Add file pattern resource hints registrar

This commit adds a utility method to register resources on the classpath
based on a location, name, and extension.

Closes gh-28626

spring-core/src/test/java/org/springframework/aot/hint/support/FilePatternResourceHintsRegistrarTests.java

@@ -0,0 +1,135 @@
+/*
+ * 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.aot.hint.support;
+
+import java.util.List;
+import java.util.function.Consumer;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.aot.hint.ResourceHints;
+import org.springframework.aot.hint.ResourcePatternHint;
+import org.springframework.aot.hint.ResourcePatternHints;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+/**
+ * Tests for {@link FilePatternResourceHintsRegistrar}.
+ *
+ * @author Stephane Nicoll
+ */
+class FilePatternResourceHintsRegistrarTests {
+
+	private final ResourceHints hints = new ResourceHints();
+
+	@Test
+	void createWithInvalidName() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new FilePatternResourceHintsRegistrar(
+						List.of("test*"), List.of(""), List.of(".txt")))
+				.withMessageContaining("cannot contain '*'");
+	}
+
+	@Test
+	void createWithInvalidExtension() {
+		assertThatIllegalArgumentException().isThrownBy(() -> new FilePatternResourceHintsRegistrar(
+						List.of("test"), List.of(""), List.of("txt")))
+				.withMessageContaining("should start with '.'");
+	}
+
+	@Test
+	void registerWithSinglePattern() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of(""), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("test*.txt"));
+	}
+
+	@Test
+	void registerWithMultipleNames() {
+		new FilePatternResourceHintsRegistrar(List.of("test", "another"), List.of(""), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("test*.txt", "another*.txt"));
+	}
+
+	@Test
+	void registerWithMultipleLocations() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of("", "META-INF"), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("test*.txt", "META-INF/test*.txt"));
+	}
+
+	@Test
+	void registerWithMultipleExtensions() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of(""), List.of(".txt", ".conf"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("test*.txt", "test*.conf"));
+	}
+
+	@Test
+	void registerWithLocationWithoutTrailingSlash() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of("META-INF"), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("META-INF/test*.txt"));
+	}
+
+	@Test
+	void registerWithLocationWithLeadingSlash() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of("/"), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("test*.txt"));
+	}
+
+	@Test
+	void registerWithLocationUsingResourceClasspathPrefix() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of("classpath:META-INF"), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("META-INF/test*.txt"));
+	}
+
+	@Test
+	void registerWithLocationUsingResourceClasspathPrefixAndTrailingSlash() {
+		new FilePatternResourceHintsRegistrar(List.of("test"), List.of("classpath:/META-INF"), List.of(".txt"))
+				.registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).singleElement()
+				.satisfies(includes("META-INF/test*.txt"));
+	}
+
+	@Test
+	void registerWithNonExistingLocationDoesNotRegisterHint() {
+		new FilePatternResourceHintsRegistrar(List.of("test"),
+				List.of("does-not-exist/", "another-does-not-exist/"),
+				List.of(".txt")).registerHints(this.hints, null);
+		assertThat(this.hints.resourcePatterns()).isEmpty();
+	}
+
+
+	private Consumer<ResourcePatternHints> includes(String... patterns) {
+		return hint -> {
+			assertThat(hint.getIncludes().stream().map(ResourcePatternHint::getPattern))
+					.containsExactlyInAnyOrder(patterns);
+			assertThat(hint.getExcludes()).isEmpty();
+		};
+	}
+
+}