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1   /*
2    *  Copyright 2003-2004 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 net.sf.collections15;
17  
18  /***
19   * Marker interface for collections, maps and iterators that are unmodifiable.
20   * <p/>
21   * This interface enables testing such as:
22   * <pre>
23   * if (coll instanceof Unmodifiable) {
24   *   coll = new ArrayList(coll);
25   * }
26   * // now we know coll is modifiable
27   * </pre>
28   * Of course all this only works if you use the Unmodifiable classes defined in
29   * this library. If you use the JDK unmodifiable class via java util Collections
30   * then the interface won't be there.
31   *
32   * @author Stephen Colebourne
33   * @version $Revision: 1.2 $ $Date: 2004/10/17 01:02:42 $
34   * @since Commons Collections15 1.0
35   */
36  public interface Unmodifiable
37  {
38      // marker interface - no methods to implement
39  }