Add support for creating layered war files with Maven

See gh-22821

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/AbstractJarWriter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -30,6 +30,7 @@ import java.util.Collection;
 import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.function.Predicate;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 import java.util.jar.JarInputStream;
@@ -90,11 +91,11 @@ public abstract class AbstractJarWriter implements LoaderClassesWriter {
 	 * @throws IOException if the entries cannot be written
 	 */
 	public void writeEntries(JarFile jarFile) throws IOException {
-		writeEntries(jarFile, EntryTransformer.NONE, UnpackHandler.NEVER);
+		writeEntries(jarFile, EntryTransformer.NONE, UnpackHandler.NEVER, (name) -> false);
 	}
 
-	final void writeEntries(JarFile jarFile, EntryTransformer entryTransformer, UnpackHandler unpackHandler)
-			throws IOException {
+	final void writeEntries(JarFile jarFile, EntryTransformer entryTransformer, UnpackHandler unpackHandler,
+			Predicate<String> libraryPredicate) throws IOException {
 		Enumeration<JarEntry> entries = jarFile.entries();
 		while (entries.hasMoreElements()) {
 			JarArchiveEntry entry = new JarArchiveEntry(entries.nextElement());
@@ -103,7 +104,8 @@ public abstract class AbstractJarWriter implements LoaderClassesWriter {
 				EntryWriter entryWriter = new InputStreamEntryWriter(inputStream);
 				JarArchiveEntry transformedEntry = entryTransformer.transform(entry);
 				if (transformedEntry != null) {
-					writeEntry(transformedEntry, entryWriter, unpackHandler, true);
+					boolean updateLayerIndex = !libraryPredicate.test(entry.getName());
+					writeEntry(transformedEntry, entryWriter, unpackHandler, updateLayerIndex);
 				}
 			}
 		}

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Layout.java

@@ -50,6 +50,28 @@ public interface Layout {
 	 */
 	String getClassesLocation();
 
+	/**
+	 * Returns the location of the classpath index file that should be written or
+	 * {@code null} if not index is required. The result should include the filename and
+	 * is relative to the root of the jar.
+	 * @return the classpath index file location
+	 * @since 2.5.0
+	 */
+	default String getClasspathIndexFileLocation() {
+		return null;
+	}
+
+	/**
+	 * Returns the location of the layer index file that should be written or {@code null}
+	 * if not index is required. The result should include the filename and is relative to
+	 * the root of the jar.
+	 * @return the layer index file location
+	 * @since 2.5.0
+	 */
+	default String getLayersIndexFileLocation() {
+		return null;
+	}
+
 	/**
 	 * Returns if loader classes should be included to make the archive executable.
 	 * @return if the layout is executable

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Layouts.java

@@ -160,6 +160,16 @@ public final class Layouts {
 			return "WEB-INF/classes/";
 		}
 
+		@Override
+		public String getClasspathIndexFileLocation() {
+			return "WEB-INF/classpath.idx";
+		}
+
+		@Override
+		public String getLayersIndexFileLocation() {
+			return "WEB-INF/layers.idx";
+		}
+
 		@Override
 		public boolean isExecutable() {
 			return true;

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Packager.java

@@ -172,7 +172,7 @@ public abstract class Packager {
 		}
 		writer.writeManifest(buildManifest(sourceJar));
 		writeLoaderClasses(writer);
-		writer.writeEntries(sourceJar, getEntityTransformer(), writeableLibraries);
+		writer.writeEntries(sourceJar, getEntityTransformer(), writeableLibraries, writeableLibraries::containsEntry);
 		writeableLibraries.write(writer);
 		if (isLayered()) {
 			writeLayerIndex(writer);
@@ -190,7 +190,7 @@ public abstract class Packager {
 	}
 
 	private void writeLayerIndex(AbstractJarWriter writer) throws IOException {
-		String name = ((RepackagingLayout) this.layout).getLayersIndexFileLocation();
+		String name = this.layout.getLayersIndexFileLocation();
 		if (StringUtils.hasLength(name)) {
 			Layer layer = this.layers.getLayer(name);
 			this.layersIndex.add(layer, name);
@@ -318,17 +318,17 @@ public abstract class Packager {
 
 	private void addBootAttributes(Attributes attributes) {
 		attributes.putValue(BOOT_VERSION_ATTRIBUTE, getClass().getPackage().getImplementationVersion());
-		Layout layout = getLayout();
-		if (layout instanceof RepackagingLayout) {
-			addBootBootAttributesForRepackagingLayout(attributes, (RepackagingLayout) layout);
-		}
-		else {
-			addBootBootAttributesForPlainLayout(attributes);
-		}
+		addBootAttributesForLayout(attributes);
 	}
 
