Add extractMatches() to RegExUtils

src/main/java/org/apache/commons/lang3/RegExUtils.java

@@ -16,9 +16,13 @@
  */
 package org.apache.commons.lang3;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.Objects;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
 
 /**
  * Helpers to process Strings using regular expressions.
@@ -751,4 +755,67 @@ private static String toStringOrNull(final CharSequence text) {
     public RegExUtils() {
         // empty
     }
+
+    /**
+     * Finds all matches in the given text according to the specified pattern.
+     *
+     * @param text    the text to search for matches
+     * @param pattern the pattern to search for
+     * @return an unmodifiable list of found matches; returns an empty List if text or pattern is null
+     */
+    public List<String> findMatches(CharSequence text, Pattern pattern) {
+        if (text == null || pattern == null){
+            return Collections.emptyList();
+        }
+
+        List<String> matches = new ArrayList<>();
+        Matcher matcher = pattern.matcher(text);
+
+        while (matcher.find()) {
+            matches.add(matcher.group());
+        }
+
+        return Collections.unmodifiableList(matches);
+    }
+
+    /**
+     * Finds all matches in the given text according to the specified pattern
+     * and returns them as an array of strings.
+     *
+     * @param text  the text to search for matches
+     * @param regex the regular expression pattern
+     * @return an array of found matches; returns an empty array if text or regex is null
+     */
+    public String[] findMatchesAsArray(CharSequence text, String regex) {
+        if (text == null ||regex == null){
+            return new String[0];
+        }
+        try {
+            Pattern pattern = Pattern.compile(regex);
+            List<String> matches = findMatches(text, pattern);
+            return matches.toArray(new String[0]);
+        }catch (PatternSyntaxException e){
+            return new String[0];
+        }
+    }
+
+    /**
+     * Finds all matches in the given text according to the specified pattern
+     * and returns them as a modifiable ArrayList.
+     *
+     * @param text    the text to search for matches
+     * @param pattern the pattern to search for
+     * @return a modifiable ArrayList of found matches; returns an empty List if text or pattern is null
+     */
+    public List<String> findMatchesModifiable(CharSequence text, Pattern pattern){
+        if (text == null || pattern == null){
+            return new ArrayList<>();
+        }
+        Matcher matcher = pattern.matcher(text);
+        List<String> matches = new ArrayList<>();
+        while (matcher.find()){
+            matches.add(matcher.group());
+        }
+        return matches;
+    }
 }

src/test/java/org/apache/commons/lang3/RegExUtilsTest.java

@@ -16,16 +16,18 @@
  */
 package org.apache.commons.lang3;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNull;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-
+import java.util.Arrays;
+import java.util.List;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import javax.annotation.RegEx;
+
+import static org.junit.jupiter.api.Assertions.*;
+
 /**
  * Tests {@link RegExUtils}.
  */
@@ -379,4 +381,149 @@ public void testReplacePatternDeprecated() {
         assertEquals("Lorem_ipsum_dolor_sit", RegExUtils.replacePattern("Lorem ipsum  dolor   sit", "( +)([a-z]+)", "_$2"));
     }
 
+    private RegExUtils utils;
+
+    @BeforeEach
+    void setUp() {
+        utils = new RegExUtils();
+    }
+
+    @Test
+    public void testFindMultipleMatches() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String> result = utils.findMatches("asd 123 fgd 456 zxc", pattern);
+        assertEquals(Arrays.asList("123", "456"), result);
+    }
+
+    @Test
+    public void testFindNoMatches() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String> result = utils.findMatches("asd zxc", pattern);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testFindMatchesWhenTextIsEmpty() {
+        String[] result = utils.findMatchesAsArray("", "\\w+");
+        assertArrayEquals(new String[0], result);
+    }
+//    @Test
+//    public void testShouldReturnArrayList() {
+//        Pattern pattern = Pattern.compile("\\w+");
+//        List<String> result = utils.findMatches("test", pattern);
+//        assertEquals(Arrays.asList("test"), result);
+//        assertTrue(result instanceof ArrayList);
+//    }
+
+    @Test
+    public void testFindMatchesWhenTextIsNull() {
+        Pattern pattern = Pattern.compile("test");
+        List<String> result = utils.findMatches(null, pattern);
+        assert (result).isEmpty();
+    }
+
+    @Test
+    public void testFindMatchesWhenPatternIsNull() {
+        List<String> result = utils.findMatches("test", null);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void testFindMatchesWithEmptyText() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String> result = utils.findMatches("", pattern);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void testFindMultipleMatchesAsArray() {
+        String[] result = utils.findMatchesAsArray("test 123 test", "\\w+");
+        assertArrayEquals(new String[]{"test", "123", "test"}, result);
+    }
+
+    @Test
+    void testFindMatchesAsArrayWhenNoMatches() {
+        String[] result = utils.findMatchesAsArray("abc", "\\d");
+        assertArrayEquals(new String[0], result);
+    }
+
+    @Test
+    void testFindMatchesAsArrayWhenTextIsNull() {
+        String[] result = utils.findMatchesAsArray(null, "\\w+");
+        assertArrayEquals(new String[0], result);
+    }
+
+    @Test
+    void testFindMatchesAsArrayWhenTextIsEmpty() {
+        String[] result = utils.findMatchesAsArray("", "\\w+");
+        assertArrayEquals(new String[0], result);
+    }
+
+    @Test
+    void testFindMatchesAsArrayWithInvalidRegex() {
+        String[] result = utils.findMatchesAsArray("text", "[a-z");
+        assertArrayEquals(new String[0], result);
+    }
+
+    @Test
+    public void testReturnedListIsUnmodifiable() {
+        Pattern pattern = Pattern.compile("\\w+");
+        List<String> result = utils.findMatches("test", pattern);
+
+        try {
+            result.add("should fail");
+            fail("Expected UnsupportedOperationException");
+        } catch (UnsupportedOperationException e) {}
+    }
+
+    @Test
+    public void testFindMultipleMatchesAsArrayList(){
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String> result = utils.findMatchesModifiable("asd 123 fgd 456 zxc", pattern);
+        assertEquals(Arrays.asList("123", "456"), result);
+    }
+
+    @Test
+    public void testShouldAddElementInFindMatchesModifiable(){
+        Pattern pattern = Pattern.compile("\\w+");
+        List<String> result = utils.findMatchesModifiable("asd test 123", pattern);
+        result.add("text");
+        assertEquals(Arrays.asList("asd", "test", "123", "text"), result);
+    }
+
+    @Test
+    public void testShouldRemoveElementInFindMatchesModifiable(){
+        Pattern pattern = Pattern.compile("\\w+");
+        List<String> result = utils.findMatchesModifiable("asd test 123", pattern);
+        result.remove("123");
+        assertEquals(Arrays.asList("asd","test"), result);
+    }
+
+    @Test
+    public void testFindNoMatchesAsArrayList() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String> result = utils.findMatchesModifiable("asd zxc", pattern);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testFindMatchesAsArrayListWhenTextIsEmpty() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String>result = utils.findMatchesModifiable("", pattern);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testFindMatchesAsArrayListWhenTextIsNull() {
+        Pattern pattern = Pattern.compile("\\d+");
+        List<String>result = utils.findMatchesModifiable(null, pattern);
+        assertTrue(result.isEmpty());
+    }
+
+    @Test
+    void testFindMatchesAsArrayListWhenPatternIsNull(){
+        List<String>result = utils.findMatchesModifiable("asd 123", null);
+        assertTrue(result.isEmpty());
+    }
+
 }