While in the traditional workflow processes the control flow is determined statically within proc... more While in the traditional workflow processes the control flow is determined statically within process definitions, in declarative workflow processes the control flow is dynamic and implicit, determined by conditions that occur in the workflow data and the service environment. The environment consists of so-called active objects, which play a double role. On the one hand, they are persistent data structures that can be queried and managed according to the syntax and semantics of a query language. On the other hand, active objects possess active parts that are executable and represent workflow processes or tasks. The approach is motivated by features that are desirable in complex and less regular business processes: (1) the possibility of dynamic changes of process instances during their run, (2) mass parallelism of process instances and their components and shifting the availability of resources that workflows deal with on the primary plan as a mean for triggering instances of process tasks. The paper presents the prototype of an object-oriented declarative workflows on a comprehensive example with roots in a real business case.
The paper presents motivations and technical assumptions of a prototype object-oriented declarati... more The paper presents motivations and technical assumptions of a prototype object-oriented declarative workflow management system that is developed and implemented at the Polish-Japanese Institute of Information Technology in Warsaw. The main assumption that differs this system from many similar systems is the possibility of dynamic changes of running process instances. The workflow environment consists of so-called active objects, which play a double role. Active objects are persistent data structures that can be queried and managed according to the syntax and semantics of a query language. On the other hand, active objects possess active parts that are executable. We distinguish four such parts: firecondition, executioncode, endcondition and endcode. An active object waits for execution until the time when its firecondition becomes true. After that, the object's execution code is executed. The execution of a given active object is terminated when either all the actions are completed or its endcondition becomes true. After fulfillment of the endcondition some terminating actions can be executed through endcode. In principle, all active objects are executed in parallel, which amounts to a fundamentally different attitude to the control flow. The flow is determined dynamically using only fireconditions and endconditions that depend on a workflow environment state, a database state, a machine state, a state of resources, etc. There are several big advantages of this approach to the workflow, in particular, parallel execution of many processes and their synchronization are not constrained and the workflow environment can be the subject to ad hoc changes. The prototype has been implemented on the basis of ODRA, an object-oriented distributed database management system. As the workflow programming language we use SBQL, an object-oriented database query and programming language developed for ODRA.
While in the traditional workflow processes the control flow is determined statically within proc... more While in the traditional workflow processes the control flow is determined statically within process definitions, in declarative workflow processes the control flow is dynamic and implicit, determined by conditions that occur in the workflow data and the service environment. The environment consists of so-called active objects, which play a double role. On the one hand, they are persistent data structures that can be queried and managed according to the syntax and semantics of a query language. On the other hand, active objects possess active parts that are executable and represent workflow processes or tasks. The approach is motivated by features that are desirable in complex and less regular business processes: (1) the possibility of dynamic changes of process instances during their run, (2) mass parallelism of process instances and their components and shifting the availability of resources that workflows deal with on the primary plan as a mean for triggering instances of process tasks. The paper presents the prototype of an object-oriented declarative workflows on a comprehensive example with roots in a real business case.
The paper presents motivations and technical assumptions of a prototype object-oriented declarati... more The paper presents motivations and technical assumptions of a prototype object-oriented declarative workflow management system that is developed and implemented at the Polish-Japanese Institute of Information Technology in Warsaw. The main assumption that differs this system from many similar systems is the possibility of dynamic changes of running process instances. The workflow environment consists of so-called active objects, which play a double role. Active objects are persistent data structures that can be queried and managed according to the syntax and semantics of a query language. On the other hand, active objects possess active parts that are executable. We distinguish four such parts: firecondition, executioncode, endcondition and endcode. An active object waits for execution until the time when its firecondition becomes true. After that, the object's execution code is executed. The execution of a given active object is terminated when either all the actions are completed or its endcondition becomes true. After fulfillment of the endcondition some terminating actions can be executed through endcode. In principle, all active objects are executed in parallel, which amounts to a fundamentally different attitude to the control flow. The flow is determined dynamically using only fireconditions and endconditions that depend on a workflow environment state, a database state, a machine state, a state of resources, etc. There are several big advantages of this approach to the workflow, in particular, parallel execution of many processes and their synchronization are not constrained and the workflow environment can be the subject to ad hoc changes. The prototype has been implemented on the basis of ODRA, an object-oriented distributed database management system. As the workflow programming language we use SBQL, an object-oriented database query and programming language developed for ODRA.
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Papers by Michal Drabik