Refine layer customization for Maven and Gradle

Simplify layer customization logic for both Maven and Gradle and
refactor some internals of the Gradle plugin.

Both Maven and Gradle now use a simpler customization format that
consists of `application`, `dependencies` and `layer order` sections.
The `application`, `dependencies` configurations support one or more
`into` blocks that are used to select content for a specific layer.

Closes gh-20526

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/JarIntegrationTests.java

@@ -26,6 +26,7 @@ import org.junit.jupiter.api.TestTemplate;
 import org.junit.jupiter.api.extension.ExtendWith;
 
 import org.springframework.boot.loader.tools.FileUtils;
+import org.springframework.boot.loader.tools.JarModeLibrary;
 import org.springframework.util.FileSystemUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -296,8 +297,7 @@ class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("BOOT-INF/layers/application/classes/")
 					.hasEntryWithNameStartingWith("BOOT-INF/layers/dependencies/lib/jar-release")
 					.hasEntryWithNameStartingWith("BOOT-INF/layers/snapshot-dependencies/lib/jar-snapshot")
-					.hasEntryWithNameStartingWith(
-							"BOOT-INF/layers/dependencies/lib/spring-boot-jarmode-layertools.jar");
+					.hasEntryWithNameStartingWith(jarModeLayerTools());
 		});
 	}
 
@@ -308,8 +308,7 @@ class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("BOOT-INF/layers/application/classes/")
 					.hasEntryWithNameStartingWith("BOOT-INF/layers/dependencies/lib/jar-release")
 					.hasEntryWithNameStartingWith("BOOT-INF/layers/snapshot-dependencies/lib/jar-snapshot")
-					.doesNotHaveEntryWithNameStartingWith(
-							"BOOT-INF/layers/dependencies/lib/spring-boot-jarmode-layertools.jar");
+					.doesNotHaveEntryWithNameStartingWith(jarModeLayerTools());
 		});
 	}
 
@@ -333,6 +332,13 @@ class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 		assertThat(firstHash).isEqualTo(secondHash);
 	}
 
+	private String jarModeLayerTools() {
+		JarModeLibrary library = JarModeLibrary.LAYER_TOOLS;
+		String version = library.getCoordinates().getVersion();
+		String layer = (version == null || !version.contains("SNAPSHOT")) ? "dependencies" : "snapshot-dependencies";
+		return "BOOT-INF/layers/" + layer + "/lib/" + library.getName();
+	}
+
 	private String buildJarWithOutputTimestamp(MavenBuild mavenBuild) {
 		AtomicReference<String> jarHash = new AtomicReference<>();
 		mavenBuild.project("jar-output-timestamp").execute((project) -> {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered-custom/jar/src/layers.xml

@@ -1,35 +1,23 @@
-<layers-configuration xmlns="http://www.springframework.org/schema/boot/layers"
-					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
-					  https://www.springframework.org/schema/layers/layers-configuration-2.3.xsd">
-	<layers>
+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/layers/layers-2.3.xsd">
+	<application>
+		<into layer="configuration">
+			<include>**/application*.*</include>
+		</into>
+		<into layer="application" />
+	</application>
+	<dependencies>
+		<into layer="snapshot-dependencies">
+			<include>*:*:*-SNAPSHOT</include>
+		</into>
+		<into layer="my-dependencies-name" />
+	</dependencies>
+	<layerOrder>
 		<layer>configuration</layer>
 		<layer>application</layer>
 		<layer>snapshot-dependencies</layer>
 		<layer>my-dependencies-name</layer>
-	</layers>
-	<libraries>
-		<layer-content layer="snapshot-dependencies">
-			<coordinates>
-				<include>*:*:*-SNAPSHOT</include>
-			</coordinates>
-		</layer-content>
-		<layer-content layer="my-dependencies-name">
-			<coordinates>
-				<include>*:*:*</include>
-			</coordinates>
-		</layer-content>
-	</libraries>
-	<application>
-		<layer-content layer="configuration">
-			<locations>
-				<include>**/application*.*</include>
-			</locations>
-		</layer-content>
-		<layer-content layer="application">
-			<locations>
-				<include>**</include>
-			</locations>
-		</layer-content>
-	</application>
-</layers-configuration>
+	</layerOrder>
+</layers>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractPackagerMojo.java

