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    1   package org.apache.turbine.modules.screens;
    2
    3   /*
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *   http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21
    22  import org.apache.turbine.pipeline.PipelineData;
    23
    24  /**
    25   * An extension to JSONScreen that performs a Security Check before invoking
    26   * doBuildTemplate().  You should extend this class and add the specific
    27   * security check needed.  If you have a number of screens that need to perform
    28   * the same check, you could make a base screen by extending this class and
    29   * implementing the isAuthorized().  Then each screen that needs to perform the
    30   * same check could extend your base screen.
    31   *
    32   * <p>Typically you would extend this class and override the doOutput() method
    33   * to use TurbineJsonRpc to register the POJOs that will provide the functions
    34   * you are making available via JSON-RPC.  Use JSONScreen if you <b>do not</b>
    35   * need the user to be logged in prior to executing the functions you provide.</p>
    36   *
    37   * <p>Here is an example from a superclass:
    38   * <code>
    39   * public void doOutput(PipelineData data) throws Exception
    40   * {
    41   *     User user = data.getUser();
    42   *
    43   *     MySecureJsonFunctions myFunctions
    44   *             = new MySecureJsonFunctions(user.getName());
    45   *
    46   *     // Session specific
    47   *     TurbineJsonRpc.registerObject(data.getSession(), "myFunctions", myFunctions);
    48   *
    49   *     // Global
    50   *     //TurbineJsonRpc.registerObjectGlobal("testGlobal", testObject);
    51   *
    52   *     super.doOutput(data);
    53   * }
    54   * </code></p>
    55   *
    56   * <p>The class MyFunctions would be something like:
    57   * <code>
    58   * public class MySecureJsonFunctions
    59   * {
    60   *     private final String name;
    61   *
    62   *     public MySecureJsonFunctions(String name)
    63   *     {
    64   *         this.name = name;
    65   *     }
    66   *
    67   *     private String getName(String clientParameter)
    68   *     {
    69   *         return "Client " + clientParameter + " says Hello World to " + name;
    70   *     }
    71   * }
    72   * </code></p>
    73   *
    74   * @author <a href="mailto:seade@policypoint.net">Scott Eade</a>
    75   * @version $Id: JSONSecureScreen.java 1773378 2016-12-09 13:19:59Z tv $
    76   */
    77  public abstract class JSONSecureScreen extends JSONScreen
    78  {
    79      /**
    80       * This method overrides the method in JSONScreen to perform a security
    81       * check prior to producing the output.
    82       *
    83       * @param pipelineData Turbine information.
    84       * @throws Exception a generic exception.
    85       */
    86      @Override
    87      protected void doOutput(PipelineData pipelineData) throws Exception
    88      {
    89          if (isAuthorized(pipelineData))
    90          {
    91              super.doOutput(pipelineData);
    92          }
    93      }
    94
    95      /**
    96       * Override this method to perform the necessary security checks.
    97       *
    98       * @param pipelineData Turbine information.
    99       * @return <code>true</code> if the user is authorized to access the screen.
    100      * @throws Exception A generic exception.
    101      */
    102     protected abstract boolean isAuthorized(PipelineData pipelineData)
    103             throws Exception;
    104 }