BookRankpublic class BookRank extends Object | Graph of a book's sales rank on a given bookshop site. |
| Fields Summary |
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| public static final String | DATA_FILE | | public static final String | GRAPH_FILE |
| Methods Summary |
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| public static void | main(java.lang.String[] args)Grab the sales rank off the web page and log it.
Properties p = new FileProperties(
args.length == 0 ? "bookrank.properties" : args[1]);
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 = FileIO.readerToString(is);
// 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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