    001// Licensed under the Apache License, Version 2.0 (the "License");
    002// you may not use this file except in compliance with the License.
    003// You may obtain a copy of the License at
    004//
    005// http://www.apache.org/licenses/LICENSE-2.0
    006//
    007// Unless required by applicable law or agreed to in writing, software
    008// distributed under the License is distributed on an "AS IS" BASIS,
    009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    010// See the License for the specific language governing permissions and
    011// limitations under the License.
    012
    013package org.apache.tapestry5.internal.services;
    014
    015import org.apache.tapestry5.Block;
    016import org.apache.tapestry5.ComponentResources;
    017import org.apache.tapestry5.annotations.Id;
    018import org.apache.tapestry5.internal.transform.ReadOnlyComponentFieldConduit;
    019import org.apache.tapestry5.ioc.ObjectLocator;
    020import org.apache.tapestry5.ioc.annotations.Inject;
    021import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    022import org.apache.tapestry5.model.MutableComponentModel;
    023import org.apache.tapestry5.plastic.FieldConduit;
    024import org.apache.tapestry5.plastic.InstanceContext;
    025import org.apache.tapestry5.plastic.PlasticField;
    026import org.apache.tapestry5.services.transform.InjectionProvider2;
    027
    028/**
    029 * Identifies fields of type {@link Block} that have the {@link Inject} annotation and converts them
    030 * into read-only
    031 * fields containing the injected Block from the template. The annotation's value is the id of the
    032 * block to inject; if
    033 * omitted, the block id is deduced from the field id.
    034 *
    035 * Must be scheduled before {@link DefaultInjectionProvider} because it uses the same annotation, Inject, with a
    036 * different interpretation.
    037 */
    038public class BlockInjectionProvider implements InjectionProvider2
    039{
    040    private static final String BLOCK_TYPE_NAME = Block.class.getName();
    041
    042    public boolean provideInjection(PlasticField field, ObjectLocator locator, MutableComponentModel componentModel)
    043    {
    044        if (!field.getTypeName().equals(BLOCK_TYPE_NAME))
    045        {
    046            return false;
    047        }
    048
    049        Id annotation = field.getAnnotation(Id.class);
    050
    051        String blockId = getBlockId(field.getName(), annotation);
    052
    053        FieldConduit<Object> conduit = createConduit(field, blockId);
    054
    055        field.setConduit(conduit);
    056
    057        return true; // claim the field
    058    }
    059
    060    private FieldConduit<Object> createConduit(PlasticField field, final String blockId)
    061    {
    062        final String className = field.getPlasticClass().getClassName();
    063        final String fieldName = field.getName();
    064
    065        return new ReadOnlyComponentFieldConduit(className, fieldName)
    066        {
    067            public Object get(Object instance, InstanceContext context)
    068            {
    069                ComponentResources resources = context.get(ComponentResources.class);
    070
    071                return resources.getBlock(blockId);
    072            }
    073        };
    074    }
    075
    076    private String getBlockId(String fieldName, Id annotation)
    077    {
    078        return annotation != null ? annotation.value() : InternalUtils.stripMemberName(fieldName);
    079    }
    080}