org.apache.avro.generic

Class GenericDatumWriter<D>

java.lang.Object

org.apache.avro.generic.GenericDatumWriter<D>

All Implemented Interfaces:

DatumWriter<D>

Direct Known Subclasses:

ProtobufDatumWriter, SpecificDatumWriter, ThriftDatumWriter

public class GenericDatumWriter<D>
extends Object
implements DatumWriter<D>

DatumWriter for generic Java objects.

Constructor Summary

Constructors

Modifier	Constructor and Description
	GenericDatumWriter()
protected	GenericDatumWriter(GenericData data)
	GenericDatumWriter(Schema root)
	GenericDatumWriter(Schema root, GenericData data)

Method Summary

Modifier and Type	Method and Description
protected AvroTypeException	addAvroTypeMsg(AvroTypeException e, String s) Helper method for adding a message to an Avro Type Exception .
protected ClassCastException	addClassCastMsg(ClassCastException e, String s) Helper method for adding a message to an Class Cast Exception .
protected <T> Object	convert(Schema schema, LogicalType logicalType, Conversion<T> conversion, Object datum) Convert a high level representation of a logical type (such as a BigDecimal) to the its underlying representation object (such as a ByteBuffer).
protected Iterator<? extends Object>	getArrayElements(Object array) Called by the default implementation of writeArray(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to enumerate array elements.
protected long	getArraySize(Object array) Called by the default implementation of writeArray(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to get the size of an array.
GenericData	getData() Return the GenericData implementation.
protected Iterable<Map.Entry<Object,Object>>	getMapEntries(Object map) Called by the default implementation of writeMap(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to enumerate map elements.
protected int	getMapSize(Object map) Called by the default implementation of writeMap(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to get the size of a map.
protected NullPointerException	npe(NullPointerException e, String s) Helper method for adding a message to an NPE .
protected int	resolveUnion(Schema union, Object datum) Called to find the index for a datum within a union.
void	setSchema(Schema root) Set the schema.
void	write(D datum, Encoder out) Write a datum.
protected void	write(Schema schema, Object datum, Encoder out) Called to write data.
protected void	writeArray(Schema schema, Object datum, Encoder out) Called to write a array.
protected void	writeBytes(Object datum, Encoder out) Called to write a bytes.
protected void	writeEnum(Schema schema, Object datum, Encoder out) Called to write an enum value.
protected void	writeField(Object datum, Schema.Field f, Encoder out, Object state) Called to write a single field of a record.
protected void	writeFixed(Schema schema, Object datum, Encoder out) Called to write a fixed value.
protected void	writeMap(Schema schema, Object datum, Encoder out) Called to write a map.
protected void	writeRecord(Schema schema, Object datum, Encoder out) Called to write a record.
protected void	writeString(Object datum, Encoder out) Called to write a string.
protected void	writeString(Schema schema, Object datum, Encoder out) Called to write a string.
protected void	writeWithoutConversion(Schema schema, Object datum, Encoder out) Called to write data.

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericDatumWriter

public GenericDatumWriter()

GenericDatumWriter

protected GenericDatumWriter(GenericData data)

GenericDatumWriter

public GenericDatumWriter(Schema root)

GenericDatumWriter

public GenericDatumWriter(Schema root,
                          GenericData data)

Method Detail

getData

public GenericData getData()

Return the GenericData implementation.

setSchema

public void setSchema(Schema root)

Description copied from interface: DatumWriter

Set the schema.

Specified by:

setSchema in interface DatumWriter<D>

write

public void write(D datum,
                  Encoder out)
           throws IOException

Description copied from interface: DatumWriter

Write a datum. Traverse the schema, depth first, writing each leaf value in the schema from the datum to the output.

Specified by:

write in interface DatumWriter<D>

Throws:

IOException

write

protected void write(Schema schema,
                     Object datum,
                     Encoder out)
              throws IOException

Called to write data.

