Package org.springframework.webflow.execution.repository.impl

Class DefaultFlowExecutionRepository

java.lang.Object
org.springframework.webflow.execution.repository.support.AbstractFlowExecutionRepository
org.springframework.webflow.execution.repository.snapshot.AbstractSnapshottingFlowExecutionRepository
org.springframework.webflow.execution.repository.impl.DefaultFlowExecutionRepository
All Implemented Interfaces:
FlowExecutionKeyFactory, FlowExecutionRepository
public class DefaultFlowExecutionRepository extends AbstractSnapshottingFlowExecutionRepository
The default flow execution repository implementation. Takes one to max flow execution snapshots, where each snapshot represents a copy of a FlowExecution taken at a point in time. Snapshots are created via a FlowExecutionSnapshotFactory and that may or may not involve creating a copy of a flow execution through Java serialization. In particular when the flow-execution-repository element is configured with max-execution-snapshots="0", creating snapshot copies is effectively turned off.

The set of active flow executions are managed by a ConversationManager implementation, which this repository delegates to.

This repository is responsible for:

  • Beginning a new Conversation when a FlowExecution is assigned a persistent key. Each conversation is assigned a unique conversation id which forms one part of the flow execution key.
  • Taking execution snapshots to persist flow execution state. A snapshot is a copy of the execution created at a point in time that can be restored and continued. Snapshotting supports users going back in their browser to continue their flow execution from a previoius point.
  • Ending conversations when flow executions end.

This repository implementation also provides support for execution invalidation after completion, where once a logical flow execution completes, it and all of its snapshots are removed. This cleans up memory and prevents the possibility of duplicate submission after completion.

Author:
Keith Donald

  • Constructor Details

    • DefaultFlowExecutionRepository

      public DefaultFlowExecutionRepository(ConversationManager conversationManager, FlowExecutionSnapshotFactory snapshotFactory)
      Create a new default flow execution repository using the given state restorer, conversation manager, and snapshot factory.
      Parameters:
      conversationManager - the conversation manager to use
      snapshotFactory - the flow execution snapshot factory to use

  • Method Details

    • getMaxSnapshots

      public int getMaxSnapshots()
      Returns the max number of snapshots allowed per flow execution by this repository.

    • setMaxSnapshots

      public void setMaxSnapshots(int maxSnapshots)
      Sets the maximum number of snapshots allowed per flow execution by this repository. Use -1 for unlimited. The default is 30.

    • nextSnapshotId

      protected Serializable nextSnapshotId(Serializable executionId)
      Description copied from class: AbstractFlowExecutionRepository
      The next snapshot id to use for a FlowExecution instance. Called when getting a flow execution key.
      Specified by:
      nextSnapshotId in class AbstractFlowExecutionRepository
      Returns:
      the id of the flow execution

    • getFlowExecution

      public FlowExecution getFlowExecution(FlowExecutionKey key)
      Description copied from interface: FlowExecutionRepository
      Return the FlowExecution indexed by the provided key. The returned flow execution represents the restored state of an executing flow from a point in time. This should be called to resume a persistent flow execution. Before calling this method, you should acquire the lock for the keyed flow execution.
      Specified by:
      getFlowExecution in interface FlowExecutionRepository
      Specified by:
      getFlowExecution in class AbstractFlowExecutionRepository
      Parameters:
      key - the flow execution key
      Returns:
      the flow execution, fully hydrated and ready to resume

    • putFlowExecution

      public void putFlowExecution(FlowExecution flowExecution)
      Description copied from interface: FlowExecutionRepository
      Place the FlowExecution in this repository under the provided key. This should be called to save or update the persistent state of an active (but paused) flow execution. Before calling this method, you should acquire the lock for the keyed flow execution.
      Specified by:
      putFlowExecution in interface FlowExecutionRepository
      Specified by:
      putFlowExecution in class AbstractFlowExecutionRepository
      Parameters:
      flowExecution - the flow execution

    • updateFlowExecutionSnapshot

      public void updateFlowExecutionSnapshot(FlowExecution execution)
      Description copied from interface: FlowExecutionKeyFactory
      Capture the current state of the flow execution by updating its snapshot in storage. Does nothing if the no key has been assigned or no snapshot has already been taken.
      Parameters:
      execution - the flow execution

    • removeFlowExecutionSnapshot

      public void removeFlowExecutionSnapshot(FlowExecution execution)
      Description copied from interface: FlowExecutionKeyFactory
      Remove the snapshot that was used to restore this flow execution, discarding it for future use. Does nothing if the no key been assigned or no snapshot has been taken.
      Parameters:
      execution - the flow execution

    • removeAllFlowExecutionSnapshots

      public void removeAllFlowExecutionSnapshots(FlowExecution execution)
      Description copied from interface: FlowExecutionKeyFactory
      Remove all snapshots associated with the flow execution from storage, invalidating all history. Does nothing if no key has been assigned or no snapshots have been taken.
      Parameters:
      execution - the flow execution

    • createFlowExecutionSnapshotGroup

      protected FlowExecutionSnapshotGroup createFlowExecutionSnapshotGroup()

    • getSnapshotGroup

      protected FlowExecutionSnapshotGroup getSnapshotGroup(Conversation conversation)
      Returns the snapshot group associated with the governing conversation.
      Parameters:
      conversation - the conversation where the snapshot group is stored
      Returns:
      the snapshot group