@@ -48,6 +48,7 @@ import org.springframework.boot.loader.tools.Layouts.None;
 import org.springframework.boot.loader.tools.Layouts.War;
 import org.springframework.boot.loader.tools.Libraries;
 import org.springframework.boot.loader.tools.Packager;
+import org.springframework.boot.loader.tools.layer.CustomLayers;
 
 /**
  * Abstract base class for classes that work with an {@link Packager}.
@@ -135,15 +136,7 @@ public abstract class AbstractPackagerMojo extends AbstractDependencyFilterMojo
 		}
 		if (this.layers != null && this.layers.isEnabled()) {
 			if (this.layers.getConfiguration() != null) {
-				try {
-					Document document = getDocumentIfAvailable(this.layers.getConfiguration());
-					CustomLayersProvider customLayersProvider = new CustomLayersProvider();
-					packager.setLayers(customLayersProvider.getLayers(document));
-				}
-				catch (Exception ex) {
-					throw new IllegalStateException("Failed to process custom layers configuration "
-							+ this.layers.getConfiguration().getAbsolutePath(), ex);
-				}
+				packager.setLayers(getCustomLayers(this.layers.getConfiguration()));
 			}
 			packager.setLayout(new LayeredJar());
 			packager.setIncludeRelevantJarModeJars(this.layers.isIncludeLayerTools());
@@ -151,8 +144,19 @@ public abstract class AbstractPackagerMojo extends AbstractDependencyFilterMojo
 		return packager;
 	}
 
-	private Document getDocumentIfAvailable(File configurationFile) throws Exception {
-		InputSource inputSource = new InputSource(new FileInputStream(configurationFile));
+	private CustomLayers getCustomLayers(File configuration) {
+		try {
+			Document document = getDocumentIfAvailable(configuration);
+			return new CustomLayersProvider().getLayers(document);
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException(
+					"Failed to process custom layers configuration " + configuration.getAbsolutePath(), ex);
+		}
+	}
+
+	private Document getDocumentIfAvailable(File xmlFile) throws Exception {
+		InputSource inputSource = new InputSource(new FileInputStream(xmlFile));
 		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
 		DocumentBuilder builder = factory.newDocumentBuilder();
 		return builder.parse(inputSource);

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/ArtifactsLibraries.java

@@ -80,8 +80,7 @@ public class ArtifactsLibraries implements Libraries {
 					name = artifact.getGroupId() + "-" + name;
 					this.log.debug("Renamed to: " + name);
 				}
-				LibraryCoordinates coordinates = new LibraryCoordinates(artifact.getGroupId(), artifact.getArtifactId(),
-						artifact.getVersion());
+				LibraryCoordinates coordinates = new ArtifactLibraryCoordinates(artifact);
 				callback.library(new Library(name, artifact.getFile(), scope, coordinates, isUnpackRequired(artifact)));
 			}
 		}
@@ -122,4 +121,37 @@ public class ArtifactsLibraries implements Libraries {
 		return sb.toString();
 	}
 
+	/**
+	 * {@link LibraryCoordinates} backed by a Maven {@link Artifact}.
+	 */
+	private static class ArtifactLibraryCoordinates implements LibraryCoordinates {
+
+		private final Artifact artifact;
+
+		ArtifactLibraryCoordinates(Artifact artifact) {
+			this.artifact = artifact;
+		}
+
+		@Override
+		public String getGroupId() {
+			return this.artifact.getGroupId();
+		}
+
+		@Override
+		public String getArtifactId() {
+			return this.artifact.getArtifactId();
+		}
+
+		@Override
+		public String getVersion() {
+			return this.artifact.getVersion();
+		}
+
+		@Override
+		public String toString() {
+			return this.artifact.toString();
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/CustomLayersProvider.java

