Implement RegexSet to validate a single user-id against multiple wildcards

pgpainless-core/src/main/java/org/pgpainless/algorithm/RegexSet.java

@@ -0,0 +1,40 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public final class RegexSet {
+
+    private final Set<Regex> regexSet = new HashSet<>();
+
+    private RegexSet(Collection<Regex> regexes) {
+        this.regexSet.addAll(regexes);
+    }
+
+    public static RegexSet matchAnything() {
+        return new RegexSet(Collections.singleton(Regex.wildcard()));
+    }
+
+    public static RegexSet matchNothing() {
+        return new RegexSet(Collections.emptySet());
+    }
+
+    public static RegexSet matchSome(Collection<Regex> regexes) {
+        return new RegexSet(regexes);
+    }
+
+    public boolean matches(String userId) {
+        for (Regex regex : regexSet) {
+            if (regex.matches(userId)) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

pgpainless-core/src/test/java/org/pgpainless/algorithm/RegexSetTest.java

@@ -0,0 +1,51 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+public class RegexSetTest {
+
+    @Test
+    public void matchNothingTest() {
+        RegexSet set = RegexSet.matchNothing();
+        assertFalse(set.matches("<alice@pgpainless.org>"));
+        assertFalse(set.matches("Alice"));
+        assertFalse(set.matches("Alice <alice@pgpainless.org>"));
+        assertFalse(set.matches(""));
+    }
+
+    @Test
+    public void matchAnything() {
+        RegexSet set = RegexSet.matchAnything();
+        assertTrue(set.matches("Alice"));
+        assertTrue(set.matches("<alice@pgpainless.org>"));
+        assertTrue(set.matches("Alice <alice@pgpainless.org>"));
+        assertTrue(set.matches("Alice <alice@example.org>"));
+        assertTrue(set.matches(""));
+    }
+
+    @Test
+    public void matchSome() {
+        Regex pgpainless_org = RegexInterpreterFactory.createDefaultMailDomainRegex("pgpainless.org");
+        Regex example_org = RegexInterpreterFactory.createDefaultMailDomainRegex("example.org");
+
+        RegexSet set = RegexSet.matchSome(Arrays.asList(pgpainless_org, example_org));
+        assertTrue(set.matches("Alice <alice@pgpainless.org>"));
+        assertTrue(set.matches("<alice@pgpainless.org>"));
+        assertTrue(set.matches("Bob <bob@example.org>"));
+        assertTrue(set.matches("<bob@example.org>"));
+        assertFalse(set.matches("Bob <bob@example.com>"));
+        assertFalse(set.matches("Alice <alice@PGPainless.org>"));
+        assertFalse(set.matches("alice@pgpainless.org"));
+        assertFalse(set.matches("Alice"));
+        assertFalse(set.matches(""));
+    }
+}