org.apache.avro.io
Class BlockingBinaryEncoder

java.lang.Object
  org.apache.avro.io.Encoder
      org.apache.avro.io.BinaryEncoder
          org.apache.avro.io.BufferedBinaryEncoder
              org.apache.avro.io.BlockingBinaryEncoder

All Implemented Interfaces:

Flushable

public class BlockingBinaryEncoder
extends BufferedBinaryEncoder

A BinaryEncoder implementation that writes large arrays and maps as a sequence of blocks. So long as individual primitive values fit in memory, arbitrarily long arrays and maps may be written and subsequently read without exhausting memory. Values are buffered until the specified block size would be exceeded, minimizing block overhead.

Use EncoderFactory.blockingBinaryEncoder(OutputStream, BinaryEncoder) to construct and configure.

BlockingBinaryEncoder buffers writes, data may not appear on the output until flush() is called.

BlockingBinaryEncoder is not thread-safe

See Also:

BinaryEncoder, EncoderFactory, Encoder

Method Summary

int	bytesBuffered() Returns the number of bytes currently buffered by this encoder.
void	flush()
void	setItemCount(long itemCount) Call this method before writing a batch of items in an array or a map.
void	startItem() Start a new item of an array or map.
void	writeArrayEnd() Call this method to finish writing an array.
void	writeArrayStart() Call this method to start writing an array.
void	writeBoolean(boolean b) Write a boolean value.
void	writeDouble(double d) Write a double.
void	writeFixed(byte[] bytes, int start, int len) Writes a fixed size binary object.
void	writeFloat(float f) Write a float.
void	writeIndex(int unionIndex) Call this method to write the tag of a union.
void	writeInt(int n) Writes a 32-bit integer.
void	writeLong(long n) Write a 64-bit integer.
void	writeMapEnd() Call this method to terminate the inner-most, currently-opened map.
void	writeMapStart() Call this to start a new map.
protected void	writeZero() Write a zero byte to the underlying output.

Methods inherited from class org.apache.avro.io.BinaryEncoder

writeBytes, writeBytes, writeEnum, writeNull, writeString, writeString

Methods inherited from class org.apache.avro.io.Encoder

writeBytes, writeFixed, writeString

Methods inherited from class java.lang.Object

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

Method Detail

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class BufferedBinaryEncoder

Throws:

IOException

writeBoolean

public void writeBoolean(boolean b)
                  throws IOException

Description copied from class: Encoder

Write a boolean value.

Overrides:

writeBoolean in class BufferedBinaryEncoder

Throws:

IOException

writeInt

public void writeInt(int n)
              throws IOException

Description copied from class: Encoder

Writes a 32-bit integer.

Overrides:

writeInt in class BufferedBinaryEncoder

Throws:

IOException

writeLong

public void writeLong(long n)
               throws IOException

Description copied from class: Encoder

Write a 64-bit integer.

Overrides:

writeLong in class BufferedBinaryEncoder

Throws:

IOException

writeFloat

public void writeFloat(float f)
                throws IOException

Description copied from class: Encoder

Write a float.

Overrides:

writeFloat in class BufferedBinaryEncoder

Throws:

IOException

writeDouble

public void writeDouble(double d)
                 throws IOException

Description copied from class: Encoder

Write a double.

Overrides:

writeDouble in class BufferedBinaryEncoder

Throws:

IOException

writeFixed

public void writeFixed(byte[] bytes,
                       int start,
                       int len)
                throws IOException

Description copied from class: Encoder

Writes a fixed size binary object.

Overrides:

writeFixed in class BufferedBinaryEncoder

Parameters:

bytes - The contents to write

start - The position within bytes where the contents start.

len - The number of bytes to write.

Throws:

IOException

writeZero

protected void writeZero()
                  throws IOException

Description copied from class: BinaryEncoder

Write a zero byte to the underlying output.

Overrides:

writeZero in class BufferedBinaryEncoder

Throws:

IOException

writeArrayStart

public void writeArrayStart()
                     throws IOException

Description copied from class: Encoder

Call this method to start writing an array. When starting to serialize an array, call Encoder.writeArrayStart(). Then, before writing any data for any item call Encoder.setItemCount(long) followed by a sequence of Encoder.startItem() and the item itself. The number of Encoder.startItem() should match the number specified in Encoder.setItemCount(long). When actually writing the data of the item, you can call any Encoder method (e.g., Encoder.writeLong(long)). When all items of the array have been written, call Encoder.writeArrayEnd(). As an example, let's say you want to write an array of records, the record consisting of an Long field and a Boolean field. Your code would look something like this:

  out.writeArrayStart();
  out.setItemCount(list.size());
  for (Record r : list) {
    out.startItem();
    out.writeLong(r.longField);
    out.writeBoolean(r.boolField);
  }
  out.writeArrayEnd();
  

Overrides:

writeArrayStart in class BinaryEncoder

Throws:

IOException

setItemCount

public void setItemCount(long itemCount)
                  throws IOException

Description copied from class: Encoder

Call this method before writing a batch of items in an array or a map. Then for each item, call Encoder.startItem() followed by any of the other write methods of Encoder. The number of calls to Encoder.startItem() must be equal to the count specified in Encoder.setItemCount(long). Once a batch is completed you can start another batch with Encoder.setItemCount(long).

Overrides:

setItemCount in class BinaryEncoder

Parameters:

itemCount - The number of Encoder.startItem() calls to follow.

Throws:

IOException

startItem

public void startItem()
               throws IOException

Description copied from class: Encoder

Start a new item of an array or map. See Encoder.writeArrayStart() for usage information.

Overrides:

startItem in class BinaryEncoder

Throws:

IOException

writeArrayEnd

public void writeArrayEnd()
                   throws IOException

Description copied from class: Encoder

Call this method to finish writing an array. See Encoder.writeArrayStart() for usage information.

Overrides:

writeArrayEnd in class BinaryEncoder

Throws:

IOException

writeMapStart

public void writeMapStart()
                   throws IOException

Description copied from class: Encoder

Call this to start a new map. See Encoder.writeArrayStart() for details on usage. As an example of usage, let's say you want to write a map of records, the record consisting of an Long field and a Boolean field. Your code would look something like this:

 out.writeMapStart();
 out.setItemCount(list.size());
 for (Map.Entry entry : map.entrySet()) {
   out.startItem();
   out.writeString(entry.getKey());
   out.writeLong(entry.getValue().longField);
   out.writeBoolean(entry.getValue().boolField);
 }
 out.writeMapEnd();
 

Overrides:

writeMapStart in class BinaryEncoder

Throws:

IOException

writeMapEnd

public void writeMapEnd()
                 throws IOException

Description copied from class: Encoder

Call this method to terminate the inner-most, currently-opened map. See Encoder.writeArrayStart() for more details.

Overrides:

writeMapEnd in class BinaryEncoder

Throws:

IOException

writeIndex

public void writeIndex(int unionIndex)
                throws IOException

Description copied from class: Encoder

Call this method to write the tag of a union. As an example of usage, let's say you want to write a union, whose second branch is a record consisting of an Long field and a Boolean field. Your code would look something like this:

 out.writeIndex(1);
 out.writeLong(record.longField);
 out.writeBoolean(record.boolField);
 

Overrides:

writeIndex in class BinaryEncoder

Throws:

IOException

bytesBuffered

public int bytesBuffered()

Description copied from class: BinaryEncoder

Returns the number of bytes currently buffered by this encoder. If this Encoder does not buffer, this will always return zero.

Call Flushable.flush() to empty the buffer to the underlying output.

Overrides:

bytesBuffered in class BufferedBinaryEncoder