org.emabrey.stackoverflow.java.StringLengthExample class

/*
 * The MIT License (MIT)
 *
 * Copyright © 2016 Emily Mabrey
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
package org.emabrey.stackoverflow.java;

import java.io.InputStream;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.text.BreakIterator;
import java.text.Normalizer;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Scanner;

/**
 * Example class for use in answering <a href="http://stackoverflow.com/a/41309320/2446574">this StackOverflow question
 * on getting the length of a String</a>. This class requires a file named "unicodetest.txt" be placed alongside it in
 * the same package as a JAR resource; that file should contain the contents of the Quick Brown Unicode file available
 * <a href="http://www.cl.cam.ac.uk/~mgk25/ucs/examples/quickbrown.txt"> here</a>.
 *
 * @see http://stackoverflow.com/a/41309320/2446574
 * @see http://www.cl.cam.ac.uk/~mgk25/ucs/examples/quickbrown.txt
 *
 * @author Emily Mabrey <[email protected]>
 */
public class StringLengthExample {

    public static void main(String[] args) {

        final String inputQuickBrownString = convertStreamToString(StringLengthExample.class.getResourceAsStream("unicodetest.txt"), StandardCharsets.UTF_8);
        final String nfcNormalizedString = Normalizer.normalize(inputQuickBrownString, Normalizer.Form.NFC);
        final String nfdNormalizedString = Normalizer.normalize(inputQuickBrownString, Normalizer.Form.NFD);

        System.out.println("Input UTF-8 String");
        printAllLengths(inputQuickBrownString);

        System.out.println("NFC Normalized UTF-8 String");
        printAllLengths(nfcNormalizedString);

        System.out.println("NFD Normalized UTF-8 String");
        printAllLengths(nfdNormalizedString);

    }

    private static void printAllLengths(String string) {

        BreakIterator englishBreaks = BreakIterator.getCharacterInstance(Locale.ENGLISH);
        englishBreaks.setText(string);
        List<Integer> graphemes = new ArrayList<>(string.length());

        while (englishBreaks.next() != BreakIterator.DONE) {
            graphemes.add(englishBreaks.current());
        }

        System.out.println(String.format(">>\tString.length() = %d", string.length()));
        System.out.println(String.format(">>\tString.codePointCount(int,int) = %d", string.codePointCount(0, string.length())));
        System.out.println(String.format(">>\tBreakIterator.getCharacterInstance(Locale) = %d", graphemes.size()));
    }

    private static String convertStreamToString(InputStream is, Charset c) {
        return new Scanner(is, c.name()).useDelimiter("\\A").next();
    }

}