org.axonframework.queryhandling

Interface QueryMessage<T,R>

All Superinterfaces:

Message<T>, Serializable

All Known Subinterfaces:

SubscriptionQueryMessage<Q,I,U>

All Known Implementing Classes:

GenericQueryMessage, GenericSubscriptionQueryMessage, GrpcBackedQueryMessage, GrpcBackedSubscriptionQueryMessage

public interface QueryMessage<T,R>
extends Message<T>

Message type that carries a Query: a request for information. Besides a payload, Query Messages also carry the expected response type. This is the type of result expected by the caller.

Handlers should only answer a query if they can respond with the appropriate response type.

Since:

3.1

Author:

Marc Gathier

Method Summary

Modifier and Type	Method and Description
QueryMessage<T,R>	andMetaData(Map<String,?> additionalMetaData) Returns a copy of this QueryMessage with its MetaData merged with given metaData.
String	getQueryName() Returns the name identifying the query to be executed.
ResponseType<R>	getResponseType() The type of response expected by the sender of the query
static String	queryName(Object payloadOrMessage) Extracts the queryName from the given payloadOrMessage, with three possible outcomes: The payloadOrMessage is an instance of QueryMessage - getQueryName() is returned. The payloadOrMessage is an instance of Message - the name of Message.getPayloadType() is returned. The payloadOrMessage is the query payload - Class.getName() is returned.
QueryMessage<T,R>	withMetaData(Map<String,?> metaData) Returns a copy of this QueryMessage with the given metaData.

Methods inherited from interface org.axonframework.messaging.Message

getIdentifier, getMetaData, getPayload, getPayloadType, serializeMetaData, serializePayload

Method Detail

getQueryName

String getQueryName()

Returns the name identifying the query to be executed.

Returns:

the name identifying the query to be executed.

queryName

static String queryName(Object payloadOrMessage)

Extracts the queryName from the given payloadOrMessage, with three possible outcomes:

• The payloadOrMessage is an instance of QueryMessage - getQueryName() is returned.
• The payloadOrMessage is an instance of Message - the name of Message.getPayloadType() is returned.
• The payloadOrMessage is the query payload - Class.getName() is returned.

Parameters:

payloadOrMessage - the object to base the queryName on

Returns:

the getQueryName(), the name of Message.getPayloadType() or the result of Class.getName(), depending on the type of the payloadOrMessage

getResponseType

ResponseType<R> getResponseType()

The type of response expected by the sender of the query

Returns:

the type of response expected by the sender of the query

withMetaData

QueryMessage<T,R> withMetaData(Map<String,?> metaData)

Returns a copy of this QueryMessage with the given metaData. The payload remains unchanged.

Specified by:

withMetaData in interface Message<T>

Parameters:

metaData - The new MetaData for the QueryMessage

Returns:

a copy of this message with the given MetaData

andMetaData

QueryMessage<T,R> andMetaData(Map<String,?> additionalMetaData)

Returns a copy of this QueryMessage with its MetaData merged with given metaData. The payload remains unchanged.

Specified by:

andMetaData in interface Message<T>

Parameters:

additionalMetaData - The MetaData to merge into the QueryMessage

Returns:

a copy of this message with the given additional MetaData