
.
The builders for named types require a name to be constructed, and optional
configuration via:
SchemaBuilder.NamedBuilder.doc()
SchemaBuilder.NamespacedBuilder.namespace(String)
SchemaBuilder.NamedBuilder.aliases(String...)
SchemaBuilder.PropBuilder.prop(String, String)
SchemaBuilder.FixedBuilder.size(int)
SchemaBuilder.EnumBuilder.symbols(String...)
SchemaBuilder.RecordBuilder.fields()
.enumeration("Suit").namespace("org.apache.test") .aliases("org.apache.test.OldSuit") .doc("CardSuits") .prop("customProp", "val") .symbols("SPADES", "HEARTS", "DIAMONDS", "CLUBS")Which is equivalent to the JSON:
{ "type":"enum", "name":"Suit", "namespace":"org.apache.test", "aliases":["org.apache.test.OldSuit"], "doc":"Card Suits", "customProp":"val", "symbols":["SPADES", "HEARTS", "DIAMONDS", "CLUBS"] }
SchemaBuilder.ArrayBuilder.items()
and SchemaBuilder.MapBuilder.values()
, respectively.
SchemaBuilder.RecordBuilder.fields()
returns a SchemaBuilder.FieldAssembler
for
defining the fields of the record and completing it.
Each field must have a name, specified via SchemaBuilder.FieldAssembler.name(String)
,
which returns a SchemaBuilder.FieldBuilder
for defining aliases, custom properties,
and documentation of the field. After configuring these optional values for
a field, the type is selected or built with SchemaBuilder.FieldBuilder.type()
.
Fields have default values that must be specified to complete the field.
SchemaBuilder.FieldDefault.noDefault()
is available for all field types, and
a specific method is available for each type to use a default, for example
SchemaBuilder.IntDefault.intDefault(int)
There are field shortcut methods on SchemaBuilder.FieldAssembler
for primitive types.
These shortcuts create required, optional, and nullable fields, but do not
support field aliases, doc, or custom properties.
SchemaBuilder.TypeBuilder.unionOf()
or
SchemaBuilder.FieldTypeBuilder.unionOf()
in the context of type selection.
This chains together multiple types, in union order. For example:
.unionOf() .fixed("IPv4").size(4).and() .fixed("IPv6").size(16).and() .nullType().endUnion()is equivalent to the Avro schema JSON:
[ {"type":"fixed", "name":"IPv4", "size":4}, {"type":"fixed", "name":"IPv6", "size":16}, "null" ]In a field context, the first type of a union defines what default type is allowed. Unions have two shortcuts for common cases. nullable() creates a union of a type and null. In a field type context, optional() is available and creates a union of null and a type, with a null default. The below two are equivalent:
.unionOf().intType().and().nullType().endUnion() .nullable().intType()The below two field declarations are equivalent:
.name("f").type().unionOf().nullType().and().longType().endUnion().nullDefault() .name("f").type().optional().longType()
.type(Schema.create(Schema.Type.INT)) // explicitly specified .type("MD5") // reference by full name or short name .type("MD5", "org.apache.avro.test") // reference by name and namespaceWhen a type is specified by name, and the namespace is absent or null, the namespace is inherited from the enclosing context. A namespace will propagate as a default to child fields, nested types, or later defined types in a union. To specify a name that has no namespace and ignore the inherited namespace, set the namespace to "".
builder(String)
returns a type builder with a default
namespace. builder()
returns a type builder with no
default namespace.Modifier and Type | Class and Description |
---|---|
static class |
SchemaBuilder.ArrayBuilder<R>
Builds an Avro Array type with optional properties.
|
static class |
SchemaBuilder.ArrayDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.BaseFieldTypeBuilder<R>
A special Builder for Record fields.
|
static class |
SchemaBuilder.BaseTypeBuilder<R>
A common API for building types within a context.
|
static class |
SchemaBuilder.BooleanBuilder<R>
Builds an Avro boolean type with optional properties.
|
static class |
SchemaBuilder.BooleanDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.BytesBuilder<R>
Builds an Avro bytes type with optional properties.
|
static class |
SchemaBuilder.BytesDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.DoubleBuilder<R>
Builds an Avro double type with optional properties.
|
static class |
SchemaBuilder.DoubleDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.EnumBuilder<R>
Builds an Avro Enum type with optional properties, namespace, doc, and
aliases.
|
static class |
SchemaBuilder.EnumDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.FieldAssembler<R> |
static class |
SchemaBuilder.FieldBuilder<R>
Builds a Field in the context of a
SchemaBuilder.FieldAssembler . |
static class |
SchemaBuilder.FieldDefault<R,S extends SchemaBuilder.FieldDefault<R,S>>
Abstract base class for field defaults.
