/*
* Copyright 2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.statemachine.state;
import java.util.Collection;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.statemachine.StateContext;
import org.springframework.statemachine.action.Action;
import org.springframework.statemachine.guard.Guard;
import org.springframework.util.Assert;
/**
* Choice implementation of a {@link PseudoState}.
*
* @author Janne Valkealahti
*
* @param <S> the type of state
* @param <E> the type of event
*/
public class ChoicePseudoState<S, E> implements PseudoState<S, E> {
private final static Log log = LogFactory.getLog(ChoicePseudoState.class);
private final List<ChoiceStateData<S, E>> choices;
/**
* Instantiates a new choice pseudo state.
*
* @param choices the choices
*/
public ChoicePseudoState(List<ChoiceStateData<S, E>> choices) {
this.choices = choices;
}
@Override
public PseudoStateKind getKind() {
return PseudoStateKind.CHOICE;
}
@Override
public State<S, E> entry(StateContext<S, E> context) {
State<S, E> s = null;
ChoiceStateData<S, E> csd = null;
for (ChoiceStateData<S, E> c : choices) {
csd = c;
if (c.guard != null && evaluateInternal(c.guard, context)) {
break;
}
}
if (csd != null) {
s = csd.getState();
executeActions(csd.getActions(), context);
}
return s;
}
@Override
public void exit(StateContext<S, E> context) {
}
@Override
public void addPseudoStateListener(PseudoStateListener<S, E> listener) {
}
@Override
public void setPseudoStateListeners(List<PseudoStateListener<S, E>> listeners) {
}
private boolean evaluateInternal(Guard<S, E> guard, StateContext<S, E> context) {
try {
return guard.evaluate(context);
} catch (Throwable t) {
log.warn("Deny guard due to throw as GUARD should not error", t);
return false;
}
}
private void executeActions(Collection<Action<S, E>> actions, StateContext<S, E> context) {
if (actions == null) {
return;
}
for (Action<S, E> action : actions) {
try {
action.execute(context);
} catch (Throwable t) {
log.warn("Action execution resulted error", t);
}
}
}
/**
* Data class wrapping choice {@link State} and {@link Guard}
* together.
*
* @param <S> the type of state
* @param <E> the type of event
*/
public static class ChoiceStateData<S, E> {
private final StateHolder<S, E> state;
private final Guard<S, E> guard;
private final Collection<Action<S, E>> actions;
/**
* Instantiates a new choice state data.
*
* @param state the state holder
* @param guard the guard
* @param actions the actions
*/
public ChoiceStateData(StateHolder<S, E> state, Guard<S, E> guard, Collection<Action<S, E>> actions) {
Assert.notNull(state, "Holder must be set");
this.state = state;
this.guard = guard;
this.actions = actions;
}
/**
* Gets the state holder.
*
* @return the state holder
*/
public StateHolder<S, E> getStateHolder() {
return state;
}
/**
* Gets the state.
*
* @return the state
*/
public State<S, E> getState() {
return state.getState();
}
/**
* Gets the guard.
*
* @return the guard
*/
public Guard<S, E> getGuard() {
return guard;
}
/**
* Gets the actions.
*
* @return the actions
*/
public Collection<Action<S, E>> getActions() {
return actions;
}
}
}