    001    // Copyright 2006, 2007, 2008, 2009, 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
    015    package org.apache.tapestry5.ioc.internal;
    016
    017    import org.apache.tapestry5.ioc.ObjectCreator;
    018    import org.apache.tapestry5.ioc.ServiceBuilderResources;
    019    import org.apache.tapestry5.ioc.internal.util.InternalUtils;
    020
    021    import java.lang.reflect.Method;
    022
    023    /**
    024     * Basic implementation of {@link org.apache.tapestry5.ioc.ObjectCreator} that handles invoking a method on the module
    025     * builder, and figures out the correct parameters to pass into the annotated method.
    026     */
    027    public class ServiceBuilderMethodInvoker extends AbstractServiceCreator
    028    {
    029        private final Method builderMethod;
    030
    031        public ServiceBuilderMethodInvoker(ServiceBuilderResources resources, String creatorDescription, Method method)
    032        {
    033            super(resources, creatorDescription);
    034
    035            builderMethod = method;
    036        }
    037
    038        private ObjectCreator<Object> plan;
    039
    040        private ObjectCreator<Object> getPlan()
    041        {
    042            if (plan == null)
    043            {
    044                // Defer getting (and possibly instantiating) the module instance until the last possible
    045                // moment. If the method is static, there's no need to even get the builder.
    046
    047                final Object moduleInstance = InternalUtils.isStatic(builderMethod) ? null : resources.getModuleBuilder();
    048
    049                plan = InternalUtils.createMethodInvocationPlan(resources.getTracker(), resources, createInjectionResources(), logger, "Constructing service implementation via " + creatorDescription, moduleInstance, builderMethod);
    050            }
    051
    052            return plan;
    053        }
    054
    055        /**
    056         * Invoked from the proxy to create the actual service implementation.
    057         */
    058        public Object createObject()
    059        {
    060            Object result = getPlan().createObject();
    061
    062            if (result == null)
    063            {
    064                throw new RuntimeException(String.format("Builder method %s (for service '%s') returned null.", creatorDescription, serviceId));
    065            }
    066
    067            return result;
    068        }
    069
    070        @Override
    071        public String toString()
    072        {
    073            return creatorDescription;
    074        }
    075    }