org.apache.avro.io

Class DecoderFactory

java.lang.Object

org.apache.avro.io.DecoderFactory

public class DecoderFactory
extends Object

A factory for creating and configuring Decoders.

Factories are thread-safe, and are generally cached by applications for performance reasons. Multiple instances are only required if multiple concurrent configurations are needed.

See Also:

Decoder

Constructor Summary

Constructors

Constructor and Description
DecoderFactory() Constructor for factory instances

Method Summary

Modifier and Type	Method and Description
BinaryDecoder	binaryDecoder(byte[] bytes, BinaryDecoder reuse) This method is shorthand for
BinaryDecoder	binaryDecoder(byte[] bytes, int offset, int length, BinaryDecoder reuse) Creates or reinitializes a BinaryDecoder with the byte array provided as the source of data.
BinaryDecoder	binaryDecoder(InputStream in, BinaryDecoder reuse) Creates or reinitializes a BinaryDecoder with the input stream provided as the source of data.
DecoderFactory	configureDecoderBufferSize(int size) Configures this factory to use the specified buffer size when creating Decoder instances that buffer their input.
BinaryDecoder	createBinaryDecoder(byte[] bytes, BinaryDecoder reuse) Deprecated. use binaryDecoder(byte[], BinaryDecoder) instead
BinaryDecoder	createBinaryDecoder(byte[] bytes, int offset, int length, BinaryDecoder reuse) Deprecated. use binaryDecoder(byte[], int, int, BinaryDecoder) instead
BinaryDecoder	createBinaryDecoder(InputStream in, BinaryDecoder reuse) Deprecated. use the equivalent binaryDecoder(InputStream, BinaryDecoder) instead
static DecoderFactory	defaultFactory() Deprecated. use the equivalent get() instead
BinaryDecoder	directBinaryDecoder(InputStream in, BinaryDecoder reuse) Creates or reinitializes a BinaryDecoder with the input stream provided as the source of data.
static DecoderFactory	get() Returns an immutable static DecoderFactory configured with default settings All mutating methods throw IllegalArgumentExceptions.
int	getConfiguredBufferSize() Returns this factory's configured preferred buffer size.
JsonDecoder	jsonDecoder(Schema schema, InputStream input) Creates a JsonDecoder using the InputStream provided for reading data that conforms to the Schema provided.
JsonDecoder	jsonDecoder(Schema schema, String input) Creates a JsonDecoder using the String provided for reading data that conforms to the Schema provided.
ResolvingDecoder	resolvingDecoder(Schema writer, Schema reader, Decoder wrapped) Creates a ResolvingDecoder wrapping the Decoder provided.
ValidatingDecoder	validatingDecoder(Schema schema, Decoder wrapped) Creates a ValidatingDecoder wrapping the Decoder provided.

Methods inherited from class java.lang.Object

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

Constructor Detail

DecoderFactory

public DecoderFactory()

Constructor for factory instances

Method Detail

defaultFactory

@Deprecated
public static DecoderFactory defaultFactory()

Deprecated. use the equivalent get() instead

get

public static DecoderFactory get()

Returns an immutable static DecoderFactory configured with default settings All mutating methods throw IllegalArgumentExceptions. All creator methods create objects with default settings.

configureDecoderBufferSize

public DecoderFactory configureDecoderBufferSize(int size)

Configures this factory to use the specified buffer size when creating Decoder instances that buffer their input. The default buffer size is 8192 bytes.

Parameters:

size - The preferred buffer size. Valid values are in the range [32, 16*1024*1024]. Values outside this range are rounded to the nearest value in the range. Values less than 512 or greater than 1024*1024 are not recommended.

Returns:

This factory, to enable method chaining:

         DecoderFactory myFactory = new DecoderFactory().useBinaryDecoderBufferSize(4096);
         

getConfiguredBufferSize

public int getConfiguredBufferSize()

Returns this factory's configured preferred buffer size. Used when creating Decoder instances that buffer. See configureDecoderBufferSize(int)

Returns:

The preferred buffer size, in bytes.

createBinaryDecoder

@Deprecated
public BinaryDecoder createBinaryDecoder(InputStream in,
                                                     BinaryDecoder reuse)

Deprecated. use the equivalent binaryDecoder(InputStream, BinaryDecoder) instead

binaryDecoder

public BinaryDecoder binaryDecoder(InputStream in,
                                   BinaryDecoder reuse)

Creates or reinitializes a BinaryDecoder with the input stream provided as the source of data. If reuse is provided, it will be reinitialized to the given input stream.

BinaryDecoder instances returned by this method buffer their input, reading up to getConfiguredBufferSize() bytes past the minimum required to satisfy read requests in order to achieve better performance. If the buffering is not desired, use directBinaryDecoder(InputStream, BinaryDecoder).

BinaryDecoder.inputStream() provides a view on the data that is buffer-aware, for users that need to interleave access to data with the Decoder API.

Parameters:

in - The InputStream to initialize to

reuse - The BinaryDecoder to attempt to reuse given the factory configuration. A BinaryDecoder implementation may not be compatible with reuse, causing a new instance to be returned. If null, a new instance is returned.

