    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *     http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.scxml;
    018
    019    import java.io.Serializable;
    020    import java.util.Collections;
    021    import java.util.HashMap;
    022    import java.util.HashSet;
    023    import java.util.Map;
    024    import java.util.Set;
    025
    026    import org.apache.commons.scxml.invoke.Invoker;
    027    import org.apache.commons.scxml.invoke.InvokerException;
    028    import org.apache.commons.scxml.model.Datamodel;
    029    import org.apache.commons.scxml.model.History;
    030    import org.apache.commons.scxml.model.TransitionTarget;
    031
    032    /**
    033     * The <code>SCInstance</code> performs book-keeping functions for
    034     * a particular execution of a state chart represented by a
    035     * <code>SCXML</code> object.
    036     */
    037    public class SCInstance implements Serializable {
    038
    039        /**
    040         * Serial version UID.
    041         */
    042        private static final long serialVersionUID = 2L;
    043
    044        /**
    045         * The notification registry.
    046         */
    047        private NotificationRegistry notificationRegistry;
    048
    049        /**
    050         * The <code>Map</code> of <code>Context</code>s per
    051         * <code>TransitionTarget</code>.
    052         */
    053        private Map contexts;
    054
    055        /**
    056         * The <code>Map</code> of last known configurations per
    057         * <code>History</code>.
    058         */
    059        private Map histories;
    060
    061        /**
    062         * <code>Map</code> for recording the run to completion status of
    063         * composite states.
    064         */
    065        private Map completions;
    066
    067        /**
    068         * The <code>Invoker</code> classes <code>Map</code>, keyed by
    069         * <invoke> target types (specified using "targettype" attribute).
    070         */
    071        private Map invokerClasses;
    072
    073        /**
    074         * The <code>Map</code> of active <code>Invoker</code>s, keyed by
    075         * (leaf) <code>State</code>s.
    076         */
    077        private Map invokers;
    078
    079        /**
    080         * The evaluator for expressions.
    081         */
    082        private Evaluator evaluator;
    083
    084        /**
    085         * The root context.
    086         */
    087        private Context rootContext;
    088
    089        /**
    090         * The owning state machine executor.
    091         */
    092        private SCXMLExecutor executor;
    093
    094        /**
    095         * Constructor.
    096         *
    097         * @param executor The executor that this instance is attached to.
    098         */
    099        SCInstance(final SCXMLExecutor executor) {
    100            this.notificationRegistry = new NotificationRegistry();
    101            this.contexts = Collections.synchronizedMap(new HashMap());
    102            this.histories = Collections.synchronizedMap(new HashMap());
    103            this.invokerClasses = Collections.synchronizedMap(new HashMap());
    104            this.invokers = Collections.synchronizedMap(new HashMap());
    105            this.completions = Collections.synchronizedMap(new HashMap());
    106            this.evaluator = null;
    107            this.rootContext = null;
    108            this.executor = executor;
    109        }
    110
    111        /**
    112         * Get the <code>Evaluator</code>.
    113         *
    114         * @return The evaluator.
    115         */
    116        public Evaluator getEvaluator() {
    117            return evaluator;
    118        }
    119
    120        /**
    121         * Set the <code>Evaluator</code>.
    122         *
    123         * @param evaluator The evaluator.
    124         */
    125        void setEvaluator(final Evaluator evaluator) {
    126            this.evaluator = evaluator;
    127        }
    128
    129        /**
    130         * Get the root context.
    131         *
    132         * @return The root context.
    133         */
    134        public Context getRootContext() {
    135            if (rootContext == null && evaluator != null) {
    136                rootContext = evaluator.newContext(null);
    137            }
    138            return rootContext;
    139        }
    140
    141        /**
    142         * Set the root context.
    143         *
    144         * @param context The root context.
    145         */
    146        void setRootContext(final Context context) {
    147            this.rootContext = context;
    148        }
    149
    150        /**
    151         * Get the notification registry.
    152         *
    153         * @return The notification registry.
    154         */
    155        public NotificationRegistry getNotificationRegistry() {
    156            return notificationRegistry;
    157        }
    158
    159        /**
    160         * Set the notification registry.
