TIBCO FTL Subscribing Input Adapter

Contents

Introduction
Adapter Properties
Using the Adapter in a StreamBase Application
Typechecking and Error Handling
Suspend and Resume Behavior
Related Topics

Introduction

The TIBCO StreamBase® Input Adapter for TIBCO FTL® allows a StreamBase application to receive FTL messages. The adapter is embedded in the StreamBase application and has one input port and two output ports. The input port is used to acknowledge received messages and to connect to, and disconnect from, the FTL realm server. The first output port emits status tuples, while the second emits tuples representing received FTL messages.

The adapter connects to the FTL realm server on start-up and asynchronously and continuously receives and converts incoming FTL messages into StreamBase tuples, which it sends downstream.

The adapter supports a subset of StreamBase data types that contains tuples and lists, though lists may not contain elements of type list. The schema of the FTL message output port is set through the Edit Schema tab of the adapter's Properties view.

The adapter is configured through several properties set in its Properties view in StreamBase Studio. The properties include parameters used to connect to the realm server and the application and endpoint names.

TIBCO Middleware Dependencies

This adapter requires access to the JAR file that implements the TIBCO FTL Java API on your system, and any files referenced by that JAR file. The adapter has been tested with FTL version 3.1, though it will likely work with newer FTL API versions as well. To make the TIBCO FTL Java API available to the adapter, copy TIBFTL_ROOT/lib/tibftl.jar to $STREAMBASE_HOME/lib/ext.

The tibftl.jar file, in turn, relies on various native libraries, such as tibftljni.dll on Windows and tibftljni.so on Linux. As with tibftl.jar, these native libraries are supplied as part of your TIBCO FTL installation and are not shipped with StreamBase. Make sure these files are locatable by the FTL JAR file by placing their parent directory on the PATH.

Adapter Properties

Property Description
Connect on Startup If enabled, the adapter connects to the realm server when it starts.
Real Server URLs A pipe-delimited ("|") list of realm server URLs to which to connect (e.g. http://localhost:8080|http://localhost:8181). Should the first server in the list become unavailable, the adapter will automatically try to connect to the next one in the list, and so on.
Username The realm server username.
Password The realm server password.
Application Name The FTL application, which includes a set of endpoints and formats as configured in the realm server.
Application Instance The FTL application instance.
Enable Secure Connection Whether to use a trust file to connect securely to the FTL server.
Trust File Name The full path to the file containing trust information to connect to the server. Only in effect if Enable Secure Connection is checked.
Endpoint Name The FTL endpoint, which abstracts the transport details.
Subscriber Name The subscriber name to use when subscribing to the endpoint.
Durable Name The durable name of the endpoint. Used for durable connections.
Content Matcher Criteria for selecting the messages of interest, or an empty string to receive all messages.
Explicit ACK If enabled, incoming messages must be acknowledged. Also, if enabled a string field named MessageID is expected to be present in the Command port's schema.
Inline Mode Whether to use Inline Mode, which improves performance by reducing inbound latency.
Log Level Controls the level of verbosity the adapter uses to send notifications to the console. This setting can be higher than the containing application's log level. If set lower, the system log level is used. Available values, in increasing order of verbosity, are: OFF, ERROR, WARN, INFO, DEBUG, TRACE.
FTL Library Log Level The log level used by the FTL library. Multiple FTL input and output adapter instances share the most verbose level configured in any adapter.

Using the Adapter in a StreamBase Application

This section discusses how to use the TIBCO FTL Subscribing Input Adapter in a StreamBase application. As shown in the diagram below (depicting the adapter's sample application), the subscribing adapter has one input port and two output ports to communicate with the surrounding application.

The TIBCO FTL Subscribing Input Adapter's ports are used as follows:

  • SubscribeControl: This input port receives tuples used to acknowledge received messages or to connect to, or disconnect from, the realm server. The Control port has the following schema:

    • Command, string: Contains one of the following commands:

      • Acknowledge

      • Connect

      • Disconnect

      • SetContentMatcher

      • JoinGroup (Note that at most one FTL operator per StreamBase application will be able to join a given group on a given realm)

      • LeaveGroup

      • GetJoinedGroupNames

    • MessageID, string: Contains the ID of the message being acknowledged, which was contained in a tuple emitted by the adapter on its SubscribeOut port. This field is required if the adapter's Explicit ACK property is enabled. This field is ignored unless the Command field's value is to Acknowledge.

