org.springframework.webflow.execution.repository.support

Class AbstractFlowExecutionRepository

java.lang.Object

org.springframework.webflow.execution.repository.support.AbstractFlowExecutionRepository

All Implemented Interfaces:

FlowExecutionKeyFactory, FlowExecutionRepository

Direct Known Subclasses:

AbstractSnapshottingFlowExecutionRepository

public abstract class AbstractFlowExecutionRepository
extends java.lang.Object
implements FlowExecutionRepository, FlowExecutionKeyFactory

Abstract base class for flow execution repository implementations. Does not make any assumptions about the storage medium used to store active flow executions. Mandates the use of a FlowExecutionStateRestorer, used to rehydrate a flow execution after it has been obtained from storage from resume.

The configured FlowExecutionStateRestorer should be compatible with the chosen FlowExecution implementation and its FlowExecutionFactory.

Author:

Keith Donald, Erwin Vervaet

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.commons.logging.Log	logger Logger, usable in subclasses

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractFlowExecutionRepository(ConversationManager conversationManager) Constructor for use in subclasses.

Method Summary

Modifier and Type	Method and Description
protected void	assertKeySet(FlowExecution execution) Assert that a flow execution key has been assigned to the execution.
protected ConversationParameters	createConversationParameters(FlowExecution flowExecution) Factory method that maps a new flow execution to a descriptive conversation parameters object.
boolean	getAlwaysGenerateNewNextKey() The flag indicating if a new FlowExecutionKey should always be generated before each put call.
protected Conversation	getConversation(FlowExecutionKey key) Returns the conversation governing the FlowExecution with the provided key.
protected Conversation	getConversation(java.io.Serializable executionId) Returns the conversation governing the logical flow execution with the given execution id.
ConversationManager	getConversationManager() The conversation service to delegate to for managing conversations initiated by this repository.
abstract FlowExecution	getFlowExecution(FlowExecutionKey key) Return the FlowExecution indexed by the provided key.
FlowExecutionKey	getKey(FlowExecution execution) Get the key to assign to the flow execution.
FlowExecutionLock	getLock(FlowExecutionKey key) Return the lock for the flow execution, allowing for the lock to be acquired or released.
protected abstract java.io.Serializable	nextSnapshotId(java.io.Serializable executionId) The next snapshot id to use for a FlowExecution instance.
FlowExecutionKey	parseFlowExecutionKey(java.lang.String encodedKey) Parse the string-encoded flow execution key into its object form.
abstract void	putFlowExecution(FlowExecution flowExecution) Place the FlowExecution in this repository under the provided key.
void	removeFlowExecution(FlowExecution flowExecution) Remove the flow execution from the repository.
void	setAlwaysGenerateNewNextKey(boolean alwaysGenerateNewNextKey) Sets the flag indicating if a new FlowExecutionKey should always be generated before each put call.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.webflow.execution.FlowExecutionKeyFactory

removeAllFlowExecutionSnapshots, removeFlowExecutionSnapshot, updateFlowExecutionSnapshot

Field Detail

logger

protected final org.apache.commons.logging.Log logger

Logger, usable in subclasses

Constructor Detail

AbstractFlowExecutionRepository

protected AbstractFlowExecutionRepository(ConversationManager conversationManager)

Constructor for use in subclasses.

Parameters:

conversationManager - the conversation manager to use

Method Detail

getConversationManager

public ConversationManager getConversationManager()

The conversation service to delegate to for managing conversations initiated by this repository.

getAlwaysGenerateNewNextKey

public boolean getAlwaysGenerateNewNextKey()

The flag indicating if a new FlowExecutionKey should always be generated before each put call.

setAlwaysGenerateNewNextKey

public void setAlwaysGenerateNewNextKey(boolean alwaysGenerateNewNextKey)

Sets the flag indicating if a new FlowExecutionKey should always be generated before each put call. By setting this to false a FlowExecution can remain identified by the same key throughout its life.

getKey

public FlowExecutionKey getKey(FlowExecution execution)

Description copied from interface: FlowExecutionKeyFactory

Get the key to assign to the flow execution. This factory simply generates the key to assign, it does not actually perform the key assignment.

