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Java > Open Source Codes > com > sun > appserv > management > util > misc > SafeSave


1 /*
2  * The contents of this file are subject to the terms
3  * of the Common Development and Distribution License
4  * (the License). You may not use this file except in
5  * compliance with the License.
6  *
7  * You can obtain a copy of the license at
8  * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9  * glassfish/bootstrap/legal/CDDLv1.0.txt.
10  * See the License for the specific language governing
11  * permissions and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL
14  * Header Notice in each file and include the License file
15  * at glassfish/bootstrap/legal/CDDLv1.0.txt.
16  * If applicable, add the following below the CDDL Header,
17  * with the fields enclosed by brackets [] replaced by
18  * you own identifying information:
19  * "Portions Copyrighted [year] [name of copyright owner]"
20  *
21  * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22  */
23  
24 /*
25  * $Header: /cvs/glassfish/admin-core/mbeanapi/src/java/com/sun/appserv/management/util/misc/SafeSave.java,v 1.3 2005/12/25 03:51:52 tcfujii Exp $
26  * $Revision: 1.3 $
27  * $Date: 2005/12/25 03:51:52 $
28  */
29  
30 package com.sun.appserv.management.util.misc;
31
32 import java.io.File JavaDoc;
33 import java.io.IOException JavaDoc;
34
35
36 /**
37     Utilities for performing a safe save involving a temp file
38  */
39 public final class SafeSave
40 {
41     private SafeSave() {}
42     
43         private static File JavaDoc
44     formTempName( String JavaDoc baseName )
45     {
46         return( new File JavaDoc ( baseName + System.currentTimeMillis() + ".temp" ) );
47     }
48     
49     /**
50         Reads a line, outputting an optional prompt first. If the prompt is null
51         then no prompt is printed.
52      */
53         public static File JavaDoc
54     getTempFile( File JavaDoc baseFile ) throws IOException JavaDoc
55     {
56         File JavaDoc tempFile = null;
57         
58         while ( (tempFile = formTempName( baseFile.toString() ) ).exists() )
59         {
60         }
61         
62         return( tempFile );
63     }
64     
65     /**
66         Replace the original file with the new file in a manner which will not result in data
67         loss, with the worst risk being that the original file will be left with a different
68         name.
69      */
70         public static void
71     replaceWithNew( File JavaDoc origFile, File JavaDoc newFile) throws IOException JavaDoc
72     {
73         final File JavaDoc origTemp = getTempFile( origFile );
74         
75         origFile.renameTo( origTemp );
76         newFile.renameTo( origFile );
77         origTemp.delete();
78     }
79 }
80
81
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