org.springframework.web.socket.adapter

Class ConvertingEncoderDecoderSupport<T,M>

java.lang.Object

org.springframework.web.socket.adapter.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 java.lang.Object

Base class that can be used to implement a standard javax.websocket.Encoder and/or javax.websocket.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 javax.websocket.Encoder and javax.websocket.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 and Description
static class	ConvertingEncoderDecoderSupport.BinaryDecoder<T> A Binary javax.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.BinaryEncoder<T> A Binary javax.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.TextDecoder<T> A Text javax.websocket.Encoder that delegates to Spring's conversion service.
static class	ConvertingEncoderDecoderSupport.TextEncoder<T> A Text javax.websocket.Encoder that delegates to Spring's conversion service.

Field Summary

Fields

Modifier and Type	Field and Description
private static java.lang.String	CONVERSION_SERVICE_BEAN_NAME

Constructor Summary

Constructors

Constructor and Description
ConvertingEncoderDecoderSupport()

Method Summary

Modifier and Type	Method and Description
T	decode(M message)
void	destroy()
M	encode(T object)
protected 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)
private java.lang.Class<?>[]	resolveTypeArguments()
boolean	willDecode(M bytes)

Methods inherited from class java.lang.Object

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

Field Detail

CONVERSION_SERVICE_BEAN_NAME

private static final java.lang.String CONVERSION_SERVICE_BEAN_NAME

See Also:

Constant Field Values

Constructor Detail

ConvertingEncoderDecoderSupport

public ConvertingEncoderDecoderSupport()

Method Detail

init

public void init(EndpointConfig config)

See Also:

javax.websocket.Encoder#init(EndpointConfig), javax.websocket.Decoder#init(EndpointConfig)

destroy

public void destroy()

See Also:

javax.websocket.Encoder#destroy(), javax.websocket.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 ApplicationContext getApplicationContext()

Returns the active ApplicationContext. Be 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.

resolveTypeArguments

private java.lang.Class<?>[] resolveTypeArguments()

encode

public M encode(T object)
         throws EncodeException

Throws:

EncodeException

See Also:

javax.websocket.Encoder.Text#encode(Object), javax.websocket.Encoder.Binary#encode(Object)

willDecode

public boolean willDecode(M bytes)

See Also:

javax.websocket.Decoder.Text#willDecode(String), javax.websocket.Decoder.Binary#willDecode(ByteBuffer)

decode

public T decode(M message)
         throws DecodeException

Throws:

DecodeException

See Also:

javax.websocket.Decoder.Text#decode(String), javax.websocket.Decoder.Binary#decode(ByteBuffer)