Merge pull request #23692 from ttddyy

* pr/23692:
  Polish "Add a composite for TaskDecorator"
  Add a composite for TaskDecorator

Closes gh-23692

spring-core/src/main/java/org/springframework/core/task/support/CompositeTaskDecorator.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2002-2023 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.core.task.support;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import org.springframework.core.task.TaskDecorator;
+import org.springframework.util.Assert;
+
+/**
+ * Composite {@link TaskDecorator} that delegates to other task decorators.
+ *
+ * @author Tadaya Tsuyukubo
+ * @since 6.1
+ */
+public class CompositeTaskDecorator implements TaskDecorator {
+
+	private final List<TaskDecorator> taskDecorators;
+
+	/**
+	 * Create a new instance.
+	 * @param taskDecorators the taskDecorators to delegate to
+	 */
+	public CompositeTaskDecorator(Collection<? extends TaskDecorator> taskDecorators) {
+		Assert.notNull(taskDecorators, "TaskDecorators must not be null");
+		this.taskDecorators = new ArrayList<>(taskDecorators);
+	}
+
+	@Override
+	public Runnable decorate(Runnable runnable) {
+		Assert.notNull(runnable, "Runnable must not be null");
+		for (TaskDecorator taskDecorator : this.taskDecorators) {
+			runnable = taskDecorator.decorate(runnable);
+		}
+		return runnable;
+	}
+
+}

spring-core/src/test/java/org/springframework/core/task/support/CompositeTaskDecoratorTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2002-2023 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.core.task.support;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.InOrder;
+
+import org.springframework.core.task.TaskDecorator;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link CompositeTaskDecorator}.
+ *
+ * @author Tadaya Tsuyukubo
+ * @author Stephane Nicoll
+ */
+class CompositeTaskDecoratorTests {
+
+	@Test
+	void createWithNullCollection() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new CompositeTaskDecorator(null))
+				.withMessage("TaskDecorators must not be null");
+	}
+
+	@Test
+	void decorateWithNullRunnable() {
+		CompositeTaskDecorator taskDecorator = new CompositeTaskDecorator(List.of());
+		assertThatIllegalArgumentException().isThrownBy(() -> taskDecorator.decorate(null))
+				.withMessage("Runnable must not be null");
+	}
+
+	@Test
+	void decorate() {
+		TaskDecorator first = mockNoOpTaskDecorator();
+		TaskDecorator second = mockNoOpTaskDecorator();
+		TaskDecorator third = mockNoOpTaskDecorator();
+		CompositeTaskDecorator taskDecorator = new CompositeTaskDecorator(List.of(first, second, third));
+		Runnable runnable = mock(Runnable.class);
+		taskDecorator.decorate(runnable);
+		InOrder ordered = inOrder(first, second, third);
+		ordered.verify(first).decorate(runnable);
+		ordered.verify(second).decorate(runnable);
+		ordered.verify(third).decorate(runnable);
+	}
+
+	@Test
+	void decorateReuseResultOfPreviousRun() {
+		Runnable original = mock(Runnable.class);
+		Runnable firstDecorated = mock(Runnable.class);
+		TaskDecorator first = mock(TaskDecorator.class);
+		given(first.decorate(original)).willReturn(firstDecorated);
+		Runnable secondDecorated = mock(Runnable.class);
+		TaskDecorator second = mock(TaskDecorator.class);
+		given(second.decorate(firstDecorated)).willReturn(secondDecorated);
+		Runnable result = new CompositeTaskDecorator(List.of(first, second)).decorate(original);
+		assertThat(result).isSameAs(secondDecorated);
+		verify(first).decorate(original);
+		verify(second).decorate(firstDecorated);
+	}
+
+	private TaskDecorator mockNoOpTaskDecorator() {
+		TaskDecorator mock = mock(TaskDecorator.class);
+		given(mock.decorate(any())).willAnswer(invocation -> invocation.getArguments()[0]);
+		return mock;
+	}
+
+}