ctrus.pa.util.CtrusHelper.java Source code

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Here is the source code for ctrus.pa.util.CtrusHelper.java

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/*******************************************************************************
 * Copyright (c) 2015, 2016  Naveen Kulkarni
 *
 * This file is part of Bag of Words program. 
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Contributors:
 *     Naveen Kulkarni (naveen.kulkarni@research.iiit.ac.in)
 *     
 *******************************************************************************/

package ctrus.pa.util;

import java.util.ArrayList;
import java.util.List;
import org.apache.commons.lang3.StringUtils;

/**
 * A utility Class
 * @author Naveen Kulkarni
 */
public class CtrusHelper {

    /**
     * A command line progress bar.
     * Author: http://nakkaya.com/2009/11/08/command-line-progress-bar/
     * @param message   Any message to be printed along side the progress bar
     * @param current   Current count
     * @param max      Maximum count
     */
    public final static void progressMonitor(String message, int current, int max) {

        StringBuilder bar = new StringBuilder("\r");
        bar.append(message).append(" [");

        int percent = (int) (current * 100 / max);

        for (int i = 0; i <= 50; i++) {
            if (i < (percent / 2)) {
                bar.append("=");
            } else if (i == (percent / 2)) {
                bar.append(">");
            } else {
                bar.append(".");
            }
        }

        bar.append("]  " + percent + "%  #(" + current + "/" + max + ")");

        // Add a new line if the processing is finished...
        if (percent == 100)
            bar.append("\n");

        System.out.print(bar.toString());
    }

    public static final void printToConsole(String message) {
        System.out.println(message);
    }

    // create a unique id using base62 encoding of a static counter
    private static final String $baseDigits = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

    public static final CharSequence uniqueId(String s) {

        if (s == null || StringUtils.isEmpty(s))
            throw new IllegalArgumentException("Input cannot be null or empty");

        //long idNum = MurmurHash2.hash64(sClean);
        long idNum = FNVHash.newHashFunction().hash64(s.getBytes());
        idNum = idNum < 0 ? -idNum : idNum;

        String uid = "";
        long mod = 0;
        int division = 17;

        while (idNum != 0) {
            mod = idNum % division;
            uid = $baseDigits.substring((int) mod, (int) mod + 1) + uid;
            idNum = idNum / division;
        }

        return uid;
    }

    public static final List<String> minHash(String s, int windowSize, List<FNVHash> hashFunctions) {
        // Build a list of shingles
        int l = s.length(), w = windowSize, i = 0;

        // Create shingles of windowSize length with a single char overlapping
        List<String> shingles = new ArrayList<String>();
        for (i = 1; i <= l - w; i += 1) {
            shingles.add(s.substring(i - 1, i + w).toLowerCase());
        }
        // any remaining substrings that are less than windowSize
        if (l > i) {
            shingles.add(s.substring(i, l).toLowerCase());
        }

        return getMinHashValue(shingles, hashFunctions);
    }

    private static List<String> getMinHashValue(List<String> shingles, List<FNVHash> hashFunctions) {
        List<String> minHashes = new ArrayList<String>();
        for (FNVHash h : hashFunctions) {
            int minHashVal = Integer.MAX_VALUE;
            for (String s : shingles) {
                int hVal = h.hash32(s.getBytes());
                if (hVal < minHashVal)
                    minHashVal = hVal;
            }
            minHashes.add(Integer.toHexString(minHashVal));
        }
        return minHashes;
    }

}