Throws:

IOException

convert

protected <T> Object convert(Schema schema,
                             LogicalType logicalType,
                             Conversion<T> conversion,
                             Object datum)

Convert a high level representation of a logical type (such as a BigDecimal) to the its underlying representation object (such as a ByteBuffer).

Throws:

IllegalArgumentException - if a null schema or logicalType is passed in while datum and conversion are not null. Please be noticed that the exception type has changed. With version 1.8.0 and earlier, in above circumstance, the exception thrown out depends on the implementation of conversion (most likely a NullPointerException). Now, an IllegalArgumentException will be thrown out instead.

writeWithoutConversion

protected void writeWithoutConversion(Schema schema,
                                      Object datum,
                                      Encoder out)
                               throws IOException

Called to write data.

Throws:

IOException

npe

protected NullPointerException npe(NullPointerException e,
                                   String s)

Helper method for adding a message to an NPE .

addClassCastMsg

protected ClassCastException addClassCastMsg(ClassCastException e,
                                             String s)

Helper method for adding a message to an Class Cast Exception .

addAvroTypeMsg

protected AvroTypeException addAvroTypeMsg(AvroTypeException e,
                                           String s)

Helper method for adding a message to an Avro Type Exception .

writeRecord

protected void writeRecord(Schema schema,
                           Object datum,
                           Encoder out)
                    throws IOException

Called to write a record. May be overridden for alternate record representations.

Throws:

IOException

writeField

protected void writeField(Object datum,
                          Schema.Field f,
                          Encoder out,
                          Object state)
                   throws IOException

Called to write a single field of a record. May be overridden for more efficient or alternate implementations.

Throws:

IOException

writeEnum

protected void writeEnum(Schema schema,
                         Object datum,
                         Encoder out)
                  throws IOException

Called to write an enum value. May be overridden for alternate enum representations.

Throws:

IOException

writeArray

protected void writeArray(Schema schema,
                          Object datum,
                          Encoder out)
                   throws IOException

Called to write a array. May be overridden for alternate array representations.

Throws:

IOException

resolveUnion

protected int resolveUnion(Schema union,
                           Object datum)

Called to find the index for a datum within a union. By default calls GenericData.resolveUnion(Schema,Object).

getArraySize

protected long getArraySize(Object array)

Called by the default implementation of writeArray(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to get the size of an array. The default implementation is for Collection.

getArrayElements

protected Iterator<? extends Object> getArrayElements(Object array)

Called by the default implementation of writeArray(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to enumerate array elements. The default implementation is for Collection.

writeMap

protected void writeMap(Schema schema,
                        Object datum,
                        Encoder out)
                 throws IOException

Called to write a map. May be overridden for alternate map representations.

Throws:

IOException

getMapSize

protected int getMapSize(Object map)

Called by the default implementation of writeMap(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to get the size of a map. The default implementation is for Map.

getMapEntries

protected Iterable<Map.Entry<Object,Object>> getMapEntries(Object map)

Called by the default implementation of writeMap(org.apache.avro.Schema, java.lang.Object, org.apache.avro.io.Encoder) to enumerate map elements. The default implementation is for Map.

writeString

protected void writeString(Schema schema,
                           Object datum,
                           Encoder out)
                    throws IOException

Called to write a string. May be overridden for alternate string representations.

Throws:

IOException

writeString

protected void writeString(Object datum,
                           Encoder out)
                    throws IOException

Called to write a string. May be overridden for alternate string representations.

Throws:

IOException

writeBytes

protected void writeBytes(Object datum,
                          Encoder out)
                   throws IOException

Called to write a bytes. May be overridden for alternate bytes representations.

Throws:

IOException

writeFixed

protected void writeFixed(Schema schema,
                          Object datum,
                          Encoder out)
                   throws IOException

Called to write a fixed value. May be overridden for alternate fixed representations.

Throws:

IOException