Apache Avro 1.11.3 · org.apache.avro.reflect

Use Java reflection to generate schemas and protocols for existing classes.

Java types are mapped to Avro schemas as follows:

Classes are mapped to Avro records. Only concrete classes with a no-argument constructor are supported. All inherited fields that are not static or transient are used. Fields are not permitted to be null unless annotated by Nullable or a Union containing java.lang.Void.
Arrays are mapped to Avro array schemas. If an array's elements are a union defined by the Union annotation, the "java-element" property is set to the union's class, e.g.:
```
{"type": "array", "java-element": "org.acme.Foo"}
```
Collection implementations are mapped to Avro array schemas with the "java-class" property set to the collection implementation, e.g.:
```
{"type": "array", "java-class": "java.util.ArrayList"}
```
java.lang.String is mapped to an Avro string schema.
byte[] is mapped to an Avro bytes schema.
short is mapped to an Avro int schema with the "java-class" property set to "java.lang.Short", e.g.:
```
{"type": "int", "java-class": "java.lang.Short"}
```
java.math.BigDecimal, java.math.BigInteger, java.net.URI, java.net.URL, java.io.File are mapped to an Avro string schema as Stringable types and serialized via their toString method and de-serialized via their java.lang.String constructor. This is done via the "java-class", "java-key-class" or "java-element-class" depending on whether it is a field, or map key or a list/map element, e.g.:
```
{"type": "string", "java-class": "java.math.BigDecimal"}
```
All other types are mapped as in the generic API.

The Union annotation can be used to support reflection of schemas for interfaces, abstract base classes and other uses of polymorphism.

The Stringable annotation will cause a type to be serialized via its toString method.

Fields annotated with AvroIgnore will not be written or read to.

The AvroName annotation renames the field in the schema to the given name. The reflect datum reader will look for a schema field with the given name, when trying to read into such an annotated java field.

The AvroMeta annotation adds an arbitrary key:value pair in the schema at the node of the java field.

The AvroSchema annotation forces the use of an custom schema.

The AvroEncode annotation forces the use of an custom encoder. This annotation overrides Stringable and Nullable.

Annotation Summary

Modifier and Type	Annotation and Description
public @interface	AvroAlias Adds the given name and space as an alias to the schema.
public @interface	AvroAliases
public @interface	AvroDefault Specifies a default value for a field as a JSON string.
public @interface	AvroDoc Sets the avrodoc for this java field.
public @interface	AvroEncode Expert: Fields with this annotation are encoded using the given custom encoder.
public @interface	AvroIgnore Marks a field as transient.
public @interface	AvroMeta Adds the given key:Value pair as metadata into the schema, at the corresponding node.
public @interface	AvroName Sets the avroname for this java field.
public @interface	AvroSchema Declares that a Java type should have a specified Avro schema, overriding the normally inferred schema.
public @interface	Nullable Declares that null is a valid value for a Java type.
public @interface	Stringable Declares that a class or field should be represented by an Avro string.
public @interface	Union Declares that a Java type should be represented by an Avro union schema.

Class Summary

Modifier and Type	Class and Description
pack-priv class	ArrayAccessor Helper class to provide native array access whenever possible.
public abstract class	CustomEncoding< The class of objects that can be serialized with this encoder / decoder. T> Expert: a custom encoder and decoder that writes an object directly to avro.
public class	DateAsLongEncoding This encoder/decoder writes a java.util.Date object as a long to avro and reads a Date object from long.
pack-priv abstract class	FieldAccess
pack-priv abstract class	FieldAccessor
pack-priv class	FieldAccessReflect
pack-priv class	FieldAccessUnsafe
public class	MapEntry< Key of the map-entry K, Value of the map-entry V> Deprecated Use org.apache.avro.util.MapEntry Class to make Avro immune from the naming variations of key/value fields among several `java.util.Map.Entry` implementations.
public class	ReflectData Utilities to use existing Java classes and interfaces via reflection.
public class	ReflectDatumReader<T> `DatumReader` for existing classes via Java reflection.
public class	ReflectDatumWriter<T> `DatumWriter` for existing classes via Java reflection.
public class	ReflectionUtil A few utility methods for using @link{java.misc.Unsafe}, mostly for private use.

Package org.apache.avro.reflect

Annotation Summary

Class Summary