@@ -17,8 +17,10 @@
 package org.springframework.boot.maven;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
-import java.util.function.Predicate;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -26,113 +28,76 @@ import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
 import org.springframework.boot.loader.tools.Layer;
+import org.springframework.boot.loader.tools.Library;
+import org.springframework.boot.loader.tools.layer.ApplicationContentFilter;
+import org.springframework.boot.loader.tools.layer.ContentFilter;
+import org.springframework.boot.loader.tools.layer.ContentSelector;
 import org.springframework.boot.loader.tools.layer.CustomLayers;
-import org.springframework.boot.loader.tools.layer.application.FilteredResourceStrategy;
-import org.springframework.boot.loader.tools.layer.application.LocationFilter;
-import org.springframework.boot.loader.tools.layer.application.ResourceFilter;
-import org.springframework.boot.loader.tools.layer.application.ResourceStrategy;
-import org.springframework.boot.loader.tools.layer.library.CoordinateFilter;
-import org.springframework.boot.loader.tools.layer.library.FilteredLibraryStrategy;
-import org.springframework.boot.loader.tools.layer.library.LibraryFilter;
-import org.springframework.boot.loader.tools.layer.library.LibraryStrategy;
-import org.springframework.util.Assert;
+import org.springframework.boot.loader.tools.layer.IncludeExcludeContentSelector;
+import org.springframework.boot.loader.tools.layer.LibraryContentFilter;
 
 /**
  * Produces a {@link CustomLayers} based on the given {@link Document}.
  *
  * @author Madhura Bhave
- * @since 2.3.0
+ * @author Phillip Webb
  */
-public class CustomLayersProvider {
+class CustomLayersProvider {
 
-	public CustomLayers getLayers(Document document) {
+	CustomLayers getLayers(Document document) {
 		Element root = document.getDocumentElement();
-		NodeList nodes = root.getChildNodes();
-		List<Layer> layers = new ArrayList<>();
-		List<LibraryStrategy> libraryStrategies = new ArrayList<>();
-		List<ResourceStrategy> resourceStrategies = new ArrayList<>();
-		for (int i = 0; i < nodes.getLength(); i++) {
-			Node node = nodes.item(i);
-			if (node instanceof Element) {
-				processNode(layers, libraryStrategies, resourceStrategies, (Element) node);
+		List<ContentSelector<String>> applicationSelectors = getApplicationSelectors(root);
+		List<ContentSelector<Library>> librarySelectors = getLibrarySelectors(root);
+		List<Layer> layers = getLayers(root);
+		return new CustomLayers(layers, applicationSelectors, librarySelectors);
+	}
+
+	private List<ContentSelector<String>> getApplicationSelectors(Element root) {
+		return getSelectors(root, "application", ApplicationContentFilter::new);
+	}
+
+	private List<ContentSelector<Library>> getLibrarySelectors(Element root) {
+		return getSelectors(root, "dependencies", LibraryContentFilter::new);
+	}
+
+	private List<Layer> getLayers(Element root) {
+		Element layerOrder = getChildElement(root, "layerOrder");
+		if (layerOrder == null) {
+			return Collections.emptyList();
+		}
+		return getChildNodeTextContent(layerOrder, "layer").stream().map(Layer::new).collect(Collectors.toList());
+	}
+
+	private <T> List<ContentSelector<T>> getSelectors(Element root, String elementName,
+			Function<String, ContentFilter<T>> filterFactory) {
+		Element element = getChildElement(root, elementName);
+		if (element == null) {
+			return Collections.emptyList();
+		}
+		List<ContentSelector<T>> selectors = new ArrayList<>();
+		NodeList children = element.getChildNodes();
+		for (int i = 0; i < children.getLength(); i++) {
+			Node child = children.item(i);
+			if (child instanceof Element) {
+				ContentSelector<T> selector = getSelector((Element) child, filterFactory);
+				selectors.add(selector);
 			}
 		}
-		return new CustomLayers(layers, resourceStrategies, libraryStrategies);
+		return selectors;
 	}
 
-	private void processNode(List<Layer> layers, List<LibraryStrategy> libraryStrategies,
-			List<ResourceStrategy> resourceStrategies, Element node) {
-		String nodeName = node.getNodeName();
-		if ("layers".equals(nodeName)) {
-			layers.addAll(getLayers(node));
-		}
-		NodeList contents = node.getChildNodes();
-		if ("libraries".equals(nodeName)) {
-			libraryStrategies.addAll(getStrategies(contents,
-					(StrategyFactory<LibraryFilter, LibraryStrategy>) FilteredLibraryStrategy::new,
-					CoordinateFilter::new, "coordinates"::equals));
-		}
-		if ("application".equals(nodeName)) {
-			resourceStrategies.addAll(getStrategies(contents,
-					(StrategyFactory<ResourceFilter, ResourceStrategy>) FilteredResourceStrategy::new,
-					LocationFilter::new, "locations"::equals));
-		}
+	private <T> ContentSelector<T> getSelector(Element element, Function<String, ContentFilter<T>> filterFactory) {
+		Layer layer = new Layer(element.getAttribute("layer"));
+		List<String> includes = getChildNodeTextContent(element, "include");
+		List<String> excludes = getChildNodeTextContent(element, "exclude");
+		return new IncludeExcludeContentSelector<>(layer, includes, excludes, filterFactory);
 	}
 
-	private List<Layer> getLayers(Element element) {
-		List<Layer> layers = new ArrayList<>();
-		NodeList childNodes = element.getChildNodes();
-		for (int i = 0; i < childNodes.getLength(); i++) {
-			Node childNode = childNodes.item(i);
-			if (childNode instanceof Element) {
-				Element childElement = (Element) childNode;
-				if ("layer".equals(childElement.getNodeName())) {
-					layers.add(new Layer(childElement.getTextContent()));
-				}
-			}
-		}
-		return layers;
-	}
-
-	private <T, E> List<T> getStrategies(NodeList nodes, StrategyFactory<E, T> strategyFactory,
-			FilterFactory<E> filterFactory, Predicate<String> filterPredicate) {
-		List<T> contents = new ArrayList<>();
-		for (int i = 0; i < nodes.getLength(); i++) {
-			Node node = nodes.item(i);
-			if (node instanceof Element) {
-				Element element = (Element) node;
-				if ("layer-content".equals(element.getTagName())) {
-					List<E> filters = getFilters(node, filterFactory, filterPredicate);
-					String layer = element.getAttribute("layer");
-					contents.add(strategyFactory.getStrategy(layer, filters));
-				}
-			}
-		}
-		return contents;
-	}
-
-	private <E> List<E> getFilters(Node node, FilterFactory<E> factory, Predicate<String> predicate) {
-		NodeList childNodes = node.getChildNodes();
-		Assert.state(childNodes.getLength() > 0, "Filters for layer-content must not be empty.");
-		List<E> filters = new ArrayList<>();
-		for (int i = 0; i < childNodes.getLength(); i++) {
-			Node childNode = childNodes.item(i);
-			if (childNode instanceof Element) {
-				List<String> include = getPatterns((Element) childNode, "include");
-				List<String> exclude = getPatterns((Element) childNode, "exclude");
-				if (predicate.test(childNode.getNodeName())) {
-					filters.add(factory.getFilter(include, exclude));
-				}
-			}
-		}
-		return filters;
-	}
-
-	private List<String> getPatterns(Element element, String key) {
+	private List<String> getChildNodeTextContent(Element element, String tagName) {
 		List<String> patterns = new ArrayList<>();
-		NodeList nodes = element.getElementsByTagName(key);
-		for (int j = 0; j < nodes.getLength(); j++) {
-			Node node = nodes.item(j);
+		NodeList nodes = element.getElementsByTagName(tagName);
+		for (int i = 0; i < nodes.getLength(); i++) {
+			Node node = nodes.item(i);
 			if (node instanceof Element) {
 				patterns.add(node.getTextContent());
 			}
@@ -140,16 +105,15 @@ public class CustomLayersProvider {
 		return patterns;
 	}
 
