org.apache.avro.io
Class JsonEncoder

java.lang.Object
  org.apache.avro.io.Encoder
      org.apache.avro.io.ParsingEncoder
          org.apache.avro.io.JsonEncoder

All Implemented Interfaces:

Flushable, Parser.ActionHandler

public class JsonEncoder
extends ParsingEncoder
implements Parser.ActionHandler

An Encoder for Avro's JSON data encoding.

Construct using EncoderFactory.

JsonEncoder buffers output, and data may not appear on the output until Flushable.flush() is called.

JsonEncoder is not thread-safe.

Field Summary

protected BitSet

isEmpty Has anything been written into the collections?

Fields inherited from class org.apache.avro.io.ParsingEncoder

pos

Method Summary

JsonEncoder	configure(JsonGenerator generator) Reconfigures this JsonEncoder to output to the JsonGenerator provided.
JsonEncoder	configure(OutputStream out) Reconfigures this JsonEncoder to use the output stream provided.
Symbol	doAction(Symbol input, Symbol top) Handle the action symbol top when the input is sought to be taken off the stack.
void	flush()
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	writeBytes(byte[] bytes, int start, int len) Write a byte string.
void	writeBytes(ByteBuffer bytes) Write a byte string.
void	writeDouble(double d) Write a double.
void	writeEnum(int e) Writes an enumeration.
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.
void	writeNull() "Writes" a null value.
void	writeString(String str) Write a Unicode character string.
void	writeString(Utf8 utf8) Write a Unicode character string.

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

depth, pop, push, setItemCount

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

Field Detail

isEmpty

protected BitSet isEmpty

Has anything been written into the collections?

Method Detail

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Throws:

IOException

configure

public JsonEncoder configure(OutputStream out)
                      throws IOException

Reconfigures this JsonEncoder to use the output stream provided.

If the OutputStream provided is null, a NullPointerException is thrown.

Otherwise, this JsonEncoder will flush its current output and then reconfigure its output to use a default UTF8 JsonGenerator that writes to the provided OutputStream.

Parameters:

out - The OutputStream to direct output to. Cannot be null.

Returns:

this JsonEncoder

Throws:

IOException

configure

public JsonEncoder configure(JsonGenerator generator)
                      throws IOException

Reconfigures this JsonEncoder to output to the JsonGenerator provided.

If the JsonGenerator provided is null, a NullPointerException is thrown.

Otherwise, this JsonEncoder will flush its current output and then reconfigure its output to use the provided JsonGenerator.

Parameters:

generator - The JsonGenerator to direct output to. Cannot be null.

Returns:

this JsonEncoder

Throws:

IOException

writeNull

public void writeNull()
               throws IOException

Description copied from class: Encoder

"Writes" a null value. (Doesn't actually write anything, but advances the state of the parser if this class is stateful.)

Specified by:

writeNull in class Encoder

Throws:

IOException

writeBoolean

public void writeBoolean(boolean b)
                  throws IOException

Description copied from class: Encoder

Write a boolean value.

Specified by:

writeBoolean in class Encoder

Throws:

IOException

writeInt

public void writeInt(int n)
              throws IOException

Description copied from class: Encoder

Writes a 32-bit integer.

Specified by:

writeInt in class Encoder

Throws:

IOException

writeLong

public void writeLong(long n)
               throws IOException

Description copied from class: Encoder

Write a 64-bit integer.

Specified by:

writeLong in class Encoder

Throws:

IOException

writeFloat

public void writeFloat(float f)
                throws IOException

Description copied from class: Encoder

Write a float.

Specified by:

writeFloat in class Encoder

Throws:

IOException

writeDouble

public void writeDouble(double d)
                 throws IOException

Description copied from class: Encoder

Write a double.

Specified by:

writeDouble in class Encoder

Throws:

IOException

writeString

public void writeString(Utf8 utf8)
                 throws IOException

Description copied from class: Encoder

Write a Unicode character string.

Specified by:

writeString in class Encoder

Throws:

IOException

writeString

public void writeString(String str)
                 throws IOException

Description copied from class: Encoder

Write a Unicode character string. The default implementation converts the String to a Utf8. Some Encoder implementations may want to do something different as a performance optimization.

Overrides:

writeString in class Encoder

Throws:

IOException

writeBytes

public void writeBytes(ByteBuffer bytes)
                throws IOException

Description copied from class: Encoder

Write a byte string.

Specified by:

writeBytes in class Encoder

Throws:

IOException

writeBytes

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

Description copied from class: Encoder

Write a byte string.

Specified by:

writeBytes in class Encoder

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.

Specified by:

writeFixed in class Encoder

Parameters:

bytes - The contents to write

start - The position within bytes where the contents start.

len - The number of bytes to write.

Throws:

IOException

writeEnum

public void writeEnum(int e)
               throws IOException

Description copied from class: Encoder

Writes an enumeration.

Specified by:

writeEnum in class Encoder

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();
  

Specified by:

writeArrayStart in class Encoder

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.

Specified by:

writeArrayEnd in class Encoder

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();
 

Specified by:

writeMapStart in class Encoder

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.

Specified by:

writeMapEnd in class Encoder

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 ParsingEncoder

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);
 

Specified by:

writeIndex in class Encoder

Throws:

IOException

doAction

public Symbol doAction(Symbol input,
                       Symbol top)
                throws IOException

Description copied from interface: Parser.ActionHandler

Handle the action symbol top when the input is sought to be taken off the stack.

Specified by:

doAction in interface Parser.ActionHandler

Parameters:

input - The input symbol from the caller of advance

top - The symbol at the top the stack.

Returns:

null if advance() is to continue processing the stack. If not null the return value will be returned by advance().

Throws:

IOException