ReflectCommandFactory


1   package org.sapia.console;
2   
3   import java.util.*;
4   
5   
6   /**
7    * A command factory that creates <code>Command</code> instances
8    * dynamically, by resolving the command name to a class. The command's
9    * name has its first letter capitalized, and it is prepended with successive
10   * package names; the first command class that is found for a given package has
11   * an object instantiated from it.
12   * <p>
13   * If all packages have been visited and no command class was found
14   * for the given command name, then a <code>CommandNotFoundException</code>
15   * is thrown.
16   *
17   * @see #getCommandFor(String)
18   * @author Yanick Duchesne
19   * 29-Nov-02
20   */
21  public class ReflectCommandFactory implements CommandFactory {
22    private List _pckgs = new ArrayList();
23  
24    /**
25     * @see org.sapia.console.CommandFactory#getCommandFor(String)
26     */
27    public Command getCommandFor(String   name) throws CommandNotFoundException {
28      Command cmd = null;
29  
30      for (int i = 0; i < _pckgs.size(); i++) {
31        try {
32          cmd = (Command) Class.forName((String  ) _pckgs.get(i) + "." +
33              firstToUpper(name)).newInstance();
34        } catch (ClassNotFoundException   e) {
35          // noop      
36        } catch (Throwable   t) {
37          throw new CommandNotFoundException(t + ": " + t.getMessage());
38        }
39      }
40  
41      if (cmd == null) {
42        throw new CommandNotFoundException(name);
43      }
44  
45      return cmd;
46    }
47  
48    /**
49     * Adds a package to this instance.
50     */
51    public ReflectCommandFactory addPackage(String   name) {
52      _pckgs.add(name);
53  
54      return this;
55    }
56  
57    private String   firstToUpper(String   name) {
58      StringBuffer   buf = new StringBuffer  ();
59  
60      for (int i = 0; i < name.length(); i++) {
61        if (i == 0) {
62          buf.append(Character.toUpperCase(name.charAt(i)));
63        } else {
64          buf.append(name.charAt(i));
65        }
66      }
67  
68      return buf.toString();
69    }
70  }
71
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags