Polish EnvConfigData

Rename classes to align with existing `SystemEnvironment...` classes
and extract common `FileExtensionHint` logic.

See gh-41609

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/ConfigDataResourceNotFoundException.java

@@ -116,7 +116,7 @@ private static String getReferenceDescription(ConfigDataResource resource, Confi
 	 * @param pathToCheck the path to check
 	 */
 	public static void throwIfDoesNotExist(ConfigDataResource resource, Path pathToCheck) {
-		throwIfDoesNotExist(resource, Files.exists(pathToCheck));
+		throwIfNot(resource, Files.exists(pathToCheck));
 	}
 
 	/**
@@ -126,7 +126,7 @@ public static void throwIfDoesNotExist(ConfigDataResource resource, Path pathToC
 	 * @param fileToCheck the file to check
 	 */
 	public static void throwIfDoesNotExist(ConfigDataResource resource, File fileToCheck) {
-		throwIfDoesNotExist(resource, fileToCheck.exists());
+		throwIfNot(resource, fileToCheck.exists());
 	}
 
 	/**
@@ -136,11 +136,11 @@ public static void throwIfDoesNotExist(ConfigDataResource resource, File fileToC
 	 * @param resourceToCheck the resource to check
 	 */
 	public static void throwIfDoesNotExist(ConfigDataResource resource, Resource resourceToCheck) {
-		throwIfDoesNotExist(resource, resourceToCheck.exists());
+		throwIfNot(resource, resourceToCheck.exists());
 	}
 
-	private static void throwIfDoesNotExist(ConfigDataResource resource, boolean exists) {
-		if (!exists) {
+	private static void throwIfNot(ConfigDataResource resource, boolean check) {
+		if (!check) {
 			throw new ConfigDataResourceNotFoundException(resource);
 		}
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/EnvConfigDataLoader.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012-2025 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.boot.context.config;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * User provided hint for an otherwise missing file extension.
+ *
+ * @author Phillip Webb
+ */
+final class FileExtensionHint {
+
+	private static final Pattern PATTERN = Pattern.compile("^(.*)\\[(\\.\\w+)](?!\\[)$");
+
+	private static final FileExtensionHint NONE = new FileExtensionHint(null);
+
+	private final Matcher matcher;
+
+	private FileExtensionHint(Matcher matcher) {
+		this.matcher = matcher;
+	}
+
+	/**
+	 * Return {@code true} if the hint is present.
+	 * @return if the hint is present
+	 */
+	boolean isPresent() {
+		return this.matcher != null;
+	}
+
+	/**
+	 * Return the extension from the hint or return the parameter if the hint is not
+	 * {@link #isPresent() present}.
+	 * @param extension the fallback extension
+	 * @return the extension either from the hint or fallback
+	 */
+	String orElse(String extension) {
+		return (this.matcher != null) ? toString() : extension;
+	}
+
+	@Override
+	public String toString() {
+		return (this.matcher != null) ? this.matcher.group(2) : "";
+	}
+
+	/**
+	 * Return the {@link FileExtensionHint} from the given value.
+	 * @param value the source value
+	 * @return the {@link FileExtensionHint} (never {@code null})
+	 */
+	static FileExtensionHint from(String value) {
+		Matcher matcher = PATTERN.matcher(value);
+		return (matcher.matches()) ? new FileExtensionHint(matcher) : NONE;
+	}
+
+	/**
+	 * Remove any hint from the given value.
+	 * @param value the source value
+	 * @return the value without any hint
+	 */
+	static String removeFrom(String value) {
+		Matcher matcher = PATTERN.matcher(value);
+		return (matcher.matches()) ? matcher.group(1) : value;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/EnvConfigDataResource.java

@@ -26,7 +26,6 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -68,8 +67,6 @@ public class StandardConfigDataLocationResolver
 
 	private static final Pattern URL_PREFIX = Pattern.compile("^([a-zA-Z][a-zA-Z0-9*]*?:)(.*$)");
 
-	private static final Pattern EXTENSION_HINT_PATTERN = Pattern.compile("^(.*)\\[(\\.\\w+)](?!\\[)$");
-
 	private static final String NO_PROFILE = null;
 
 	private final Log logger;
@@ -238,17 +235,16 @@ private Deque<StandardConfigDataReference> getReferencesForConfigName(String nam
 
 	private Set<StandardConfigDataReference> getReferencesForFile(ConfigDataLocation configDataLocation, String file,
 			String profile) {
-		Matcher extensionHintMatcher = EXTENSION_HINT_PATTERN.matcher(file);
-		boolean extensionHintLocation = extensionHintMatcher.matches();
-		if (extensionHintLocation) {
-			file = extensionHintMatcher.group(1) + extensionHintMatcher.group(2);
+		FileExtensionHint fileExtensionHint = FileExtensionHint.from(file);
+		if (fileExtensionHint.isPresent()) {
+			file = FileExtensionHint.removeFrom(file) + fileExtensionHint;
 		}
 		for (PropertySourceLoader propertySourceLoader : this.propertySourceLoaders) {
-			String extension = getLoadableFileExtension(propertySourceLoader, file);
-			if (extension != null) {
-				String root = file.substring(0, file.length() - extension.length() - 1);
+			String fileExtension = getLoadableFileExtension(propertySourceLoader, file);
+			if (fileExtension != null) {
+				String root = file.substring(0, file.length() - fileExtension.length() - 1);
 				StandardConfigDataReference reference = new StandardConfigDataReference(configDataLocation, null, root,
-						profile, (!extensionHintLocation) ? extension : null, propertySourceLoader);
+						profile, (!fileExtensionHint.isPresent()) ? fileExtension : null, propertySourceLoader);
 				return Collections.singleton(reference);
 			}
 		}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/config/FileExtensionHint.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2025 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.boot.context.config;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.springframework.core.env.PropertySource;
+
+/**
+ * {@link ConfigDataLoader} to load data from system environment variables.
+ *
+ * @author Moritz Halbritter
+ */
+class SystemEnvironmentConfigDataLoader implements ConfigDataLoader<SystemEnvironmentConfigDataResource> {
+
+	@Override
+	public ConfigData load(ConfigDataLoaderContext context, SystemEnvironmentConfigDataResource resource)
+			throws IOException, ConfigDataResourceNotFoundException {
+		List<PropertySource<?>> loaded = resource.load();
+		if (loaded == null) {
+			throw new ConfigDataResourceNotFoundException(resource);
+		}
+		return new ConfigData(loaded);
+	}
+
+}