org.apache.avro.generic
Class GenericDatumReader<D>

java.lang.Object
  org.apache.avro.generic.GenericDatumReader<D>

All Implemented Interfaces:

DatumReader<D>

Direct Known Subclasses:

ReflectDatumReader

public class GenericDatumReader<D>
extends Object
implements DatumReader<D>

DatumReader for generic Java objects.

Constructor Summary

GenericDatumReader()

GenericDatumReader(Schema actual)

GenericDatumReader(Schema actual, Schema expected)

Method Summary

protected void	addField(Object record, String name, int position, Object o) Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a record fields value to a record instance.
protected void	addToArray(Object array, Object e) Called by the default implementation of readArray(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a value.
protected void	addToMap(Object map, Object key, Object value) Called by the default implementation of readMap(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a key/value pair.
protected Object	createBytes(byte[] value) Called to create byte arrays from default values.
protected Object	createEnum(String symbol, Schema schema) Called to create an enum value.
protected Object	createFixed(Object old, byte[] bytes, Schema schema) Called to create an fixed value.
protected Object	createFixed(Object old, Schema schema) Called to create an fixed value.
protected Object	createString(String value) Called to create a string from a default value.
protected Object	defaultFieldValue(Object old, Schema schema, JsonNode json) Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to construct a default value for a field.
protected Object	getField(Object record, String name, int position) Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to retrieve a record field value from a reused instance.
protected Object	newArray(Object old, int size, Schema schema) Called to create new array instances.
protected Object	newMap(Object old, int size) Called to create new array instances.
protected Object	newRecord(Object old, Schema schema) Called to create new record instances.
protected Object	peekArray(Object array) Called by the default implementation of readArray(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to retrieve a value from a reused instance.
D	read(D reuse, Decoder in) Read a datum.
protected Object	read(Object old, Schema actual, Schema expected, Decoder in) Called to read data.
protected Object	readArray(Object old, Schema actual, Schema expected, Decoder in) Called to read an array instance.
protected Object	readBytes(Object old, Decoder in) Called to read byte arrays.
protected Object	readEnum(Schema actual, Schema expected, Decoder in) Called to read an enum value.
protected Object	readFixed(Object old, Schema actual, Schema expected, Decoder in) Called to read a fixed value.
protected Object	readMap(Object old, Schema actual, Schema expected, Decoder in) Called to read a map instance.
protected Object	readRecord(Object old, Schema actual, Schema expected, Decoder in) Called to read a record instance.
protected Object	readString(Object old, Decoder in) Called to read strings.
protected void	removeField(Object record, String field, int position) Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to remove a record field value from a reused instance.
void	setExpected(Schema expected)
void	setSchema(Schema actual) Set the schema.
static void	skip(Schema schema, Decoder in) Skip an instance of a schema.

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericDatumReader

public GenericDatumReader()

GenericDatumReader

public GenericDatumReader(Schema actual)

GenericDatumReader

public GenericDatumReader(Schema actual,
                          Schema expected)

Method Detail

setSchema

public void setSchema(Schema actual)

Description copied from interface: DatumReader

Set the schema.

Specified by:

setSchema in interface DatumReader<D>

setExpected

public void setExpected(Schema expected)

read

public D read(D reuse,
              Decoder in)
       throws IOException

Description copied from interface: DatumReader

Read a datum. Traverse the schema, depth-first, reading all leaf values in the schema into a datum that is returned. If the provided datum is non-null it may be reused and returned.

Specified by:

read in interface DatumReader<D>

Throws:

IOException

read

protected Object read(Object old,
                      Schema actual,
                      Schema expected,
                      Decoder in)
               throws IOException

Called to read data.

Throws:

IOException

readRecord

protected Object readRecord(Object old,
                            Schema actual,
                            Schema expected,
                            Decoder in)
                     throws IOException

Called to read a record instance. May be overridden for alternate record representations.

