Read a file containing an offset, and a String at that offset
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.IOException;
import java.io.RandomAccessFile;
/**
* Read a file containing an offset, and a String at that offset.
*
* @author Ian F. Darwin, http://www.darwinsys.com/
* @version $Id: ReadRandom.java,v 1.6 2004/03/07 17:30:35 ian Exp $
*/
public class RandomRead {
final static String FILENAME = "random.dat";
protected String fileName;
protected RandomAccessFile seeker;
public static void main(String[] argv) throws IOException {
RandomRead r = new RandomRead(FILENAME);
System.out.println("Offset is " + r.readOffset());
System.out.println("Message is \"" + r.readMessage() + "\".");
}
/** Constructor: save filename, construct RandomAccessFile */
public RandomRead(String fname) throws IOException {
fileName = fname;
seeker = new RandomAccessFile(fname, "r");
}
/** Read the Offset field, defined to be at location 0 in the file. */
public int readOffset() throws IOException {
seeker.seek(0); // move to very beginning
return seeker.readInt(); // and read the offset
}
/** Read the message at the given offset */
public String readMessage() throws IOException {
seeker.seek(readOffset()); // move to the offset
return seeker.readLine(); // and read the String
}
}
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