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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.vfs.util;
18  
19  import org.apache.commons.vfs.FileObject;
20  import org.apache.commons.vfs.FileSystemException;
21  import org.apache.commons.vfs.impl.DecoratedFileObject;
22  import org.apache.commons.vfs.provider.AbstractFileObject;
23  
24  /***
25   * Stuff to get some strange things from an FileObject
26   *
27   * @author <a href="mailto:imario@apache.org">Mario Ivankovits</a>
28   * @version $Revision: 480428 $ $Date: 2006-11-29 07:15:24 +0100 (Mi, 29 Nov 2006) $
29   */
30  public class FileObjectUtils
31  {
32  	private FileObjectUtils()
33  	{
34  	}
35  
36  	/***
37  	 * get access to the base object even if decorated
38  	 */
39  	public static AbstractFileObject getAbstractFileObject(final FileObject fileObject) throws FileSystemException
40  	{
41  		Object searchObject = fileObject;
42  		while (searchObject instanceof DecoratedFileObject)
43  		{
44  			searchObject = ((DecoratedFileObject) searchObject).getDecoratedFileObject();
45  		}
46  		if (searchObject instanceof AbstractFileObject)
47  		{
48  			return (AbstractFileObject) searchObject;
49  		}
50          if (searchObject == null)
51          {
52              return null;
53          }
54  
55          throw new FileSystemException("vfs.util/find-abstract-file-object.error", fileObject==null?"null":fileObject.getClass().getName());
56  	}
57  
58  	/***
59  	 * check if the given FileObject is instance of given class argument
60  	 */
61  	public static boolean isInstanceOf(final FileObject fileObject, final Class wantedClass) throws FileSystemException
62  	{
63  		Object searchObject = fileObject;
64  		while (searchObject instanceof DecoratedFileObject)
65  		{
66  			if (wantedClass.isInstance(searchObject))
67  			{
68  				return true;
69  			}
70  
71  			searchObject = ((DecoratedFileObject) searchObject).getDecoratedFileObject();
72  		}
73  
74  		if (wantedClass.isInstance(searchObject))
75  		{
76  			return true;
77  		}
78  
79  		return false;
80  	}
81  }