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.lang.reflect.Modifier;
018
019import org.apache.hivemind.ApplicationRuntimeException;
020import org.apache.hivemind.Location;
021import org.apache.hivemind.service.BodyBuilder;
022import org.apache.hivemind.service.MethodSignature;
023import org.apache.tapestry.IPage;
024import org.apache.tapestry.spec.InjectSpecification;
025
026/**
027 * Injects code to access a named page within the application.
028 * 
029 * @author Howard Lewis Ship
030 * @since 4.0
031 */
032public class InjectPageWorker implements InjectEnhancementWorker
033{
034    public void performEnhancement(EnhancementOperation op, InjectSpecification spec)
035    {
036        performEnhancement(op, spec.getObject(), spec.getProperty(), spec.getLocation());
037    }
038
039    public void performEnhancement(EnhancementOperation op, String pageName, String propertyName,
040            Location location)
041    {
042        Class propertyType = op.getPropertyType(propertyName);
043
044        if (propertyType == null)
045            propertyType = Object.class;
046        else if (propertyType.isPrimitive())
047            throw new ApplicationRuntimeException(EnhanceMessages.wrongTypeForPageInjection(
048                    propertyName,
049                    propertyType), null, location, null);
050
051        op.claimReadonlyProperty(propertyName);
052
053        MethodSignature sig = new MethodSignature(propertyType, op
054                .getAccessorMethodName(propertyName), null, null);
055
056        BodyBuilder builder = new BodyBuilder();
057
058        builder.add("return ");
059
060        // If the property type is not IPage or a superclass of IPage then a cast
061        // is needed.
062
063        if (!propertyType.isAssignableFrom(IPage.class))
064            builder.add("({0})", propertyType.getName());
065
066        builder.add("getPage().getRequestCycle().getPage(\"{0}\");", pageName);
067
068        op.addMethod(Modifier.PUBLIC, sig, builder.toString(), location);
069    }
070}