Working with Logic Plug-Ins

 

The following sections provide key concepts and procedures for configuring and working with logic plug-ins on the C-Hub Administration Console:

• What Are Logic Plug-Ins?

• Setting Up a Logic Plug-In

• Viewing Logic Plug-Ins on a C-Hub

• Modifying an Existing Logic Plug-In

• Removing a Logic Plug-In

For more information on logic plug-ins, see Developing Logic Plug-Ins in the BEA WebLogic Collaborate Developer Guide.

 

---

What Are Logic Plug-Ins?

The message flow through the c-hub begins with an incoming message from a c-enabler, proceeds to the routing service, and ends with the c-hub sending an outgoing message. This flow is usually described from the perspective of the c-enabler client, rather than the c-hub. In this context, the incoming message flow through the router is considered to be part of send-side routing (because the message is sent by the c-enabler to the c-hub). The outgoing message sent by the c-hub is considered to be available for receive-side filtering (because it is received by the c-enabler from the c-hub).

WebLogic Collaborate provides a router and a filter for each business protocol that it supports. Each router and each filter consists of a chain of logic plug-ins. You can add your own logic plug-ins to the routers and filters. The plug-in code must conform to BEA guidelines and interfaces. These logic plug-ins (components in filters and routers) allow you as a c-hub owner to provide additional processing (rules) for the information passing through the c-hub.

• On the send-side, the router determines the trading partner(s) to whom a message should be routed. Router plug-ins, either provided by BEA or written by the c-hub owner, can add or remove recipients from the list.

• On the receive-side, the filter receives a message destined for a single trading partner recipient and decides whether to send the message. C-hub owners can add their own filter plug-ins, or use those provided by BEA.

However, you are not limited to using the plug-ins strictly for filtering and routing tasks. As a c-hub owner, you can customize the "filter" and "router" plug-ins for many purposes other than filtering and routing, such as sampling, validating, auditing, billing, and so on. The following table shows some simple examples of the kinds of additional processing rules you might want to implement and perform on data flowing through the c-hub.

Table 12-1 Examples of Using Router and Filter Logic Plug-Ins on the C-Hub for Various Types of Additional Processing

Plug-In to Use	Example Rule to be Implemented
Router	"If a computer chip order over $1M is submitted, make sure that NewChipCo is one of the recipients."
Filter or Router	"After January 1, 2000, no orders should be sent to OldChipCo."
Filter or Router	"Log all senders/recipients of messages for billing purposes."
Filter or Router	"Sample 1 out of every N messages of type X for standards compliance."
Filter or Router	"For messages of type X, how many are conversation version 1 versus conversation version 2?"

 

For more information on what logic plug-ins are and how to construct and use them, see Developing Logic Plug-Ins in the BEA WebLogic Collaborate Developer Guide.

 

---

Setting Up a Logic Plug-In

Setting up a new logic plug-in definition on the c-hub consists of the following tasks:

• Step 1. Name Plug-In and Provide Parameters.

• Step 2. Assign the Logic Plug-In to a Business Protocol Definition.

Step 1. Name Plug-In and Provide Parameters.

1. Click Configuration in the left navigation bar.

2. Click the Logic Plug-Ins tab to display the Logic Plug-Ins configuration screen.

   Figure 12-1 Logic Plug-Ins Configuration

   

    

   The Logic Plug-Ins list shows the logic plug-ins currently defined and available for use. The Business Protocols Definitions list shows the protocol assigned for each plug-in.

   Note: If a logic plug-in has a parameter name of bea.hidden and a value of true, then it will not show up on the Logic Plug-Ins screen list unless you have checked Show hidden logic plug-ins in the Preferences screen. (For more information on the "hidden logic plug-ins" setting, see Setting Preferences.)

3. Fill in the fields as described in the following table.

   Table 12-2 Logic Plug-Ins Fields

   Field	Description
   Logic Plug-In Name	Enter the name of a new logic plug-in you want to create. The logic plug-in is one that you define based on code you have written and what you want to track or accomplish with regard to the data passing through your c-hub.
   Java Class	Name - Enter the name of the Java class specifying your implementation of this particular logic plug-in. Parameters - In the Parameter Name field, enter the name of a parameter to be read at initialization. For example, you might want to specify the name of a database where you want to store data, the type of message you want to audit, or a time to start or stop operations. In the Parameter Value field, enter a value for your initialization parameter. When you have the parameter name and value specified as desired, use the right arrow button to move the parameter you have defined into the Assigned list box for Java class parameters.

