org.springframework.webflow.engine.impl

Class FlowExecutionImpl

java.lang.Object

org.springframework.webflow.engine.impl.FlowExecutionImpl

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, FlowExecution, FlowExecutionContext

public class FlowExecutionImpl
extends java.lang.Object
implements FlowExecution, java.io.Externalizable

Default implementation of FlowExecution that uses a stack-based data structure to manage spawned flow sessions. This class is closely coupled with package-private FlowSessionImpl and RequestControlContextImpl . The three classes work together to form a complete flow execution implementation based on a finite state machine.

This implementation of FlowExecution is serializable so it can be safely stored in an HTTP session or other persistent store such as a file, database, or client-side form field. Once deserialized, the FlowExecutionImplFactory is expected to be used to restore the execution to a usable state.

Author:

Keith Donald, Erwin Vervaet, Jeremy Grelle

See Also:

FlowExecutionImplFactory, Serialized Form

Constructor Summary

Constructors

Constructor and Description
FlowExecutionImpl() Default constructor required for externalizable serialization.
FlowExecutionImpl(Flow flow) Create a new flow execution executing the provided flow.

Method Summary

Modifier and Type	Method and Description
protected org.springframework.webflow.engine.impl.FlowSessionImpl	createFlowSession(Flow flow, org.springframework.webflow.engine.impl.FlowSessionImpl parent) Create a new flow session object.
protected RequestControlContext	createRequestContext(ExternalContext externalContext, MessageContext messageContext) Create a flow execution control context.
FlowSession	getActiveSession() Returns the active flow session of this flow execution.
AttributeMap<java.lang.Object>	getAttributes() Returns runtime execution attributes that may influence the behavior of flow artifacts, such as states and actions.
java.lang.String	getCaption()
MutableAttributeMap<java.lang.Object>	getConversationScope() Returns a mutable map for data held in "conversation scope".
FlowDefinition	getDefinition() Returns the root flow definition associated with this executing flow.
MutableAttributeMap<java.lang.Object>	getFlashScope() Returns a mutable map for data held in "flash scope".
FlowExecutionKey	getKey() Returns the key assigned to this flow execution.
FlowExecutionOutcome	getOutcome() Returns the outcome reached by this execution, or null if this execution has not yet ended.
boolean	hasEnded() Returns a flag indicating if this execution has ended.
boolean	hasStarted() Returns a flag indicating if this execution has been started.
boolean	isActive() Is the flow execution active? A flow execution is active once it has an active session and remains active until it has ended.
void	readExternal(java.io.ObjectInput in)
void	resume(ExternalContext externalContext) Resume this flow execution.
void	setCurrentState(java.lang.String stateId) Jump to a state of the currently active flow.
void	start(MutableAttributeMap<?> input, ExternalContext externalContext) Start this flow execution.
java.lang.String	toString()
void	viewRendered(View view, RequestContext context)
void	viewRendering(View view, RequestContext context)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

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

Constructor Detail

FlowExecutionImpl

public FlowExecutionImpl()

Default constructor required for externalizable serialization. Should NOT be called programmatically.

FlowExecutionImpl

public FlowExecutionImpl(Flow flow)

Create a new flow execution executing the provided flow. Flow executions are normally created by a flow execution factory.

Parameters:

flow - the root flow of this flow execution

Method Detail

getCaption

public java.lang.String getCaption()

getKey

public FlowExecutionKey getKey()

Description copied from interface: FlowExecutionContext

Returns the key assigned to this flow execution. The flow execution key is the flow execution's persistent identity.

Specified by:

getKey in interface FlowExecutionContext

Returns:

the flow execution key; may be null if a key has not yet been assigned.

getDefinition

public FlowDefinition getDefinition()

Description copied from interface: FlowExecutionContext

Returns the root flow definition associated with this executing flow.

A call to this method always returns the same flow definition -- the top-level "root" -- no matter what flow may actually be active (for example, if subflows have been spawned).

Specified by:

getDefinition in interface FlowExecutionContext

Returns:

the root flow definition

hasStarted

public boolean hasStarted()

Description copied from interface: FlowExecutionContext

Returns a flag indicating if this execution has been started. A flow execution that has started and is active is currently in progress. A flow execution that has started and is not active has ended.

Specified by:

hasStarted in interface FlowExecutionContext

Returns:

true if started, false if not started

See Also:

FlowExecutionContext.isActive()

isActive

public boolean isActive()

Description copied from interface: FlowExecutionContext

Is the flow execution active? A flow execution is active once it has an active session and remains active until it has ended.

