Abstract: A distributed messaging system supporting stateful subscriptions is provided. A stateful publish-subscribe system extends the functionality of the content-based approach to include more general state-valued expressions. Stateful subscriptions may refer to one or more message histories and may include more complex expressions. Therefore, subscribers may receive different information than that provided in the published messages. A plurality of broker machines is provided to deliver messages sent by publishing clients toward subscribing clients based upon the contents of the messages and stateful transformations requested by the subscribing clients. Subscription specifications are analyzed by a compiler and converted into a collection of transform objects and view objects. The messaging system builds a structure containing all transform objects and view objects needed for all intermediate and subscribed views of all subscriptions.

Abstract: A computer implemented method, system and computer program product for delivering published messages to at least one subscriber in a publish-subscribe messaging system. A computer implemented method for delivering published messages to a subscriber includes receiving a plurality of message streams, and analyzing at least one message from each of the plurality of message streams in accordance with criteria established by the subscriber specifying a message content and a message content quality. At least one message that satisfies the criteria is delivered to the subscriber.

Abstract: Methods and apparatus for integrating relational and hierarchical data, schema definitions, and queries in a data processing system are provided. It is determined if one or more schema definitions or one or more query expressions are provided as input to the data processing system. The one or more schema definitions are converted into an intermediate schema language component of an intermediate data language when one or more schema definitions are provided. The one or more query expressions are converted into an intermediate query language component of the intermediate data language when one or more query expressions are provided. The intermediate schema language component or the intermediate query language component is compiled in an intermediate data language processing engine into a run-time representation in accordance with a relational-hierarchical analysis.

Abstract: A computer implemented method, apparatus, and computer usable program code for controlling when to send messages in a stream processing system. A policy is determined by utilizing probability statistics and a cost function prior to stream processing. The policy specifies under which conditions a message is sent eagerly and under which other conditions the message is delayed. A filter is operated during stream processing that selects which of the messages to send from a sending transform based upon a threshold. A controller is operated during stream processing that observes a current state of a receiving transform and that applies the policy based on the current state to determine whether to change the threshold.

Abstract: A technique for reliably multicasting a message within a router network is provided. At least one special router in the network has associated persistent storage for logging a message being routed to one or more clients. When a message is received at this logger node, the logger places the message in persistent storage and sends a logging acknowledgment back to those routers to which the message was originally routed, as well as back towards the source of the message. The logger acknowledgment includes the message id, the logger id, and a logging number. When the logger acknowledgment is received by a router, it looks up the routing information from the original message, and sends the acknowledgment to those neighboring routers to which the original message was sent, excluding the link from which the logger acknowledgment was received. If the original message corresponding to the logger acknowledgment was buffered at this router waiting to be delivered, the message is then delivered to its client nodes.

Abstract: A system and method featuring a collection of model objects which hold data to be shared, and supporting interfaces to read and write the data, to create and destroy collaboration relationships and to attach “view objects” containing application code which will be automatically notified of value changes. Each user environment is provided with a model object control entity, referred to herein as a Collaboration Manager, which creates model objects, executes transactions, and creates association objects related to the collaboration. A concurrency control mechanism records the reads and updates of the data and of collaboration relationships within a single transaction site and guarantees that they are applied atomically and consistently to both the local and to all remote replica objects of the collaboration.

Abstract: An apparatus for implementing “links” between objects or content items in applications or documents in a distributed system such that changes to the source objects or items are reflected in changes to the target objects or content items. The apparatus includes mechanisms for allowing users to establish links, to break individual links, to copy documents or content including links, and to determine locations and/or descriptions of the source of a given target or any or all of the multiple targets of a given source. Advantageously, the apparatus of this invention uses remote message passing for communication, thereby permitting links to be established even when the source and target applications execute on different platforms and even when they share no common file system. The apparatus includes an availability server which can serve as a surrogate for applications which are currently not running.

Abstract: Reconfiguration of a continuously available routing network of a publish/subscribe system is achieved by quiescing data messages and control messages within the routing network to preserve first-in first-out ordering thereof, and then, reconfiguring the quiesced routing network. This reconfiguration technique is particularly applicable to a routing network having at least one special node comprising one of a logger node or a sequencer node, wherein the logger node is used to store a message to persistent storage within the routing network prior to delivery of the message to one or more clients, and the sequencer sequences a message with other messages received by the network prior to delivery thereof for ordered delivery of the messages to one or more clients of the network.

Abstract: A technique for reliably multicasting a message within a router network in a sequenced order with other messages is provided. At least one special router in the network has associated persistent storage for sequencing a message being routed to one or more clients. When a message is received at this sequencer node, the sequencer places a sequence number for the message in persistent storage and sends a sequencing acknowledgment back to those routers to which the message was originally routed, as well as back towards the source of the message. The sequencer acknowledgment includes the message id, and the sequencing number. When the sequencer acknowledgment is received by a router, it looks up the routing information from the original message, and sends the acknowledgment to those neighboring routers to which the original message was sent, excluding the link from which the sequencer acknowledgment was received.

Abstract: A publish/subscribe system is non-disruptively reconfigured, such that messages are not lost during the reconfiguration. After reconfiguration is initiated, messages that are to be delivered within the publish/subscribe system are forwarded using either an old path or a new path. That is, until the reconfigured system is stabilized, some messages may be delivered using the old path, while other messages are delivered using a new path. After the system is stabilized, the new path is used for delivery of all the messages, until another reconfiguration is initiated.

Abstract: A system and method featuring a collection of model objects which hold data to be shared, and supporting interfaces to read and write the data, to create and destroy collaboration relationships and to attach “view objects” containing application code which will be automatically notified of value changes. Each user environment is provided with a model object control entity, referred to herein as a Collaboration Manager, which creates model objects, executes transactions, and creates association objects related to the collaboration. A concurrency control mechanism records the reads and updates of the data and of collaboration relationships within a single transaction site and guarantees that they are applied atomically and consistently to both the local and to all remote replica objects of the collaboration.

Abstract: A system and method featuring a collection of model objects which hold data to be shared, and supporting interfaces to read and write the data, to create and destroy collaboration relationships and to attach “view objects” containing application code which will be automatically notified of value changes. Each user environment is provided with a model object control entity, referred to herein as a Collaboration Manager, which creates model objects, executes transactions, and creates association objects related to the collaboration. A concurrency control mechanism records the reads and updates of the data and of collaboration relationships within a single transaction site and guarantees that they are applied atomically and consistently to both the local and to all remote replica objects of the collaboration.

Abstract: A generalized search data structure is used to match consumers to events in event computing systems. The search data structure includes one or more paths from a root of the structure to one or more leaves of the structure. Each path has at least one level and each level corresponds to a filter attribute. The value of at least one filter attribute in at least one path is a don't care value indicating traversal of that path is guaranteed to proceed. In addition to following the path with the don't care value, one or more additional paths may also be followed. Thus, traversal of the search data structure may yield zero or more results, indicating that zero or more consumers match the specified event. Various optimizations of the search data structure are possible.

Abstract: A router within a network uses the data of a message received at the router to determine on which links out of the router the message needs to be forwarded. The router does not need any destination information from the message, and thus, the message need not include any destination information. Instead, the router uses an annotated search data structure to determine which links correspond to consumers interested in receiving the message. The message is sent only over those links.