1    package classUtils.pack.util; 
2     
3    import java.io.File; 
4    import java.util.ArrayList; 
5    import java.util.Iterator; 
6    import java.util.List; 
7    import java.util.StringTokenizer; 
8     
9     
10   /** 
11    * An utility class to compute normalized paths (i.e. paths that do not contain 
12    * neither "." nor "..") 
13    * 
14    * @author C. Sadun 
15    * @version 1.0 
16    */ 
17   public class PathNormalizer { 
18    
19       /** 
20        * Normalizes a file object. The returned file object will 
21        * return the normalize path when File.getAbsolutePath() is invoked. 
22        * @param path the File object to be normalized 
23        * @return a File object whose absolute path name is normalized 
24        */ 
25       public static File normalize(File path) { 
26           return new File(normalizePath(path.getAbsolutePath())); 
27       } 
28    
29       /** 
30        * Normalizes a string path. The returned path does not 
31        * contain ".." or "." references 
32        * @param path the path to be normalized. 
33        * @return a String object containing the normalized path 
34        */ 
35       public static String normalizePath(String path) { 
36           File f = new File(path); 
37           boolean trailingFSep=path.endsWith(File.separator); 
38           path=f.getAbsolutePath(); 
39           StringTokenizer st = new StringTokenizer(path, File.separator); 
40           List names=new ArrayList(); 
41           while(st.hasMoreTokens()) { 
42               String step = st.nextToken(); 
43               if (".".equals(step)) continue; 
44               else if ("..".equals(step)) names.remove(names.size()-1); 
45               else names.add(step); 
46           } 
47    
48           StringBuffer sb = new StringBuffer(); 
49           for(Iterator i=names.iterator(); i.hasNext(); ) { 
50               sb.append(i.next()); 
51               if (i.hasNext()) sb.append(File.separator); 
52           } 
53           if (trailingFSep) 
54              sb.append(File.separator); 
55           return sb.toString(); 
56       } 
57    
58   }