RequestParameterRule


1   /*
2    * Copyright 2000,2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.webapp.balancer.rules;
17  
18  import javax.servlet.http.HttpServletRequest  ;
19  
20  
21  /**
22   * This rule accepts or rejects requests
23   * based on the presence of a parameter
24   * in the request.
25   *
26   * @author Yoav Shapira
27   */
28  public class RequestParameterRule extends BaseRule {
29      /**
30       * The target parameter name (parameter
31       * must be present for match to succeed).
32       */
33      private String   paramName;
34  
35      /**
36       * The target parameter value.  This
37       * is optional: null means any parameter
38       * value is OK for a match.  A non-null
39       * value will be matches exactly.
40       */
41      private String   paramValue;
42  
43      /**
44       * Sets the target parameter name.
45       *
46       * @param theParamName The parameter name
47       */
48      public void setParamName(String   theParamName) {
49          if (theParamName == null) {
50              throw new IllegalArgumentException  ("paramName cannot be null.");
51          } else {
52              paramName = theParamName;
53          }
54      }
55  
56      /**
57       * Returns the target parameter name.
58       *
59       * @return String The target parameter name.
60       */
61      protected String   getParamName() {
62          return paramName;
63      }
64  
65      /**
66       * Sets the parameter value, which may be null.
67       *
68       * @param theParamValue The parameter value
69       */
70      public void setParamValue(String   theParamValue) {
71          paramValue = theParamValue;
72      }
73  
74      /**
75       * Returns the target parameter value,
76       * which may be null.
77       *
78       * @return String The target parameter value
79       */
80      protected String   getParamValue() {
81          return paramValue;
82      }
83  
84      /**
85       * @see org.apache.webapp.balancer.Rule#matches(HttpServletRequest)
86       */
87      public boolean matches(HttpServletRequest   request) {
88          String   actualParamValue = request.getParameter(getParamName());
89  
90          if (actualParamValue == null) {
91              return (getParamValue() == null);
92          } else {
93              return (actualParamValue.compareTo(getParamValue()) == 0);
94          }
95      }
96  
97      /**
98       * Returns a String representation of this object.
99       *
100      * @return String
101      */
102     public String   toString() {
103         StringBuffer   buffer = new StringBuffer  ();
104 
105         buffer.append("[");
106         buffer.append(getClass().getName());
107         buffer.append(": ");
108 
109         buffer.append("Target param name: ");
110         buffer.append(getParamName());
111         buffer.append(" / ");
112 
113         buffer.append("Target param value: ");
114         buffer.append(getParamValue());
115         buffer.append(" / ");
116 
117         buffer.append("Redirect URL: ");
118         buffer.append(getRedirectUrl());
119 
120         buffer.append("]");
121 
122         return buffer.toString();
123     }
124 }
125 
126 
127 // End of file: RequestParameterRule.java
128
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