1 /*

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

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

     4  *

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

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

     7  * published by the Free Software Foundation.  Oracle designates this

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

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

    10  *

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

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

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

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

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

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

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

    23  * questions.

    24  */

    25 

    26 

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

    28 

    29 import java.io.BufferedReader;

    30 import java.io.FileReader;

    31 import java.util.HashMap;

    32 

    33 public class Combine {

    34 

    35     private static HashMap map = new HashMap(10007);

    36 

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

    38         try {

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

    40 

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

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

    43             // not be repeated.

    44 

    45         lineLoop:

    46             while (true) {

    47                 String line = br.readLine();

    48                 if (line == null)

    49                     break;

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

    51                     System.out.println(line);

    52                     map.put(line,line);

    53                 }

    54             }

    55             br.close();

    56         } catch (Exception e) {

    57             e.printStackTrace();

    58             System.exit(1);

    59         }

    60     }

    61 

    62 

    63     public static void main(String[] args) {

    64 

    65         if (args.length < 2) {

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

    67             System.exit(2);

    68         }

    69 

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

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

    72     }

    73 }