-	interface StrategyFactory<E, T> {
-
-		T getStrategy(String layer, List<E> filters);
-
-	}
-
-	interface FilterFactory<E> {
-
-		E getFilter(List<String> includes, List<String> excludes);
-
+	private Element getChildElement(Element element, String tagName) {
+		NodeList nodes = element.getElementsByTagName(tagName);
+		if (nodes.getLength() == 0) {
+			return null;
+		}
+		if (nodes.getLength() > 1) {
+			throw new IllegalStateException("Multiple '" + tagName + "' nodes found");
+		}
+		return (Element) nodes.item(0);
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/xsd/layers-2.3.xsd

@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<xsd:schema elementFormDefault="qualified"
+	xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+	targetNamespace="http://www.springframework.org/schema/boot/layers">
+	<xsd:element name="layers" type="layersType" />
+	<xsd:complexType name="layersType">
+		<xsd:sequence>
+			<xsd:element name="application" type="applicationType" />
+			<xsd:element name="dependencies" type="dependenciesType" />
+			<xsd:element name="layerOrder" type="layerOrderType" />
+		</xsd:sequence>
+	</xsd:complexType>
+	<xsd:complexType name="applicationType">
+		<xsd:annotation>
+			<xsd:documentation><![CDATA[
+	The 'into layer' selections that should be applied to application classes and resources.
+				]]></xsd:documentation>
+		</xsd:annotation>
+		<xsd:sequence maxOccurs="unbounded">
+			<xsd:element name="into" type="intoType" />
+		</xsd:sequence>
+	</xsd:complexType>
+	<xsd:complexType name="dependenciesType">
+		<xsd:annotation>
+			<xsd:documentation><![CDATA[
+	The 'into layer' selections that should be applied to dependencies.
+				]]></xsd:documentation>
+		</xsd:annotation>
+		<xsd:sequence maxOccurs="unbounded">
+			<xsd:element name="into" type="intoType" />
+		</xsd:sequence>
+	</xsd:complexType>
+	<xsd:complexType name="layerOrderType">
+		<xsd:annotation>
+			<xsd:documentation><![CDATA[
+	The order that layers should be added (starting with the least frequently changed layer).
+				]]></xsd:documentation>
+		</xsd:annotation>
+		<xsd:sequence>
+			<xsd:element name="layer" maxOccurs="unbounded">
+				<xsd:annotation>
+					<xsd:documentation><![CDATA[
+	The layer name.
+				]]></xsd:documentation>
+				</xsd:annotation>
+				<xsd:simpleType>
+					<xsd:restriction base="xsd:string">
+						<xsd:minLength value="1" />
+					</xsd:restriction>
+				</xsd:simpleType>
+			</xsd:element>
+		</xsd:sequence>
+	</xsd:complexType>
+	<xsd:complexType name="intoType">
+		<xsd:choice maxOccurs="unbounded">
+			<xsd:element type="xsd:string" name="include"
+				minOccurs="0" maxOccurs="unbounded">
+				<xsd:annotation>
+					<xsd:documentation><![CDATA[
+	Pattern of the elements to include.
+			]]></xsd:documentation>
+				</xsd:annotation>
+			</xsd:element>
+			<xsd:element type="xsd:string" name="exclude"
+				minOccurs="0" maxOccurs="unbounded">
+				<xsd:annotation>
+					<xsd:documentation><![CDATA[
+	Pattern of the elements to exclude.
+			]]></xsd:documentation>
+				</xsd:annotation>
+			</xsd:element>
+		</xsd:choice>
+		<xsd:attribute type="xsd:string" name="layer"
+			use="required" />
+	</xsd:complexType>
+
+</xsd:schema>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/xsd/layers-configuration-2.3.xsd

@@ -1,96 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<xsd:schema elementFormDefault="qualified"
-			xmlns="http://www.springframework.org/schema/boot/layers"
-			xmlns:xsd="http://www.w3.org/2001/XMLSchema"
-			targetNamespace="http://www.springframework.org/schema/boot/layers">
-	<xsd:element name="layers-configuration" type="layersConfigurationType"/>
-	<xsd:complexType name="layersConfigurationType">
-		<xsd:sequence>
-			<xsd:element type="layersType" name="layers"/>
-			<xsd:element type="librariesType" name="libraries" minOccurs="0"/>
-			<xsd:element type="applicationType" name="application" minOccurs="0"/>
-		</xsd:sequence>
-	</xsd:complexType>
-	<xsd:complexType name="layersType">
-		<xsd:sequence>
-			<xsd:element type="xsd:string" name="layer" maxOccurs="unbounded">
-				<xsd:annotation>
-					<xsd:documentation><![CDATA[
-	The name of a layer. Each layer in the configuration must be referenced once and the
-	order matches how the content is likely to change. Put layers that are frequently
-	updated first, layers that are more stable (such as non-snapshot dependencies) last.
-				]]></xsd:documentation>
-				</xsd:annotation>
-			</xsd:element>
-		</xsd:sequence>
-	</xsd:complexType>
-	<xsd:complexType name="librariesType">
-		<xsd:annotation>
-			<xsd:documentation><![CDATA[
-	Strategies that should be applied to libraries. If no strategies are defined, two
-	layers are created out-of-the-box. A "snapshot-dependencies" layer with SNAPSHOT
-	libraries and a "dependencies" layer with all the other libraries.
-				]]></xsd:documentation>
-		</xsd:annotation>
-		<xsd:choice maxOccurs="unbounded">
-			<xsd:element type="librariesLayerContentType" name="layer-content">
-				<xsd:annotation>
-					<xsd:documentation><![CDATA[
-	Strategy to apply on libraries.
-				]]></xsd:documentation>
-				</xsd:annotation>
-			</xsd:element>
-		</xsd:choice>
-	</xsd:complexType>
-	<xsd:complexType name="librariesLayerContentType" mixed="true">
-		<xsd:sequence>
-			<xsd:element type="filterType" name="coordinates" minOccurs="0"/>
-		</xsd:sequence>
-		<xsd:attribute type="xsd:string" name="layer" use="required"/>
-	</xsd:complexType>
-	<xsd:complexType name="applicationType">
-		<xsd:annotation>
-			<xsd:documentation><![CDATA[
-	Strategies that should be applied to application classes and resources. If no strategies are defined, a single
-	"application" layer is created out-of-the-box.
-				]]></xsd:documentation>
-		</xsd:annotation>
-		<xsd:choice maxOccurs="unbounded">
-			<xsd:element type="applicationLayerContentType" name="layer-content" maxOccurs="unbounded"
-						 minOccurs="0">
-				<xsd:annotation>
-					<xsd:documentation><![CDATA[
-	Strategy to apply on application classes and resources.
-				]]></xsd:documentation>
-				</xsd:annotation>
-			</xsd:element>
-		</xsd:choice>
-	</xsd:complexType>
-	<xsd:complexType name="applicationLayerContentType" mixed="true">
-		<xsd:sequence>
-			<xsd:element type="filterType" name="locations" minOccurs="0"/>
-		</xsd:sequence>
-		<xsd:attribute type="xsd:string" name="layer" use="required"/>
-	</xsd:complexType>
-
-	<xsd:complexType name="filterType">
-		<xsd:sequence>
-			<xsd:element type="xsd:string" name="exclude" minOccurs="0" maxOccurs="unbounded">
-				<xsd:annotation>
-					<xsd:documentation><![CDATA[
-	Pattern of the elements to exclude. An exclude pattern takes precedence over an
-	include pattern and must be declared first.
-			]]></xsd:documentation>
-				</xsd:annotation>
-			</xsd:element>
-			<xsd:element type="xsd:string" name="include" minOccurs="0" maxOccurs="unbounded">
-				<xsd:annotation>
-					<xsd:documentation><![CDATA[
-	Pattern of the elements to include.
-			]]></xsd:documentation>
-				</xsd:annotation>
-			</xsd:element>
-		</xsd:sequence>
-	</xsd:complexType>
-
-</xsd:schema>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/CustomLayersProviderTests.java

