Core, stable abstractions for representing runtime executions of flow definitions.

The central concept defined by this package is the {@link org.springframework.webflow.execution.FlowExecution} interface, which represents a single instance of a top-level flow definition.

The following classes and interfaces are of particular interest:

- {@link org.springframework.webflow.execution.FlowExecutionFactory} - An abstract factory for creating new flow executions.
- {@link org.springframework.webflow.execution.repository.FlowExecutionRepository} - A DAO for persisting and restoring existing flow executions.
- {@link org.springframework.webflow.execution.FlowExecutionListener} - An observer interface to be implemented by objects that are interested in flow execution lifecycle events.

Package Usage example:

        // create flow execution
        FlowDefinition definition = ...
        FlowExecutionFactory factory = ...
        FlowExecution execution = factory.createFlowExecution(definition);

        // start execution
        ExternalContext context = ...
        ViewSelection response = execution.start(null, context);

This package depends on the definition package.