Instructions

Test suite

Solution

Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:

The quick brown fox jumps over the lazy dog.

The alphabet used consists of ASCII letters a to z, inclusive, and is case insensitive. Input will not contain non-ASCII symbols.

Setup

Go through the setup instructions for Java to install the necessary dependencies:

https://exercism.io/tracks/java/installation

Running the tests

You can run all the tests for an exercise by entering the following in your terminal:

$ gradle test

In the test suites all tests but the first have been skipped.

Once you get a test passing, you can enable the next one by removing the @Ignore("Remove to run test") annotation.

Source

Wikipedia https://en.wikipedia.org/wiki/Pangram

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

PangramCheckerTest.java

import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

public class PangramCheckerTest {

    private PangramChecker pangramChecker;

    @Before
    public void setup() {
        pangramChecker = new PangramChecker();
    }

    @Test
    public void emptySentenceIsNotPangram() {
        assertFalse(pangramChecker.isPangram(""));
    }

    @Ignore("Remove to run test")
    @Test
    public void perfectLowerCasePhraseIsPangram() {
        assertTrue(pangramChecker.isPangram("abcdefghijklmnopqrstuvwxyz"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseWithOnlyLowerCaseIsPangram() {
        assertTrue(pangramChecker.isPangram("the quick brown fox jumps over the lazy dog"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseMissingCharacterXIsNotPangram() {
        assertFalse(pangramChecker.isPangram("a quick movement of the enemy will jeopardize five gunboats"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseMissingCharacterHIsNotPangram() {
        assertFalse(pangramChecker.isPangram("five boxing wizards jump quickly at it"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseWithUnderscoresIsPangram() {
        assertTrue(pangramChecker.isPangram("the_quick_brown_fox_jumps_over_the_lazy_dog"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseWithNumbersIsPangram() {
        assertTrue(pangramChecker.isPangram("the 1 quick brown fox jumps over the 2 lazy dogs"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseWithMissingLettersReplacedByNumbersIsNotPangram() {
        assertFalse(pangramChecker.isPangram("7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog"));
    }

    @Ignore("Remove to run test")
    @Test
    public void phraseWithMixedCaseAndPunctuationIsPangram() {
        assertTrue(pangramChecker.isPangram("\"Five quacking Zephyrs jolt my wax bed.\""));
    }

    @Ignore("Remove to run test")
    @Test
    public void caseInsensitivePhraseIsNotPangram() {
        assertFalse(pangramChecker.isPangram("the quick brown fox jumps over with lazy FX"));
    }
}

src/main/java/PangramChecker.java

import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class PangramChecker {
    private static final int ALPHABET_COUNT = 26;

    public boolean isPangram(String input) {
        if ( Objects.isNull( input) ) {
            return false;
        }

        String strUpper = input.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);
    }

}

src/test/java/PangramCheckerTest.java

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

public class PangramCheckerTest {

    private PangramChecker pangramChecker;

    @Before
    public void setup() {
        pangramChecker = new PangramChecker();
    }

    @Test
    public void emptySentenceIsNotPangram() {
        assertFalse(pangramChecker.isPangram(""));
    }

    @Test
    public void perfectLowerCasePhraseIsPangram() {
        assertTrue(pangramChecker.isPangram("abcdefghijklmnopqrstuvwxyz"));
    }

    @Test
    public void phraseWithOnlyLowerCaseIsPangram() {
        assertTrue(pangramChecker.isPangram("the quick brown fox jumps over the lazy dog"));
    }

    @Test
    public void phraseMissingCharacterXIsNotPangram() {
        assertFalse(pangramChecker.isPangram("a quick movement of the enemy will jeopardize five gunboats"));
    }

    @Test
    public void phraseMissingCharacterHIsNotPangram() {
        assertFalse(pangramChecker.isPangram("five boxing wizards jump quickly at it"));
    }

    @Test
    public void phraseWithUnderscoresIsPangram() {
        assertTrue(pangramChecker.isPangram("the_quick_brown_fox_jumps_over_the_lazy_dog"));
    }

    @Test
    public void phraseWithNumbersIsPangram() {
        assertTrue(pangramChecker.isPangram("the 1 quick brown fox jumps over the 2 lazy dogs"));
    }

    @Test
    public void phraseWithMissingLettersReplacedByNumbersIsNotPangram() {
        assertFalse(pangramChecker.isPangram("7h3 qu1ck brown fox jumps ov3r 7h3 lazy dog"));
    }

    @Test
    public void phraseWithMixedCaseAndPunctuationIsPangram() {
        assertTrue(pangramChecker.isPangram("\"Five quacking Zephyrs jolt my wax bed.\""));
    }

    @Test
    public void caseInsensitivePhraseIsNotPangram() {
        assertFalse(pangramChecker.isPangram("the quick brown fox jumps over with lazy FX"));
    }
}

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paul-tinius's solution

to Pangram in the Java Track