@@ -52,8 +52,8 @@ public class CustomLayersProviderTests {
 	@Test
 	void getLayerResolverWhenDocumentValid() throws Exception {
 		CustomLayers layers = this.customLayersProvider.getLayers(getDocument("layers.xml"));
-		assertThat(layers).extracting("name").containsExactly("configuration", "application", "my-resources",
-				"snapshot-dependencies", "my-deps", "my-dependencies-name");
+		assertThat(layers).extracting("name").containsExactly("my-deps", "my-dependencies-name",
+				"snapshot-dependencies", "my-resources", "configuration", "application");
 		Library snapshot = mockLibrary("test-SNAPSHOT.jar", "org.foo", "1.0.0-SNAPSHOT");
 		Library groupId = mockLibrary("my-library", "com.acme", null);
 		Library otherDependency = mockLibrary("other-library", "org.foo", null);
@@ -68,22 +68,26 @@ public class CustomLayersProviderTests {
 	private Library mockLibrary(String name, String groupId, String version) {
 		Library library = mock(Library.class);
 		given(library.getName()).willReturn(name);
-		given(library.getCoordinates()).willReturn(new LibraryCoordinates(groupId, null, version));
+		given(library.getCoordinates()).willReturn(LibraryCoordinates.of(groupId, null, version));
 		return library;
 	}
 
 	@Test
-	void getLayerResolverWhenDocumentContainsLibraryLayerWithNoFilters() {
-		assertThatIllegalStateException()
-				.isThrownBy(() -> this.customLayersProvider.getLayers(getDocument("library-layer-no-filter.xml")))
-				.withMessage("Filters for layer-content must not be empty.");
+	void getLayerResolverWhenDocumentContainsLibraryLayerWithNoFilters() throws Exception {
+		CustomLayers layers = this.customLayersProvider.getLayers(getDocument("dependencies-layer-no-filter.xml"));
+		Library library = mockLibrary("my-library", "com.acme", null);
+		assertThat(layers.getLayer(library).toString()).isEqualTo("my-deps");
+		assertThatIllegalStateException().isThrownBy(() -> layers.getLayer("application.yml"))
+				.withMessageContaining("match any layer");
 	}
 
 	@Test
-	void getLayerResolverWhenDocumentContainsResourceLayerWithNoFilters() {
-		assertThatIllegalStateException()
-				.isThrownBy(() -> this.customLayersProvider.getLayers(getDocument("resource-layer-no-filter.xml")))
-				.withMessage("Filters for layer-content must not be empty.");
+	void getLayerResolverWhenDocumentContainsResourceLayerWithNoFilters() throws Exception {
+		CustomLayers layers = this.customLayersProvider.getLayers(getDocument("application-layer-no-filter.xml"));
+		Library library = mockLibrary("my-library", "com.acme", null);
+		assertThat(layers.getLayer("application.yml").toString()).isEqualTo("my-layer");
+		assertThatIllegalStateException().isThrownBy(() -> layers.getLayer(library))
+				.withMessageContaining("match any layer");
 	}
 
 	private Document getDocument(String resourceName) throws Exception {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/resources/application-layer-no-filter.xml

