Example usage for org.apache.commons.scxml TriggerEvent EMPTY_EVENT

Introduction

In this page you can find the example usage for org.apache.commons.scxml TriggerEvent EMPTY_EVENT.

Prototype

String EMPTY_EVENT

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Document

This constant contains the name of the event which is used to debug an scxml interpretation.

Usage

From source file:de.dfki.iui.mmds.scxml.engine.impl.SCXMLEngineImpl.java

@Override
public Map<String, Map<String, List<Object[]>>> getAvailableEventsStates() {
    Map<String, Map<String, List<Object[]>>> eventsStates = new HashMap<String, Map<String, List<Object[]>>>();
    if (engine.getCurrentStatus().isFinal())
        // stop the interpretation by sending an empty config/available
        // event states
        return eventsStates;

    String event, id;//from  w ww.  j  av a2  s  .  c om
    Map<String, List<Object[]>> states;
    Map<String, Object> vars, rootVars;
    List<Object[]> state;
    int pos;
    SCInstance sci = engine.getSCInstance();
    Set<String> datas;

    for (TransitionTarget tt : engine.getCurrentStatus().getAllStates()) {
        id = tt.getId();
        pos = 0;
        for (Transition t : tt.getTransitionsList()) {
            event = t.getEvent();
            event = (event != null || engine.isSuperStep()) ? event : TriggerEvent.EMPTY_EVENT;
            if (event != null) {
                // 1. add all events to the configuration
                if (!eventsStates.containsKey(event)) {
                    eventsStates.put(event, new HashMap<String, List<Object[]>>());
                }

                // 2. add all active source states to the config
                states = eventsStates.get(event);
                if (!states.containsKey(id)) {
                    states.put(id, new LinkedList<Object[]>());
                }

                // 3. add the transition condition to the config
                state = states.get(id);

                /*
                 * the following 4 values in the Object array indicate: i)
                 * the position of the transition ii) the condition of the
                 * transition iii) that the evaluation of the transition's
                 * condition is not performed in the last step, i.e. it is
                 * 'UNKNOWN' // * iii) that the transition condition was not
                 * changed in the last step, i.e. no dynamical change and
                 * this is not a 'refresh' event
                 */
                state.add(new Object[] { pos, t.getCond() == null ? "" : t.getCond(), -1 });

                // 4. add all contexts to the config
                vars = new HashMap<String, Object>();
                while (tt != null) {
                    vars.putAll(sci.getContext(tt).getVars());
                    tt = tt.getParent();
                }
                rootVars = sci.getRootContext().getVars();
                if (rootVars != null) {
                    vars.putAll(rootVars);
                }

                // to skip double entries the names of all datas in the
                // state config are needed
                // the following set/for-loop could be removed if the used
                // list would check double occurrences itself -> exchange
                // LinkedList by something else
                datas = new HashSet<String>();
                for (Object[] data : state) {
                    if (data[0] instanceof String) {
                        datas.add((String) data[0]);
                    }
                }
                for (Entry<String, Object> e : vars.entrySet()) {
                    /*
                     * the following 3 values in the Object array indicate:
                     * i) the name of the data ii) the current value of the
                     * data iii) that the data value was not changed in the
                     * last step, i.e. no dynamical change and this is not a
                     * 'refresh' event
                     */
                    if (!datas.contains(e.getKey())) {
                        state.add(new Object[] { e.getKey(), e.getValue(), false });
                        datas.add(e.getKey());
                    }
                }
            }
            pos++;
        }
    }
    return eventsStates;
}

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