Package org.apache.beam.sdk.schemas

Class JavaFieldSchema

java.lang.Object

org.apache.beam.sdk.schemas.GetterBasedSchemaProvider

org.apache.beam.sdk.schemas.JavaFieldSchema

All Implemented Interfaces:

java.io.Serializable, SchemaProvider

@Experimental(SCHEMAS)
public class JavaFieldSchema
extends GetterBasedSchemaProvider

A SchemaProvider for Java POJO objects.

This provider finds all public fields (recursively) in a Java object, and creates schemas and rows that bind to those fields. The field order in the schema is not guaranteed to match the field order in the class. The Java object is expected to have implemented a correct .equals() and .hashCode() methods. The equals method must be completely determined by the schema fields. i.e. if the object has hidden fields that are not reflected in the schema but are compared in equals, then results will be incorrect.

TODO: Validate equals() method is provided, and if not generate a "slow" equals method based on the schema.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	JavaFieldSchema.JavaFieldTypeSupplier	FieldValueTypeSupplier that's based on public fields.

Constructor Summary

Constructors

Constructor	Description
JavaFieldSchema()

Method Summary

Modifier and Type	Method	Description
java.util.List<FieldValueGetter>	fieldValueGetters(java.lang.Class<?> targetClass, Schema schema)	Implementing class should override to return FieldValueGetters.
java.util.List<FieldValueTypeInformation>	fieldValueTypeInformations(java.lang.Class<?> targetClass, Schema schema)	Implementing class should override to return a list of type-informations.
<T> Schema	schemaFor(TypeDescriptor<T> typeDescriptor)	Lookup a schema for the given type.
SchemaUserTypeCreator	schemaTypeCreator(java.lang.Class<?> targetClass, Schema schema)	Implementing class should override to return a constructor.

Methods inherited from class org.apache.beam.sdk.schemas.GetterBasedSchemaProvider

equals, fromRowFunction, hashCode, toRowFunction

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaFieldSchema

public JavaFieldSchema()

Method Detail

schemaFor

public <T> Schema schemaFor(TypeDescriptor<T> typeDescriptor)

Description copied from interface: SchemaProvider

Lookup a schema for the given type. If no schema exists, returns null.

fieldValueGetters

public java.util.List<FieldValueGetter> fieldValueGetters(java.lang.Class<?> targetClass,
                                                          Schema schema)

Description copied from class: GetterBasedSchemaProvider

Implementing class should override to return FieldValueGetters.

Specified by:

fieldValueGetters in class GetterBasedSchemaProvider

fieldValueTypeInformations

public java.util.List<FieldValueTypeInformation> fieldValueTypeInformations(java.lang.Class<?> targetClass,
                                                                            Schema schema)

Description copied from class: GetterBasedSchemaProvider

Implementing class should override to return a list of type-informations.

Specified by:

fieldValueTypeInformations in class GetterBasedSchemaProvider

schemaTypeCreator

public SchemaUserTypeCreator schemaTypeCreator(java.lang.Class<?> targetClass,
                                               Schema schema)

Description copied from class: GetterBasedSchemaProvider

Implementing class should override to return a constructor.

Specified by:

schemaTypeCreator in class GetterBasedSchemaProvider