    001package org.apache.turbine.modules.screens;
    002
    003/*
    004 * Licensed to the Apache Software Foundation (ASF) under one
    005 * or more contributor license agreements.  See the NOTICE file
    006 * distributed with this work for additional information
    007 * regarding copyright ownership.  The ASF licenses this file
    008 * to you under the Apache License, Version 2.0 (the
    009 * "License"); you may not use this file except in compliance
    010 * with the License.  You may obtain a copy of the License at
    011 *
    012 *   http://www.apache.org/licenses/LICENSE-2.0
    013 *
    014 * Unless required by applicable law or agreed to in writing,
    015 * software distributed under the License is distributed on an
    016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    017 * KIND, either express or implied.  See the License for the
    018 * specific language governing permissions and limitations
    019 * under the License.
    020 */
    021
    022import org.apache.turbine.pipeline.PipelineData;
    023
    024/**
    025 * An extension to JSONScreen that performs a Security Check before invoking
    026 * doBuildTemplate().  You should extend this class and add the specific
    027 * security check needed.  If you have a number of screens that need to perform
    028 * the same check, you could make a base screen by extending this class and
    029 * implementing the isAuthorized().  Then each screen that needs to perform the
    030 * same check could extend your base screen.
    031 *
    032 * <p>Typically you would extend this class and override the doOutput() method
    033 * to use TurbineJsonRpc to register the POJOs that will provide the functions
    034 * you are making available via JSON-RPC.  Use JSONScreen if you <p>do not</b>
    035 * need the user to be logged in prior to executing the functions you provide.
    036 *
    037 * <p>Here is an example from a superclass:
    038 * <code>
    039 * public void doOutput(PipelineData data) throws Exception
    040 * {
    041 *     User user = data.getUser();
    042 *
    043 *     MySecureJsonFunctions myFunctions
    044 *             = new MySecureJsonFunctions(user.getName());
    045 *
    046 *     // Session specific
    047 *     TurbineJsonRpc.registerObject(data.getSession(), "myFunctions", myFunctions);
    048 *
    049 *     // Global
    050 *     //TurbineJsonRpc.registerObjectGlobal("testGlobal", testObject);
    051 *
    052 *     super.doOutput(data);
    053 * }
    054 * </code>
    055 *
    056 * <p>The class MyFunctions would be something like:
    057 * <code>
    058 * public class MySecureJsonFunctions
    059 * {
    060 *     private final String name;
    061 *
    062 *     public MySecureJsonFunctions(String name)
    063 *     {
    064 *         this.name = name;
    065 *     }
    066 *
    067 *     private String getName(String clientParameter)
    068 *     {
    069 *         return "Client " + clientParameter + " says Hello World to " + name;
    070 *     }
    071 * }
    072 * </code>
    073 *
    074 * @author <a href="mailto:seade@policypoint.net">Scott Eade</a>
    075 * @version $Id: JSONSecureScreen.java 1695634 2015-08-13 00:35:47Z tv $
    076 */
    077public abstract class JSONSecureScreen extends JSONScreen
    078{
    079    /**
    080     * This method overrides the method in JSONScreen to perform a security
    081     * check prior to producing the output.
    082     *
    083     * @param pipelineData Turbine information.
    084     * @exception Exception, a generic exception.
    085     */
    086    @Override
    087    protected void doOutput(PipelineData pipelineData) throws Exception
    088    {
    089        if (isAuthorized(pipelineData))
    090        {
    091            super.doOutput(pipelineData);
    092        }
    093    }
    094
    095    /**
    096     * Override this method to perform the necessary security checks.
    097     *
    098     * @param pipelineData Turbine information.
    099     * @return <code>true</code> if the user is authorized to access the screen.
    100     * @exception Exception A generic exception.
    101     */
    102    protected abstract boolean isAuthorized(PipelineData pipelineData)
    103            throws Exception;
    104}