Throws:

IOException

addField

protected void addField(Object record,
                        String name,
                        int position,
                        Object o)

Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a record fields value to a record instance. The default implementation is for GenericRecord.

getField

protected Object getField(Object record,
                          String name,
                          int position)

Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to retrieve a record field value from a reused instance. The default implementation is for GenericRecord.

removeField

protected void removeField(Object record,
                           String field,
                           int position)

Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to remove a record field value from a reused instance. The default implementation is for GenericRecord.

defaultFieldValue

protected Object defaultFieldValue(Object old,
                                   Schema schema,
                                   JsonNode json)
                            throws IOException

Called by the default implementation of readRecord(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to construct a default value for a field.

Throws:

IOException

readEnum

protected Object readEnum(Schema actual,
                          Schema expected,
                          Decoder in)
                   throws IOException

Called to read an enum value. May be overridden for alternate enum representations. By default, returns the symbol as a String.

Throws:

IOException

createEnum

protected Object createEnum(String symbol,
                            Schema schema)

Called to create an enum value. May be overridden for alternate enum representations. By default, returns the symbol as a String.

readArray

protected Object readArray(Object old,
                           Schema actual,
                           Schema expected,
                           Decoder in)
                    throws IOException

Called to read an array instance. May be overridden for alternate array representations.

Throws:

IOException

peekArray

protected Object peekArray(Object array)

Called by the default implementation of readArray(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to retrieve a value from a reused instance. The default implementation is for GenericArray.

addToArray

protected void addToArray(Object array,
                          Object e)

Called by the default implementation of readArray(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a value. The default implementation is for GenericArray.

readMap

protected Object readMap(Object old,
                         Schema actual,
                         Schema expected,
                         Decoder in)
                  throws IOException

Called to read a map instance. May be overridden for alternate map representations.

Throws:

IOException

addToMap

protected void addToMap(Object map,
                        Object key,
                        Object value)

Called by the default implementation of readMap(java.lang.Object, org.apache.avro.Schema, org.apache.avro.Schema, org.apache.avro.io.Decoder) to add a key/value pair. The default implementation is for Map.

readFixed

protected Object readFixed(Object old,
                           Schema actual,
                           Schema expected,
                           Decoder in)
                    throws IOException

Called to read a fixed value. May be overridden for alternate fixed representations. By default, returns GenericFixed.

Throws:

IOException

createFixed

protected Object createFixed(Object old,
                             Schema schema)

Called to create an fixed value. May be overridden for alternate fixed representations. By default, returns GenericFixed.

createFixed

protected Object createFixed(Object old,
                             byte[] bytes,
                             Schema schema)

Called to create an fixed value. May be overridden for alternate fixed representations. By default, returns GenericFixed.

newRecord

protected Object newRecord(Object old,
                           Schema schema)

Called to create new record instances. Subclasses may override to use a different record implementation. The returned instance must conform to the schema provided. If the old object contains fields not present in the schema, they should either be removed from the old object, or it should create a new instance that conforms to the schema. By default, this returns a GenericData.Record.

newArray

protected Object newArray(Object old,
                          int size,
                          Schema schema)

Called to create new array instances. Subclasses may override to use a different array implementation. By default, this returns a GenericData.Array.

newMap

protected Object newMap(Object old,
                        int size)

Called to create new array instances. Subclasses may override to use a different map implementation. By default, this returns a HashMap.

readString

protected Object readString(Object old,
                            Decoder in)
                     throws IOException

Called to read strings. Subclasses may override to use a different string representation. By default, this calls Decoder.readString(Utf8).

Throws:

IOException

createString

protected Object createString(String value)

Called to create a string from a default value. Subclasses may override to use a different string representation. By default, this calls Utf8.Utf8(String).

readBytes

protected Object readBytes(Object old,
                           Decoder in)
                    throws IOException

Called to read byte arrays. Subclasses may override to use a different byte array representation. By default, this calls Decoder.readBytes(ByteBuffer).

Throws:

IOException

createBytes

protected Object createBytes(byte[] value)

Called to create byte arrays from default values. Subclasses may override to use a different byte array representation. By default, this calls ByteBuffer.wrap(byte[]).

skip

public static void skip(Schema schema,
                        Decoder in)
                 throws IOException

Skip an instance of a schema.

Throws:

IOException