Package org.apache.avro.io
Class BinaryEncoder
java.lang.Object
org.apache.avro.io.Encoder
org.apache.avro.io.BinaryEncoder
- All Implemented Interfaces:
Flushable
- Direct Known Subclasses:
BufferedBinaryEncoder,DirectBinaryEncoder
An abstract
Encoder for Avro's binary encoding.
To construct and configure instances, use EncoderFactory- See Also:
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionabstract intReturns the number of bytes currently buffered by this encoder.voidsetItemCount(long itemCount) Call this method before writing a batch of items in an array or a map.voidStart a new item of an array or map.voidCall this method to finish writing an array.voidCall this method to start writing an array.voidwriteBytes(byte[] bytes, int start, int len) Write a byte string.voidwriteBytes(ByteBuffer bytes) Write a byte string.voidwriteEnum(int e) Writes an enumeration.voidwriteIndex(int unionIndex) Call this method to write the tag of a union.voidCall this method to terminate the inner-most, currently-opened map.voidCall this to start a new map.void"Writes" a null value.voidwriteString(String string) Write a Unicode character string.voidwriteString(Utf8 utf8) Write a Unicode character string.protected abstract voidWrite a zero byte to the underlying output.Methods inherited from class org.apache.avro.io.Encoder
writeBoolean, writeBytes, writeDouble, writeFixed, writeFixed, writeFixed, writeFloat, writeInt, writeLong, writeString
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Constructor Details
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BinaryEncoder
public BinaryEncoder()
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Method Details
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writeNull
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:
writeNullin classEncoder- Throws:
IOException
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writeString
Description copied from class:EncoderWrite a Unicode character string.- Specified by:
writeStringin classEncoder- Throws:
IOException
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writeString
Description copied from class:EncoderWrite a Unicode character string. The default implementation converts the String to aUtf8. Some Encoder implementations may want to do something different as a performance optimization.- Overrides:
writeStringin classEncoder- Throws:
IOException
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writeBytes
Description copied from class:EncoderWrite a byte string.- Specified by:
writeBytesin classEncoder- Throws:
IOException
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writeBytes
Description copied from class:EncoderWrite a byte string.- Specified by:
writeBytesin classEncoder- Throws:
IOException
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writeEnum
Description copied from class:EncoderWrites an enumeration.- Specified by:
writeEnumin classEncoder- Parameters:
e-- Throws:
IOException
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writeArrayStart
Description copied from class:EncoderCall this method to start writing an array. When starting to serialize an array, callEncoder.writeArrayStart(). Then, before writing any data for any item callEncoder.setItemCount(long)followed by a sequence ofEncoder.startItem()and the item itself. The number ofEncoder.startItem()should match the number specified inEncoder.setItemCount(long). When actually writing the data of the item, you can call anyEncodermethod (e.g.,Encoder.writeLong(long)). When all items of the array have been written, callEncoder.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:
writeArrayStartin classEncoder- Throws:
IOException
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setItemCount
Description copied from class:EncoderCall this method before writing a batch of items in an array or a map. Then for each item, callEncoder.startItem()followed by any of the other write methods ofEncoder. The number of calls toEncoder.startItem()must be equal to the count specified inEncoder.setItemCount(long). Once a batch is completed you can start another batch withEncoder.setItemCount(long).- Specified by:
setItemCountin classEncoder- Parameters:
itemCount- The number ofEncoder.startItem()calls to follow.- Throws:
IOException
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startItem
Description copied from class:EncoderStart a new item of an array or map. SeeEncoder.writeArrayStart()for usage information.- Specified by:
startItemin classEncoder- Throws:
IOException
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writeArrayEnd
Description copied from class:EncoderCall this method to finish writing an array. SeeEncoder.writeArrayStart()for usage information.- Specified by:
writeArrayEndin classEncoder- Throws:
IOException
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writeMapStart
Description copied from class:EncoderCall this to start a new map. SeeEncoder.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.Entryinvalid input: '<'String, Record> entry : map.entrySet()) { out.startItem(); out.writeString(entry.getKey()); out.writeLong(entry.getValue().longField); out.writeBoolean(entry.getValue().boolField); } out.writeMapEnd();- Specified by:
writeMapStartin classEncoder- Throws:
IOException
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writeMapEnd
Description copied from class:EncoderCall this method to terminate the inner-most, currently-opened map. SeeEncoder.writeArrayStart()for more details.- Specified by:
writeMapEndin classEncoder- Throws:
IOException
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writeIndex
Description copied from class:EncoderCall 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:
writeIndexin classEncoder- Throws:
IOException
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writeZero
Write a zero byte to the underlying output.- Throws:
IOException
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bytesBuffered
public abstract int bytesBuffered()Returns the number of bytes currently buffered by this encoder. If this Encoder does not buffer, this will always return zero. CallFlushable.flush()to empty the buffer to the underlying output.
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