|
static class |
SchemaBuilder.FieldTypeBuilder<R>
FieldTypeBuilder adds
SchemaBuilder.FieldTypeBuilder.unionOf() , SchemaBuilder.FieldTypeBuilder.nullable() , and SchemaBuilder.FieldTypeBuilder.optional()
to BaseFieldTypeBuilder. |
static class |
SchemaBuilder.FixedBuilder<R>
Builds an Avro Fixed type with optional properties, namespace, doc, and
aliases.
|
static class |
SchemaBuilder.FixedDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.FloatBuilder<R>
Builds an Avro float type with optional properties.
|
static class |
SchemaBuilder.FloatDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.GenericDefault<R> |
static class |
SchemaBuilder.IntBuilder<R>
Builds an Avro int type with optional properties.
|
static class |
SchemaBuilder.IntDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.LongBuilder<R>
Builds an Avro long type with optional properties.
|
static class |
SchemaBuilder.LongDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.MapBuilder<R>
Builds an Avro Map type with optional properties.
|
static class |
SchemaBuilder.MapDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.NamedBuilder<S extends SchemaBuilder.NamedBuilder<S>>
An abstract type that provides builder methods for configuring the name,
doc, and aliases of all Avro types that have names (fields, Fixed, Record,
and Enum).
|
static class |
SchemaBuilder.NamespacedBuilder<R,S extends SchemaBuilder.NamespacedBuilder<R,S>>
An abstract type that provides builder methods for configuring the
namespace for all Avro types that have namespaces (Fixed, Record, and
Enum).
|
static class |
SchemaBuilder.NullBuilder<R>
Builds an Avro null type with optional properties.
|
static class |
SchemaBuilder.NullDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.PropBuilder<S extends SchemaBuilder.PropBuilder<S>>
An abstract builder for all Avro types.
|
static class |
SchemaBuilder.RecordBuilder<R> |
static class |
SchemaBuilder.RecordDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.StringBldr<R>
Builds an Avro string type with optional properties.
|
static class |
SchemaBuilder.StringDefault<R>
Choose whether to use a default value for the field or not.
|
static class |
SchemaBuilder.TypeBuilder<R>
A Builder for creating any Avro schema type.
|
static class |
SchemaBuilder.UnionAccumulator<R>
Accumulates all of the types in a union.
|
static class |
SchemaBuilder.UnionFieldTypeBuilder<R>
Builder for a union field.
|
Modifier and Type | Method and Description |
---|---|
static SchemaBuilder.ArrayBuilder<Schema> |
array()
Create a builder for an Avro array
This is equivalent to:
|
static SchemaBuilder.TypeBuilder<Schema> |
builder()
Create a builder for Avro schemas.
|
static SchemaBuilder.TypeBuilder<Schema> |
builder(String namespace)
Create a builder for Avro schemas with a default namespace.
|
static SchemaBuilder.EnumBuilder<Schema> |
enumeration(String name)
Create a builder for an Avro enum with the specified name and symbols (values).
|
static SchemaBuilder.FixedBuilder<Schema> |
fixed(String name)
Create a builder for an Avro fixed type with the specified name and size.
|
static SchemaBuilder.MapBuilder<Schema> |
map()
Create a builder for an Avro map
This is equivalent to:
|
static SchemaBuilder.BaseTypeBuilder<Schema> |
nullable()
Create a builder for a union of a type and null.
|
static SchemaBuilder.RecordBuilder<Schema> |
record(String name)
Create a builder for an Avro record with the specified name.
|
static SchemaBuilder.BaseTypeBuilder<SchemaBuilder.UnionAccumulator<Schema>> |
unionOf()
Create a builder for an Avro union
This is equivalent to:
|
public static SchemaBuilder.TypeBuilder<Schema> builder()
public static SchemaBuilder.TypeBuilder<Schema> builder(String namespace)
public static SchemaBuilder.RecordBuilder<Schema> record(String name)
builder().record(name);
name
- the record namepublic static SchemaBuilder.EnumBuilder<Schema> enumeration(String name)
builder().enumeration(name);
name
- the enum namepublic static SchemaBuilder.FixedBuilder<Schema> fixed(String name)
builder().fixed(name);
name
- the fixed namepublic static SchemaBuilder.ArrayBuilder<Schema> array()
builder().array();
public static SchemaBuilder.MapBuilder<Schema> map()
builder().map();
public static SchemaBuilder.BaseTypeBuilder<SchemaBuilder.UnionAccumulator<Schema>> unionOf()
builder().unionOf();
public static SchemaBuilder.BaseTypeBuilder<Schema> nullable()
builder().nullable();and the following two lines are equivalent:
nullable().intType();
unionOf().intType().and().nullType().endUnion();
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