Returns:

A BinaryDecoder that uses in as its source of data. If reuse is null, this will be a new instance. If reuse is not null, then it may be reinitialized if compatible, otherwise a new instance will be returned.

See Also:

BinaryDecoder, Decoder

directBinaryDecoder

public BinaryDecoder directBinaryDecoder(InputStream in,
                                         BinaryDecoder reuse)

Creates or reinitializes a BinaryDecoder with the input stream provided as the source of data. If reuse is provided, it will be reinitialized to the given input stream.

BinaryDecoder instances returned by this method do not buffer their input. In most cases a buffering BinaryDecoder is sufficient in combination with BinaryDecoder.inputStream() which provides a buffer-aware view on the data.

A "direct" BinaryDecoder does not read ahead from an InputStream or other data source that cannot be rewound. From the perspective of a client, a "direct" decoder must never read beyond the minimum necessary bytes to service a BinaryDecoder API read request.

In the case that the improved performance of a buffering implementation does not outweigh the inconvenience of its buffering semantics, a "direct" decoder can be used.

Parameters:

in - The InputStream to initialize to

reuse - The BinaryDecoder to attempt to reuse given the factory configuration. A BinaryDecoder implementation may not be compatible with reuse, causing a new instance to be returned. If null, a new instance is returned.

Returns:

A BinaryDecoder that uses in as its source of data. If reuse is null, this will be a new instance. If reuse is not null, then it may be reinitialized if compatible, otherwise a new instance will be returned.

See Also:

DirectBinaryDecoder, Decoder

createBinaryDecoder

@Deprecated
public BinaryDecoder createBinaryDecoder(byte[] bytes,
                                                     int offset,
                                                     int length,
                                                     BinaryDecoder reuse)

Deprecated. use binaryDecoder(byte[], int, int, BinaryDecoder) instead

binaryDecoder

public BinaryDecoder binaryDecoder(byte[] bytes,
                                   int offset,
                                   int length,
                                   BinaryDecoder reuse)

Creates or reinitializes a BinaryDecoder with the byte array provided as the source of data. If reuse is provided, it will attempt to reinitialize reuse to the new byte array. This instance will use the provided byte array as its buffer.

BinaryDecoder.inputStream() provides a view on the data that is buffer-aware and can provide a view of the data not yet read by Decoder API methods.

Parameters:

bytes - The byte array to initialize to

offset - The offset to start reading from

length - The maximum number of bytes to read from the byte array

reuse - The BinaryDecoder to attempt to reinitialize. if null a new BinaryDecoder is created.

Returns:

A BinaryDecoder that uses bytes as its source of data. If reuse is null, this will be a new instance. reuse may be reinitialized if appropriate, otherwise a new instance is returned. Clients must not assume that reuse is reinitialized and returned.

createBinaryDecoder

@Deprecated
public BinaryDecoder createBinaryDecoder(byte[] bytes,
                                                     BinaryDecoder reuse)

Deprecated. use binaryDecoder(byte[], BinaryDecoder) instead

binaryDecoder

public BinaryDecoder binaryDecoder(byte[] bytes,
                                   BinaryDecoder reuse)

This method is shorthand for

 createBinaryDecoder(bytes, 0, bytes.length, reuse);
 

binaryDecoder(byte[], int, int, BinaryDecoder)

jsonDecoder

public JsonDecoder jsonDecoder(Schema schema,
                               InputStream input)
                        throws IOException

Creates a JsonDecoder using the InputStream provided for reading data that conforms to the Schema provided.

Parameters:

schema - The Schema for data read from this JsonEncoder. Cannot be null.

input - The InputStream to read from. Cannot be null.

Returns:

A JsonEncoder configured with input and schema

Throws:

IOException

jsonDecoder

public JsonDecoder jsonDecoder(Schema schema,
                               String input)
                        throws IOException

Creates a JsonDecoder using the String provided for reading data that conforms to the Schema provided.

Parameters:

schema - The Schema for data read from this JsonEncoder. Cannot be null.

input - The String to read from. Cannot be null.

Returns:

A JsonEncoder configured with input and schema

Throws:

IOException

validatingDecoder

public ValidatingDecoder validatingDecoder(Schema schema,
                                           Decoder wrapped)
                                    throws IOException

Creates a ValidatingDecoder wrapping the Decoder provided. This ValidatingDecoder will ensure that operations against it conform to the schema provided.

Parameters:

schema - The Schema to validate against. Cannot be null.

wrapped - The Decoder to wrap.

Returns:

A ValidatingDecoder configured with wrapped and schema

Throws:

IOException

resolvingDecoder

public ResolvingDecoder resolvingDecoder(Schema writer,
                                         Schema reader,
                                         Decoder wrapped)
                                  throws IOException

Creates a ResolvingDecoder wrapping the Decoder provided. This ResolvingDecoder will resolve input conforming to the writer schema from the wrapped Decoder, and present it as the reader schema.

Parameters:

writer - The Schema that the source data is in. Cannot be null.

reader - The Schema that the reader wishes to read the data as. Cannot be null.

wrapped - The Decoder to wrap.

Returns:

A ResolvingDecoder configured to resolve writer to reader from in

Throws:

IOException