    161         *
    162         * @param notifRegistry The notification registry.
    163         */
    164        void setNotificationRegistry(final NotificationRegistry notifRegistry) {
    165            this.notificationRegistry = notifRegistry;
    166        }
    167
    168        /**
    169         * Get the <code>Context</code> for this <code>TransitionTarget</code>.
    170         * If one is not available it is created.
    171         *
    172         * @param transitionTarget The TransitionTarget.
    173         * @return The Context.
    174         */
    175        public Context getContext(final TransitionTarget transitionTarget) {
    176            Context context = (Context) contexts.get(transitionTarget);
    177            if (context == null) {
    178                TransitionTarget parent = transitionTarget.getParent();
    179                if (parent == null) {
    180                    // docroot
    181                    context = evaluator.newContext(getRootContext());
    182                } else {
    183                    context = evaluator.newContext(getContext(parent));
    184                }
    185                Datamodel datamodel = transitionTarget.getDatamodel();
    186                SCXMLHelper.cloneDatamodel(datamodel, context, evaluator, null);
    187                contexts.put(transitionTarget, context);
    188            }
    189            return context;
    190        }
    191
    192        /**
    193         * Get the <code>Context</code> for this <code>TransitionTarget</code>.
    194         * May return <code>null</code>.
    195         *
    196         * @param transitionTarget The <code>TransitionTarget</code>.
    197         * @return The Context.
    198         */
    199        Context lookupContext(final TransitionTarget transitionTarget) {
    200            return (Context) contexts.get(transitionTarget);
    201        }
    202
    203        /**
    204         * Set the <code>Context</code> for this <code>TransitionTarget</code>.
    205         *
    206         * @param transitionTarget The TransitionTarget.
    207         * @param context The Context.
    208         */
    209        void setContext(final TransitionTarget transitionTarget,
    210                final Context context) {
    211            contexts.put(transitionTarget, context);
    212        }
    213
    214        /**
    215         * Get the last configuration for this history.
    216         *
    217         * @param history The history.
    218         * @return Returns the lastConfiguration.
    219         */
    220        public Set getLastConfiguration(final History history) {
    221            Set lastConfiguration = (Set) histories.get(history);
    222            if (lastConfiguration == null) {
    223                lastConfiguration = new HashSet();
    224                histories.put(history, lastConfiguration);
    225            }
    226            return lastConfiguration;
    227        }
    228
    229        /**
    230         * Set the last configuration for this history.
    231         *
    232         * @param history The history.
    233         * @param lc The lastConfiguration to set.
    234         */
    235        public void setLastConfiguration(final History history,
    236                final Set lc) {
    237            Set lastConfiguration = getLastConfiguration(history);
    238            lastConfiguration.clear();
    239            lastConfiguration.addAll(lc);
    240        }
    241
    242        /**
    243         * Check whether we have prior history.
    244         *
    245         * @param history The history.
    246         * @return Whether we have a non-empty last configuration
    247         */
    248        public boolean isEmpty(final History history) {
    249            Set lastConfiguration = (Set) histories.get(history);
    250            if (lastConfiguration == null || lastConfiguration.isEmpty()) {
    251                return true;
    252            }
    253            return false;
    254        }
    255
    256        /**
    257         * Resets the history state.
    258         *
    259         * @param history The history.
    260         * @see org.apache.commons.scxml.SCXMLExecutor#reset()
    261         */
    262        public void reset(final History history) {
    263            Set lastConfiguration = (Set) histories.get(history);
    264            if (lastConfiguration != null) {
    265                lastConfiguration.clear();
    266            }
    267        }
    268
    269        /**
    270         * Get the {@link SCXMLExecutor} this instance is attached to.
    271         *
    272         * @return The SCXMLExecutor this instance is attached to.
    273         * @see org.apache.commons.scxml.SCXMLExecutor
    274         */
    275        public SCXMLExecutor getExecutor() {
    276            return executor;
    277        }
    278
    279        /**
    280         * Register an {@link Invoker} class for this target type.
    281         *
    282         * @param targettype The target type (specified by "targettype"
    283         *                   attribute of <invoke> tag).