    • ContentMatcher, string: Contains the new value of the content matcher for this subscription. If left null, no content matcher is specified. This field is ignored unless the Command field's value is to SetContentMatcher.

      Note

      The SetContentMatcher command can be used to change the content matcher string set for this subscription. However, since FTL does not allow on-the-fly changes to this setting, the connection is recycled in order for this setting to take effect.

    • GroupID, string: Identifier of the group to join or leave (used by the JoinGroup and LeaveGroup commmands).

    • IsObserver, boolean: Whether to join the group as a member (false) or an observer (true) (used by the JoinGroup commmand).

    • GroupMemberDescriptor, string: JSON string to use as a group member decriptor (used by the JoinGroup commmand).

    • GroupActivationInterval, double: Number of milliseconds to use as an activation interval (used by the JoinGroup commmand).

  • SubscribeStatus: This output port emits status, information, and error tuples. The Status port has the following schema:

    • Status, string: Describes the type of event that occurred.

    • Time, timestamp: The time at which this status occurred.

    • info, list<tuple>: A list of name / value pair tuples containing any additional information for the event.

  • SubscribeOut: The adapter emits a tuple on its second output port for each FTL message received. The port's schema is derived from the Edit Schema tab of the adapter's property view and can contain a subset of StreamBase data types, including lists and (nested) tuples to accommodate hierarchy in FTL messages. FTL message fields are mapped to tuple fields by case-sensitive name. List fields may contain elements of type double, long, string, timestamp, or tuple.

    In processing incoming FTL messages, the adapter converts FTL data types to StreamBase data types. As shown in the table below, Each FTL type has a single corresponding StreamBase type. When an attempt to perform an invalid conversion occurs, a one-time warning for the field is displayed and the corresponding field in the tuple is set to null.

    FTL Type StreamBase Type
    DATETIME timestamp
    DATETIME_ARRAY list<timestamp>
    DOUBLE double
    DOUBLE_ARRAY list<double>
    LONG long
    LONG_ARRAY list<long>
    MESSAGE tuple
    MESSAGE_ARRAY list<tuple>
    OPAQUE blob
    STRING string
    STRING_ARRAY list<string>

Add an instance of the adapter to a new StreamBase application as follows:

  1. In StreamBase Studio, create a project, and create an EventFlow application file to host the adapter.

  2. Drag an instance of the TIBCO FTL Subscribing Input Adapter from the Operators and Adapter drawer in the Palette view to the canvas.

  3. Connect an input stream to the adapter's input port and output streams to its two output ports.

  4. Configure the schema of input stream with a Command field and, if the Explicit ACK property is enabled, a MessageID field.

  5. Configure the schema of the FTL message output stream (port 2) using the Edit Schema tab of the adapter's property view to match the set of fields expected in the incoming FTL messages.

  6. Select the adapter icon, and in the Properties view, select Adapter Settings and fill in any desired properties.

Typechecking and Error Handling

The TIBCO FTL Subscribing Input adapter uses typecheck messages to help you configure the adapter in your StreamBase application. In particular, the adapter generates typecheck messages when a required property has not been specified, the control input schema is missing a required field, or an input or output schema contains unsupported StreamBase data types.

The adapter generates messages on the status port during runtime under various conditions, including:

  • The adapter connects, or fails to connect, to the realm server during start-up.

  • An FTL message is acknowledged.

  • The adapter is administratively disabled by the realm server.

  • The adapter receives an advisory message.

  • The adapter fails to dispatch an event on its event queue.

  • The adapter fails to process an incoming FTL message.

  • The adapter is suspended or resumed.

Suspend and Resume Behavior

When suspended, the TIBCO FTL Subscribing Input Adapter disconnects from the realm server and stops processing incoming FTL messages.

When resumed, the adapter re-connects to the realm server, if it had been connected before being suspended, and resumes processing incoming FTL messages.

Related Topics