SONARJAVA-5745 Stop using org.apache.commons.lang3.StringUtils::countMatches (#5288)

Co-authored-by: Dorian Burihabwa <75226315+dorian-burihabwa-sonarsource@users.noreply.github.com>

Author: tomasz-tylenda-sonarsource

java-checks/src/main/java/org/sonar/java/checks/AbstractPrintfChecker.java

@@ -29,7 +29,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import javax.annotation.Nullable;
-import org.apache.commons.lang3.StringUtils;
+
+import org.sonar.java.checks.helpers.StringUtils;
 import org.sonar.java.checks.methods.AbstractMethodDetection;
 import org.sonar.java.model.LiteralUtils;
 import org.sonar.plugins.java.api.semantic.MethodMatchers;

java-checks/src/main/java/org/sonar/java/checks/HardcodedIpCheck.java

@@ -21,8 +21,8 @@
 import java.util.Optional;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import org.apache.commons.lang3.StringUtils;
 import org.sonar.check.Rule;
+import org.sonar.java.checks.helpers.StringUtils;
 import org.sonar.java.model.LiteralUtils;
 import org.sonar.plugins.java.api.JavaFileScanner;
 import org.sonar.plugins.java.api.JavaFileScannerContext;

java-checks/src/main/java/org/sonar/java/checks/PreparedStatementAndResultSetCheck.java

@@ -19,9 +19,9 @@
 import java.util.Optional;
 import javax.annotation.CheckForNull;
 import javax.annotation.Nullable;
-import org.apache.commons.lang3.StringUtils;
 import org.sonar.check.Rule;
 import org.sonar.java.checks.helpers.ReassignmentFinder;
+import org.sonar.java.checks.helpers.StringUtils;
 import org.sonar.java.checks.methods.AbstractMethodDetection;
 import org.sonar.java.model.ExpressionUtils;
 import org.sonar.plugins.java.api.semantic.MethodMatchers;

java-checks/src/main/java/org/sonar/java/checks/helpers/StringUtils.java

@@ -0,0 +1,44 @@
+/*
+ * SonarQube Java
+ * Copyright (C) 2012-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.java.checks.helpers;
+
+import javax.annotation.Nullable;
+
+public class StringUtils {
+  private StringUtils() {}
+
+  /** Check if the string is null or empty. */
+  public static boolean isEmpty(@Nullable String s) {
+    return s == null || s.isEmpty();
+  }
+
+  /** Count non-overlapping occurrences of <code>pattern</code> in the <code>string</code>. */
+  public static int countMatches(@Nullable String string, @Nullable String pattern) {
+    if (isEmpty(string) || isEmpty(pattern)) {
+      return 0;
+    }
+
+    int count = 0;
+    int idx = 0;
+    while ((idx = string.indexOf(pattern, idx)) != -1) {
+      count++;
+      idx += pattern.length();
+    }
+
+    return count;
+  }
+}

java-checks/src/main/java/org/sonar/java/checks/regex/RegexComplexityCheck.java

@@ -20,9 +20,9 @@
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
-import org.apache.commons.lang3.StringUtils;
 import org.sonar.check.Rule;
 import org.sonar.check.RuleProperty;
+import org.sonar.java.checks.helpers.StringUtils;
 import org.sonar.java.model.ExpressionUtils;
 import org.sonar.java.model.LineUtils;
 import org.sonar.plugins.java.api.JavaFileScannerContext;

java-checks/src/test/java/org/sonar/java/checks/helpers/StringUtilsTest.java

@@ -0,0 +1,45 @@
+/*
+ * SonarQube Java
+ * Copyright (C) 2012-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.java.checks.helpers;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StringUtilsTest {
+  @Test
+  void testIsEmpty() {
+    assertThat(StringUtils.isEmpty(null)).isTrue();
+    assertThat(StringUtils.isEmpty("")).isTrue();
+    assertThat(StringUtils.isEmpty(" ")).isFalse();
+    assertThat(StringUtils.isEmpty("abc")).isFalse();
+  }
+
+  @Test
+  void testCountMatches() {
+    assertThat(StringUtils.countMatches(null, "ab")).isZero();
+    assertThat(StringUtils.countMatches("", "ab")).isZero();
+    assertThat(StringUtils.countMatches("ab", null)).isZero();
+    assertThat(StringUtils.countMatches("ab", "")).isZero();
+
+    assertThat(StringUtils.countMatches("abababab", "cccc")).isZero();
+    assertThat(StringUtils.countMatches("abababab", "ab")).isEqualTo(4);
+
+    assertThat(StringUtils.countMatches("abaTaba", "aba")).isEqualTo(2);
+    assertThat(StringUtils.countMatches("abababa", "aba")).isEqualTo(2);
+  }
+}