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Merge pull request #6052 from jainvarz/BAEL-2536-check-for-a-panagram-string 

BAEL-2536-check-for-a-panagram-string
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Eric Martin 2019-01-07 19:59:02 -06:00 committed by GitHub
parent 1fdf586336 082724abec
commit 3da571a218
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2 changed files with 104 additions and 0 deletions
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61
java-strings/src/main/java/com/baeldung/string/Pangram.java Normal file
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package com.baeldung.string;
import java.util.Arrays;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class Pangram {
private static final int ALPHABET_COUNT = 26;
public static boolean isPangram(String str) {
if (str == null)
return false;
Boolean[] alphabetMarker = new Boolean[ALPHABET_COUNT];
Arrays.fill(alphabetMarker, false);
int alphabetIndex = 0;
String strUpper = str.toUpperCase();
for (int i = 0; i < str.length(); i++) {
if ('A' <= strUpper.charAt(i) && strUpper.charAt(i) <= 'Z') {
alphabetIndex = strUpper.charAt(i) - 'A';
alphabetMarker[alphabetIndex] = true;
}
}
for (boolean index : alphabetMarker) {
if (!index)
return false;
}
return true;
}
public static boolean isPangramWithStreams(String str) {
if (str == null)
return false;
// filtered character stream
String strUpper = str.toUpperCase();
Stream<Character> filteredCharStream = strUpper.chars()
.filter(item -> ((item >= 'A' && item <= 'Z')))
.mapToObj(c -> (char) c);
Map<Character, Boolean> alphabetMap = filteredCharStream.collect(Collectors.toMap(item -> item, k -> Boolean.TRUE, (p1, p2) -> p1));
return (alphabetMap.size() == ALPHABET_COUNT);
}
public static boolean isPerfectPangram(String str) {
if (str == null)
return false;
// filtered character stream
String strUpper = str.toUpperCase();
Stream<Character> filteredCharStream = strUpper.chars()
.filter(item -> ((item >= 'A' && item <= 'Z')))
.mapToObj(c -> (char) c);
Map<Character, Long> alphabetFrequencyMap = filteredCharStream.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
return (alphabetFrequencyMap.size() == ALPHABET_COUNT && alphabetFrequencyMap.values()
.stream()
.allMatch(item -> item == 1));
}
}

43
java-strings/src/test/java/com/baeldung/string/PangramUnitTest.java Normal file
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package com.baeldung.string;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import org.junit.Test;
public class PangramUnitTest {
@Test
public void givenValidString_isPangram_shouldReturnSuccess() {
String input = "Two driven jocks help fax my big quiz";
assertTrue(Pangram.isPangram(input));
assertTrue(Pangram.isPangramWithStreams(input));
}
@Test
public void givenNullString_isPangram_shouldReturnFailure() {
String input = null;
assertFalse(Pangram.isPangram(input));
assertFalse(Pangram.isPangramWithStreams(input));
assertFalse(Pangram.isPerfectPangram(input));
}
@Test
public void givenPerfectPangramString_isPerfectPangram_shouldReturnSuccess() {
String input = "abcdefghijklmNoPqrStuVwxyz";
assertTrue(Pangram.isPerfectPangram(input));
}
@Test
public void givenNonPangramString_isPangram_shouldReturnFailure() {
String input = "invalid pangram";
assertFalse(Pangram.isPangram(input));
assertFalse(Pangram.isPangramWithStreams(input));
}
@Test
public void givenPangram_isPerfectPangram_shouldReturnFailure() {
String input = "Two driven jocks help fax my big quiz";
assertFalse(Pangram.isPerfectPangram(input));
}
}