ParamHelper


1   /*
2    * Copyright 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   * $Header:$
17   */
18  package org.apache.beehive.netui.util;
19  
20  import java.util.Map  ;
21  import java.util.List  ;
22  import java.lang.reflect.Array  ;
23  import org.apache.beehive.netui.util.logging.Logger;
24  
25  /**
26   * This class is used by NetUI tags that use parameters.
27   */
28  public class ParamHelper
29  {
30      private static final Logger logger = Logger.getInstance(ParamHelper.class);
31  
32      /**
33       * Add a new parameter or update an existing parameter's list of values.
34       * <p/>
35       * <em>Implementation Note:</em> in the case that a Map was provided for
36       * the <code>value</code> parameter, the this returns without doing
37       * anything; in any other case, params is updated (even in
38       * <code>value</code> is null).
39       * </p>
40       * <p/>
41       * If value is some object (not an array or list), the string
42       * representation of that object is added as a value for name.  If the
43       * value is a list (or array) of objects, then the string representation
44       * of each element is added as a value for name.  When there are multiple
45       * values for a name, then an array of Strings is used in Map.
46       * </p>
47       *
48       * @param params an existing Map of names and values to update
49       * @param name   the name of the parameter to add or update
50       * @param value  an item or list of items to put into the map
51       * @throws IllegalArgumentException in the case that either the params
52       *                                  <p/>
53       *                                  or name given was null
54       */
55      public static void addParam(Map   params, String   name, Object   value)
56      {
57  
58  
59          if (params == null)
60              throw new IllegalArgumentException  ("Parameter map cannot be null");
61          if (name == null)
62              throw new IllegalArgumentException  ("Parameter name cannot be null");
63  
64          if (value instanceof Map  ) {
65              logger.warn(Bundle.getString("Tags_BadParameterType", name));
66              return;
67          }
68  
69          if (value == null)
70              value = "";
71  
72          // check to see if we are adding a new element
73          //      or if this is an existing element
74          Object   o = params.get(name);
75          int length = 0;
76  
77          if (o != null) {
78              assert (o instanceof String   ||
79                      o instanceof String  []);
80  
81              if (o.getClass().isArray()) {
82                  length = Array.getLength(o);
83              }
84              else {
85                  length++;
86              }
87          }
88  
89          // check how much size the output needs to be
90          if (value.getClass().isArray()) {
91              length += Array.getLength(value);
92          }
93          else if (value instanceof List  ) {
94              length += ((List  ) value).size();
95          }
96          else {
97              length++;
98          }
99  
100         if (length == 0)
101             return;
102 
103         //System.err.println("Number of vaues:" + length);
104         // if there is only a single value push it to the parameter table
105         if (length == 1) {
106             if (value.getClass().isArray()) {
107                 Object   val = Array.get(value, 0);
108                 if (val != null)
109                     params.put(name,val.toString());
110                 else
111                     params.put(name,"");
112             }
113             else if (value instanceof List  ) {
114                 List   list = (List  ) value;
115                 Object   val = list.get(0);
116                 if (val != null)
117                     params.put(name,val.toString());
118                 else
119                     params.put(name,"");
120             }
121             else
122                 params.put(name,value.toString());
123             return;
124         }
125 
126         // allocate the string for the multiple values
127         String  [] values = new String  [length];
128         int offset = 0;
129 
130         // if we had old values, push them to the new array
131         if (o != null) {
132             if (o.getClass().isArray()) {
133                 String  [] obs = (String  []) o;
134                 for (;offset<obs.length;offset++) {
135                     values[offset] = obs[offset];
136                 }
137             }
138             else {
139                 values[0] = o.toString();
140                 offset = 1;
141             }
142         }
143 
144         // now move the new values to the array starting at the offset
145         // position
146         if (value.getClass().isArray())
147         {
148             //need to convert this array into a String[]
149             int size = Array.getLength(value);
150             for (int i=0; i < size; i++)
151             {
152                 Object   val = Array.get(value, i);
153                 if (val != null)
154                     values[i+offset] = val.toString();
155                 else
156                    values[i+offset] = "";
157             }
158         }
159         else if (value instanceof List  )
160         {
161             List   list = (List  ) value;
162             int size = list.size();
163             for (int i=0; i < size; i++)
164             {
165                 if (list.get(i) != null)
166                     values[i+offset] = list.get(i).toString();
167                 else
168                     values[i+offset] = "";
169             }
170         }
171         else {
172             values[offset] = value.toString();
173         }
174         // store the new values array
175         params.put(name, values);
176     }
177 }
178
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags