Patent Application
20070112928
The present invention relates to message services in a distributed object system in which one or more message service servers interact with a number of publishers and subscribers. More specifically, the present invention relates to a system, method and medium for providing one or more message servers which communicate with one or more publishers configured to create and publish messages having changeable or selectable subject information, the published subject information being of potential interest to one or more of the subscribers.
Distributed object systems are designed to increase the efficiency of computer program development by enabling object reuse and simplifying system maintenance through clear separation of functions. Each object in a distributed object system encapsulates the data for that object and the procedures or methods for operating on that data. Encapsulation means that the data for an object can be manipulated only by that object using the defined methods. These features of distributed object systems allow the objects to be reused and portable. Exemplary distributed object systems include: COM (Common Object Model), COM+, DCOM (Distributed Component Object Model) and CORBA (Common Object Request Broker Architecture).
One of the features of the distributed object system is a message service. A conventional message service system includes one or more publishers, subscribers and message servers. A publisher is a program (object or method) that makes calls that initiate sending messages that contain data, and a subscriber is another program (object or method) that receives the messages from a publisher. A subscriber indicates to (e.g., registers with) its message server that it wishes to receive messages from a publisher.
An exemplary conventional message service server is Message Queuing Services (MSMQ) developed by Microsoft may be used. MSMQ implements asynchronous message service by enabling applications (e.g., data providers) to send messages to other applications (e.g., data receivers). While the messages are being forwarded from senders to receivers, MSMQ keeps the messages in queues. The MSMQ queues may protect messages from being lost in transit and provide a place for receivers to look for messages when they are ready. MSMQ is configured to support IPX (Internet Packet eXchange) and TCP/IP (Transmission Control Protocol/Internet Protocol) networking protocols. In the distributed object system parlance, a publisher is a data provider (e.g., the method sending the message) and a subscriber is a data receiver (e.g., the method receiving the message).
The conventional distributed systems fall short when messages are to be exchanged between a large number of publishers and subscribers, because in such a case the conventional message service system is required to predefine the relation between the data providers and data receivers (e.g., certain types of messages are predefined to be received by certain subscribers). In particular, the conventional system may provide adequate message services when all the relations are predefined and do not change. However, the conventional message system fails when the relations are to be dynamic. For example, assume a subset of the data providers are to send messages to one subset of the data receivers under one condition while the same subset of the data providers are required to send messages to another subset of the data receivers under another condition. Under such a scenario, the connections between data providers and data receivers are required to be updated dynamically (e.g., as the conditions change and/or as the messages are created).
Accordingly, embodiments of the present invention provides an improved system, method and medium of sending messages in a distributed object system. More specifically, embodiments of the present invention contemplate receiving a message that includes subject information that is generated based on one or more pre-selected portions as the message is generated. The message is then delivered based on the subject information. Embodiments of the present invention also contemplates a message delivery system in a client-server environment. The message delivery system may include a server configured to receive a message that includes subject information that is generated based on one or more pre-selected portions as the message is created and configured to forward the message based on the subject information.
The detailed description of a preferred embodiment of the present invention showing various distinctive features over prior art message servers may be best understood when the detailed description is read in reference to the appended drawing in which:
In
Publishers 102, 104, subscribers 106, 108 and ES servers 110, 114 typically reside in one or more computers. For example, the publishers may reside within a first group of computers, while the subscribers may reside within a second group of computers. Further, the ES servers may reside in a third group of computers. In an alternative embodiment, one or more publishers and subscribers may reside in one computer. In general, it should be understood that embodiments of the present invention envision that any number of computers may be utilized to include any combination of the publishers, subscribers and ES servers. The communication link among the publishers, subscribers and ES servers may include local area networks (LAN), wide area networks (WAN), the Internet (TCP/IP protocol), cable, optical, wireless or the like (or any combination thereof).
Each of messages to be serviced by the present invention preferably includes subject information (subject) and content information (content). The subject of a message characterizes and/or identifies it. The content is the substantive information of the message. In the parlance of the distributed object systems, the publishing of messages may be viewed as events.
