NameFactory


1   /*
2    * Copyright 2007 Google Inc.
3    *  
4    * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5    * use this file except in compliance with the License. You may obtain a copy of
6    * 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, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations under
14   * the License.
15   */
16  package com.google.gwt.dev.generator;
17  
18  import java.util.Set  ;
19  import java.util.HashSet  ;
20  import java.util.Collection  ;
21  
22  /**
23   * Generates unqiue identifiers. Use this class to avoid generating
24   * conflicting names with user code. This class isn't smart enough to know
25   * about scopes (which isn't generally a problem for generators in any case).
26   */
27  public class NameFactory {
28  
29    private final Set   usedNames = new HashSet  ();
30  
31    /**
32     * Creates a new <code>NameFactory</code> that knows about
33     * <code>existingNames</code>.
34     *
35     * @param existingNames a list of names that may be <code>null</code>.
36     */
37    public NameFactory(Collection   existingNames) {
38      if (existingNames == null) {
39        return;
40      }
41      usedNames.addAll(existingNames);
42    }
43  
44    /**
45     * Creates a new <code>NameFactory</code> that doesn't know about any existing
46     * names.
47     */
48    public NameFactory() {
49      this(null);
50    }
51  
52    /**
53     * Adds a name to the set of already known identifiers. Has no affect if the
54     * name is already considered an existing identifier.
55     *
56     * @param name a not <code>null</code> name
57     */
58    public void addName(String   name) {
59      usedNames.add(name);
60    }
61  
62    /**
63     * Creates a new unique name based off of <code>name</code> and adds it to
64     * the list of known names.
65     *
66     * @param name a not <code>null</code> name to base the new unique name from
67     * @return a new unique, not <code>null</code> name. This name may be possibly
68     * identical to <code>name</code>.
69     */
70    public String   createName(String   name) {
71      String   newName = name;
72  
73      for (int count = 0; true; ++count) {
74        if (usedNames.contains(newName)) {
75          newName = name + count;
76        } else {
77          return newName;
78        }
79      }
80    }
81  }
82
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags