Struts example source code file (RolesInterceptor.java)

This example Struts source code file (RolesInterceptor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

abstractinterceptor, arraylist, arraylist, exception, exception, http, httpservletrequest, httpservletresponse, list, list, object, request, response, rolesinterceptor, servlet, string, string, util

The Struts RolesInterceptor.java source code

/*
 * $Id: RolesInterceptor.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.struts2.interceptor;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

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

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;

import org.apache.struts2.ServletActionContext;

/**
 * <!-- START SNIPPET: description --> This interceptor ensures that the action
 * will only be executed if the user has the correct role. <!--
 * END SNIPPET: description -->
 *
 * <p/> Interceptor parameters:
 *
 * <!-- START SNIPPET: parameters -->
 *
 * <ul>
 *
 * <li>allowedRoles - a comma-separated list of roles to allow
 *
 * <li>disallowedRoles - a comma-separated list of roles to disallow
 *
 * </ul>
 *
 * <!-- END SNIPPET: parameters -->
 *
 * <!-- START SNIPPET: extending --> There are two extensions to the
 * existing interceptor:
 * <ul>
 *   <li>isAllowed(HttpServletRequest,Object) - whether or not to allow
 *       the passed action execution with this request</li>
 *   <li>handleRejection(ActionInvocation) - handles an unauthorized
 *       request.</li>
 * </ul>
 * <!-- END SNIPPET: extending -->
 *
 * <pre>
 *  <!-- START SNIPPET: example -->
 *  <!-- only allows the admin and member roles -->
 *  <action name="someAction" class="com.examples.SomeAction">
 *      <interceptor-ref name="completeStack"/>
 *      <interceptor-ref name="roles">
 *        <param name="allowedRoles">admin,member</param>
 *      </interceptor-ref>
 *      <result name="success">good_result.ftl</result>
 *  </action>
 *  <!-- END SNIPPET: example -->
 * </pre>
 */
public class RolesInterceptor extends AbstractInterceptor {

    private List<String> allowedRoles = new ArrayList();
    private List<String> disallowedRoles = new ArrayList();

    public void setAllowedRoles(String roles) {
        this.allowedRoles = stringToList(roles);
    }

    public void setDisallowedRoles(String roles) {
        this.disallowedRoles = stringToList(roles);
    }

    public String intercept(ActionInvocation invocation) throws Exception {
        HttpServletRequest request = ServletActionContext.getRequest();
        HttpServletResponse response = ServletActionContext.getResponse();
        String result = null;
        if (!isAllowed(request, invocation.getAction())) {
            result = handleRejection(invocation, response);
        } else {
            result = invocation.invoke();
        }
        return result;
    }

    /**
     * Splits a string into a List
     */
    protected List<String> stringToList(String val) {
        if (val != null) {
            String[] list = val.split("[ ]*,[ ]*");
            return Arrays.asList(list);
        } else {
            return Collections.EMPTY_LIST;
        }
    }

    /**
     * Determines if the request should be allowed for the action
     *
     * @param request The request
     * @param action The action object
     * @return True if allowed, false otherwise
     */
    protected boolean isAllowed(HttpServletRequest request, Object action) {
        if (allowedRoles.size() > 0) {
            boolean result = false;
            for (String role : allowedRoles) {
                if (request.isUserInRole(role)) {
                    result = true;
                }
            }
            return result;
        } else if (disallowedRoles.size() > 0) {
            for (String role : disallowedRoles) {
                if (request.isUserInRole(role)) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Handles a rejection by sending a 403 HTTP error
     *
     * @param invocation The invocation
     * @return The result code
     * @throws Exception
     */
    protected String handleRejection(ActionInvocation invocation,
            HttpServletResponse response)
            throws Exception {
        response.sendError(HttpServletResponse.SC_FORBIDDEN);
        return null;
    }
}