    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.services;
    016
    017import org.apache.tapestry5.Block;
    018import org.apache.tapestry5.ComponentResources;
    019import org.apache.tapestry5.annotations.Id;
    020import org.apache.tapestry5.internal.transform.ReadOnlyComponentFieldConduit;
    021import org.apache.tapestry5.ioc.ObjectLocator;
    022import org.apache.tapestry5.ioc.annotations.Inject;
    023import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    024import org.apache.tapestry5.model.MutableComponentModel;
    025import org.apache.tapestry5.plastic.FieldConduit;
    026import org.apache.tapestry5.plastic.InstanceContext;
    027import org.apache.tapestry5.plastic.PlasticField;
    028import org.apache.tapestry5.services.transform.InjectionProvider2;
    029
    030/**
    031 * Identifies fields of type {@link Block} that have the {@link Inject} annotation and converts them
    032 * into read-only
    033 * fields containing the injected Block from the template. The annotation's value is the id of the
    034 * block to inject; if
    035 * omitted, the block id is deduced from the field id.
    036 * <p/>
    037 * Must be scheduled before {@link DefaultInjectionProvider} because it uses the same annotation, Inject, with a
    038 * different interpretation.
    039 */
    040public class BlockInjectionProvider implements InjectionProvider2
    041{
    042    private static final String BLOCK_TYPE_NAME = Block.class.getName();
    043
    044    public boolean provideInjection(PlasticField field, ObjectLocator locator, MutableComponentModel componentModel)
    045    {
    046        if (!field.getTypeName().equals(BLOCK_TYPE_NAME))
    047        {
    048            return false;
    049        }
    050
    051        Id annotation = field.getAnnotation(Id.class);
    052
    053        String blockId = getBlockId(field.getName(), annotation);
    054
    055        FieldConduit<Object> conduit = createConduit(field, blockId);
    056
    057        field.setConduit(conduit);
    058
    059        return true; // claim the field
    060    }
    061
    062    private FieldConduit<Object> createConduit(PlasticField field, final String blockId)
    063    {
    064        final String className = field.getPlasticClass().getClassName();
    065        final String fieldName = field.getName();
    066
    067        return new ReadOnlyComponentFieldConduit(className, fieldName)
    068        {
    069            public Object get(Object instance, InstanceContext context)
    070            {
    071                ComponentResources resources = context.get(ComponentResources.class);
    072
    073                return resources.getBlock(blockId);
    074            }
    075        };
    076    }
    077
    078    private String getBlockId(String fieldName, Id annotation)
    079    {
    080        return annotation != null ? annotation.value() : InternalUtils.stripMemberName(fieldName);
    081    }
    082}