injectpagelinkannotationworker.java

tapestry4.0应用,特别适用于初学者

package com.cucu.tapestry.annotation;

import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.hivemind.Location;
import org.apache.hivemind.service.BodyBuilder;
import org.apache.hivemind.service.MethodSignature;
import org.apache.tapestry.annotations.AnnotationUtils;
import org.apache.tapestry.annotations.MethodAnnotationEnhancementWorker;
import org.apache.tapestry.engine.ILink;
import org.apache.tapestry.enhance.EnhancementOperation;
import org.apache.tapestry.spec.IComponentSpecification;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

/**
 * @author Chris
 * @version $Id$
 */
public class InjectPageLinkAnnotationWorker implements MethodAnnotationEnhancementWorker {
    public void performEnhancement(EnhancementOperation op, IComponentSpecification spec, Method method, Location location) {
        if (!method.getReturnType().equals(ILink.class))
            throw new ApplicationRuntimeException("InjectPage annotation must return ILink");
        InjectPageLink injectPageLink = method.getAnnotation(InjectPageLink.class);
        String pageName = injectPageLink.value();
        BodyBuilder builder = new BodyBuilder();
        builder.begin();
        builder.addln("return getPage().getRequestCycle().getInfrastructure().getServiceMap().getService(org.apache.tapestry.Tapestry.PAGE_SERVICE).getLink(false,\"{0}\");", pageName);
        builder.end();
        op.addMethod(Modifier.PUBLIC, new MethodSignature(method), builder.toString(), location);
        if (isGetter(method)) op.claimReadonlyProperty(AnnotationUtils.getPropertyName(method));
    }

    boolean isGetter(Method method) {
        return method.getName().startsWith("get") && method.getParameterTypes().length == 0;
    }
}