BAEL-9450

core-java-modules/core-java-regex-4/src/main/java/com/baeldung/regex/regexvalidator/RegexValidator.java

@@ -0,0 +1,16 @@
+package com.baeldung.regex.regexvalidator;
+
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+public class RegexValidator {
+
+    public static boolean isValid(String regex) {
+        try {
+            Pattern.compile(regex);
+            return true;
+        } catch (PatternSyntaxException e) {
+            return false;
+        }
+    }
+}

core-java-modules/core-java-regex-4/src/test/java/com/baeldung/regex/regexvalidator/PatternSyntaxExceptionUnitTest.java

@@ -0,0 +1,80 @@
+package com.baeldung.regex.regexvalidator;
+
+import com.baeldung.regex.regexvalidator.RegexValidator;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class PatternSyntaxExceptionUnitTest {
+
+    @Test
+    void givenUnclosedCharacterClass_whenCompile_thenThrowException() {
+        String regex = "[a-z";
+
+        assertThrows(PatternSyntaxException.class, () -> {
+            Pattern.compile(regex);
+        });
+    }
+
+    @Test
+    void givenValidCharacterClass_whenCompile_thenSuccess() {
+        String regex = "[a-z]";
+
+        Pattern pattern = Pattern.compile(regex);
+
+        assertNotNull(pattern);
+    }
+
+    @Test
+    void givenEscapedBracket_whenCompile_thenSuccess() {
+        String regex = "[abc\\[]";
+
+        assertDoesNotThrow(() -> Pattern.compile(regex));
+    }
+
+    @Test
+    void givenInvalidRegex_whenValidate_thenReturnFalse() {
+        assertFalse(RegexValidator.isValid("[a-z"));
+    }
+
+    @Test
+    void givenValidRegex_whenValidate_thenReturnTrue() {
+        assertTrue(RegexValidator.isValid("[a-z]"));
+    }
+
+    @Test
+    void given2DArray_whenSplitWithEscapedRegex_thenSplitCorrectly() {
+        String[][] array2d = {
+                {"a", "b"},
+                {"c", "d"}
+        };
+
+        String str = Arrays.deepToString(array2d);
+        str = str.substring(1, str.length() - 1);
+
+        String[] result = str.split("\\], \\[");
+
+        assertEquals(2, result.length);
+        assertTrue(result[0].contains("a"));
+        assertTrue(result[1].contains("c"));
+    }
+
+    @Test
+    void givenInvalidSplitRegex_whenSplit_thenThrowException() {
+        String[][] array2d = {
+                {"a", "b"},
+                {"c", "d"}
+        };
+
+        String str = Arrays.deepToString(array2d);
+
+        assertThrows(PatternSyntaxException.class, () -> {
+            str.split("], [");
+        });
+    }
+
+}