    

4. Click Add/Update to create the new logic plug-in. Your new logic plug-in should show up in the Logic Plug-Ins list.

   (You can also click Reset to discard your current changes and start again.)

   Initially, your new logic plug-in will not be assigned to a business protocol, so [NONE] will show up under Business Protocols list for that logic plug-in.

   Figure 12-2 New Logic Plug-In Added

   

    

Step 2. Assign the Logic Plug-In to a Business Protocol Definition.

You can create new "flavors" of an existing business protocol based on the particulars of your enterprise, but this is not a task that can be handled in the C-Hub Administration Console.

You will probably be accessing the Business Protocol Definitions tab in the C-Hub Administration Console primarily for the purpose of assigning logic plug-ins (components in filters and routers) to an existing protocol like XOCP.

For information on developing logic plug-ins to use in routers and filters, see Developing Logic Plug-Ins in the BEA WebLogic Collaborate Developer Guide. For more information on using XOCP filters and routers, see Routing and Filtering XOCP Business Messages.

To assign a logic plug-in to a business protocol:

1. Click on the business protocol name under the Business Protocols Definitions list on the Logic Plug-Ins tab. In our example, we select XOCP. (If you haven't assigned a business protocol yet, you can click on [NONE] which shows up under Business Protocols list for that logic plug-in.)

   This brings up the main Business Protocol Definitions Screen.

   Figure 12-3 Business Protocol Definitions Screen

   

    

2. Click on the business protocol you want to use. The C-Hub Administration Console displays the Business Protocol Definitions screen where you can assign logic plug-ins (components in filters and routers) to the selected business protocol. (For our "MyNewPlugin" example, we choose XOCP.) Logic plug-ins you have defined on the Logic Plug-in tab show up on the detail screen for a business protocol definition as available logic plug-ins in the Filter Chain and Router Chain group areas. You can move them into the Assigned list box to assign them to filter and router chains.

   Figure 12-4 Assign Logic Plug-Ins to a Business Protocol Definition

   

    

   Note: If a logic plug-in has a parameter name of bea.hidden and a value of true, then it will not show up on Available Logic Plug-ins lists in the Filter and Router Chain lists unless you have checked Show hidden logic plug-ins on the Preferences screen.

3. To create Filter Chains and Router Chains, use the arrow buttons to move the logic plug-ins you want to assign to this business protocol into the Assigned lists. Once you have the appropriate filters and routers showing in the "Assigned" list box, use the up and down arrow buttons to order the chain of filters and routers appropriately.

   Note: XOCP filters and routers can be used only for XOCP business protocol definitions. Likewise, RosettaNet filters and routers can be used only for RosettaNet business protocol definitions.

4. To define an XPath expression for the XOCP filter logic plug-in or the XOCP router logic plug-in, use the XOCP Filter Configuration and XOCP Router Configuration groups, respectively, as described in the following table.

   Note: If you define an XPath expression in the XOCP Filter Configuration group, this XPath expression will be added to the XOCP filter logic plug-in. Similarly, if you define an XPath expression in the XOCP Router Configuration group, this XPath expression will be added to the XOCP router logic plug-in.

   Table 12-3 XPath Fields for XOCP Filter and XOCP Router Configurations

   Field	Description
   XPath Expression	Enter an XPath expression in this text field. (XPath is the XML path language. An XPath expression is a string that specifies intended recipients of a business message using XPath syntax.) These XPath expressions are evaluated in sequence at run time against the message-context XML document, which has the content of the message along with meta information about the message, such as the sending and receiving trading partners, conversation information, and versioning. In the XOCP router logic plug-in, each XPath router expression can examine different parts of the message-context document and select a different set of recipient trading partners. The trading partners produced by each expression can either replace the previously generated set of recipient trading partners or add to the current set. In the XOCP filter logic plug-in, each XPath filter expression can examine different parts of the message-context document to determine whether or not to forward the message to the recipient trading partner. Each XPath filter expression can return true or false using different selection criteria. After an XPath filter expression returns false, the message is blocked from further evaluation and is not sent to the intended recipient. For example, you might want to filter messages for trading partners that are shippers so that they receive only shipping requests, while all other types of trading partners receive all messages: (/c-hub/message/@message-def-name='Shipping Request' AND /c-hub/trading-partner/extended-property-set/business='shipper') OR (/c-hub/trading-partner/extended-property-set/business!='shipper')
   Type	Select either Append or Replace. If you choose Append, the results of evaluating the new XPath expression are added to the results of the evaluations of any preceding XPath expressions. If you choose Replace, the results of evaluating the new XPath expression replace the results of the evaluations of all preceding XPath expressions.
   Use Payload	Select whether to use payload. (A checkmark indicates payload will be used.) If you select Use Payload, the generated message-context document will include message parts from the payload.

