org.springframework.webflow.execution.repository.continuation
Class ContinuationFlowExecutionRepository

java.lang.Object
  org.springframework.webflow.execution.repository.support.AbstractFlowExecutionRepository
      org.springframework.webflow.execution.repository.support.AbstractConversationFlowExecutionRepository
          org.springframework.webflow.execution.repository.continuation.ContinuationFlowExecutionRepository

All Implemented Interfaces:

FlowExecutionRepository

public class ContinuationFlowExecutionRepository
extends AbstractConversationFlowExecutionRepository

Stores one to many flow execution continuations (snapshots) per conversation, where each continuation represents a paused, restorable view-state of a flow execution snapshotted at a point in time.

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

This repository is responsible for:

• Beginning a new conversation when a new flow execution is made persistent. Each conversation is assigned a unique conversartion id which forms one part of the flow execution key.
• Associating a flow execution with that conversation by adding a FlowExecutionContinuation to a continuation group.
  When a flow execution is placed in this repository a new continuation snapshot is created, assigned an id, and added to the group. Each continuation logically represents a state of the conversation at a point in time that can be restored and continued. These continuations can be restored to support users going back in their browser to continue a conversation from a previous point.
• Ending existing conversations when persistent flow executions end, as part of a repository removal operation.

This repository implementation also provides support for conversation invalidation after completion, where once a logical conversation completes (by one of its FlowExecution's reaching an end state), the entire conversation (including all continuations) is invalidated. This prevents the possibility of duplicate submission after completion.

This repository implementation should be considered when you do have to support browser navigational button use, e.g. you cannot lock down the browser and require that all navigational events to be routed explicitly through Spring Web Flow.

Author:

Keith Donald

Constructor Summary

ContinuationFlowExecutionRepository(FlowExecutionStateRestorer executionStateRestorer, ConversationManager conversationManager)
Create a new continuation based flow execution repository using given state restorer and conversation manager.

Method Summary

protected java.io.Serializable	generateContinuationId(FlowExecution flowExecution) Template method used to generate a new continuation id for given flow execution.
protected FlowExecutionContinuation	getContinuation(FlowExecutionKey key) Returns the continuation in the group with the specified key.
FlowExecutionContinuationFactory	getContinuationFactory() Returns the continuation factory that encapsulates the construction of continuations stored in this repository.
UidGenerator	getContinuationIdGenerator() Returns the uid generation strategy used to generate continuation identifiers.
FlowExecution	getFlowExecution(FlowExecutionKey key) Return the FlowExecution indexed by the provided key.
int	getMaxContinuations() Returns the maximum number of continuations allowed per conversation in this repository.
protected void	onBegin(Conversation conversation) An "on begin conversation" callback, allowing for insertion of custom logic after a new conversation has begun.
protected java.io.Serializable	parseContinuationId(java.lang.String encodedId) Template method to parse the continuation id from the encoded string.
void	putFlowExecution(FlowExecutionKey key, FlowExecution flowExecution) Place the FlowExecution in this repository under the provided key.
void	setContinuationFactory(FlowExecutionContinuationFactory continuationFactory) Sets the continuation factory that encapsulates the construction of continuations stored in this repository.
void	setContinuationIdGenerator(UidGenerator continuationIdGenerator) Sets the uid generation strategy used to generate unique continuation identifiers for flow execution keys.
void	setMaxContinuations(int maxContinuations) Sets the maximum number of continuations allowed per conversation in this repository.

Methods inherited from class org.springframework.webflow.execution.repository.support.AbstractConversationFlowExecutionRepository

createConversationParameters, generateKey, getContinuationId, getConversation, getConversationId, getConversationManager, getConversationScope, getLock, getNextKey, onEnd, parseFlowExecutionKey, putConversationScope, removeFlowExecution

Methods inherited from class org.springframework.webflow.execution.repository.support.AbstractFlowExecutionRepository

getExecutionStateRestorer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ContinuationFlowExecutionRepository

public ContinuationFlowExecutionRepository(FlowExecutionStateRestorer executionStateRestorer,
                                           ConversationManager conversationManager)

Create a new continuation based flow execution repository using given state restorer and conversation manager.

Parameters:

executionStateRestorer - the state restoration strategy to use

conversationManager - the conversation manager to use

Method Detail

getContinuationFactory

public FlowExecutionContinuationFactory getContinuationFactory()

Returns the continuation factory that encapsulates the construction of continuations stored in this repository. Defaults to SerializedFlowExecutionContinuationFactory.

setContinuationFactory

public void setContinuationFactory(FlowExecutionContinuationFactory continuationFactory)

Sets the continuation factory that encapsulates the construction of continuations stored in this repository.

getContinuationIdGenerator

public UidGenerator getContinuationIdGenerator()

Returns the uid generation strategy used to generate continuation identifiers. Defaults to RandomGuidUidGenerator.

setContinuationIdGenerator

public void setContinuationIdGenerator(UidGenerator continuationIdGenerator)

Sets the uid generation strategy used to generate unique continuation identifiers for flow execution keys.

getMaxContinuations

public int getMaxContinuations()

Returns the maximum number of continuations allowed per conversation in this repository.

setMaxContinuations

public void setMaxContinuations(int maxContinuations)

Sets the maximum number of continuations allowed per conversation in this repository. Use -1 for unlimited.

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.

Specified by:

getFlowExecution in interface FlowExecutionRepository

Specified by:

getFlowExecution in class AbstractConversationFlowExecutionRepository

Parameters:

key - the flow execution key

Returns:

the flow execution, fully hydrated and ready to signal an event against

putFlowExecution

public void putFlowExecution(FlowExecutionKey key,
                             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.

Specified by:

putFlowExecution in interface FlowExecutionRepository

Specified by:

putFlowExecution in class AbstractConversationFlowExecutionRepository

Parameters:

key - the flow execution key

flowExecution - the flow execution

onBegin

protected void onBegin(Conversation conversation)

Description copied from class: AbstractConversationFlowExecutionRepository

An "on begin conversation" callback, allowing for insertion of custom logic after a new conversation has begun. This implementation is emtpy.

Overrides:

onBegin in class AbstractConversationFlowExecutionRepository

Parameters:

conversation - the conversation that has begun

generateContinuationId

protected java.io.Serializable generateContinuationId(FlowExecution flowExecution)

Description copied from class: AbstractConversationFlowExecutionRepository

Template method used to generate a new continuation id for given flow execution. Subclasses must override.

Specified by:

generateContinuationId in class AbstractConversationFlowExecutionRepository

Parameters:

flowExecution - the flow execution

Returns:

the continuation id

parseContinuationId

protected java.io.Serializable parseContinuationId(java.lang.String encodedId)

Description copied from class: AbstractConversationFlowExecutionRepository

Template method to parse the continuation id from the encoded string.

Specified by:

parseContinuationId in class AbstractConversationFlowExecutionRepository

Parameters:

encodedId - the string identifier

Returns:

the parsed continuation id

getContinuation

protected FlowExecutionContinuation getContinuation(FlowExecutionKey key)
                                             throws FlowExecutionRestorationFailureException

Returns the continuation in the group with the specified key.

Parameters:

key - the flow execution key

Returns:

the continuation.

Throws:

FlowExecutionRestorationFailureException