BAEL-5179: Introduction to HexFormat in Java 17 (#11387)

core-java-modules/core-java-17/src/test/java/com/baeldung/hexformat/ByteHexadecimalConversionUnitTest.java

@@ -0,0 +1,23 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ByteHexadecimalConversionUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of();
+
+    @Test
+    void givenInitialisedHexFormat_whenHexStringIsPassed_thenByteArrayRepresentationIsReturned() {
+        byte[] hexBytes = hexFormat.parseHex("ABCDEF0123456789");
+        assertArrayEquals(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119 }, hexBytes);
+    }
+
+    @Test
+    void givenInitialisedHexFormat_whenByteArrayIsPassed_thenHexStringRepresentationIsReturned() {
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertEquals("abcdef0123456789", bytesAsString);
+    }
+}

core-java-modules/core-java-17/src/test/java/com/baeldung/hexformat/PrimitiveTypeHexadecimalConversionUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class PrimitiveTypeHexadecimalConversionUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of();
+
+    @Test
+    void givenInitialisedHexFormat_whenPrimitiveByteIsPassed_thenHexStringRepresentationIsReturned() {
+        String fromByte = hexFormat.toHexDigits((byte)64);
+        assertEquals("40", fromByte);
+    }
+
+    @Test
+    void givenInitialisedHexFormat_whenPrimitiveLongIsPassed_thenHexStringRepresentationIsReturned() {
+        String fromLong = hexFormat.toHexDigits(1234_5678_9012_3456L);
+        assertEquals("000462d53c8abac0", fromLong);
+    }
+}

core-java-modules/core-java-17/src/test/java/com/baeldung/hexformat/StringFormattingUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StringFormattingUnitTest {
+
+    private HexFormat hexFormat = HexFormat.of().withPrefix("[").withSuffix("]").withDelimiter(", ");
+
+    @Test
+    public void givenInitialisedHexFormatWithFormattedStringOptions_whenByteArrayIsPassed_thenHexStringRepresentationFormattedCorrectlyIsReturned() {
+        assertEquals("[48], [0c], [11]", hexFormat.formatHex(new byte[] {72, 12, 17}));
+    }
+}

core-java-modules/core-java-17/src/test/java/com/baeldung/hexformat/UppercaseLowercaseOutputUnitTest.java

@@ -0,0 +1,40 @@
+package com.baeldung.hexformat;
+
+import java.util.HexFormat;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class UppercaseLowercaseOutputUnitTest {
+
+    @Test
+    public void givenInitialisedHexFormat_whenByteArrayIsPassed_thenLowerCaseHexStringRepresentationIsReturned() {
+        HexFormat hexFormat = HexFormat.of();
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertTrue(isLowerCase(bytesAsString));
+    }
+
+    @Test
+    public void givenInitialisedHexFormatWithUpperCaseOption_whenByteArrayIsPassed_thenLowerCaseHexStringRepresentationIsReturned() {
+        HexFormat hexFormat = HexFormat.of().withUpperCase();
+        String bytesAsString = hexFormat.formatHex(new byte[] { -85, -51, -17, 1, 35, 69, 103, -119});
+        assertTrue(isUpperCase(bytesAsString));
+    }
+
+    private boolean isLowerCase(String str) {
+        char[] charArray = str.toCharArray();
+        for (int i=0; i < charArray.length; i++) {
+            if (Character.isUpperCase(charArray[i]))
+                return false;
+        }
+        return true;
+    }
+
+    private boolean isUpperCase(String str) {
+        char[] charArray = str.toCharArray();
+        for (int i=0; i < charArray.length; i++) {
+            if (Character.isLowerCase(charArray[i]))
+                return false;
+        }
+        return true;
+    }
+}