edu.cornell.mannlib.vitro.webapp.controller.ajax.VitroAjaxController.java Source code

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Here is the source code for edu.cornell.mannlib.vitro.webapp.controller.ajax.VitroAjaxController.java

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/* $This file is distributed under the terms of the license in /doc/license.txt$ */

package edu.cornell.mannlib.vitro.webapp.controller.ajax;

import static edu.cornell.mannlib.vitro.webapp.auth.requestedAction.AuthorizationRequest.AUTHORIZED;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import edu.cornell.mannlib.vitro.webapp.auth.policy.PolicyHelper;
import edu.cornell.mannlib.vitro.webapp.auth.requestedAction.AuthorizationRequest;
import edu.cornell.mannlib.vitro.webapp.controller.VitroRequest;
import edu.cornell.mannlib.vitro.webapp.freemarker.config.FreemarkerConfiguration;
import freemarker.template.Configuration;
import freemarker.template.Template;

/**
 * A base class for servlets that handle AJAX requests.
 */
public abstract class VitroAjaxController extends HttpServlet {

    private static final Log log = LogFactory.getLog(VitroAjaxController.class);

    /**
     * Sub-classes must implement this method to handle both GET and POST
     * requests.
     */
    protected abstract void doRequest(VitroRequest vreq, HttpServletResponse resp)
            throws ServletException, IOException;

    /**
     * Sub-classes should not override this. Instead, implement doRequest().
     */
    @Override
    protected final void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        VitroRequest vreq = new VitroRequest(req);
        if (PolicyHelper.isAuthorizedForActions(vreq, requiredActions(vreq))) {
            doRequest(vreq, resp);
        } else {
            resp.sendError(HttpServletResponse.SC_FORBIDDEN, "Not authorized");
        }
    }

    /**
     * Sub-classes should not override this. Instead, implement doRequest().
     */
    @Override
    protected final void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        doGet(req, resp);
    }

    /**
     * By default, a controller requires authorization for no actions.
     * Subclasses that require authorization to process their page will override 
    *    to return the actions that require authorization.
    * In some cases, the choice of actions will depend on the contents of the request.
     */
    @SuppressWarnings("unused")
    protected AuthorizationRequest requiredActions(VitroRequest vreq) {
        return AUTHORIZED;
    }

    /**
     * Process data through a Freemarker template and output the result.
     */
    protected void writeTemplate(String templateName, Map<String, Object> map, HttpServletRequest req,
            HttpServletResponse response) {
        Configuration config = FreemarkerConfiguration.getConfig(req);
        try {
            Template template = config.getTemplate(templateName);
            PrintWriter out = response.getWriter();
            template.process(map, out);
        } catch (Exception e) {
            log.error(e, e);
        }
    }

    protected void doError(HttpServletResponse response, String errorMsg, int httpstatus) {
        response.setStatus(httpstatus);
        try {
            response.getWriter().write(errorMsg);
        } catch (IOException e) {
            log.debug("IO exception during output", e);
        }
    }
}