Regular Expressions in Action
/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/
import java.io.BufferedReader;
import java.io.FileWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Properties;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Graph of a book's sales rank on a given bookshop site.
*
* @author Ian F. Darwin, http://www.darwinsys.com/, Java Cookbook author,
* originally translated fairly literally from Perl into Java.
* @author Patrick Killelea <p@patrick.net>: original Perl version, from the 2nd
* edition of his book "Web Performance Tuning".
* @version $Id: BookRank.java,v 1.8 2004/03/20 20:48:03 ian Exp $
*/
public class BookRank {
public final static String DATA_FILE = "book.sales";
public final static String GRAPH_FILE = "book.png";
/** Grab the sales rank off the web page and log it. */
public static void main(String[] args) throws Exception {
Properties p = new Properties();
String title = p.getProperty("title", "NO TITLE IN PROPERTIES");
// The url must have the "isbn=" at the very end, or otherwise
// be amenable to being string-catted to, like the default.
String url = p.getProperty("url", "http://test.ing/test.cgi?isbn=");
// The 10-digit ISBN for the book.
String isbn = p.getProperty("isbn", "0000000000");
// The RE pattern (MUST have ONE capture group for the number)
String pattern = p.getProperty("pattern", "Rank: (\\d+)");
// Looking for something like this in the input:
// <b>QuickBookShop.web Sales Rank: </b>
// 26,252
// </font><br>
Pattern r = Pattern.compile(pattern);
// Open the URL and get a Reader from it.
BufferedReader is = new BufferedReader(new InputStreamReader(new URL(
url + isbn).openStream()));
// Read the URL looking for the rank information, as
// a single long string, so can match RE across multi-lines.
String input = "input from console";
// System.out.println(input);
// If found, append to sales data file.
Matcher m = r.matcher(input);
if (m.find()) {
PrintWriter pw = new PrintWriter(new FileWriter(DATA_FILE, true));
String date = // `date +'%m %d %H %M %S %Y'`;
new SimpleDateFormat("MM dd hh mm ss yyyy ").format(new Date());
// Paren 1 is the digits (and maybe ','s) that matched; remove comma
Matcher noComma = Pattern.compile(",").matcher(m.group(1));
pw.println(date + noComma.replaceAll(""));
pw.close();
} else {
System.err.println("WARNING: pattern `" + pattern
+ "' did not match in `" + url + isbn + "'!");
}
// Whether current data found or not, draw the graph, using
// external plotting program against all historical data.
// Could use gnuplot, R, any other math/graph program.
// Better yet: use one of the Java plotting APIs.
String gnuplot_cmd = "set term png\n" + "set output \"" + GRAPH_FILE
+ "\"\n" + "set xdata time\n"
+ "set ylabel \"Book sales rank\"\n" + "set bmargin 3\n"
+ "set logscale y\n" + "set yrange [1:60000] reverse\n"
+ "set timefmt \"%m %d %H %M %S %Y\"\n" + "plot \"" + DATA_FILE
+ "\" using 1:7 title \"" + title + "\" with lines\n";
Process proc = Runtime.getRuntime().exec("/usr/local/bin/gnuplot");
PrintWriter gp = new PrintWriter(proc.getOutputStream());
gp.print(gnuplot_cmd);
gp.close();
}
}
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