Specified by:

isActive in interface FlowExecutionContext

Returns:

true if active, false if the flow execution has terminated or has not yet been started

hasEnded

public boolean hasEnded()

Description copied from interface: FlowExecutionContext

Returns a flag indicating if this execution has ended. A flow execution that has ended has been started but is no longer active.

Specified by:

hasEnded in interface FlowExecutionContext

Returns:

true if ended, false if not started or still active

See Also:

FlowExecutionContext.hasStarted(), FlowExecutionContext.isActive()

getOutcome

public FlowExecutionOutcome getOutcome()

Description copied from interface: FlowExecutionContext

Returns the outcome reached by this execution, or null if this execution has not yet ended.

Specified by:

getOutcome in interface FlowExecutionContext

Returns:

the outcome, or null if this execution has not yet ended

getActiveSession

public FlowSession getActiveSession()

Description copied from interface: FlowExecutionContext

Returns the active flow session of this flow execution. The active flow session is the currently executing session. It may be the "root flow" session, or it may be a subflow session if this flow execution has spawned a subflow.

Specified by:

getActiveSession in interface FlowExecutionContext

Returns:

the active flow session

See Also:

FlowExecutionContext.isActive()

getFlashScope

public MutableAttributeMap<java.lang.Object> getFlashScope()

Description copied from interface: FlowExecutionContext

Returns a mutable map for data held in "flash scope". Attributes in this map are cleared out on the next view rendering. Flash attributes survive flow execution refresh operations.

Specified by:

getFlashScope in interface FlowExecutionContext

Returns:

flash scope

getConversationScope

public MutableAttributeMap<java.lang.Object> getConversationScope()

Description copied from interface: FlowExecutionContext

Returns a mutable map for data held in "conversation scope". Conversation scope is a data structure that exists for the life of this flow execution and is accessible to all flow sessions.

Specified by:

getConversationScope in interface FlowExecutionContext

Returns:

conversation scope

getAttributes

public AttributeMap<java.lang.Object> getAttributes()

Description copied from interface: FlowExecutionContext

Returns runtime execution attributes that may influence the behavior of flow artifacts, such as states and actions.

Specified by:

getAttributes in interface FlowExecutionContext

Returns:

execution attributes

start

public void start(MutableAttributeMap<?> input,
                  ExternalContext externalContext)
           throws FlowExecutionException,
                  java.lang.IllegalStateException

Description copied from interface: FlowExecution

Start this flow execution. This method should only be called once.

When this method returns, execution status is either "paused" or "ended". If ended, the flow execution cannot be used again. If "paused", the flow execution may be resumed.

Specified by:

start in interface FlowExecution

Parameters:

input - flow execution input

externalContext - the external context representing the calling environment

Throws:

FlowExecutionException - if an exception was thrown within a state of the flow execution during request processing

java.lang.IllegalStateException

resume

public void resume(ExternalContext externalContext)
            throws FlowExecutionException,
                   java.lang.IllegalStateException

Description copied from interface: FlowExecution

Resume this flow execution. May be called when the flow execution is paused. When this method returns, execution status is either "paused" or "ended". If ended, the flow execution cannot be used again. If "paused", the flow execution may be resumed again.

Specified by:

resume in interface FlowExecution

Parameters:

externalContext - the external context, representing the calling environment, where something happened this flow execution should respond to

Throws:

FlowExecutionException - if an exception was thrown within a state of the resumed flow execution during event processing

java.lang.IllegalStateException

setCurrentState

public void setCurrentState(java.lang.String stateId)

Jump to a state of the currently active flow. If this execution has not been started, a new session will be activated and its current state will be set. This is a implementation-internal method that bypasses the start(MutableAttributeMap, ExternalContext) operation and allows for jumping to an arbitrary flow state. Useful for testing.

Parameters:

stateId - the identifier of the state to jump to

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

Throws:

java.io.IOException

java.lang.ClassNotFoundException

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Specified by:

writeExternal in interface java.io.Externalizable

Throws:

java.io.IOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

createRequestContext

protected RequestControlContext createRequestContext(ExternalContext externalContext,
                                                     MessageContext messageContext)

Create a flow execution control context.

Parameters:

externalContext - the external context triggering this request

createFlowSession

protected org.springframework.webflow.engine.impl.FlowSessionImpl createFlowSession(Flow flow,
                                                                                    org.springframework.webflow.engine.impl.FlowSessionImpl parent)

Create a new flow session object. Subclasses can override this to return a special implementation if required.

Parameters:

flow - the flow that should be associated with the flow session

parent - the flow session that should be the parent of the newly created flow session (may be null)

Returns:

the newly created flow session

viewRendering

public void viewRendering(View view,
                          RequestContext context)

viewRendered

public void viewRendered(View view,
                         RequestContext context)