org.caleydo.view.tourguide.stratomex.s.StateMachineImpl.java Source code

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Here is the source code for org.caleydo.view.tourguide.stratomex.s.StateMachineImpl.java

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/*******************************************************************************
 * Caleydo - Visualization for Molecular Biology - http://caleydo.org
 * Copyright (c) The Caleydo Team. All rights reserved.
 * Licensed under the new BSD license, available at http://caleydo.org/license
 ******************************************************************************/
package org.caleydo.view.tourguide.stratomex.s;

import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import org.caleydo.core.event.EventListenerManager.DeepScan;
import org.caleydo.view.tourguide.api.state.IState;
import org.caleydo.view.tourguide.api.state.IStateMachine;
import org.caleydo.view.tourguide.api.state.ITransition;
import org.caleydo.view.tourguide.api.state.RootState;
import org.caleydo.view.tourguide.api.state.SimpleState;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.BiMap;
import com.google.common.collect.HashBiMap;
import com.google.common.collect.Iterables;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.Lists;

class StateMachineImpl implements IStateMachine {
    @DeepScan
    private final BiMap<String, IState> states = HashBiMap.create();
    @DeepScan
    private final ListMultimap<IState, ITransition> transitions = ArrayListMultimap.create();
    private IState current = null;

    private final Deque<IState> history = new LinkedList<>();

    public StateMachineImpl() {
        current = addState("root", new SimpleState(""));
    }

    @Override
    public IState addState(String id, IState state) {
        states.put(id, state);
        return state;
    }

    /**
     * @return
     */
    public RootState findNearestRoot() {
        if (history.isEmpty())
            return null;
        for (Iterator<IState> it = history.descendingIterator(); it.hasNext();) {
            IState next = it.next();
            if (next instanceof RootState)
                return (RootState) next;
        }
        return null;
    }

    @Override
    public Collection<RootState> getRootStates() {
        return Lists.newArrayList(Iterables.filter(this.states.values(), RootState.class));
    }

    /**
     * @param target
     * @return
     */
    public void move(IState target) {
        this.history.add(this.current);
        this.current.onLeave();
        this.current = target;
        this.current.onEnter();
    }

    public void goBack() {
        IState previous = history.pollLast();
        this.current.onLeave();
        this.current = previous;
        this.current.onEnter();
    }

    public IState getPrevious() {
        return history.isEmpty() ? null : history.getLast();
    }

    @Override
    public void addTransition(IState source, ITransition transition) {
        if (!states.inverse().containsKey(source)) // add if not already part of
            addState(source.getLabel(), source);
        transitions.put(source, transition);
    }

    @Override
    public IState get(String id) {
        return states.get(id);
    }

    @Override
    public Set<String> getStates() {
        return Collections.unmodifiableSet(states.keySet());
    }

    @Override
    public IState getCurrent() {
        return current;
    }

    @Override
    public List<ITransition> getTransitions(IState state) {
        return Collections.unmodifiableList(transitions.get(state));
    }

}