/******************************************************************************
 * Compilation:  javac FileIndex.java
 * Execution:    java FileIndex file1.txt file2.txt file3.txt ...
 * Dependencies: ST.java SET.java In.java StdIn.java StdOut.java
 * Data files:   http://algs4.cs.princeton.edu/35applications/ex1.txt
 * http://algs4.cs.princeton.edu/35applications/ex2.txt
 * http://algs4.cs.princeton.edu/35applications/ex3.txt
 * http://algs4.cs.princeton.edu/35applications/ex4.txt
 *
 * % java FileIndex ex*.txt
 * age
 * ex3.txt
 * ex4.txt
 * best
 * ex1.txt
 * was
 * ex1.txt
 * ex2.txt
 * ex3.txt
 * ex4.txt
 *
 * % java FileIndex *.txt
 *
 * % java FileIndex *.java
 ******************************************************************************/

package com.brianway.learning.algorithms.algs4utils;

import java.io.File;

/**
 * The <tt>FileIndex</tt> class provides a client for indexing a set of files,
 * specified as command-line arguments. It takes queries from standard input
 * and prints each file that contains the given query.
 * <p>
 * For additional documentation, see <a href="http://algs4.cs.princeton.edu/35applications">Section 3.5</a> of
 * <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
 *
 * @author Robert Sedgewick
 * @author Kevin Wayne
 */
public class FileIndex {

    // Do not instantiate.
    private FileIndex() {
    }

    public static void main(String[] args) {

        // key = word, value = set of files containing that word
        ST<String, SET<File>> st = new ST<String, SET<File>>();

        // create inverted index of all files
        StdOut.println("Indexing files");
        for (String filename : args) {
            StdOut.println("  " + filename);
            File file = new File(filename);
            In in = new In(file);
            while (!in.isEmpty()) {
                String word = in.readString();
                if (!st.contains(word)) st.put(word, new SET<File>());
                SET<File> set = st.get(word);
                set.add(file);
            }
        }

        // read queries from standard input, one per line
        while (!StdIn.isEmpty()) {
            String query = StdIn.readString();
            if (st.contains(query)) {
                SET<File> set = st.get(query);
                for (File file : set) {
                    StdOut.println("  " + file.getName());
                }
            }
        }

    }

}

/******************************************************************************
 * Copyright 2002-2015, Robert Sedgewick and Kevin Wayne.
 *
 * This file is part of algs4.jar, which accompanies the textbook
 *
 * Algorithms, 4th edition by Robert Sedgewick and Kevin Wayne,
 * Addison-Wesley Professional, 2011, ISBN 0-321-57351-X.
 * http://algs4.cs.princeton.edu
 *
 *
 * algs4.jar is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * algs4.jar 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with algs4.jar.  If not, see http://www.gnu.org/licenses.
 ******************************************************************************/
