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Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.util.fsm;
import java.util.EnumSet;
/**
* A {@link Transition} represents a transition in a {@link FiniteStateMachine} from one
* or more possible states to a desired state.
*
* @param the type of the state of the {@link FiniteStateMachine}
*
* @author Brian Oliver
* @since Coherence 12.2.1
*/
public class Transition>
{
// ----- constructors ---------------------------------------------------
/**
* Constructs a {@link Transition} (without an {@link TransitionAction}).
*
* @param sName the name of the {@link Transition} (used for display
* and logging purposes)
* @param statesFrom the set of states from which this {@link Transition} may occur
* @param stateTo the state once the {@link TransitionAction} has been
* successfully performed
*/
public Transition(String sName, EnumSet statesFrom, S stateTo)
{
this(sName, statesFrom, stateTo, /* no action */ null);
}
/**
* Constructs a {@link Transition} (without an {@link TransitionAction}).
*
* @param sName the name of the {@link Transition} (used for display
* and logging purposes)
* @param stateFrom the state from which this {@link Transition} may occur
* @param stateTo the state once the {@link TransitionAction} has been
* successfully performed
*/
public Transition(String sName, S stateFrom, S stateTo)
{
this(sName, stateFrom, stateTo, /* no action */ null);
}
/**
* Constructs a {@link Transition}.
*
* @param sName the name of the {@link Transition} (used for display
* and logging purposes)
* @param statesFrom the set of states from which this {@link Transition} may occur
* @param stateTo the state once the {@link TransitionAction} has been
* successfully performed
* @param action the {@link TransitionAction} to be perform for the
* {@link Transition}
*/
public Transition(String sName, EnumSet statesFrom, S stateTo, TransitionAction action)
{
m_sName = sName;
m_statesFrom = statesFrom;
m_stateTo = stateTo;
m_action = action;
}
/**
* Constructs a {@link Transition}.
*
* @param sName the name of the {@link Transition} (used for display and logging purposes)
* @param stateFrom the state from which this {@link Transition} may occur
* @param stateTo the state once the {@link TransitionAction} has been successfully performed
* @param action the {@link TransitionAction} to be perform for the {@link Transition}
*/
public Transition(String sName, S stateFrom, S stateTo, TransitionAction action)
{
m_sName = sName;
m_statesFrom = EnumSet.of(stateFrom);
m_stateTo = stateTo;
m_action = action;
}
// ----- Transition methods ---------------------------------------------
/**
* Obtains the name of the {@link Transition}.
*
* @return the name of the {@link Transition}
*/
public String getName()
{
return m_sName;
}
/**
* Determines if the specified state is one of the possible starting
* states for the {@link Transition}.
*
* @param state the state to check
*
* @return true if the specified state is one of the
* starting states for the {@link Transition}
*/
public boolean isStartingState(S state)
{
return m_statesFrom.contains(state);
}
/**
* Obtains the {@link TransitionAction} to be performed for the {@link Transition}.
*
* @return the {@link TransitionAction} for the transition
*/
public TransitionAction getAction()
{
return m_action;
}
/**
* Obtains the state to which the {@link FiniteStateMachine} will be in
* once this {@link Transition} has occurred.
*
* @return the state of the {@link FiniteStateMachine} after this {@link
* Transition} has occurred
*/
public S getEndingState()
{
return m_stateTo;
}
// ----- Object methods -------------------------------------------------
/**
* {@inheritDoc}
*/
@Override
public String toString()
{
return String.format("Transition{name=%s, from=%s, to=%s, action=%s}",
m_sName, m_statesFrom, m_stateTo, m_action);
}
// ----- data members ---------------------------------------------------
/**
* The name of the {@link Transition}.
*
* This is used for display and logging purposes.
*/
private final String m_sName;
/**
* The set of states from which this {@link Transition} may occur.
*/
private final EnumSet m_statesFrom;
/**
* The state of the {@link FiniteStateMachine} once the {@link TransitionAction}
* has been successfully performed.
*/
private final S m_stateTo;
/**
* The {@link TransitionAction} to be performed for the {@link Transition}.
*
* This may be null if no action is to be performed.
*/
private final TransitionAction m_action;
}