info.boytsov.lucene.CheckSort.java Source code

Introduction

Here is the source code for info.boytsov.lucene.CheckSort.java

Source

/**
 *
 * This code is released under the
 * Apache License Version 2.0 http://www.apache.org/licenses/.
 *  
 */
package info.boytsov.lucene;

import java.io.File;
import java.util.Arrays;

import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.store.FSDirectory;

public class CheckSort {
    public static void main(String[] args) {
        if (args.length != 2) {
            printUsage();
            System.exit(1);
        }
        int dir = 1;

        String srcDirName = args[0];
        System.out.println("Source dir: " + srcDirName);
        if (args[1].equals("forward"))
            dir = 1;
        else if (args[1].equals("backward"))
            dir = -1;
        else {
            System.err.println("Invalid direction: " + args[1]);
            printUsage();
            System.exit(1);
        }

        try {
            IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(srcDirName)));

            int docQty = reader.maxDoc();
            int sortTable[] = new int[docQty];

            Arrays.fill(sortTable, -1);

            int sortedQty = 0;

            double sortedStreak = 0;
            int sortedStreakQty = 0;

            URL2DocID remap[] = new URL2DocID[docQty];

            String prevURL = "";

            int prevSorted = 0;

            for (int docID = 0; docID < docQty; ++docID) {
                Document doc = reader.document(docID);
                String url = doc.get("url");
                if (dir > 0) {
                    remap[docID] = new URL2DocID(url, docID);
                } else {
                    remap[docQty - 1 - docID] = new URL2DocID(url, docID);
                }
                if (docID % 100000 == 0) {
                    System.out.println("Collected " + (docID + 1) + " URLs, sorted so far, direct " + sortedQty
                            + " avg. sorted streak QTY: " + (sortedStreak / sortedStreakQty) + " sortedStreakQty: "
                            + sortedStreakQty);
                }
                // Assuming the increasing order
                if (dir * url.compareTo(prevURL) >= 0) {
                    ++sortedQty;
                } else {
                    sortedStreak += docID - prevSorted - 1;
                    sortedStreakQty++;

                    prevSorted = docID;
                }
                prevURL = url;
            }

            System.out.println("Collected " + docQty + " URLs, sorted so far, direct " + sortedQty
                    + " avg. sorted streak QTY: " + (sortedStreak / sortedStreakQty) + " sortedStreakQty: "
                    + sortedStreakQty);

            double invQty = Inversions.count(remap);
            System.out.println("A total number of inversions: " + invQty + " relative to n*(n-1)/2: "
                    + (invQty * 2.0 / docQty / (docQty + 1)));

        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
            e.printStackTrace();
            System.exit(1);
        }

    }

    private static void printUsage() {
        System.out.println("mvn exec:java " + " -Dexec.mainClass=info.boytsov.lucene.CheckSort " + " -Dexec.args=\""
                + " <index dir> <direction forward:backward>\"");
    }

}