WhiteFilter.java


Below is the syntax highlighted version of WhiteFilter.java from §3.5 Searching Applications.


/******************************************************************************
 *  Compilation:  javac WhiteFilter.java
 *  Execution:    java WhiteFilter whitelist.txt < input.txt
 *  Dependencies: SET In.java StdIn.java StdOut.java
 *  Data files:   https://algs4.cs.princeton.edu/35applications/tinyTale.txt
 *                https://algs4.cs.princeton.edu/35applications/list.txt
 * 
 *  Read in a whitelist of words from a file. Then read in a list of
 *  words from standard input and print out all those words that
 *  are in the first file.
 * 
 *  % more tinyTale.txt 
 *  it was the best of times it was the worst of times 
 *  it was the age of wisdom it was the age of foolishness 
 *  it was the epoch of belief it was the epoch of incredulity 
 *  it was the season of light it was the season of darkness 
 *  it was the spring of hope it was the winter of despair
 *
 *  % more list.txt 
 *  was it the of 
 * 
 *  % java WhiteFilter list.txt < tinyTale.txt 
 *  it was the of it was the of
 *  it was the of it was the of
 *  it was the of it was the of
 *  it was the of it was the of
 *  it was the of it was the of
 *
 ******************************************************************************/

/**
 *  The {@code WhiteFilter} class provides a client for reading in a <em>whitelist</em>
 *  of words from a file; then, reading in a sequence of words from standard input,
 *  printing out each word that appears in the file.
 *  It is useful as a test client for various symbol table implementations.
 *  <p>
 *  For additional documentation, see <a href="https://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 WhiteFilter {  

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

    public static void main(String[] args) {
        SET<String> set = new SET<String>();

        // read in strings and add to set
        In in = new In(args[0]);
        while (!in.isEmpty()) {
            String word = in.readString();
            set.add(word);
        }

        // read in string from standard input, printing out all exceptions
        while (!StdIn.isEmpty()) {
            String word = StdIn.readString();
            if (set.contains(word))
                StdOut.println(word);
        }
    }
}


Copyright © 2000–2017, Robert Sedgewick and Kevin Wayne.
Last updated: Fri Oct 20 12:50:46 EDT 2017.