FileIndex.java
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/******************************************************************************
* 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 edu.princeton.cs.algs4;
import java.io.File;
/**
* The {@code FileIndex} 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 2002-2016, 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.
******************************************************************************/