01: /*
02: * Copyright 2003-2004 The Apache Software Foundation
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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 org.apache.commons.collections;
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
29: * in this library. If you use the JDK unmodifiable class via java util Collections
30: * then the interface won't be there.
31: *
32: * @since Commons Collections 3.0
33: * @version $Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
34: *
35: * @author Stephen Colebourne
36: */
37: public interface Unmodifiable {
38: // marker interface - no methods to implement
39: }
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