A method of operation envisioned by embodiments of the present invention is described in conjunction with the flow chart of
When a subscriber is registered with an ES server, the ES server makes an entry into a registration database (e.g., a registration database 112 of
In embodiments of the present invention, an ES server is allowed to be instantiated many times. In addition, each ES server notifies its registered subscribers to other instantiated ES servers. This feature allows a direct routing of published messages.
For instance, assume Publisher 1 is configured to fire (e.g., send) its messages to ES Server 1 and Subscriber N is registered with ES Server M. In embodiments of the present invention, ES Server M notifies ES Server 1 that Subscriber N is registered to receive messages having certain subject information. Accordingly, when a message having subject information identical to the subject information registered by Subscribe N is published by Publisher 1, the message is delivered directly from ES Server 1 to Subscriber N. The efficiency is gained by preventing the message being routed from ES Server 1 to ES Server M before it can be delivered to Subscriber N.
It follows that embodiments of the present invention may be configured to increase the capacity of its messaging services (e.g., be linearly scalable). In other words, when more messaging services are required, more ES servers are instantiated to handle the increased capacity. In embodiments of the present invention, there is no bottle neck that prevents the ES server to be linearly scalable.
A registration database may be stored and maintained in a memory bank at a remote location (117 of
The next step as contemplated by embodiments of the present invention is for a publisher to create a message (e.g., an event) having a subject that is selectable as the message is generated (step 206). Step 206 is described in greater detail by referring to
First, in step 302, GC may include one or more context elements (e.g., possible subject elements). In an example contemplated herein, each context element may include a name, type, value and size thereof. Each context element could be of type integer, float, string, or a generic context (e.g., nested generic context), or an array of integers, an array float, an array of string, or an array of generic context. Table 1 below illustrates an exemplary nested GC. More specifically, the exemplary GC includes elements such as “LotNo,” “Weight,” “Loc,” and “LotId” while it also includes arrays of GC elements designated as “GC1” and “GC2.” Although not shown in Table 1, the size is also defined for each element.
The above described GC or nested GC forms exemplary content of a message to be created. In addition, embodiments of the present invention contemplate that for a message to be created, its “subject” is also generated. The subject can include two portions: a design time subject and a run-time subject. The design time subject (e.g., a fixed portion) is a portion of the subject that is specific to the publisher that created the message. Thus, each of the publishers has associated with it a design time subject, which becomes a part of the overall subject of a message generated by a publisher. In addition, as each message is created by a publisher, a run-time subject (e.g., a changeable portion) is appended to the design time subject of the publisher. Unlike the design time subject, the run-time subject is selectable by a user (e.g., an operator or automated entity). The subject, as it includes both the design time subject portion and the run-time subject portion, describes the format or the information relating to content (e.g., the values of each element).
As an example of the design time subject,
As an example of the run-time subject,
A user may also select the position of the “bstrDSNameSpace” element to be 2 and the position of the “bstrDSName” element to be 1. In this example, the subject information may be:
The above described feature of selecting run-time subject is preferably performed by a meta-data server which may be a part of an ES server. In particular, the meta-data server allows a user to select any combination of all available run-time subject elements and also allows the user to arrange the selected elements in any order using the position options. Once the user selects and arranges the run-time subject for a particular publisher, that information is stored in the meta-data server. Subsequently, when the publisher is creating a message, based on its design time subject, the publisher retrieves the user selection and arrangement information from the meta-data server. The publisher then creates the message with subject information, the run-time subject of which is generated according to the retrieved information. Embodiments of the present invention contemplate that the user selection and arrangement information can be retrieved from the meta-data server and stored in the publisher's cache memory. In this scenario, unless the information in the cache memory is lost, it is envisioned that the meta-data server is not accessed again to retrieve the user selection and arrangement information.
Although not shown in
Referring back to
Referring back to
Referring back to
Embodiments of the present invention contemplate that a guarantee message delivery (GMD) mechanism can be provided. GMD can be used when hardware (e.g., computers) and network connections may be unstable.