    

   When you have defined the XPath expression you want to use and set the type and payload filtering options, click on the right arrow button to move the XPath expression into the Assigned list. (You can use the left arrow button to remove an expression from the Assigned list.)

   These fields and options work the same way for both XOCP Filter Configuration and XOCP Router Configuration.

   Note: When you use the Business Protocol Definitions tab to create an XPath expression, you are defining a c-hub XPath expression. C-hub XPath expressions are applied to all XOCP business messages flowing through the c-hub. (In contrast, you can also define XPath expressions for a particular trading partner which are applied only to XOCP business messages sent or received by a particular trading partner.)

5. When you have the appropriate logic plug-ins listed in the Filters and Routers lists, click Add/Update to assign these plug-ins to the selected business protocol.

   The plug-in assignments are processed, and you are returned to the main Business Protocol Definitions screen. A status message is displayed indicating that the business protocol assignment has been made to the appropriate logic plug-in.

   If you now click the Logic Plug-Ins tab to display the main Logic Plug-Ins configuration screen, you should see your new plug-in assigned to the appropriate business protocol.

   Figure 12-5 New Logic Plug-In Added to Plug-Ins List with Protocol Assignment

   

    

For more information on business protocols, see Working with Business Protocol Definitions.

 

---

Viewing Logic Plug-Ins on a C-Hub

To view logic plug-ins on a c-hub:

1. Click Configuration in the left navigation bar.

2. Click the Logic Plug-Ins tab to display the logic plug-ins configuration screen.

   Figure 12-6 Viewing Logic Plug-Ins

   

    

   The Logic Plug-Ins configuration screen shows a table of logic plug-ins currently defined in the c-hub (except those configured as bea.hidden) and the business protocols associated with each plug-in.

Using the Query Feature to Find Logic Plug-Ins

Notice the * in the Logic Plug-In Name field. This is a special wildcard character used for queries. In the above screen, the table shows all the logic plug-ins on the c-hub (except those configured as bea.hidden). You can type text strings in the Logic Plug-In Name field and do queries on them to refine the table display. For instance, to display just logic plug-ins that start with "XOCP", you can input XOCP* in the Logic Plug-In Name field and click Query. (The query is case-sensitive.) To display information just for XOCP-Router, you can enter XOCP-Router in the Logic Plug-In Name field and click Query, or just click on the XOCP-Router name in the Logic Plug-Ins list.

 

---

Modifying an Existing Logic Plug-In

You can modify any or all of the existing logic plug-ins set up on a c-hub.

From the main Logic Plug-Ins configuration tab, click on a logic plug-in name under Logic Plug-Ins to display the configuration for that plug-in. (As an example, the following figure shows the configuration screen for a logic plug-in named "XOCP-Router".)

Figure 12-7 Configuration for an Individual Logic Plug-In

 

You can modify the configuration for the selected plug-in from this screen. Simply redefine the name, parameters, or other attributes as needed, then click Add/Update to save the changes. (For details on the fields, see Table 12-2.)

 

---

Removing a Logic Plug-In

Warning: Do not remove the BEA-provided logic plug-ins for XOCP or RosettaNet. Removal of these plug-ins will disable the WebLogic Collaborate c-hub. You can add and remove your own, customized logic plug-ins as needed.

To remove a customized logic plug-in:

1. Click Configuration in the left navigation bar.

2. Click the Logic Plug-Ins tab to display the Logic Plug-Ins configuration screen.

3. In the Logic Plug-In Name field, enter the full name of the logic plug-in that you want to remove, and click Remove.

   or

   Click on the logic plug-in you want to remove to display the configuration details for that logic plug-in. On this screen, click Remove.

   A confirmation dialog is displayed. Click OK to remove the specified logic plug-in in. You are returned to the main Logic Plug-Ins configuration screen.

Note: If the object you remove references or is referenced by other objects (for example, if a business protocol is using a logic plug-in you are about to remove), those references will be removed. If the object you remove contains other objects, those objects will be removed. See Table 8-2 for details on relationships and dependencies that can exist among configured c-hub objects.