/*

 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

// Append files to one another without duplicating any lines.

import java.io.BufferedReader;

import java.io.FileReader;

import java.util.HashMap;

public class Combine {

    private static HashMap map = new HashMap(10007);

    private static void appendFile(String fileName, boolean keep) {

        try {

            BufferedReader br = new BufferedReader(new FileReader(fileName));

            // Read a line at a time.  If the line does not appear in the

            // hashmap, print it and add it to the hashmap, so that it will

            // not be repeated.

        lineLoop:

            while (true) {

                String line = br.readLine();

                if (line == null)

                    break;

                if (keep || !map.containsKey(line)) {

                    System.out.println(line);

                    map.put(line,line);

                }

            }

            br.close();

        } catch (Exception e) {

            e.printStackTrace();

            System.exit(1);

        }

    }

    public static void main(String[] args) {

        if (args.length < 2) {

            System.err.println("Usage:  java Combine  file1  file2  ...");

            System.exit(2);

        }

        for (int i = 0; i < args.length; ++i)

            appendFile(args[i], i == 0);

    }

}