# JSONEntityState.java

    /*
     * Copyright (c) 2009-2011, Rickard Öberg. All Rights Reserved.
     * Copyright (c) 2007-2013, Niclas Hedhman. All Rights Reserved.
     * Copyright (c) 2013-2014, Paul Merlin. All Rights Reserved.
     *
     * 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.spi.entitystore.helpers;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    import org.qi4j.api.common.QualifiedName;
    import org.qi4j.api.entity.EntityDescriptor;
    import org.qi4j.api.entity.EntityReference;
    import org.qi4j.api.property.PropertyDescriptor;
    import org.qi4j.api.type.ValueType;
    import org.qi4j.api.value.ValueSerialization;
    import org.qi4j.api.value.ValueSerializationException;
    import org.qi4j.spi.entity.EntityState;
    import org.qi4j.spi.entity.EntityStatus;
    import org.qi4j.spi.entity.ManyAssociationState;
    import org.qi4j.spi.entity.NamedAssociationState;
    import org.qi4j.spi.entitystore.EntityStoreException;

    /**
     * Standard JSON implementation of EntityState.
     */
    public final class JSONEntityState
        implements EntityState
    {
        private static final String[] EMPTY_NAMES = new String[ 0 ];
        private static final String[] CLONE_NAMES =
            {
                JSONKeys.IDENTITY,
                JSONKeys.APPLICATION_VERSION,
                JSONKeys.TYPE,
                JSONKeys.VERSION,
                JSONKeys.MODIFIED
            };

        private final ValueSerialization valueSerialization;
        private final String version;
        private final EntityReference identity;
        private final EntityDescriptor entityDescriptor;

        private EntityStatus status;
        private long lastModified;
        private JSONObject state;

        /* package */ JSONEntityState( long time,
                                       ValueSerialization valueSerialization,
                                       EntityReference identity,
                                       EntityDescriptor entityDescriptor,
                                       JSONObject initialState
        )
        {
            this( valueSerialization,
                  "",
                  time,
                  identity,
                  EntityStatus.NEW,
                  entityDescriptor,
                  initialState );
        }

        /* package */ JSONEntityState( ValueSerialization valueSerialization,
                                       String version,
                                       long lastModified,
                                       EntityReference identity,
                                       EntityStatus status,
                                       EntityDescriptor entityDescriptor,
                                       JSONObject state
        )
        {
            this.valueSerialization = valueSerialization;
            this.version = version;
            this.lastModified = lastModified;
            this.identity = identity;
            this.status = status;
            this.entityDescriptor = entityDescriptor;
            this.state = state;
        }

        // EntityState implementation
        @Override
        public final String version()
        {
            return version;
        }

        @Override
        public long lastModified()
        {
            return lastModified;
        }

        @Override
        public EntityReference identity()
        {
            return identity;
        }

        @Override
        public Object propertyValueOf( QualifiedName stateName )
        {
            try
            {
                Object json = state.getJSONObject( JSONKeys.PROPERTIES ).opt( stateName.name() );
                if( JSONObject.NULL.equals( json ) )
                {
                    return null;
                }
                else
                {
                    PropertyDescriptor descriptor = entityDescriptor.state().findPropertyModelByQualifiedName( stateName );
                    if( descriptor == null )
                    {
                        return null;
                    }
                    return valueSerialization.deserialize( descriptor.valueType(), json.toString() );
                }
            }
            catch( ValueSerializationException | JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        @Override
        public void setPropertyValue( QualifiedName stateName, Object newValue )
        {
            try
            {
                Object jsonValue;
                if( newValue == null || ValueType.isPrimitiveValue( newValue ) )
                {
                    jsonValue = newValue;
                }
                else
                {
                    String serialized = valueSerialization.serialize( newValue );
                    if( serialized.startsWith( "{" ) )
                    {
                        jsonValue = new JSONObject( serialized );
                    }
                    else if( serialized.startsWith( "[" ) )
                    {
                        jsonValue = new JSONArray( serialized );
                    }
                    else
                    {
                        jsonValue = serialized;
                    }
                }
                cloneStateIfGlobalStateLoaded();
                state.getJSONObject( JSONKeys.PROPERTIES ).put( stateName.name(), jsonValue );
                markUpdated();
            }
            catch( ValueSerializationException | JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        private JSONObject cloneJSON( JSONObject jsonObject )
            throws JSONException
        {
            String[] names = JSONObject.getNames( jsonObject );
            if( names == null )
            {
                names = EMPTY_NAMES;
            }
            return new JSONObject( jsonObject, names );
        }