    284         * @param invokerClass The <code>Invoker</code> <code>Class</code>.
    285         */
    286        void registerInvokerClass(final String targettype,
    287                final Class invokerClass) {
    288            invokerClasses.put(targettype, invokerClass);
    289        }
    290
    291        /**
    292         * Remove the {@link Invoker} class registered for this target
    293         * type (if there is one registered).
    294         *
    295         * @param targettype The target type (specified by "targettype"
    296         *                   attribute of <invoke> tag).
    297         */
    298        void unregisterInvokerClass(final String targettype) {
    299            invokerClasses.remove(targettype);
    300        }
    301
    302        /**
    303         * Get the {@link Invoker} for this {@link TransitionTarget}.
    304         * May return <code>null</code>. A non-null <code>Invoker</code> will be
    305         * returned if and only if the <code>TransitionTarget</code> is
    306         * currently active and contains an <invoke> child.
    307         *
    308         * @param targettype The type of the target being invoked.
    309         * @return An {@link Invoker} for the specified type, if an
    310         *         invoker class is registered against that type,
    311         *         <code>null</code> otherwise.
    312         * @throws InvokerException When a suitable {@link Invoker} cannot
    313         *                          be instantiated.
    314         */
    315        public Invoker newInvoker(final String targettype)
    316        throws InvokerException {
    317            Class invokerClass = (Class) invokerClasses.get(targettype);
    318            if (invokerClass == null) {
    319                throw new InvokerException("No Invoker registered for "
    320                    + "targettype \"" + targettype + "\"");
    321            }
    322            Invoker invoker = null;
    323            try {
    324                invoker = (Invoker) invokerClass.newInstance();
    325            } catch (InstantiationException ie) {
    326                throw new InvokerException(ie.getMessage(), ie.getCause());
    327            } catch (IllegalAccessException iae) {
    328                throw new InvokerException(iae.getMessage(), iae.getCause());
    329            }
    330            return invoker;
    331        }
    332
    333        /**
    334        * Get the {@link Invoker} for this {@link TransitionTarget}.
    335         * May return <code>null</code>. A non-null {@link Invoker} will be
    336         * returned if and only if the {@link TransitionTarget} is
    337         * currently active and contains an <invoke> child.
    338         *
    339         * @param transitionTarget The <code>TransitionTarget</code>.
    340         * @return The Invoker.
    341         */
    342        public Invoker getInvoker(final TransitionTarget transitionTarget) {
    343            return (Invoker) invokers.get(transitionTarget);
    344        }
    345
    346        /**
    347         * Set the {@link Invoker} for this {@link TransitionTarget}.
    348         *
    349         * @param transitionTarget The TransitionTarget.
    350         * @param invoker The Invoker.
    351         */
    352        public void setInvoker(final TransitionTarget transitionTarget,
    353                final Invoker invoker) {
    354            invokers.put(transitionTarget, invoker);
    355        }
    356
    357        /**
    358         * Return the Map of {@link Invoker}s currently "active".
    359         *
    360         * @return The map of invokers.
    361         */
    362        public Map getInvokers() {
    363            return invokers;
    364        }
    365
    366        /**
    367         * Get the completion status for this composite
    368         * {@link TransitionTarget}.
    369         *
    370         * @param transitionTarget The <code>TransitionTarget</code>.
    371         * @return The completion status.
    372         *
    373         * @since 0.7
    374         */
    375        public boolean isDone(final TransitionTarget transitionTarget) {
    376            Boolean done = (Boolean) completions.get(transitionTarget);
    377            if (done == null) {
    378                return false;
    379            } else {
    380                return done.booleanValue();
    381            }
    382        }
    383
    384        /**
    385         * Set the completion status for this composite
    386         * {@link TransitionTarget}.
    387         *
    388         * @param transitionTarget The TransitionTarget.
    389         * @param done The completion status.
    390         *
    391         * @since 0.7
    392         */
    393        public void setDone(final TransitionTarget transitionTarget,
    394                final boolean done) {
    395            completions.put(transitionTarget, done ? Boolean.TRUE : Boolean.FALSE);
    396        }
    397
    398    }
    399