ListType


1   /*
2    * Copyright (c) 2005, Rob Gordon.
3    */
4   package org.oddjob.values.types;
5   
6   import java.util.ArrayList  ;
7   import java.util.Arrays  ;
8   import java.util.Collection  ;
9   import java.util.Iterator  ;
10  import java.util.List  ;
11  
12  import org.oddjob.arooa.ArooaHandler;
13  import org.oddjob.arooa.ArooaContext;
14  import org.oddjob.arooa.handlers.ValueHandler;
15  import org.oddjob.arooa.reflect.IntrospectionHelper;
16  
17  /**
18   * @oddjob.description A list can list any other type including another list.
19   * <p>
20   * If the merge property is set to true then sub lists are merged 
21   * with the main list. This feature is currently unsupported in
22   * Oddjob Designer.
23   * 
24   * @oddjob.example
25   * 
26   * <pre>
27   * &lt;list&gt;
28   *   &lt;value value="Hello World"/&gt;
29   *   &lt;value value="Goodbye World"/&gt;
30   *   &lt;list&gt;
31   *     &lt;value value="42"/&gt;
32   *   &lt;/list&gt;
33   * &lt;/list&gt;
34   * </pre>
35   * 
36   * @author Rob Gordon.
37   */
38  public class ListType {
39      
40      /**
41       * @oddjob.element values
42       * @oddjob.description Any values.
43       * @oddjob.required No.
44       */
45      private final transient List   types = new ArrayList  ();
46              
47      /**
48       * @oddjob.element 
49       * @oddjob.description If true then sub lists are merged in with
50       * this list..
51       * @oddjob.required No, defaults to false.
52       */
53      private boolean merge;
54      
55      /**
56       * Add a value to the list.
57       * 
58       * @param type The type.
59       */
60      public void addConfiguredValue(Object   type) {       
61          types.add(type);
62      }
63      
64      public Object   valueFor(Class   required) 
65      throws ClassCastException  , NumberFormatException   {
66          if (required.isAssignableFrom(Object  .class)) {
67              return convertTypes(Object  .class).toArray();
68          }
69          if (required.isAssignableFrom(List  .class)) {
70              return convertTypes(Object  .class);
71          }
72          if (required.isArray()) {
73              return convertTypes(required.getComponentType())
74                  .toArray();
75          }
76  
77          throw new ClassCastException  ("Can not convert a List to " + required);
78      }
79  
80      private List   convertTypes(Class   required) {
81          List   results= new ArrayList  (); 
82          for (Iterator   it = types.iterator(); it.hasNext(); ) {
83              Object   proxy = it.next();
84              // use helper to get value by inspection.
85              Object   o = IntrospectionHelper.valueFor(proxy, required);
86              if (merge && o.getClass().isArray()) {
87                      Object  [] os = (Object  [])o;
88                      results.addAll(Arrays.asList(os));
89              }
90              else if (merge && o instanceof Collection  ) {
91                  results.addAll((Collection  ) o);
92              }
93              else {
94                  results.add(o);
95              }
96          }
97          return results;
98      }
99  
100     public String   toString() {
101         return "List of " + types.size() + " things.";
102     }
103     
104     /**
105      * Provide our own handler for the values.
106      * 
107      * @param context Not required.
108      * @return Our handler.
109      */
110     public ArooaHandler handlerFor(ArooaContext context) {
111         return new ValueHandler();
112     }
113         
114     /**
115      * @return Returns the merge.
116      */
117     public boolean isMerge() {
118         return merge;
119     }
120     /**
121      * @param merge The merge to set.
122      */
123     public void setMerge(boolean merge) {
124         this.merge = merge;
125     }
126 }
127
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