# SimpleAlarmModelService.java

    /*
     * Copyright 1996-2011 Niclas Hedhman.
     *
     * 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.qi4j.library.alarm;

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Date;
    import java.util.List;
    import java.util.Locale;
    import java.util.ResourceBundle;
    import org.qi4j.api.entity.Identity;
    import org.qi4j.api.injection.scope.Structure;
    import org.qi4j.api.mixin.Mixins;
    import org.qi4j.api.service.ServiceComposite;
    import org.qi4j.api.value.ValueBuilder;
    import org.qi4j.api.value.ValueBuilderFactory;

    @Mixins( SimpleAlarmModelService.SimpleAlarmModelMixin.class)
    public interface SimpleAlarmModelService extends AlarmModel, ServiceComposite
    {
        /**
         * The Simple AlarmPoint Model is centered around the Normal and Activated.
         * The triggers "activate" and "deactivate". The following matrix details the
         * resulting grid.
         * <table summary="Transitions">
         * <tr><th>Initial State</th><th>Trigger</th><th>Resulting State</th><th>Event Generated</th></tr>
         * <tr><td>Normal</td><td>activate</td><td>Activated</td><td>activation</td></tr>
         * <tr><td>Normal</td><td>deactivate</td><td>Normal</td><td>-</td></tr>
         * <tr><td>Activated</td><td>activate</td><td>Activated</td><td>-</td></tr>
         * <tr><td>Activated</td><td>deactivate</td><td>Deactivated</td><td>deactivation</td></tr>
         * </table>
         */
        class SimpleAlarmModelMixin
            implements AlarmModel
        {
            private static final List<String> ALARM_TRIGGERS;
            private static final List<String> ALARM_STATUSES;

            static
            {
                List<String> list1 = new ArrayList<String>();

                list1.add( AlarmPoint.TRIGGER_ACTIVATE );
                list1.add( AlarmPoint.TRIGGER_DEACTIVATE );
                ALARM_TRIGGERS = Collections.unmodifiableList( list1 );

                List<String> list2 = new ArrayList<String>();
                list2.add( AlarmPoint.STATUS_NORMAL );
                list2.add( AlarmPoint.STATUS_ACTIVATED );
                ALARM_STATUSES = Collections.unmodifiableList( list2 );
            }

            @Structure
            private ValueBuilderFactory vbf;

            static ResourceBundle getResourceBundle( Locale locale )
            {
                if( locale == null )
                {
                    locale = Locale.getDefault();
                }
                ClassLoader cl = SimpleAlarmModelMixin.class.getClassLoader();
                return ResourceBundle.getBundle( MODEL_BUNDLE_NAME, locale, cl );
            }

            /**
             * Returns the Name of the AlarmModel.
             * This normally returns the human readable technical name of
             * the AlarmModel.
             *
             * @return The system name of this AlarmPoint Model.
             */
            @Override
            public String modelName()
            {
                return "org.qi4j.library.alarm.model.simple";
            }

            /**
             * Returns a Description of the AlarmModel in the default Locale.
             * This normally returns a full Description of the AlarmModel in the
             * default Locale.
             *
             * @return the description of the ModelProvider.
             */
            @Override
            public String modelDescription()
            {
                return modelDescription( null );
            }

            /**
             * Returns a Description of the AlarmModel.
             * This normally returns a full Description of the AlarmModel in the
             * Locale. If Locale is <code><b>null</b></code>, then the
             * default Locale is used.
             *
             * @param locale The locale for which the description is wanted.
             *
             * @return the description of th
             */
            @Override
            public String modelDescription( Locale locale )
            {
                ResourceBundle rb = getResourceBundle( locale );
                return rb.getString( "MODEL_DESCRIPTION_SIMPLE" );
            }

            @Override
            public List<String> statusList()
            {
                return ALARM_STATUSES;
            }

            /**
             * Execute the required changes upon an AlarmTrigger.
             * The AlarmSystem calls this method, for the AlarmStatus
             * in the the AlarmPoint to be updated, as well as an AlarmEvent
             * to be created.
             *
             * @param trigger the AlarmTrigger that was used.
             */
            @Override
            public AlarmEvent evaluate( AlarmPoint alarm, String trigger )
            {
                if( trigger.equals( AlarmPoint.TRIGGER_ACTIVATE ) )
                {
                    return activation( alarm );
                }
                else if( trigger.equals( AlarmPoint.TRIGGER_DEACTIVATE ) )
                {
                    return deactivation( alarm );
                }
                else
                {
                    throw new IllegalArgumentException( "'" + trigger + "' is not supported by this AlarmModel." );
                }
            }

            /**
             * Returns all the supported AlarmPoint triggers.
             */
            @Override
            public List<String> alarmTriggers()
            {
                return ALARM_TRIGGERS;
            }

            @Override
            public String computeTrigger( AlarmStatus status, boolean condition )
            {
                if( condition )
                {
                    if( AlarmPoint.STATUS_NORMAL.equals( status.name(null) ) )
                    {
                        return AlarmPoint.TRIGGER_ACTIVATE;
                    }
                }
                else
                {
                    if( AlarmPoint.STATUS_ACTIVATED.equals( status.name(null) ) )
                    {
                        return AlarmPoint.TRIGGER_DEACTIVATE;
                    }
                }
                return null;
            }

            @Override
            public boolean computeCondition( AlarmStatus status )
            {
                return status.name(null).equals( AlarmPoint.STATUS_ACTIVATED );
            }

            /**
             * StateMachine change for activate trigger.
             *
             * @param alarm the AlarmPoint that the activation is done on.
             *
             * @return the resulting AlarmEvent of the activation, or null if no change.
             */
            private AlarmEvent activation( AlarmPoint alarm )
            {
                AlarmStatus oldStatus = alarm.currentStatus();
                if( oldStatus.name(null).equals( AlarmPoint.STATUS_NORMAL ) )
                {
                    AlarmStatus newStatus = createStatus( AlarmPoint.STATUS_ACTIVATED );
                    return createEvent( (Identity) alarm, oldStatus, newStatus, AlarmPoint.EVENT_ACTIVATION );
                }
                return null;
            }

            /**
             * StateMachine change for activate trigger.
             *
             * @param alarm the alarm that is causing the activation.
             *
             * @return the resulting AlarmEvent of the activation.
             */
            private AlarmEvent deactivation( AlarmPoint alarm )
            {
                AlarmStatus oldStatus = alarm.currentStatus();
                if( oldStatus.name(null).equals( AlarmPoint.STATUS_ACTIVATED ) )
                {
                    AlarmStatus newStatus = createStatus( AlarmPoint.STATUS_NORMAL );
                    return createEvent( (Identity) alarm, oldStatus, newStatus, AlarmPoint.EVENT_DEACTIVATION );
                }
                return null;
            }

            private AlarmStatus createStatus( String status )
            {
                ValueBuilder<AlarmStatus> builder = vbf.newValueBuilder( AlarmStatus.class );
                AlarmStatus.State prototype = builder.prototypeFor(AlarmStatus.State.class);
                prototype.name().set( status );
                prototype.creationDate().set( new Date() );
                return builder.newInstance();
            }

            private AlarmEvent createEvent( Identity alarmId,
                                            AlarmStatus oldStatus,
                                            AlarmStatus newStatus, String eventSystemName
            )
            {
                ValueBuilder<AlarmEvent> builder = vbf.newValueBuilder( AlarmEvent.class );
                AlarmEvent prototype = builder.prototype();
                prototype.alarmIdentity().set( alarmId.identity().get() );
                prototype.eventTime().set( new Date() );
                prototype.newStatus().set( newStatus );
                prototype.oldStatus().set( oldStatus );
                prototype.systemName().set( eventSystemName );
                return builder.newInstance();
            }
        }
    }