Activities are elements in a BP model that specify the logical flow of information. There are several different types of activities you can use in a BP, and each activity performs a different function within the process. Activities are categorized by the following types:
Activity elements include those activities that are common to most BPs, such as Start, End, Receive, Reply, and so on. Table 2 lists and describes the activity elements. These activities are all available from the Business Process Designer toolbar except the start and end nodes, which appear automatically on the Business Process Designer canvas when a BP is created.
Table 2 Activity Elements
Name |
Description |
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Indicates the start of the process. This element appears in the Business Process Designer by default when you create a new BP model; it does not have a corresponding icon on the Business Process Designer toolbar. A start node can only link to a receive activity, and cannot be deleted. |
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Indicates the completed state of a BP. This element appears in the Business Process Designer by default when you create a new BP model; it does not have a corresponding icon on the Business Process Designer toolbar. An end node cannot be deleted. |
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Indicates the invocation of a BP, or indicates to wait for the arrival of an inbound message. The receive activity represents the actual method by which a BP is initiated. |
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Invokes a web service or a Java CAPS component. Depending upon the configuration of the component, a response might be required. |
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Allows a BP to respond to the external system or user that originally invoked the BP. The receive activity at the beginning of the BP is paired with the reply activity at the end of the process. In cases where a message must be sent back to the caller of the BP, the reply activity uses information that correlates the message in the calling system. A reply activity is the last step in a BP in which the BP acts as a web service or sub-process. It correlates the outbound message back to the calling process; for example, it can reply to an external system as a web service. |
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Maps and manipulates data using the Business Rule Designer (see The Business Rule Editor). You can also add a Business Rule to some links for the same purpose. |
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Invokes compensation on an inner scope that has already completed normally. This construct can be invoked only from within a fault handler or another compensation handler. |
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Allows data to pass through without any changes. |
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Delays processing for a set period of time. |
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Represents a step in a BP that requires human intervention. This activity must be configured by adding task assignments to the Worklist Manager. When a BP instance comes to a user activity, it creates a task and polls a table for the status of the task. In order for the user activity to complete, the user or the external application must update the status of the task. |
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Represents and configures a step in a BP that requires human intervention from an external application. This activity must also be configured by adding task assignments to the Worklist Manager. |
Branching activities are elements in a BP model that specify the logical flow of information when there are two or more possible paths. BPM provides three different kinds of branching activities—decisions, event-based decisions, and flows.
Table 3 Branching Activities
Name |
Description |
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Exposes the commands described below. These commands allow you to define several possible paths to execute based on expression logic. |
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Allows you to define complex expressions that are evaluated to determine the proper BP flow. This element also contains the expression and connection names. Expressions are built using the Business Rule Designer and BP attributes. |
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Allows multiple inbound messages to be juxtaposed against one or more message or timeout conditions, so the type of message received determines the appropriate BP path. |
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Allows you to specify one or more BP paths to be performed concurrently. |
Intermediate events are those activities that can receive a BP. Some intermediate events handle exceptions or compensate for exceptions. The intermediate events are available from the Intermediate Events menu on the Business Process Designer toolbar except Throw and Terminate Process, which are both available directly from the toolbar.
Table 4 Intermediate Events
A Scope element defines the behavior for one or more activities. A scope can provide exception handlers, event handlers, and a compensation handler. The exception handlers for the scope can be used to catch the faults caused by the possible exception responses.
Table 5 Scope Element
Name |
Function |
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Scope |
Allows you to apply exception handling to a set of sequential or simultaneous steps in a BP. |
A While element makes it possible to have repeating or looping logic inside a BP.
Table 6 While Element
Command |
Function |
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While |
Allows you to create a looping process within a BP (for instance, a negotiation process might take several weeks, but the manager wants to review the daily status). The loop continues until the process is complete, and then the BP continues. |