In operation of the GMD feature, the ES servers keep messages for the subscriber when the subscriber is off-line. At the same time, a system-wide timeout period is set for each message. If a timeout happens before the subscriber retrieves its message, the message is preferably re-routed to an ES server where a predefined action may be taken. For instance, if a subscriber designated to receive a message is off-line for longer than a predetermined period (e.g., 5 minutes, a day, etc.), the ES server preferably sends a notice (e.g., a pager, an e-mail message, etc.) to an operator to take appropriate action.
Referring to
The messaging service of the present invention is described below in a pair of practical exemplary applications. Although only two applications are illustrated below, other applications in which messaging service utilizing publisher/subscriber configuration (e.g., a weather monitoring system, medical monitoring system or the like) are also contemplated within this invention and may be obvious variations of the present the exemplary applications described below.
The first exemplary illustration is described in conjunction with
For instance, an etcher is a manufacturing apparatus configured to etch a layer or layers of a substrate during manufacture of an electronic device. Similarly a layer depositor is an apparatus configured to deposit a layer or layers on a substrate during manufacture of an electronic device. Preferably, assembly line devices (e.g., etchers, depositors) and controllers include a computer or computer-like device that includes a processor, a read-only memory device and a random access memory. Each of the assembly line devices and controller are also preferably configured to include at least one subscriber and one publisher operating in their respective computer or computer-like devices. In an alternative embodiment, one or more assembly line devices may include only a subscriber or a publisher operating in their respective computer or computer-like devices. In another alternative embodiment, one or more assembly line device may include no subscriber or publisher operating in their respective computer or computer-like devices. In yet another embodiment, one or more assembly line device may not include any computer or computer like devices.
One or more ES servers can reside in one or more server computers (not shown in
Embodiments of the present invention contemplate that, the manufacturing system depicted in
Now referring to
Subsequently, one or more subscribers located among the assembly line devices may create one or more messages (step 806). Such messages may include content information relating to, for example, the operating temperature of the devices, status of processes (e.g., etching or deposition) and/or maintenance information. Depending upon the character of the content information, the run-time subject is generated, which is appended to corresponding design time subjects.
Table 2 above illustrates a detailed example of information relating to generating a run-time subject. In particular, the exemplary run-time subject may include five possible elements: “EntityNamespace,” “EntityID” . . . “Quantity.” Each element is defined by its name (i.e., metadata name), data type, and a publish flag and subject position definition. In this example, assume that the “EntityNamespace” element is defined as “Assembly line Q,” and the EntityID element is defined as “Etcher—1.” The “pub_flag” specifies whether particular element is to be published as part of the run-time subject: “1” designates that the element is to be published, “0” designates that the element is not to be published , and “−1” designates that the element is not to be included as a part of the runtime subject. If the element is to be published, then the “sub_pos” element specifies where the element is to be placed in the run-time subject. Assuming the design time subject is a string “Design_Time_Subject—1,” then the subject specified in the above example may appear as the following:
A user, by means of a graphical user interface similar to the one depicted in
Upon receiving the messages, the one or more ES servers refer to their corresponding registration databases to identify which one or more of registered subscribers registered interest in receiving messages having subjects that include the subjects of the received messages. The messages are forward to the identified subscribers (step 807).
In continuing with the above example described in connection with Table 2, assume two subscribers registered to receive messages having the following subjects:
Examples of the use of the option field as contemplated by embodiments of the present invention will now be described. First, for the sake of this example, assume that the existence of a given uniquely identifiable character (e.g., “>”), means that any message that includes the subject elements previous to the character or any other elements appended thereto would be delivered to a subscriber registered with such an option. Thus, for example, assume further that the registered subject of the first subscriber is as follows:
In this example, any message that includes “Design_Time_Subject.Assembly_Line_Q” or any other elements appended thereto (e.g., Design_Time Subject.Assembly Line_Q.Etcher—1, Design_Time_Subject.Assembly_Line_Q.Etcher—2.Quantiy—1, etc.) as its subject would be delivered to the first subscriber.
