org.ripla.web.util.RiplaRequestHandler.java Source code

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Here is the source code for org.ripla.web.util.RiplaRequestHandler.java

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/*******************************************************************************
 * Copyright (c) 2013 RelationWare, Benno Luthiger
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * RelationWare, Benno Luthiger
 ******************************************************************************/
package org.ripla.web.util;

import java.io.IOException;

import org.ripla.exceptions.NoControllerFoundException;
import org.ripla.web.Constants;
import org.ripla.web.interfaces.IBodyComponent;
import org.ripla.web.interfaces.IPluggable;
import org.ripla.web.internal.services.UseCaseRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.vaadin.server.RequestHandler;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinResponse;
import com.vaadin.server.VaadinServlet;
import com.vaadin.server.VaadinServletService;
import com.vaadin.server.VaadinSession;

/**
 * Request handler to handle request parameters:
 * 
 * <pre>
 * http://my.host.org/ripla?request=parameter
 * </pre>
 * 
 * @author Luthiger
 */
@SuppressWarnings("serial")
public class RiplaRequestHandler implements RequestHandler {
    private static final Logger LOG = LoggerFactory.getLogger(RiplaRequestHandler.class);

    private static final String TMPL_REQUEST_URL = "%s?%s=%s&%s=%s"; //$NON-NLS-1$

    private IRequestParameter requestParameter;

    private final String requestURL;

    /**
     * RequestHandler constructor.
     */
    public RiplaRequestHandler() {
        requestURL = VaadinServlet.getCurrent().getServletContext().getContextPath()
                + VaadinServletService.getCurrentServletRequest().getServletPath();
    }

    @Override
    public boolean handleRequest(final VaadinSession inSession, final VaadinRequest inRequest,
            final VaadinResponse inResponse) throws IOException {
        final String lParameter = inRequest.getParameter(Constants.KEY_REQUEST_PARAMETER);
        if (lParameter != null) {
            requestParameter = createRequestParameter(lParameter);
            requestParameter.handleParameters(inSession, inRequest, inResponse);
            LOG.trace("Handling request parameter '{}'.", lParameter);
        }
        return false;
    }

    /**
     * Displays the requested view in the main view.
     * 
     * @param inBody
     *            {@link IBodyComponent}
     * @return boolean <code>true</code> if the parameter request has been
     *         processed successfully, <code>false</code> if no parameter
     *         request provided.
     */
    public boolean process(final IBodyComponent inBody) {
        if (requestParameter == null) {
            return false;
        }

        try {
            final String lControllerName = requestParameter.getControllerName();
            requestParameter = null; // NOPMD by Luthiger on 10.09.12 00:21
            inBody.setContentView(UseCaseRegistry.INSTANCE.getControllerManager().getContent(lControllerName));
            return true;
        } catch (final NoControllerFoundException exc) { // NOPMD by Luthiger
            // intentionally left empty
        }
        return false;
    }

    /**
     * Creates the URL to the view of the specified task, e.g.
     * <code>http://localhost:8084/demo?request=org.ripla.web.demo.config/org.ripla.web.demo.config.controller.SkinSelectController&key=value</code>
     * .
     * 
     * @param inTask
     *            {@link IPluggableTask} the task that is called in the request
     * @param inIsForum
     *            boolean <code>true</code> if the requested url should call the
     *            forum application, <code>false</code> for the admin
     *            application
     * @param inKey
     *            String the additional parameter's key
     * @param inValue
     *            Long the additional parameter's value
     * @return the bookmarkable URL to the view of the specified task
     */
    public String createRequestedURL(final Class<? extends IPluggable> inTask, final boolean inIsForum,
            final String inKey, final Long inValue) {
        return String.format(TMPL_REQUEST_URL, getRequestURL(), Constants.KEY_REQUEST_PARAMETER,
                UseCaseHelper.createFullyQualifiedControllerName(inTask), inKey, inValue.toString());
    }

    /**
     * @return String e.g. <code>http://localhost:8084/demo</code>
     */
    public String getRequestURL() {
        return requestURL;
    }

    /**
     * Factory method, subclasses may override.
     * <p>
     * This implementation returns an instance of {@link DftRequestParameter}.
     * </p>
     * 
     * @param inControllerName
     *            String we assume as parameter the name of the controller to
     *            display the view in the main window.
     * 
     * @return {@link IRequestParameter}
     */
    protected IRequestParameter createRequestParameter(final String inControllerName) {
        return new DftRequestParameter(inControllerName);
    }

    // ---

    /**
     * Interface for classes wrapping the servlet's request parameter.
     * 
     * @author Luthiger
     */
    public interface IRequestParameter {
        /**
         * Do something with the parameters passed in the servlet request, e.g.
         * store them locally.
         * 
         * @param inSession
         *            {@link VaadinSession}
         * @param inRequest
         *            {@link VaadinRequest}
         * @param inResponse
         *            {@link VaadinResponse}
         */
        void handleParameters(final VaadinSession inSession, final VaadinRequest inRequest,
                final VaadinResponse inResponse);

        /**
         * Returns the name of the controller the request is calling.
         * 
         * @return String controller name
         */
        String getControllerName();
    }

    protected static class DftRequestParameter implements IRequestParameter {
        private final String controllerName;

        public DftRequestParameter(final String inControllerName) {
            controllerName = inControllerName;
        }

        @Override
        public void handleParameters(final VaadinSession inSession, final VaadinRequest inRequest,
                final VaadinResponse inResponse) {
            // do nothing
        }

        @Override
        public String getControllerName() {
            return controllerName;
        }
    }

}