org.axonframework.messaging

Class MessageDecorator<T>

java.lang.Object

org.axonframework.messaging.MessageDecorator<T>

All Implemented Interfaces:

Serializable, Message<T>, SerializationAware

Direct Known Subclasses:

GenericCommandMessage, GenericEventMessage, GenericQueryMessage, GenericQueryResponseMessage, GenericSubscriptionQueryUpdateMessage

public abstract class MessageDecorator<T>
extends Object
implements Message<T>, SerializationAware

Abstract implementation of a Message that delegates to an existing message. Extend this decorator class to extend the message with additional features.

Messages of this type are SerializationAware meaning they will not be serialized more than once by the same serializer.

Author:

Rene de Waele

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MessageDecorator(Message<T> delegate) Initializes a new decorator with given delegate message.

Method Summary

Modifier and Type	Method and Description
protected void	describeTo(StringBuilder stringBuilder) Describe the message specific properties to the given stringBuilder.
protected String	describeType() Describe the type of message, used in toString().
protected Message<T>	getDelegate() Returns the wrapped message delegate.
String	getIdentifier() Returns the identifier of this message.
MetaData	getMetaData() Returns the meta data for this event.
T	getPayload() Returns the payload of this Event.
Class<T>	getPayloadType() Returns the type of the payload.
<S> SerializedObject<S>	serializeMetaData(Serializer serializer, Class<S> expectedRepresentation) Serialize the meta data of this message using given serializer, using given expectedRepresentation.
<S> SerializedObject<S>	serializePayload(Serializer serializer, Class<S> expectedRepresentation) Serialize the payload of this message using given serializer, using given expectedRepresentation.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.axonframework.messaging.Message

andMetaData, withMetaData

Constructor Detail

MessageDecorator

protected MessageDecorator(Message<T> delegate)

Initializes a new decorator with given delegate message. The decorator delegates to the delegate for the message's payload, metadata and identifier.

Parameters:

delegate - the message delegate

Method Detail

getIdentifier

public String getIdentifier()

Description copied from interface: Message

Returns the identifier of this message. Two messages with the same identifiers should be interpreted as different representations of the same conceptual message. In such case, the meta-data may be different for both representations. The payload may be identical.

Specified by:

getIdentifier in interface Message<T>

Returns:

the unique identifier of this message

getMetaData

public MetaData getMetaData()

Description copied from interface: Message

Returns the meta data for this event. This meta data is a collection of key-value pairs, where the key is a String, and the value is a serializable object.

Specified by:

getMetaData in interface Message<T>

Returns:

the meta data for this event

getPayload

public T getPayload()

Description copied from interface: Message

Returns the payload of this Event. The payload is the application-specific information.

Specified by:

getPayload in interface Message<T>

Returns:

the payload of this Event

getPayloadType

public Class<T> getPayloadType()

Description copied from interface: Message

Returns the type of the payload.

Is semantically equal to getPayload().getClass(), but allows implementations to optimize by using lazy loading or deserialization.

Specified by:

getPayloadType in interface Message<T>

Returns:

the type of payload.

serializePayload

public <S> SerializedObject<S> serializePayload(Serializer serializer,
                                                Class<S> expectedRepresentation)

Description copied from interface: SerializationAware

Serialize the payload of this message using given serializer, using given expectedRepresentation. This method should return the same SerializedObject instance when invoked multiple times using the same serializer.

Specified by:

serializePayload in interface SerializationAware

Type Parameters:

S - The type of data to serialize to

Parameters:

serializer - The serializer to serialize payload with

expectedRepresentation - The type of data to serialize to

Returns:

a SerializedObject containing the serialized representation of the message's payload

serializeMetaData

public <S> SerializedObject<S> serializeMetaData(Serializer serializer,
                                                 Class<S> expectedRepresentation)

Description copied from interface: SerializationAware

Serialize the meta data of this message using given serializer, using given expectedRepresentation. This method should return the same SerializedObject instance when invoked multiple times using the same serializer.

Specified by:

serializeMetaData in interface SerializationAware

Type Parameters:

S - The type of data to serialize to

Parameters:

serializer - The serializer to serialize meta data with

expectedRepresentation - The type of data to serialize to

Returns:

a SerializedObject containing the serialized representation of the message's meta data

getDelegate

protected Message<T> getDelegate()

Returns the wrapped message delegate.

Returns:

the delegate message

toString

public String toString()

Overrides:

toString in class Object

describeTo

protected void describeTo(StringBuilder stringBuilder)

Describe the message specific properties to the given stringBuilder. Subclasses should override this method, calling the super method and appending their own properties to the end (or beginning).

As convention, String values should be enclosed in single quotes, Objects in curly brackets and numeric values may be appended without enclosing. All properties should be preceded by a comma when appending, or finish with a comma when prefixing values.

Parameters:

stringBuilder - the builder to append data to

describeType

protected String describeType()

Describe the type of message, used in toString().

Defaults to the simple class name of the actual instance.

Returns:

the type of message