## Package cascading.flow

Interface Summary
FlowCollector: Interface FlowCollector is the base "collector" interface used internally to pass `Tuple` instances between operations.
FlowElement: Interface FlowElement is a utility interface used internally to simplify DAG management.
FlowListener: Interface FlowListener provides hooks for receiving events on various stages of a `Flow` execution.
FlowSkipStrategy: Interface FlowSkipStrategy is used to create new strategies that decide when a `Flow` should be skipped when executed in a `Cascade`.

Class Summary
ElementGraph: Class ElementGraph represents the executable FlowElement graph.
ElementGraph.Extent
Flow: A `Pipe` assembly is connected to the necessary number of `Tap` sinks and sources into a Flow.
Flow.FlowHolder: Class FlowHolder is a helper class for wrapping Flow instances.
FlowConnector: Use the FlowConnector to link source and sink `Tap` instances with an assembly of `Pipe` instances into an executable `Flow`.
FlowMapper: Class FlowMapper is the Hadoop Mapper implementation.
FlowPlanner: Class FlowPlanner is the base class for all planner implementations.
FlowProcess: FlowProcess implementations provide a call-back interface into the current computing system.
FlowReducer: Class FlowReducer is the Hadoop Reducer implementation.
FlowSession: FlowSession implementations provide a call-back interface into the current flow management system, if any.
FlowSkipIfSinkExists: Class FlowSkipIfSinkExists is a `FlowSkipStrategy` implementation that returns `true` if the Flow sink exists, regardless if it is stale or not.
FlowSkipIfSinkStale: Class FlowSkipIfSinkStale is a `FlowSkipStrategy` implementation that returns `true` if the Flow sink exists and is stale in relation to the Flow sources.
FlowStep: Class FlowStep is an internal representation of a given Job to be executed on a remote cluster.
FlowStepJob
MapReduceFlow: Class MapReduceFlow is a `Flow` subclass that supports custom MapReduce jobs pre-configured via the `JobConf` object.
MapReduceFlowStep: Class MapReduceFlowStep wraps a `JobConf` and allows it to be executed as a `Flow`.
MultiMapReducePlanner: Class MultiMapReducePlanner is the core Hadoop MapReduce planner.
ProcessFlow<P>: Class ProcessFlow is a `Flow` subclass that supports custom Riffle jobs.
Scope: Class Scope is an internal representation of the linkages between operations.
StepGraph: Class StepGraph is an internal representation of `FlowStep` instances.

Enum Summary
Scope.Kind: Enum Kind
StepCounters: Enum FlowCounters lists all counters

Exception Summary
ElementGraphException: Class ElementGraphException is thrown during rendering of a pipe assembly to the Cascading internal "graph" representation.
FlowException: FlowException instances are thrown on errors when executing a Flow.
PlannerException: Class PlannerException is thrown when a job planner fails.

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