workflow

Features

LightJ embedded workflow engine is a lightweight framework implemented in pure java with no more than 30 core classes, support the following features

• Persistent or transient state by choice (currently support mysql, oracle, and hsqldb)
• Persistent or transient execution context by choice
• Crash recovery
• Cluster safe (cluster implementation based on shoal/grizzly GMS)
• Built-in synchronous, asynchronous, split/merge, loop, schedule execution pattern support
• Built-in error handling, no error will “fall through the crack”
• Built-in logging and flow event handling
• Many built-in flow fine tune features by annotations.
• Nested flows or flow join support
• Standard flow control interface, start, stop, pause, resume, kill
• Flow validation at initialization, straightforward initialization and registration
• Spring compatible, flow can be initialized by spring DI
• Workflow logic and transition completely built by java, easy to learn, easy to use, easy to support
• Minimal external dependencies, no complicated XML workflow definition in XML

Key design

• Workflow implementation by extending FlowSession base class
• FlowDefinition annotation for flow information, and concurrent execution grouping
• FlowStep enum provide state definition of the flow
• Each enum value in FlowStep enum maps to a method in flow implementation using the same name, the method is responsible of building the execution logic for the step
• StepExecution contains execution logic for a flow step, there are 2 main flavors
• StepTransition is returned by a FlowStepExecution and provide information of state transition.
• FlowContext contains context information that can be persisted and accessed each step of the way
• FlowDrive drives the flow from start to end or to as far as it can be run.
• FlowProperty for flow specific properties eg. cluster, recovery, concurrency etc.
• FlowStepProperty annotation for step properties eg. weight
• FlowEvent enum defines flowevent generated by the framework at runtime
• FlowEventListener interface to handle flow event

To Learn More

For more details, check out LightJ source code package org.lightj.session.*, examples in lightj-examples.zip at download section