Package org.springframework.web.socket.adapter.standard

Class ConvertingEncoderDecoderSupport<T,M>

java.lang.Object

org.springframework.web.socket.adapter.standard.ConvertingEncoderDecoderSupport<T,M>

Type Parameters:

T - the type being converted to (for Encoder) or from (for Decoder)

M - the WebSocket message type (String or ByteBuffer)

Direct Known Subclasses:

ConvertingEncoderDecoderSupport.BinaryDecoder, ConvertingEncoderDecoderSupport.BinaryEncoder, ConvertingEncoderDecoderSupport.TextDecoder, ConvertingEncoderDecoderSupport.TextEncoder

public abstract class ConvertingEncoderDecoderSupport<T,M>
extends Object

Base class that can be used to implement a standard Encoder and/or Decoder. It provides encode and decode method implementations that delegate to a Spring ConversionService.

By default, this class looks up a ConversionService registered in the active ApplicationContext under the name 'webSocketConversionService'. This works fine for both client and server endpoints, in a Servlet container environment. If not running in a Servlet container, subclasses will need to override the getConversionService() method to provide an alternative lookup strategy.

Subclasses can extend this class and should also implement one or both of Encoder and Decoder. For convenience ConvertingEncoderDecoderSupport.BinaryEncoder, ConvertingEncoderDecoderSupport.BinaryDecoder, ConvertingEncoderDecoderSupport.TextEncoder and ConvertingEncoderDecoderSupport.TextDecoder subclasses are provided.

Since JSR-356 only allows Encoder/Decoder to be registered by type, instances of this class are therefore managed by the WebSocket runtime, and do not need to be registered as Spring Beans. They can, however, by injected with Spring-managed dependencies via @Autowire.

Converters to convert between the type and String or ByteBuffer should be registered.

Since:

4.0

Author:

Phillip Webb

See Also:

• ConvertingEncoderDecoderSupport.BinaryEncoder
• ConvertingEncoderDecoderSupport.BinaryDecoder
• ConvertingEncoderDecoderSupport.TextEncoder
• ConvertingEncoderDecoderSupport.TextDecoder

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ConvertingEncoderDecoderSupport.BinaryDecoder<T>	A binary jakarta.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.BinaryEncoder<T>	A binary jakarta.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.TextDecoder<T>	A Text jakarta.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.TextEncoder<T>	A text jakarta.websocket.Encoder that delegates to Spring's conversion service.

Constructor Summary

Constructors

Constructor	Description
ConvertingEncoderDecoderSupport()

Method Summary

Modifier and Type	Method	Description
@Nullable T	decode(M message)	Decode the message into an object.
void	destroy()	Called to destroy the encoder/decoder.
@Nullable M	encode(T object)	Encode an object to a message.
protected @Nullable ApplicationContext	getApplicationContext()	Returns the active ApplicationContext.
protected ConversionService	getConversionService()	Strategy method used to obtain the ConversionService.
protected TypeDescriptor	getMessageType()	Returns the websocket message type.
protected TypeDescriptor	getType()	Returns the type being converted.
void	init(EndpointConfig config)	Called to initialize the encoder/decoder.
boolean	willDecode(M bytes)	Determine if a given message can be decoded.

Methods inherited from class java.lang.Object

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

Constructor Details

ConvertingEncoderDecoderSupport

public ConvertingEncoderDecoderSupport()

Method Details

init

public void init(EndpointConfig config)

Called to initialize the encoder/decoder.

See Also:

• Encoder.init(EndpointConfig)
• Decoder.init(EndpointConfig)

destroy

public void destroy()

Called to destroy the encoder/decoder.

See Also:

• Encoder.destroy()
• Decoder.destroy()

getConversionService

protected ConversionService getConversionService()

Strategy method used to obtain the ConversionService. By default, this method expects a bean named 'webSocketConversionService' in the active ApplicationContext.

Returns:

the ConversionService (never null)

getApplicationContext

protected @Nullable ApplicationContext getApplicationContext()

Returns the active ApplicationContext. By default, this method obtains the context via ContextLoader.getCurrentWebApplicationContext(), which finds the ApplicationContext loaded via ContextLoader typically in a Servlet container environment. When not running in a Servlet container and not using ContextLoader, this method should be overridden.

Returns:

the ApplicationContext or null

getType

protected TypeDescriptor getType()

Returns the type being converted. By default, the type is resolved using the generic arguments of the class.

getMessageType

protected TypeDescriptor getMessageType()

Returns the websocket message type. By default, the type is resolved using the generic arguments of the class.

encode

public @Nullable M encode(T object)
                   throws EncodeException

Encode an object to a message.

Throws:

EncodeException

See Also:

• Encoder.Text.encode(Object)
• Encoder.Binary.encode(Object)

willDecode

public boolean willDecode(M bytes)

Determine if a given message can be decoded.

See Also:

• decode(Object)
• Decoder.Text.willDecode(String)
• Decoder.Binary.willDecode(ByteBuffer)

decode

public @Nullable T decode(M message)
                   throws DecodeException

Decode the message into an object.

Throws:

DecodeException

See Also:

• Decoder.Text.decode(String)
• Decoder.Binary.decode(ByteBuffer)