A process can be either synchronous or asynchronous.
- Synchronous Process
When executing a synchronous process, the process may respond with a response message. At design time this response message is provided using the input mapping of the message end event. The response message is sent once. The initiator waits synchronously during the time frame that is required to execute the process between the start and message end event. To model a synchronous process, you need to create a WSDL file (service interface definition) that has an operation with input and output parameters.
To provide process context data back to the process initiator, the output parameter of the WSDL operation can be filled with the input mapping of the message end event.
Facts about Synchronous Process Parameters:
- The process may respond with a response message.
- The response is provided using the input mapping of the message end event.
- The response message is sent once.
- The initiator waits for the process to execute from start to the message end event.
- To model a synchronous process, you need a service interface definition with an operation containing input and output parameters.
We recommend that you do not model any human activities in synchronous processes because of several timeouts (for example, from Web Service Navigator, Web Service Client, BPM runtime) with a duration of a few minutes.
When a timeout occurs outside BPM, an HTTP error is returned and the process runs asynchronously. If the process server notices that a timeout has occurred, the process is terminated with an error that is described in the default trace.
Synchronous processes run synchronously if you initiate them through a web service call. Otherwise, processes modeled as synchronous processes are executed asynchronously if you start them in the Process Repository or with the Debugger.
- Asynchronous Process
The process does not send a response message in an asynchronous process. The initiator of an asynchronous process is not kept waiting for a response. To model an asynchronous process, you only need to define input parameters for the operation in the assigned WSDL file.
Facts about Asynchronous Process Parameters:
- The process does not send a message response.
- The initiator is not kept waiting for a response.
- To model an asynchronous process, you need a service interface definition with an operation containing input parameter.