The OBE server runtime depends upon a number of workflow services.
services themselves are defined as interfaces and OBE supplies at least
one default implementation of each. In some cases, two implementations
are supplied: a basic, non-transactional, local in-memory
implementation suitable for simple applications and a persistent,
transactional, distributed J2EE-based implementation.
Many of the services initialize themselves from one or more XML and/or
Java properties-format configuration files. These files can be located
$OBE_CONFIG_DIR directory or in the
obeconfig.jar.; entries in the
XML files have
the general form:
<type id="nmtoken" type="nmtoken"? threadsafe="true|false"?>
<!-- Additional service-specific elements -->
- The unique ID of the entry.
- The ID of the entry which this entry extends.
- Indicates whether an instance of the described entry is
- The name to be displayed in design tools.
- The name of the author or organisation which created the
- Textual description of the entry.
- A URL to online documentation for the entry.
type attribute provides a
reuse and extensibility mechanism for user-defined entries. The value
match the ID of one of the other entries in the configuration file. Any
properties which are not set explicitly on the child entry will be
recursively inherited from the parent type. It is thus possible to set
hierarchies of configuration data. N.B.
The system does not detect circular dependencies - they will cause
infinite loops when the system attempts to resolve an unset property.
The definitive specification of the elements and attributes supported
by the XML configuration files is the Castor mapping file
- Provides an interface to external asynchronous event
sources including timers.
- Provides support for pluggable strategies for assigning
work items to workflow participants.
- Async Manager
- Provides support for asynchronous execution of workflow
- Provides temporal computation services.
- Provides support for pluggable activity completion
- Data Converter
- Provides data conversion services.
- Provides support for evaluation of expressions in arbitrary
- Provides support for user-defined functions in expression
- Provides storage and lookup for process instances.
- Provides storage and lookup for workflow process
- Provides storage and lookup for arbitrary XML and other
- Security Realm
- Provides security principal resolution services.
- Tool Agent
- Provides support for client- and server-side invocation of
arbitrary applications and procedures.
- Provides notification services for all workflow lifecycle
- XPDL Parser
- Provides support for parsing and serialization of XPDL