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    1   /*
    2    * $Id: Token.java 651946 2008-04-27 13:41:38Z apetrelli $
    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   package org.apache.struts2.components;
   23   
   24   import java.util.Map;
   25   
   26   import javax.servlet.http.HttpServletRequest;
   27   import javax.servlet.http.HttpServletResponse;
   28   
   29   import org.apache.struts2.views.annotations.StrutsTag;
   30   import org.apache.struts2.util.TokenHelper;
   31   
   32   import com.opensymphony.xwork2.util.ValueStack;
   33   
   34   /**
   35    * <!-- START SNIPPET: javadoc -->
   36    * Stop double-submission of forms.</p>
   37    *
   38    * The token tag is used to help with the "double click" submission problem. It is needed if you are using the
   39    * TokenInterceptor or the TokenSessionInterceptor. The s:token tag merely places a hidden element that contains
   40    * the unique token.</p>
   41    * <!-- END SNIPPET: javadoc -->
   42    *
   43    * <p/> <b>Examples</b>
   44    *
   45    * <pre>
   46    * <!-- START SNIPPET: example -->
   47    * &lt;s:token /&gt;
   48    * <!-- END SNIPPET: example -->
   49    * </pre>
   50    *
   51    * @see org.apache.struts2.interceptor.TokenInterceptor
   52    * @see org.apache.struts2.interceptor.TokenSessionStoreInterceptor
   53    *
   54    */
   55   @StrutsTag(name="token", tldTagClass="org.apache.struts2.views.jsp.ui.TokenTag", description="Stop double-submission of forms")
   56   public class Token extends UIBean {
   57   
   58       public static final String TEMPLATE = "token";
   59   
   60       public Token(ValueStack stack, HttpServletRequest request, HttpServletResponse response) {
   61           super(stack, request, response);
   62       }
   63   
   64       protected String getDefaultTemplate() {
   65           return TEMPLATE;
   66       }
   67   
   68       /**
   69        * First looks for the token in the PageContext using the supplied name (or {@link org.apache.struts2.util.TokenHelper#DEFAULT_TOKEN_NAME}
   70        * 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
   71        * the token is not in the PageContext, a new Token is created and set into the Session and the PageContext with
   72        * the name.
   73        */
   74       protected void evaluateExtraParams() {
   75           super.evaluateExtraParams();
   76   
   77           String tokenName;
   78           Map parameters = getParameters();
   79   
   80           if (parameters.containsKey("name")) {
   81               tokenName = (String) parameters.get("name");
   82           } else {
   83               if (name == null) {
   84                   tokenName = TokenHelper.DEFAULT_TOKEN_NAME;
   85               } else {
   86                   tokenName = findString(name);
   87   
   88                   if (tokenName == null) {
   89                       tokenName = name;
   90                   }
   91               }
   92   
   93               addParameter("name", tokenName);
   94           }
   95   
   96           String token = buildToken(tokenName);
   97           addParameter("token", token);
   98           addParameter("tokenNameField", TokenHelper.TOKEN_NAME_FIELD);
   99       }
  100   
  101       /**
  102        * This will be removed in a future version of Struts.
  103        * @deprecated Templates should use $parameters from now on, not $tag.
  104        */
  105       public String getTokenNameField() {
  106           return TokenHelper.TOKEN_NAME_FIELD;
  107       }
  108   
  109       private String buildToken(String name) {
  110           Map context = stack.getContext();
  111           Object myToken = context.get(name);
  112   
  113           if (myToken == null) {
  114               myToken = TokenHelper.setToken(name);
  115               context.put(name, myToken);
  116           }
  117   
  118           return myToken.toString();
  119       }
  120   }

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