Specified by:

getKey in interface FlowExecutionKeyFactory

Parameters:

execution - the flow execution

Returns:

the key to assign to the flow execution

parseFlowExecutionKey

public FlowExecutionKey parseFlowExecutionKey(java.lang.String encodedKey)
                                       throws FlowExecutionRepositoryException

Description copied from interface: FlowExecutionRepository

Parse the string-encoded flow execution key into its object form. Essentially, the reverse of FlowExecutionKey.toString().

Specified by:

parseFlowExecutionKey in interface FlowExecutionRepository

Parameters:

encodedKey - the string encoded key

Returns:

the parsed flow execution key, the persistent identifier for exactly one flow execution

Throws:

FlowExecutionRepositoryException

getLock

public FlowExecutionLock getLock(FlowExecutionKey key)
                          throws FlowExecutionRepositoryException

Description copied from interface: FlowExecutionRepository

Return the lock for the flow execution, allowing for the lock to be acquired or released. Caution: care should be made not to allow for a deadlock situation. If you acquire a lock make sure you release it when you are done. The general pattern for safely doing work against a locked conversation follows:

 FlowExecutionLock lock = repository.getLock(key);
 lock.lock();
 try {
        FlowExecution execution = repository.getFlowExecution(key);
        // do work
 } finally {
        lock.unlock();
 }
 

Specified by:

getLock in interface FlowExecutionRepository

Parameters:

key - the identifier of the flow execution to lock

Returns:

the lock

Throws:

FlowExecutionRepositoryException - a problem occurred accessing the lock object

removeFlowExecution

public void removeFlowExecution(FlowExecution flowExecution)
                         throws FlowExecutionRepositoryException

Description copied from interface: FlowExecutionRepository

Remove the flow execution from the repository. This should be called when the flow execution ends (is no longer active). Before calling this method, you should acquire the lock for the keyed flow execution.

Specified by:

removeFlowExecution in interface FlowExecutionRepository

Parameters:

flowExecution - the flow execution

Throws:

FlowExecutionRepositoryException - the flow execution could not be removed.

nextSnapshotId

protected abstract java.io.Serializable nextSnapshotId(java.io.Serializable executionId)

The next snapshot id to use for a FlowExecution instance. Called when getting a flow execution key.

Returns:

the id of the flow execution

getFlowExecution

public abstract FlowExecution getFlowExecution(FlowExecutionKey key)
                                        throws FlowExecutionRepositoryException

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

Parameters:

key - the flow execution key

Returns:

the flow execution, fully hydrated and ready to resume

Throws:

FlowExecutionRepositoryException - if no flow execution was indexed with the key provided

putFlowExecution

public abstract void putFlowExecution(FlowExecution flowExecution)
                               throws FlowExecutionRepositoryException

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

Parameters:

flowExecution - the flow execution

Throws:

FlowExecutionRepositoryException - the flow execution could not be stored

createConversationParameters

protected ConversationParameters createConversationParameters(FlowExecution flowExecution)

Factory method that maps a new flow execution to a descriptive conversation parameters object.

Parameters:

flowExecution - the new flow execution

Returns:

the conversation parameters object to pass to the conversation manager when the conversation is started

getConversation

protected Conversation getConversation(FlowExecutionKey key)
                                throws NoSuchFlowExecutionException

Returns the conversation governing the FlowExecution with the provided key.

Parameters:

key - the flow execution key

Returns:

the governing conversation

Throws:

NoSuchFlowExecutionException - when the conversation for identified flow execution cannot be found

getConversation

protected Conversation getConversation(java.io.Serializable executionId)
                                throws NoSuchConversationException

Returns the conversation governing the logical flow execution with the given execution id.

Parameters:

executionId - the flow execution id

Returns:

the governing conversation

Throws:

NoSuchConversationException - when the conversation for identified flow execution cannot be found

assertKeySet

protected void assertKeySet(FlowExecution execution)
                     throws java.lang.IllegalStateException

Assert that a flow execution key has been assigned to the execution.

Parameters:

execution - the flow execution

Throws:

java.lang.IllegalStateException - if a key has not yet been assigned as expected