com.caplin.datasource.messaging

Interface MessageFactory

public interface MessageFactory

A message factory is used to create DataSource messages that can be published to other DataSources.

You do not have to implement this interface yourself. An implementation is provided, and can be retrieved from any Publisher by calling the Publisher.getMessageFactory() method.

Method Summary

Methods

Modifier and Type	Method and Description
ContainerMessage	createContainerMessage(java.lang.String subject) Creates a message that defines a container.
GenericMessage	createGenericMessage(java.lang.String subject) Creates an empty Generic message to which structured data can be added.
MappingMessage	createMappingMessage(java.lang.String subject, java.lang.String mapping) Creates a MappingMessage for mapping subjects
NewsMessage	createNewsMessage(java.lang.String subject, java.lang.String headline, java.lang.String storyReference, java.lang.String newsDateTime) Creates a News message for the given subject.
PageMessage	createPageMessage(java.lang.String subject, int maxColumns, int maxRows) Creates a Page message for the given subject.
PermissionMessage	createPermissionMessage(java.lang.String subject, java.lang.String key) Creates a Permission message for the given subject.
RecordType1Message	createRecordType1Message(java.lang.String subject) Creates a Record message to which Type 1 structured data can be added.
RecordType2Message	createRecordType2Message(java.lang.String subject, java.lang.String type2IndexField, java.lang.String type2IndexValue) Creates a Record message to which Type 2 structured data can be added.
RecordType3Message	createRecordType3Message(java.lang.String subject) Creates a Record message to which Type 3 structured data can be added.
StoryMessage	createStoryMessage(java.lang.String subject, java.lang.String text) Creates a Story message for the given subject.
SubjectErrorEvent	createSubjectErrorEvent(java.lang.String subject, SubjectError error)
SubjectErrorEvent	createSubjectErrorEvent(java.lang.String subject, SubjectError error, SubjectError.Flags... flags) Creates a subject error event.
SubjectStatusEvent	createSubjectStatusEvent(java.lang.String subject, SubjectStatus status, java.lang.String message) Creates a subject status event.
WrapperMessage	createWrapperMessage(java.lang.String subject) Creates a Wrapper message for the given subject.

Method Detail

createRecordType1Message

RecordType1Message createRecordType1Message(java.lang.String subject)

Creates a Record message to which Type 1 structured data can be added.

The returned message contains no data. To populate the message with data, use the appropriate methods of RecordType1Message.

Parameters:

subject - The subject of the Record.

Returns:

A new Type 1 Record message.

createRecordType2Message

RecordType2Message createRecordType2Message(java.lang.String subject,
                                          java.lang.String type2IndexField,
                                          java.lang.String type2IndexValue)

Creates a Record message to which Type 2 structured data can be added.

The returned message contains no data. To populate the message with data, use the appropriate methods of RecordType2Message.

Parameters:

subject - The subject of the Record.

type2IndexField - Field name of the type2 index.

type2IndexValue - The value of the type2 index.

Returns:

A new Type 2 Record message.

createRecordType3Message

RecordType3Message createRecordType3Message(java.lang.String subject)

Creates a Record message to which Type 3 structured data can be added.

The returned message contains no data. To populate the message with data, use the appropriate methods of RecordType3Message.

Parameters:

subject - The subject of the Record.

Returns:

A new Type 3 Record message.

createGenericMessage

GenericMessage createGenericMessage(java.lang.String subject)

Creates an empty Generic message to which structured data can be added.

Generic messages can be used without specifying field mappings in a separate adapter configuration file. This may be useful when receiving updates from a provider which supplies a variable or unknown number of fields. The returned message contains no data. To populate the message with data, use the appropriate methods of GenericMessage.

Parameters:

subject - The subject of the Record.

Returns:

A new Generic Type message.

createMappingMessage

MappingMessage createMappingMessage(java.lang.String subject,
                                  java.lang.String mapping)

Creates a MappingMessage for mapping subjects

The returned message contains the mapped subject.

Parameters:

subject - The subject of the message.

mapping - The mapped subject of the message

Returns:

A new MappingMessage.

createContainerMessage

ContainerMessage createContainerMessage(java.lang.String subject)

Creates a message that defines a container. The name of the container is the given subject.

