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    1   /*
    2    * $Id: Token.java 497654 2007-01-19 00:21:57Z rgielen $
    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  package org.apache.struts2.components;
    22
    23  import java.util.Map;
    24
    25  import javax.servlet.http.HttpServletRequest;
    26  import javax.servlet.http.HttpServletResponse;
    27
    28  import org.apache.struts2.views.annotations.StrutsTag;
    29  import org.apache.struts2.util.TokenHelper;
    30
    31  import com.opensymphony.xwork2.util.ValueStack;
    32
    33  /***
    34   * <!-- START SNIPPET: javadoc -->
    35   * Stop double-submission of forms.</p>
    36   *
    37   * The token tag is used to help with the "double click" submission problem. It is needed if you are using the
    38   * TokenInterceptor or the TokenSessionInterceptor. The s:token tag merely places a hidden element that contains
    39   * the unique token.</p>
    40   * <!-- END SNIPPET: javadoc -->
    41   *
    42   * <p/> <b>Examples</b>
    43   *
    44   * <pre>
    45   * <!-- START SNIPPET: example -->
    46   * &lt;s:token /&gt;
    47   * <!-- END SNIPPET: example -->
    48   * </pre>
    49   *
    50   * @see org.apache.struts2.interceptor.TokenInterceptor
    51   * @see org.apache.struts2.interceptor.TokenSessionStoreInterceptor
    52   *
    53   */
    54  @StrutsTag(name="token", tldTagClass="org.apache.struts2.views.jsp.ui.TokenTag", description="Stop double-submission of forms")
    55  public class Token extends UIBean {
    56
    57      public static final String TEMPLATE = "token";
    58
    59      public Token(ValueStack stack, HttpServletRequest request, HttpServletResponse response) {
    60          super(stack, request, response);
    61      }
    62
    63      protected String getDefaultTemplate() {
    64          return TEMPLATE;
    65      }
    66
    67      /***
    68       * First looks for the token in the PageContext using the supplied name (or {@link org.apache.struts2.util.TokenHelper#DEFAULT_TOKEN_NAME}
    69       * if no name is provided) so that the same token can be re-used for the scope of a request for the same name. If
    70       * the token is not in the PageContext, a new Token is created and set into the Session and the PageContext with
    71       * the name.
    72       */
    73      protected void evaluateExtraParams() {
    74          super.evaluateExtraParams();
    75
    76          String tokenName;
    77          Map parameters = getParameters();
    78
    79          if (parameters.containsKey("name")) {
    80              tokenName = (String) parameters.get("name");
    81          } else {
    82              if (name == null) {
    83                  tokenName = TokenHelper.DEFAULT_TOKEN_NAME;
    84              } else {
    85                  tokenName = findString(name);
    86
    87                  if (tokenName == null) {
    88                      tokenName = name;
    89                  }
    90              }
    91
    92              addParameter("name", tokenName);
    93          }
    94
    95          String token = buildToken(tokenName);
    96          addParameter("token", token);
    97          addParameter("tokenNameField", TokenHelper.TOKEN_NAME_FIELD);
    98      }
    99
    100     /***
    101      * This will be removed in a future version of Struts.
    102      * @deprecated Templates should use $parameters from now on, not $tag.
    103      */
    104     public String getTokenNameField() {
    105         return TokenHelper.TOKEN_NAME_FIELD;
    106     }
    107
    108     private String buildToken(String name) {
    109         Map context = stack.getContext();
    110         Object myToken = context.get(name);
    111
    112         if (myToken == null) {
    113             myToken = TokenHelper.setToken(name);
    114             context.put(name, myToken);
    115         }
    116
    117         return myToken.toString();
    118     }
    119 }