it.amattioli.workstate.core
Class State

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java.lang.Object
  it.amattioli.workstate.core.State

All Implemented Interfaces:

AttributeReader

Direct Known Subclasses:

PseudoState, RealState

public abstract class State
extends Object
implements AttributeReader

Represent a generic state. Each state is associated to a MetaState that represents its configuration. After creation a state is not active and only the enter() method can be called on it. This method activate the state and initialize it. Calling exit() the state will be exited and it will be no more active. At creation time a unuique id will be created for the state.

Constructor Summary

State(MetaState metastate, CompositeState parent)

Method Summary

void	addAvailableEvents(Collection<MetaEvent> coll)
abstract boolean	admitEvent(Event event)
Event	buildEvent(String name, Map<String,Object> stringParameters)
protected void	checkActive() Verifies if this state is active.
void	enter() Enter this state and activate it.
boolean	equals(Object o)
void	exit() Exit a state and de-activate it.
CompositeState	findAncestor(MetaState ancestorMetaState) Search for an ancestor of this state whose MetaState is given.
Map<String,Object>	getAllAttributes() Return all the attributes of this state.
Object	getAttribute(String tag) Return the value of an attribute of this state.
Collection<MetaEvent>	getAvailableEvents()
String	getId() Return the identifier of this state.
StateMemento	getMemento()
protected abstract StateMemento	getMemento(StateMemento parent)
CompositeState	getParent() Return the composite state that is parent of this state.
Machine	getRootMachine()
boolean	hasMetaState(MetaState metastate) Check if the given MetaState is this state meta-state.
boolean	isActive() Verifies if this state is active.
boolean	isRegion() Check if this state is a region of a ConcurrentState.
abstract void	receiveEvent(Event event)
protected void	reEnter() Re-enter a state that was exited for exception handling purposes.
protected void	reExit() Re-exit a state that was entered for exception handling purposes.
abstract void	restore(StateMemento memento)

Methods inherited from class java.lang.Object

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

Constructor Detail

State

public State(MetaState metastate,
             CompositeState parent)

Method Detail

enter

public void enter()
           throws WorkflowException

Enter this state and activate it.

Throws:

IllegalStateException - if this state is already

WorkflowException

reEnter

protected void reEnter()

Re-enter a state that was exited for exception handling purposes.

exit

public void exit()
          throws WorkflowException

Exit a state and de-activate it.

Throws:

IllegalStateException - if the state is not active

WorkflowException

reExit

protected void reExit()

Re-exit a state that was entered for exception handling purposes.

getParent

public CompositeState getParent()

Return the composite state that is parent of this state.

Returns:

the composite state that is parent of this state or null if this is root

findAncestor

public CompositeState findAncestor(MetaState ancestorMetaState)

Search for an ancestor of this state whose MetaState is given.

Throws:

IllegalArgumentException - if no ancestor of this has the given MetaState

isActive

public boolean isActive()

Verifies if this state is active.

Returns:

true if this state is active, false otherwise

checkActive

protected void checkActive()

Verifies if this state is active. If this state is not active an exception will be raised.

Throws:

IllegalStateException - if this state is not active

hasMetaState

public boolean hasMetaState(MetaState metastate)

Check if the given MetaState is this state meta-state.

Parameters:

metastate - the MetaState to be checked

Returns:

true if the given MetaState is this state meta-state, false otherwise

getRootMachine

public Machine getRootMachine()

receiveEvent

public abstract void receiveEvent(Event event)
                           throws WorkflowException

Throws:

WorkflowException

admitEvent

public abstract boolean admitEvent(Event event)

getAttribute

public Object getAttribute(String tag)

Return the value of an attribute of this state. A generic state has no attributes. Sub-class of this must implement this method so to handle attributes.

Specified by:

getAttribute in interface AttributeReader

Parameters:

tag - the attribute tag

Returns:

the attribute value

Throws:

IllegalStateException - if the state is not active

IllegalArgumentException - if there is no attribute with the given name

getAllAttributes

public Map<String,Object> getAllAttributes()

Return all the attributes of this state. A generic state has no attributes. Sub-class of this must implement this method so to handle attributes.

Specified by:

getAllAttributes in interface AttributeReader

getId

public String getId()

Return the identifier of this state. The identifier is a random string generated when the state is created.

Returns:

this state identifier

getMemento

protected abstract StateMemento getMemento(StateMemento parent)

getMemento

public StateMemento getMemento()

restore

public abstract void restore(StateMemento memento)
                      throws WorkflowException

Throws:

WorkflowException

equals

public boolean equals(Object o)

Overrides:

equals in class Object

isRegion

public boolean isRegion()

Check if this state is a region of a ConcurrentState. Only SequentialStates can be regions so the default implementation of this method return false.

Returns:

true if this state is a region of a ConcurrentState, false otherwise

buildEvent

public Event buildEvent(String name,
                        Map<String,Object> stringParameters)
                 throws WorkflowException

Throws:

WorkflowException

addAvailableEvents

public void addAvailableEvents(Collection<MetaEvent> coll)

getAvailableEvents

public Collection<MetaEvent> getAvailableEvents()