001// Copyright 2005 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.tapestry.enhance;
016
017import java.util.Iterator;
018
019import org.apache.hivemind.ErrorLog;
020import org.apache.hivemind.Location;
021import org.apache.hivemind.service.BodyBuilder;
022import org.apache.hivemind.service.ClassFabUtils;
023import org.apache.hivemind.util.Defense;
024import org.apache.tapestry.IComponent;
025import org.apache.tapestry.TapestryUtils;
026import org.apache.tapestry.spec.IComponentSpecification;
027import org.apache.tapestry.spec.IContainedComponent;
028
029/**
030 * Injects components for which the property attribute of the <component> element was
031 * specified. This makes it easier to reference a particular component from Java code.
032 * 
033 * @author Howard M. Lewis Ship
034 * @since 4.0
035 */
036public class InjectComponentWorker implements EnhancementWorker
037{
038    private ErrorLog _errorLog;
039
040    public void performEnhancement(EnhancementOperation op, IComponentSpecification spec)
041    {
042        Iterator i = spec.getComponentIds().iterator();
043
044        while (i.hasNext())
045        {
046            String id = (String) i.next();
047
048            IContainedComponent cc = spec.getComponent(id);
049
050            String propertyName = cc.getPropertyName();
051
052            if (propertyName != null)
053            {
054                try
055                {
056                    injectComponent(op, id, propertyName, cc.getLocation());
057                }
058                catch (Exception ex)
059                {
060                    _errorLog.error(EnhanceMessages.errorAddingProperty(propertyName, op
061                            .getBaseClass(), ex), cc.getLocation(), ex);
062                }
063            }
064        }
065    }
066
067    public void injectComponent(EnhancementOperation op, String componentId, String propertyName,
068            Location location)
069    {
070        Defense.notNull(op, "op");
071        Defense.notNull(componentId, "componentId");
072        Defense.notNull(propertyName, "propertyName");
073
074        Class propertyType = EnhanceUtils.extractPropertyType(op, propertyName, null);
075
076        op.claimReadonlyProperty(propertyName);
077
078        String fieldName = "_$" + propertyName;
079        String classField = op.getClassReference(propertyType);
080        String locationField = op.addInjectedField(
081                fieldName + "$location",
082                Location.class,
083                location);
084
085        op.addField(fieldName, propertyType);
086
087        EnhanceUtils.createSimpleAccessor(op, fieldName, propertyName, propertyType, location);
088
089        // I.e. _$fred = (IComponent) TapestryUtils.getComponent(this, "fred", IComponent.class,
090        // location)
091
092        BodyBuilder builder = new BodyBuilder();
093
094        builder.add("{0} = ({1}) ", fieldName, ClassFabUtils.getJavaClassName(propertyType));
095        builder.add("{0}#getComponent(this, ", TapestryUtils.class.getName());
096        builder.addQuoted(componentId);
097        builder.add(", {0}, {1});", classField, locationField);
098
099        op.extendMethodImplementation(IComponent.class, EnhanceUtils.FINISH_LOAD_SIGNATURE, builder
100                .toString());
101    }
102
103    public void setErrorLog(ErrorLog errorLog)
104    {
105        _errorLog = errorLog;
106    }
107}