/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
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 * Header, with the fields enclosed by brackets [] replaced by your own
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 * its licensees as provided above.  However, if you add GPL Version 2 code
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/*
 * $Header: /cvs/glassfish/appserv-api/src/java/com/sun/appserv/management/util/misc/SafeSave.java,v 1.2 2007/05/05 05:31:06 tcfujii Exp $
 * $Revision: 1.2 $
 * $Date: 2007/05/05 05:31:06 $
 */
 
package com.sun.appserv.management.util.misc;

import java.io.File;
import java.io.IOException;


/**
	Utilities for performing a safe save involving a temp file
 */
public final class SafeSave
{
	private SafeSave()	{}
	
		private static File
	formTempName( String baseName )
	{
		return( new File ( baseName + System.currentTimeMillis() + ".temp" ) );
	}
	
	/**
		Reads a line, outputting an optional prompt first.  If the prompt is null
		then no prompt is printed.
	 */
		public static File
	getTempFile( File baseFile ) throws IOException
	{
		File	tempFile	= null;
		
		while ( (tempFile = formTempName( baseFile.toString() ) ).exists() )
		{
		}
		
		return( tempFile );
	}
	
	/**
		Replace the original file with the new file in a manner which will not result in data
		loss, with the worst risk being that the original file will be left with a different
		name.
	 */
		public static void
	replaceWithNew( File origFile, File newFile) throws IOException
	{
		final File	origTemp	= getTempFile( origFile );
		
		origFile.renameTo( origTemp );
		newFile.renameTo( origFile );
		origTemp.delete();
	}
}