001// Copyright 2007, 2008, 2010, 2011 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.internal.transform;
016
017import org.apache.tapestry5.annotations.SessionState;
018import org.apache.tapestry5.func.F;
019import org.apache.tapestry5.func.Predicate;
020import org.apache.tapestry5.internal.services.ComponentClassCache;
021import org.apache.tapestry5.model.MutableComponentModel;
022import org.apache.tapestry5.plastic.FieldConduit;
023import org.apache.tapestry5.plastic.InstanceContext;
024import org.apache.tapestry5.plastic.PlasticClass;
025import org.apache.tapestry5.plastic.PlasticField;
026import org.apache.tapestry5.services.ApplicationStateManager;
027import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2;
028import org.apache.tapestry5.services.transform.TransformationSupport;
029
030import java.util.List;
031
032/**
033 * Looks for the {@link org.apache.tapestry5.annotations.SessionState} annotations and
034 * converts read and write access on such fields into calls to the {@link ApplicationStateManager}.
035 */
036public class ApplicationStateWorker implements ComponentClassTransformWorker2
037{
038    private final ApplicationStateManager applicationStateManager;
039
040    private final ComponentClassCache componentClassCache;
041
042    public ApplicationStateWorker(ApplicationStateManager applicationStateManager,
043            ComponentClassCache componentClassCache)
044    {
045        this.applicationStateManager = applicationStateManager;
046        this.componentClassCache = componentClassCache;
047    }
048
049    public void transform(PlasticClass plasticClass, TransformationSupport support, MutableComponentModel model)
050    {
051        for (PlasticField field : plasticClass.getFieldsWithAnnotation(SessionState.class))
052        {
053            SessionState annotation = field.getAnnotation(SessionState.class);
054
055            transform(plasticClass, field, annotation.create());
056
057            field.claim(annotation);
058        }
059    }
060
061    @SuppressWarnings("unchecked")
062    private void transform(PlasticClass transformation, PlasticField field, final boolean create)
063    {
064        final Class fieldClass = componentClassCache.forName(field.getTypeName());
065
066        field.setConduit(new FieldConduit()
067        {
068            public void set(Object instance, InstanceContext context, Object newValue)
069            {
070                applicationStateManager.set(fieldClass, newValue);
071            }
072
073            public Object get(Object instance, InstanceContext context)
074            {
075                return create ? applicationStateManager.get(fieldClass) : applicationStateManager
076                        .getIfExists(fieldClass);
077            }
078        });
079
080        final String expectedName = field.getName() + "Exists";
081
082        List<PlasticField> fields = F.flow(transformation.getAllFields()).filter(new Predicate<PlasticField>()
083        {
084            public boolean accept(PlasticField field)
085            {
086                return field.getTypeName().equals("boolean") && field.getName().equalsIgnoreCase(expectedName);
087            }
088        }).toList();
089
090        for (PlasticField existsField : fields)
091        {
092            existsField.claim(this);
093
094            final String className = transformation.getClassName();
095
096            final String fieldName = existsField.getName();
097
098            existsField.setConduit(new ReadOnlyComponentFieldConduit(className, fieldName)
099            {
100                public Object get(Object instance, InstanceContext context)
101                {
102                    return applicationStateManager.exists(fieldClass);
103                }
104            });
105        }
106    }
107}