Using Message Throw and Catch to Communicate Between Processes

6-24 Modeling and Implementation Guide for Oracle Business Process Management Most flow objects can contain only one default out going sequence flow. Only parallel gateways can contain multiple unconditional sequence flows which represent the parallel paths of your process. Exclusive, inclusive, and conditional gateways cannot have unconditional outgoing sequence flows. These gateways use conditional and default sequence flows to determine the flow of your process.

6.6.3 Introduction to Conditional Sequence Flows

Conditional sequence flows are used to control the flow of a process based on certain conditions. Like unconditional sequence flows, conditional sequence flows are displayed by an arrow lined arrow. Figure 6–29 shows two outgoing conditional sequence flows and a default sequence flow. Figure 6–29 Conditional and Default Sequence Flows This graphic shows a process flow that passes to an exclusive gateway. From the exclusive gateway, there are two arrowed lines representing conditional sequence flows that connect to two rectangles representing the conditional parts of a process flow. There is also an arrowed line with tic mark representing the default flow of the process path that is followed when none of the conditions evaluate to true. Not all flow objects can use outgoing conditional sequence flows. Only the following types of gateways can have outgoing conditional sequence flows: ■ Exclusive gateways ■ Inclusive gateways ■ Conditional gateways ■ Event-based gateways The conditions used within a conditional sequence flow are defined using expressions. See Section 22.1, Introduction to Expressions in Oracle BPM for information on using the expression editor to define expressions.

6.6.4 Introduction to Default Sequence Flows

Like conditional sequence flows, default sequence flows are used as outgoing sequence flows to exclusive, inclusive, and conditional gateways. Default sequence Modeling Business Processes with Oracle BPM 6-25 flows represent the path your process will take out of these gateways when none of the conditions evaluate to true. Default sequence flows are represented by an arrowed line with a tic mark on one end as shown in Figure 6–29 .

6.7 Controlling Process Flow Using Gateways

This section describes how to use gateways to control process flow and behavior.

6.7.1 Introduction to Gateways

Gateways are flow elements that define the flow of your process. Gateways determine the path a token takes through a process. They define control points within your process by splitting and merging paths. When possible, gateways are used for paths that are exceptions to or deviate from the default path of the process.

6.7.1.1 Split-Merge Pairs

The following gateways require a split-merge pair: ■ Parallel Gateway ■ Inclusive Gateway ■ Complex Gateway When you add one of these gateways to a BPMN process, Oracle BPM Studio automatically creates the split and merge flow objects. Although the merge portion of the gateway is required, you do not have to ensure that all paths out of the split return to the merge. Although it is possible to have process paths that split at a gateway without merging through the gateway, this is not usually good practice. For more details on the merge behavior of gateways, see the following sections for each gateway type.

6.7.2 Introduction to the Exclusive Gateway

The exclusive gateway enables you to split your process into two or more paths. However, the process only continues down one of these paths even if multiple outgoing sequence flows are present. Exclusive gateways can have conditional outgoing sequence flows and must have at least one default outgoing sequence flow. You can define expressions that are used to determine if your process continues down a conditional sequence flow. If your process has multiple outgoing sequence flows for an exclusive gateway, you can define the order in which they are evaluated. The order of evaluation is configured in the properties of the exclusive gateway. If you have an exclusive gateway where more than one conditional evaluates to true, the process will continue down the first conditional sequence flow determined by this order. Unlike other gateways, the exclusive gateway does not require a corresponding merge to be explicitly defined in your process after splitting. Note: If you delete the merge gateway from a process, the corresponding split is also deleted.