Parameters:

subject - The subject defining the name of the container.

Returns:

A message defining the container.

createNewsMessage

NewsMessage createNewsMessage(java.lang.String subject,
                            java.lang.String headline,
                            java.lang.String storyReference,
                            java.lang.String newsDateTime)

Creates a News message for the given subject.

The method parameters allow you to set the basic content of the message: its subject, headline, story reference, and date+time. To add keywords or terms describing the news headline, call the NewsMessage.getTags() method on the newly created message (see NewsMessage). To set permissions for the NewsMessage, call NewsMessage.setPermission(String).

Parameters:

subject - The subject identifying the news message.

headline - The news headline.

storyReference - The reference to the news story associated with the headline.

newsDateTime - The date and time of the news headline.

Returns:

A new News message.

createPageMessage

PageMessage createPageMessage(java.lang.String subject,
                            int maxColumns,
                            int maxRows)

Creates a Page message for the given subject.

The returned message contains no data. To populate the message with data, use the appropriate methods of PageMessage.

Parameters:

subject - The subject of the page message.

maxColumns - The maximum horizontal size of the page in columns of text characters.

maxRows - The maximum vertical size of the page in rows of text.

Returns:

A new Page Message.

createPermissionMessage

PermissionMessage createPermissionMessage(java.lang.String subject,
                                        java.lang.String key)

Creates a Permission message for the given subject.

The returned message contains no data. To populate the message with data, use the appropriate methods of PermissionMessage.

Parameters:

subject - The subject of the Permission message.

key - The permission key.

Returns:

A new Permission message.

createStoryMessage

StoryMessage createStoryMessage(java.lang.String subject,
                              java.lang.String text)

Creates a Story message for the given subject.

Parameters:

subject - The subject of the story.

text - The story text.

Returns:

A new Story message.

createWrapperMessage

WrapperMessage createWrapperMessage(java.lang.String subject)

Creates a Wrapper message for the given subject.

Parameters:

subject - The subject of the story.

Returns:

A new Wrapper message.

createSubjectErrorEvent

SubjectErrorEvent createSubjectErrorEvent(java.lang.String subject,
                                        SubjectError error,
                                        SubjectError.Flags... flags)

Creates a subject error event.

Parameters:

subject - The subject to which the error relates.

error - The error.

flags - Additional flags to be set on the nodata

Returns:

A subject error event.

The following example shows how to create an SubjectErrorEvent for a specified subject, and send it to all peers that have requested that subject:

import com.caplin.datasource.SubjectError;
import com.caplin.datasource.SubjectErrorEvent;
import com.caplin.datasource.publisher.Publisher;

public class SendSubjectErrorEvent
{
        public void sendSubjectErrorEvent(Publisher publisher, String subject)
        {
                // Create a SubjectErrorEvent
                SubjectErrorEvent ev = publisher.getMessageFactory().createSubjectErrorEvent(subject, SubjectError.NotFound);
                
                // Distribute the error to all peers that have requested this subject.
                publisher.publishSubjectErrorEvent(ev);
        }
}

createSubjectErrorEvent

SubjectErrorEvent createSubjectErrorEvent(java.lang.String subject,
                                        SubjectError error)

createSubjectStatusEvent

SubjectStatusEvent createSubjectStatusEvent(java.lang.String subject,
                                          SubjectStatus status,
                                          java.lang.String message)

Creates a subject status event.

Parameters:

subject - The subject to which the status relates.

status - The status.

message - A free form textual message indicating the reason for the status message being raised.

Returns:

A subject status event.

The following example shows how to create an ISubjectStatusEvent for a specified subject, and send it to all peers that have requested that subject:

import com.caplin.datasource.SubjectStatus;
import com.caplin.datasource.SubjectStatusEvent;
import com.caplin.datasource.publisher.Publisher;

public class SendSubjectStatusEvent
{
        public void sendSubjectStatusToSubscribedPeers(Publisher publisher, String subject)
        {
                // Create a Stale subject status event.
                SubjectStatusEvent ev = publisher.getMessageFactory().createSubjectStatusEvent(subject, SubjectStatus.Stale, "Object is stale");
                
                // And publish to all subscribed peers.
                publisher.publishSubjectStatusEvent(ev);
        }
}