/*
 *
 * Copyright (c) 1998 Scott Oaks. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and
 * without fee is hereby granted.
 *
 * This sample source code is provided for example only,
 * on an unsupported, as-is basis. 
 *
 * AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. AUTHOR SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  AUTHOR
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */


import java.io.*;
import java.security.*;

public class ReceiveStream {
	public static void main(String args[]) {
		try {
			FileInputStream fis = new FileInputStream("test");
			MessageDigest md = MessageDigest.getInstance("SHA");
			DigestInputStream dis = new DigestInputStream(fis, md);
			ObjectInputStream ois = new ObjectInputStream(dis);
			Object o = ois.readObject();
			if (!(o instanceof String)) {
				System.out.println("Unexpected data in file");
				System.exit(-1);
			}
			String data = (String) o;
			System.out.println("Got message " + data);
			dis.on(false);
			o = ois.readObject();
			if (!(o instanceof byte[])) {
				System.out.println("Unexpected data in file");
				System.exit(-1);
			}
			byte origDigest[] = (byte []) o;
			if (MessageDigest.isEqual(md.digest(), origDigest))
				System.out.println("Message is valid");
			else System.out.println("Message was corrupted");
		} catch (Exception e) {
			System.out.println(e);
		}
	}
}