It also follows that if the second subscriber has registered its subject as “Design_Time_Subject.Assembly_Line_Q.Etcher—1.>”, then any message that includes “Design_Time_Subject.Assembly_Line_Q.Etcher—1” or any other elements appended thereto as their subject would be delivered to the second subscriber.
In another example, assume that the existence of another uniquely identifiable character (“*”), means that any message that includes the subject elements previous to the character or one element appended thereto would be delivered to a subscriber registered with such an option. Thus, for example, assume further that the registered subject of the first subscriber is as follows:
In this example, any message that includes “Design_Time_Subject.Assembly_Line_Q” or one other element appended thereto (e.g., Design_Time_Subject.Assembly_Line_Q.Etcher—1, Design_Time_Subject.Assembly_Line_Q.Etcher—2, etc.) as its subject would be delivered to the first subscriber. The second subscriber functions similarly.
The above relationship between subjects of a message to be delivered and the subscribers is also applicable without regard to the number of elements specified. It should be noted that the above provided examples of option field characters (e.g., “*” and “>”) are provided only as sample examples. Other conventions available in the art are contemplated by embodiments of the present invention.
In this example, it is envisioned that, the subscribers residing in the controllers register with the ES servers to receive messages from the publishers residing in the assembly line devices. Alternatively and/or in addition, one or more subscribers located in one or more assembly line devices may register to receive messages published by one or more publishers residing in other assembly line devices. In any event, and referring back to
After determining that one or more messages are desired to be forwarded to one or more assembly line devices, (which, in this example, are envisioned to contain certain commands) messages with corresponding contents and subjects are created (step 809). The created messages are then fired (step 810) to the ES servers which forwards messages to appropriate subscribers based on corresponding registration databases (step 811). When the message is delivered to one or more subscribers (and/or controllers) they are unpacked (step 812). The unpacked message (and any commands therein) is processed to take further action, if any.
Continuing with the above example of an overheated etcher, when the etcher receives the message which contains a command to shut down, the etcher preferably shuts itself down. If messages are sent to each of the assembly line devices in that assembly line, then the whole assembly line may shut itself down.
It should be noted that sending and receiving messages among different assembly line devices and controllers are not required to occur in the sequence describe above. More specifically, one or more of the assembly line devices may be receiving messages from one or more controllers while one or more of the assembly line devices may be creating and firing a message to one or more controllers. In addition, one or more assembly line devices and controllers may be receiving, creating and firing messages simultaneously—a multithreaded processing feature of embodiments of the present invention.
The second exemplary illustration is now described with regard to
For instance, subscriber 1 registers to receive stock price quotes of companies named from AA to BB and subscriber 2 registers to receive stock price quotes of companies named from CC to DD.
Subsequently, the publisher creates messages containing stock quotes of the stock trading companies. Then, the messages are fired to the ES servers. Upon receiving the message, ES servers then forward the message to appropriate subscribers. For instance, if the message includes a stock quote of company AB, then it would be sent to Subscriber 1, and so on.
A display interface 1172 interfaces display 1148 and permits information from the bus 1156 to be displayed on display 1148. Display 1148 is also an optional accessory. For example, display 1148 could be substituted or omitted. Display 1148 may be used in displaying graphical user interface as shown in
Although system 1111 in
In general, it should be emphasized that the various components of embodiments of the present invention can be implemented in hardware, software or a combination thereof. In such embodiments, the various components and steps would be implemented in hardware and/or software to perform the functions of embodiments of the present invention. Any presently available or future developed computer software language and/or hardware components can be employed in such embodiments of the present invention. For example, at least some of the functionality mentioned above could be implemented using Visual Basic, C, C++, or any assembly language appropriate in view of the processor(s) being used. It could also be written in an interpretive environment such as Java and transported to multiple destinations to various users.
The many features and advantages of embodiments of the present invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09725908 | Nov 2000 | US |
| Child | 11652075 | Jan 2007 | US |
