NewMatcherMethods.java

package javax0.j9regex.samples;

import org.junit.Test;

import java.util.concurrent.atomic.AtomicInteger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

import static org.junit.Assert.assertEquals;

public class NewMatcherMethods {

    @Test
    public void demoReplaceAllFunction() {
        Pattern pattern = Pattern.compile("dog");
        Matcher matcher = pattern.matcher("zzzdogzzzdogzzz");
        String result = matcher.replaceAll(mr -> mr.group().toUpperCase());
        assertEquals("zzzDOGzzzDOGzzz", result);
    }


    @Test
    public void countSampleReplaceAllFunction() {
        //Pattern pattern = Pattern.compile("\\d+(?:\\.\\d+)?(?:[Ee][+-]?\\d{1,2})?");
        AtomicInteger counter = new AtomicInteger(0);
        Pattern pattern = Pattern.compile("#+");
        Matcher matcher = pattern.matcher("# first item\n" +
                "# second item\n" +
                "## third and fourth\n" +
                "## item 5 and 6\n" +
                "# item 7");
        String result = matcher.replaceAll(mr -> "" + counter.addAndGet(mr.group().length()));
        assertEquals("1 first item\n" +
                "2 second item\n" +
                "4 third and fourth\n" +
                "6 item 5 and 6\n" +
                "7 item 7", result);
    }


    @Test
    public void calculateSampleReplaceAllFunction() {
        Pattern pattern = Pattern.compile("\\d+(?:\\.\\d+)?(?:[Ee][+-]?\\d{1,2})?");
        Matcher matcher = pattern.matcher("The sin(pi) is 3.1415926");
        String result = matcher.replaceAll(mr -> "" + (Math.sin(Double.parseDouble(mr.group()))));
        assertEquals("The sin(pi) is 5.3589793170057245E-8", result);
    }

    @Test
    public void resultsTest() {
        Pattern pattern = Pattern.compile("\\d+(?:\\.\\d+)?(?:[Ee][+-]?\\d{1,2})?");
        Matcher matcher = pattern.matcher("Pi is around 3.1415926 and not 3.2 even in Indiana");
        String result = String.join(",",
                matcher
                        .results()
                        .map(mr -> "" + (Math.sin(Double.parseDouble(mr.group()))))
                        .collect(Collectors.toList()));
        assertEquals("5.3589793170057245E-8,-0.058374143427580086", result);
    }

    @Test
    public void testAppendReplacement() {

        Pattern p = Pattern.compile("cat(?<plural>z?s?)");
        //Pattern p = Pattern.compile("cat(z?s?)");
        Matcher m = p.matcher("one catz two cats in the yard");
        StringBuilder sb = new StringBuilder();
        while (m.find()) {
            m.appendReplacement(sb, "dog${plural}");
            //m.appendReplacement(sb, "dog$001");
        }
        m.appendTail(sb);
        String result = sb.toString();
        assertEquals("one dogz two dogs in the yard", result);
    }

}