Simplify AuthorizationManager composition

Closes gh-11625

core/src/main/java/org/springframework/security/authorization/AuthorizationManagers.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.authorization;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A factory class to create an {@link AuthorizationManager} instances.
+ *
+ * @author Evgeniy Cheban
+ * @since 5.8
+ */
+public final class AuthorizationManagers {
+
+	/**
+	 * Creates an {@link AuthorizationManager} that grants access if at least one
+	 * {@link AuthorizationManager} granted or abstained, if <code>managers</code> are
+	 * empty then denied decision is returned.
+	 * @param <T> the type of object that is being authorized
+	 * @param managers the {@link AuthorizationManager}s to use
+	 * @return the {@link AuthorizationManager} to use
+	 */
+	@SafeVarargs
+	public static <T> AuthorizationManager<T> anyOf(AuthorizationManager<T>... managers) {
+		return (authentication, object) -> {
+			List<AuthorizationDecision> decisions = new ArrayList<>();
+			for (AuthorizationManager<T> manager : managers) {
+				AuthorizationDecision decision = manager.check(authentication, object);
+				if (decision == null || decision.isGranted()) {
+					return decision;
+				}
+				decisions.add(decision);
+			}
+			return new CompositeAuthorizationDecision(false, decisions);
+		};
+	}
+
+	/**
+	 * Creates an {@link AuthorizationManager} that grants access if all
+	 * {@link AuthorizationManager}s granted or abstained, if <code>managers</code> are
+	 * empty then granted decision is returned.
+	 * @param <T> the type of object that is being authorized
+	 * @param managers the {@link AuthorizationManager}s to use
+	 * @return the {@link AuthorizationManager} to use
+	 */
+	@SafeVarargs
+	public static <T> AuthorizationManager<T> allOf(AuthorizationManager<T>... managers) {
+		return (authentication, object) -> {
+			List<AuthorizationDecision> decisions = new ArrayList<>();
+			for (AuthorizationManager<T> manager : managers) {
+				AuthorizationDecision decision = manager.check(authentication, object);
+				if (decision != null && !decision.isGranted()) {
+					return decision;
+				}
+				decisions.add(decision);
+			}
+			return new CompositeAuthorizationDecision(true, decisions);
+		};
+	}
+
+	private AuthorizationManagers() {
+	}
+
+	private static final class CompositeAuthorizationDecision extends AuthorizationDecision {
+
+		private final List<AuthorizationDecision> decisions;
+
+		private CompositeAuthorizationDecision(boolean granted, List<AuthorizationDecision> decisions) {
+			super(granted);
+			this.decisions = decisions;
+		}
+
+		@Override
+		public String toString() {
+			return "CompositeAuthorizationDecision [decisions=" + this.decisions + ']';
+		}
+
+	}
+
+}

core/src/test/java/org/springframework/security/authorization/AuthorizationManagersTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.authorization;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link AuthorizationManagers}.
+ *
+ * @author Evgeniy Cheban
+ */
+class AuthorizationManagersTests {
+
+	@Test
+	void checkAnyOfWhenOneGrantedThenGrantedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.anyOf((a, o) -> new AuthorizationDecision(false),
+				(a, o) -> new AuthorizationDecision(true));
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isTrue();
+	}
+
+	@Test
+	void checkAnyOfWhenOneAbstainedThenAbstainedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.anyOf((a, o) -> new AuthorizationDecision(false),
+				(a, o) -> null);
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNull();
+	}
+
+	@Test
+	void checkAnyOfWhenEmptyThenDeniedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.anyOf();
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isFalse();
+	}
+
+	@Test
+	void checkAllOfWhenAllGrantedThenGrantedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.allOf((a, o) -> new AuthorizationDecision(true),
+				(a, o) -> new AuthorizationDecision(true));
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isTrue();
+	}
+
+	@Test
+	void checkAllOfWhenOneAbstainedThenGrantedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.allOf((a, o) -> new AuthorizationDecision(true),
+				(a, o) -> null);
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isTrue();
+	}
+
+	@Test
+	void checkAllOfWhenOneDeniedThenDeniedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.allOf((a, o) -> new AuthorizationDecision(true),
+				(a, o) -> new AuthorizationDecision(false));
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isFalse();
+	}
+
+	@Test
+	void checkAllOfWhenEmptyThenGrantedDecision() {
+		AuthorizationManager<?> composed = AuthorizationManagers.allOf();
+		AuthorizationDecision decision = composed.check(null, null);
+		assertThat(decision).isNotNull();
+		assertThat(decision.isGranted()).isTrue();
+	}
+
+}