ClassInvoker.java

/*****************************************************************************
 * Copyright 2011 Zdenko Vrabel
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 *****************************************************************************/
package org.zdevra.guice.mvc;

import java.util.Collection;
import java.util.Collections;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

/**
 * The class representing data structure which provide
 * and separate invocation of the class's methods. 
 */
class ClassInvoker {

    private final Class<?> controllerClass;
    private final Collection<String> sessionAttrs;
    private final Collection<MethodInvoker> methodInvokers;

    /**
     * Constructor
     * 
     * @param controllerClass
     * @param methodInvokers
     * @param sessionAttrList 
     */
    public ClassInvoker(Class<?> controllerClass, Collection<MethodInvoker> methodInvokers, List<String> sessionAttrList) {
        this.controllerClass = controllerClass;
        this.methodInvokers = Collections.unmodifiableCollection(methodInvokers);
        this.sessionAttrs = Collections.unmodifiableCollection(sessionAttrList);
    }

    /**
     * It invokes concrete methods of the controller class.
     * @param data
     */
    public ModelAndView invoke(InvokeData data) {
        ModelAndView mav = new ModelAndView();
        if (sessionAttrs.size() > 0) {
            mav.getModel().getObjectsFromSession(sessionAttrs, data.getRequest().getSession(true));
        }
        InvokeData dataWithModel = new InvokeData(mav.getModel(), data);

        int invokedcount = 0;
        for (MethodInvoker invoker : this.methodInvokers) {
            ModelAndView methodMav = invoker.invoke(dataWithModel);
            if (methodMav != null) {
                mav.mergeModelAndView(methodMav);
                invokedcount++;
            }
        }

        if (invokedcount == 0) {
            return null;
        }

        return mav;
    }

    /**
     * Method moves the data defined in {@literal @}Controller's
     * sessionAttribute from model to session. 
     * 
     * @param m
     * @param request
     */
    public void moveDataToSession(ModelMap m, HttpServletRequest request) {
        if (sessionAttrs.size() > 0) {
            m.moveObjectsToSession(sessionAttrs, request.getSession(true));
        }
    }


    /**
     * returns the controller class associated to
     * this invoker.
     */
    public Class<?> getControllerClass() {
        return controllerClass;
    }

}