        @Override
        public EntityReference associationValueOf( QualifiedName stateName )
        {
            try
            {
                Object jsonValue = state.getJSONObject( JSONKeys.ASSOCIATIONS ).opt( stateName.name() );
                if( jsonValue == null )
                {
                    return null;
                }

                EntityReference value = jsonValue == JSONObject.NULL
                                        ? null
                                        : EntityReference.parseEntityReference( (String) jsonValue );
                return value;
            }
            catch( JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        @Override
        public void setAssociationValue( QualifiedName stateName, EntityReference newEntity )
        {
            try
            {
                cloneStateIfGlobalStateLoaded();
                state.getJSONObject( JSONKeys.ASSOCIATIONS ).put( stateName.name(), newEntity == null
                                                                                    ? null
                                                                                    : newEntity.identity() );
                markUpdated();
            }
            catch( JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        @Override
        public ManyAssociationState manyAssociationValueOf( QualifiedName stateName )
        {
            try
            {
                JSONObject manyAssociations = state.getJSONObject( JSONKeys.MANY_ASSOCIATIONS );
                JSONArray jsonValues = manyAssociations.optJSONArray( stateName.name() );
                if( jsonValues == null )
                {
                    jsonValues = new JSONArray();
                    manyAssociations.put( stateName.name(), jsonValues );
                }
                return new JSONManyAssociationState( this, jsonValues );
            }
            catch( JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        @Override
        public NamedAssociationState namedAssociationValueOf( QualifiedName stateName )
        {
            try
            {
                JSONObject namedAssociations = state.getJSONObject( JSONKeys.NAMED_ASSOCIATIONS );
                JSONObject jsonValues = namedAssociations.optJSONObject( stateName.name() );
                if( jsonValues == null )
                {
                    jsonValues = new JSONObject();
                    namedAssociations.put( stateName.name(), jsonValues );
                }
                return new JSONNamedAssociationState( this, jsonValues );
            }
            catch( JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }

        @Override
        public void remove()
        {
            status = EntityStatus.REMOVED;
        }

        @Override
        public EntityStatus status()
        {
            return status;
        }

        @Override
        public boolean isAssignableTo( Class<?> type )
        {
            return entityDescriptor.isAssignableTo( type );
        }

        @Override
        public EntityDescriptor entityDescriptor()
        {
            return entityDescriptor;
        }

        public JSONObject state()
        {
            return state;
        }

        @Override
        public String toString()
        {
            return identity + "(" + state + ")";
        }

        public void markUpdated()
        {
            if( status == EntityStatus.LOADED )
            {
                status = EntityStatus.UPDATED;
            }
        }

        void cloneStateIfGlobalStateLoaded()
        {
            if( status != EntityStatus.LOADED )
            {
                return;
            }

            try
            {
                JSONObject newProperties = cloneJSON( state.getJSONObject( JSONKeys.PROPERTIES ) );
                JSONObject newAssoc = cloneJSON( state.getJSONObject( JSONKeys.ASSOCIATIONS ) );
                JSONObject newManyAssoc = cloneJSON( state.getJSONObject( JSONKeys.MANY_ASSOCIATIONS ) );
                JSONObject newNamedAssoc = cloneJSON( state.getJSONObject( JSONKeys.NAMED_ASSOCIATIONS ) );
                JSONObject stateClone = new JSONObject( state, CLONE_NAMES );
                stateClone.put( JSONKeys.PROPERTIES, newProperties );
                stateClone.put( JSONKeys.ASSOCIATIONS, newAssoc );
                stateClone.put( JSONKeys.MANY_ASSOCIATIONS, newManyAssoc );
                stateClone.put( JSONKeys.NAMED_ASSOCIATIONS, newNamedAssoc );
                state = stateClone;
            }
            catch( JSONException e )
            {
                throw new EntityStoreException( e );
            }
        }
    }