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Java > Open Source Codes > org > apache > geronimo > common > FileUtils


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.geronimo.common;
18
19 import java.io.File JavaDoc;
20 import java.io.DataInputStream JavaDoc;
21 import java.io.BufferedInputStream JavaDoc;
22 import java.io.FileInputStream JavaDoc;
23 import java.io.IOException JavaDoc;
24 import java.util.zip.ZipFile JavaDoc;
25
26 /**
27  * Utility functions related to Files.
28  *
29  * @version $Rev: 476049 $ $Date: 2006-11-16 23:35:17 -0500 (Thu, 16 Nov 2006) $
30  */
31 public class FileUtils {
32     /**
33      * Determine whether a file is a JAR File.
34      */
35     public static boolean isJarFile(File JavaDoc file) throws IOException JavaDoc {
36         if(!isZipFile(file)) {
37             return false;
38         }
39         ZipFile JavaDoc zip = new ZipFile JavaDoc(file);
40         boolean manifest = zip.getEntry("META-INF/MANIFEST.MF") != null;
41         zip.close();
42         return manifest;
43     }
44
45     /**
46      * Determine whether a file is a ZIP File.
47      */
48     public static boolean isZipFile(File JavaDoc file) throws IOException JavaDoc {
49         if(file.isDirectory()) {
50             return false;
51         }
52         if(!file.canRead()) {
53             throw new IOException JavaDoc("Cannot read file "+file.getAbsolutePath());
54         }
55         if(file.length() < 4) {
56             return false;
57         }
58         DataInputStream JavaDoc in = new DataInputStream JavaDoc(new BufferedInputStream JavaDoc(new FileInputStream JavaDoc(file)));
59         int test = in.readInt();
60         in.close();
61         return test == 0x504b0304;
62     }
63
64 }
65
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