@@ -0,0 +1,11 @@
+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/boot/layers/layers.xsd">
+	<application>
+		<into layer="my-layer" />
+	</application>
+	<layerOrder>
+		<layer>my-layer</layer>
+	</layerOrder>
+</layers>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/resources/dependencies-layer-no-filter.xml

@@ -0,0 +1,11 @@
+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/boot/layers/layers-2.3.xsd">
+	<dependencies>
+		<into layer="my-deps" />
+	</dependencies>
+	<layerOrder>
+		<layer>my-deps</layer>
+	</layerOrder>
+</layers>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/resources/layers.xml

@@ -1,47 +1,32 @@
-<layers-configuration xmlns="http://www.springframework.org/schema/boot/layers"
-					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
-					  https://www.springframework.org/schema/boot/layers/layers-configuration-2.3.xsd">
-	<layers>
-		<layer>configuration</layer>
-		<layer>application</layer>
-		<layer>my-resources</layer>
-		<layer>snapshot-dependencies</layer>
+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/boot/layers/layers-2.3.xsd">
+	<application>
+		<into layer="my-resources">
+			<include>META-INF/resources/**</include>
+			<exclude>*.properties</exclude>
+		</into>
+		<into layer="configuration">
+			<include>**/application*.*</include>
+		</into>
+		<into layer="application" />
+	</application>
+	<dependencies>
+		<into layer="snapshot-dependencies">
+			<include>*:*:*-SNAPSHOT</include>
+		</into>
+		<into layer="my-deps">
+			<include>com.acme:*</include>
+		</into>
+		<into layer="my-dependencies-name"/>
+	</dependencies>
+	<layerOrder>
 		<layer>my-deps</layer>
 		<layer>my-dependencies-name</layer>
-	</layers>
-	<libraries>
-		<layer-content layer="snapshot-dependencies">
-			<coordinates>
-				<include>*:*:*-SNAPSHOT</include>
-			</coordinates>
-		</layer-content>
-		<layer-content layer="my-deps">
-			<coordinates>
-				<include>com.acme:*</include>
-			</coordinates>
-		</layer-content>
-		<layer-content layer="my-dependencies-name">
-			<coordinates>
-				<include>*:*:*</include>
-			</coordinates>
-		</layer-content>
-	</libraries>
-	<application>
-		<layer-content layer="my-resources">
-			<locations>
-				<include>META-INF/resources/**</include>
-			</locations>
-		</layer-content>
-		<layer-content layer="configuration">
-			<locations>
-				<include>**/application*.*</include>
-			</locations>
-		</layer-content>
-		<layer-content layer="application">
-			<locations>
-				<include>**</include>
-			</locations>
-		</layer-content>
-	</application>
-</layers-configuration>
+		<layer>snapshot-dependencies</layer>
+		<layer>my-resources</layer>
+		<layer>configuration</layer>
+		<layer>application</layer>
+	</layerOrder>	
+</layers>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/resources/library-layer-no-filter.xml

@@ -1,11 +0,0 @@
-<layers-configuration xmlns="http://www.springframework.org/schema/boot/layers"
-					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
-					  https://www.springframework.org/schema/boot/layers/layers-configuration-2.3.xsd">
-	<layers>
-		<layer>my-deps</layer>
-	</layers>
-	<libraries>
-		<layer-content layer="my-deps"/>
-	</libraries>
-</layers-configuration>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/resources/resource-layer-no-filter.xml

@@ -1,11 +1,11 @@
-<layers-configuration xmlns="http://www.springframework.org/schema/boot/layers"
-					  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-					  xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
-					  https://www.springframework.org/schema/boot/layers/layers-configuration-2.3.xsd">
-	<layers>
-		<layer>my-layer</layer>
-	</layers>
+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/boot/layers/layers-2.3.xsd">
 	<application>
-		<layer-content layer="my-layer"/>
+		<into layer="my-layer" />
 	</application>
-</layers-configuration>
+	<layerOrder>
+		<layer>my-layer</layer>
+	</layerOrder>
+</layers>