facescontroller.java

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/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * 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 de.mindmatters.faces.spring.context.servlet;

import java.util.Map;

import javax.faces.FactoryFinder;
import javax.faces.context.FacesContext;
import javax.faces.lifecycle.Lifecycle;
import javax.faces.lifecycle.LifecycleFactory;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.mvc.AbstractController;

/**
 * <strong>FacesController</strong> is a Controller that manages the request
 * processing lifecycle for web applications that are utilizing JavaServer Faces
 * to construct the user interface.
 * 
 * <p>
 * This Controller is an appropriate alternative for the <strong>FacesServlet</strong>.
 * </p>
 * 
 * <p>
 * <h4>Exposed configuration properties:</h4>
 * <table class="javaDoc">
 * <tr>
 * <th>name</th>
 * <th>default</th>
 * <th>description</th>
 * </tr>
 * <tr>
 * <td>lifecycleId</td>
 * <td>{@link LifecycleFactory#DEFAULT_LIFECYCLE}</td>
 * <td>the identifier of the {@link Lifecycle} this Controller is delegating
 * the request processing</td>
 * </tr>
 * </table>
 * 
 * @author Andreas Kuhrwahl
 * 
 * @see javax.faces.webapp.FacesServlet
 * 
 */
public class FacesController extends AbstractController implements
        InitializingBean {

    /**
     * {@link View} implementation. Delegates to
     * {@link Lifecycle#render(FacesContext)} of the proper lifecycle the
     * nesting Controller runs in.
     * 
     * @author Andreas Kuhrwahl
     * 
     */
    private class DefaultFacesView implements View {

        /**
         * {@inheritDoc}
         */
        public String getContentType() {
            return null;
        }

        /**
         * {@inheritDoc}
         */
        public void render(final Map model, final HttpServletRequest request,
                final HttpServletResponse response) throws Exception {
            FacesController.this.lifecycle.render(FacesContext
                    .getCurrentInstance());
        }

    }

    /** The JSF lifecycle for execution and rendering. */
    private Lifecycle lifecycle;

    /** The id for the currently used lifecycle. */
    private String lifecycleId = LifecycleFactory.DEFAULT_LIFECYCLE;

    /**
     * Initializes the faces lifecycle this controller runs in.
     * 
     * @throws Exception
     *             in cases of errors
     */
    public final void afterPropertiesSet() throws Exception {
        LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder
                .getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        this.lifecycle = lifecycleFactory.getLifecycle(this.lifecycleId);
        initFacesController();
    }

    /**
     * This method allows the bean instance to perform initialization only
     * possible when all bean properties have been set and to throw an exception
     * in the event of misconfiguration.
     * 
     * @throws Exception
     *             in the event of misconfiguration (such as failure to set an
     *             essential property) or if initialization fails.
     */
    protected void initFacesController() throws Exception {
    }

    /**
     * Sets the lifecycle id for identifying the proper lifecycle this
     * controller will run in. If not set the
     * {@link LifecycleFactory#DEFAULT_LIFECYCLE} will be used.
     * 
     * @param lifecycleId
     *            the lifecycle id for identifying the proper lifecycle
     */
    public final void setLifecycleId(final String lifecycleId) {
        Assert.notNull(lifecycleId);
        this.lifecycleId = lifecycleId;
    }

    /**
     * Executes the faces lifecycle.
     * 
     * @param request
     *            current HTTP request
     * @param response
     *            current HTTP response
     * @return a ModelAndView to render
     * @throws Exception
     *             in case of errors
     */
    protected final ModelAndView handleRequestInternal(
            final HttpServletRequest request, final HttpServletResponse response)
            throws Exception {
        FacesContext context = FacesContext.getCurrentInstance();
        Assert.notNull(context);
        this.lifecycle.execute(context);
        return new ModelAndView(new DefaultFacesView());
    }

}