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comparison servlet/src/digilib/io/FileOps.java @ 1:0ff3ede32060

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Initial revision
author robcast
date Thu, 17 Jan 2002 15:25:46 +0100
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children 2ea78a56ecf8 6d2032b6121d 9cedd170b581
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0:ffd2df307e81 1:0ff3ede32060
1 /* FileOps -- Utility class for file operations
2
3 Digital Image Library servlet components
4
5 Copyright (C) 2001, 2002 Robert Casties (robcast@mail.berlios.de)
6
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
11
12 Please read license.txt for the full details. A copy of the GPL
13 may be found at http://www.gnu.org/copyleft/lgpl.html
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 */
20
21 package digilib.io;
22
23 import java.io.*;
24 import java.util.*;
25
26 import digilib.*;
27
28
29 public class FileOps {
30
31 private Utils util = null;
32 public static String[] fileTypes = {
33 "jpg", "image/jpeg",
34 "jpeg", "image/jpeg",
35 "png", "image/png",
36 "gif", "image/gif",
37 "tif", "image/tiff",
38 "tiff", "image/tiff"};
39
40 public FileOps() {
41 util = new Utils();
42 }
43
44 public FileOps(Utils u) {
45 util = u;
46 }
47
48 public void setUtils(Utils u) {
49 util = u;
50 }
51
52
53 /**
54 * get the mime type for a file format (by extension)
55 */
56 public static String mimeForFile(File f) {
57 String fn = f.getName();
58 for (int i = 0; i < fileTypes.length; i += 2) {
59 if (fn.toLowerCase().endsWith(fileTypes[i])) {
60 return fileTypes[i+1];
61 }
62 }
63 return null;
64 }
65
66 /**
67 * get a filehandle for a file or directory name
68 * returns File number n if fn is directory (starts with 1)
69 */
70 public File getFile(String fn, int n) throws FileOpException {
71 util.dprintln(4, "getFile ("+fn+", "+n+")");
72
73 File f = new File(fn);
74 // if fn is a file name then return file
75 if (f.isFile()) {
76 return f;
77 }
78 // if fn is a directory name then open directory
79 if (f.isDirectory()) {
80 File[] fl = f.listFiles(new ImgFileFilter());
81 Arrays.sort(fl);
82 if ((n > 0) && (n <= fl.length)) {
83 return fl[n - 1];
84 }
85 }
86 throw new FileOpException("Unable to find file: "+fn);
87 }
88
89 /**
90 * get the number of files in a directory
91 * (almost the same as getFile)
92 * returns 0 in case of problems
93 */
94 public int getNumFiles(String fn) throws FileOpException {
95 util.dprintln(4, "getNumFiles ("+fn+")");
96
97 File f = new File(fn);
98 // if fn is a file name then return 1
99 if (f.isFile()) {
100 return 1;
101 }
102 // if fn is a directory name then return the number of files
103 if (f.isDirectory()) {
104 return f.listFiles(new ImgFileFilter()).length;
105 }
106 // then fn must be something strange...
107 return 0;
108 }
109
110
111 /**
112 * get a filehandle for a file or directory name out of a list
113 * dirs is a list of base directories, fn is the appended file/dirname
114 * searches dirs until fn exists (backwards if fwd is false)
115 * returns File number n if fn is directory (starts with 1)
116 */
117 public File getFileVariant(String[] dirs, String fn, int n, boolean fwd) throws FileOpException {
118 util.dprintln(4, "getVariantFile ("+dirs+", "+fn+", "+n+")");
119
120 File f = null;
121 int start = 0;
122 int inc = 1;
123 int end = dirs.length;
124 if (fwd == false) {
125 start = dirs.length - 1;
126 inc = -1;
127 end = 0;
128 }
129
130 for (int i = start; i != end; i += inc) {
131 try {
132 f = getFile(dirs[i]+fn, n);
133 } catch (FileOpException e) {
134 f = null;
135 }
136 if (f != null) {
137 return f;
138 }
139 }
140 throw new FileOpException("Unable to find file: "+fn);
141 }
142
143 /**
144 * get the number of files in a directory
145 * (almost the same as getFileVariant)
146 * returns 0 in case of problems
147 */
148 public int getNumFilesVariant(String[] dirs, String fn, boolean fwd) throws FileOpException {
149 util.dprintln(4, "getNumFilesVariant ("+dirs+", "+fn+")");
150
151 int nf = 0;
152 int start = 0;
153 int inc = 1;
154 int end = dirs.length;
155 if (fwd == false) {
156 start = dirs.length - 1;
157 inc = -1;
158 end = 0;
159 }
160
161 for (int i = start; i != end; i += inc) {
162 try {
163 nf = getNumFiles(dirs[i]+fn);
164 } catch (FileOpException e) {
165 nf = 0;
166 }
167 if (nf > 0) {
168 return nf;
169 }
170 }
171 return 0;
172 }
173
174 /**
175 * FileFilter for image types (helper class for getFile)
176 */
177 private class ImgFileFilter implements FileFilter {
178
179 public boolean accept(File f) {
180 if (f.isFile()) {
181 return (mimeForFile(f) != null);
182 } else {
183 return false;
184 }
185 }
186 }
187
188 }