-	private void addBootBootAttributesForRepackagingLayout(Attributes attributes, RepackagingLayout layout) {
-		attributes.putValue(BOOT_CLASSES_ATTRIBUTE, layout.getRepackagedClassesLocation());
+	private void addBootAttributesForLayout(Attributes attributes) {
+		Layout layout = getLayout();
+		if (layout instanceof RepackagingLayout) {
+			attributes.putValue(BOOT_CLASSES_ATTRIBUTE, ((RepackagingLayout) layout).getRepackagedClassesLocation());
+		}
+		else {
+			attributes.putValue(BOOT_CLASSES_ATTRIBUTE, layout.getClassesLocation());
+		}
 		putIfHasLength(attributes, BOOT_LIB_ATTRIBUTE, getLayout().getLibraryLocation("", LibraryScope.COMPILE));
 		putIfHasLength(attributes, BOOT_CLASSPATH_INDEX_ATTRIBUTE, layout.getClasspathIndexFileLocation());
 		if (isLayered()) {
@@ -336,11 +336,6 @@ public abstract class Packager {
 		}
 	}
 
-	private void addBootBootAttributesForPlainLayout(Attributes attributes) {
-		attributes.putValue(BOOT_CLASSES_ATTRIBUTE, getLayout().getClassesLocation());
-		putIfHasLength(attributes, BOOT_LIB_ATTRIBUTE, getLayout().getLibraryLocation("", LibraryScope.COMPILE));
-	}
-
 	private void putIfHasLength(Attributes attributes, String name, String value) {
 		if (StringUtils.hasLength(value)) {
 			attributes.putValue(name, value);
@@ -348,7 +343,7 @@ public abstract class Packager {
 	}
 
 	private boolean isLayered() {
-		return this.layers != null && getLayout() instanceof Layouts.Jar;
+		return this.layers != null;
 	}
 
 	/**
@@ -466,6 +461,10 @@ public abstract class Packager {
 			return Digest.sha1(library::openStream);
 		}
 
+		boolean containsEntry(String name) {
+			return this.libraries.containsKey(name);
+		}
+
 		private void write(AbstractJarWriter writer) throws IOException {
 			for (Entry<String, Library> entry : this.libraries.entrySet()) {
 				String path = entry.getKey();
@@ -473,12 +472,12 @@ public abstract class Packager {
 				String location = path.substring(0, path.lastIndexOf('/') + 1);
 				writer.writeNestedLibrary(location, library);
 			}
-			if (getLayout() instanceof RepackagingLayout) {
-				writeClasspathIndex((RepackagingLayout) getLayout(), writer);
+			if (Packager.this.layout instanceof RepackagingLayout) {
+				writeClasspathIndex(getLayout(), writer);
 			}
 		}
 
-		private void writeClasspathIndex(RepackagingLayout layout, AbstractJarWriter writer) throws IOException {
+		private void writeClasspathIndex(Layout layout, AbstractJarWriter writer) throws IOException {
 			List<String> names = this.libraries.keySet().stream().map((path) -> "- \"" + path + "\"")
 					.collect(Collectors.toList());
 			writer.writeIndexFile(layout.getClasspathIndexFileLocation(), names);

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/RepackagingLayout.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -31,26 +31,4 @@ public interface RepackagingLayout extends Layout {
 	 */
 	String getRepackagedClassesLocation();
 
-	/**
-	 * Returns the location of the classpath index file that should be written or
-	 * {@code null} if not index is required. The result should include the filename and
-	 * is relative to the root of the jar.
-	 * @return the classpath index file location
-	 * @since 2.3.0
-	 */
-	default String getClasspathIndexFileLocation() {
-		return null;
-	}
-
-	/**
-	 * Returns the location of the layer index file that should be written or {@code null}
-	 * if not index is required. The result should include the filename and is relative to
-	 * the root of the jar.
-	 * @return the layer index file location
-	 * @since 2.3.0
-	 */
-	default String getLayersIndexFileLocation() {
-		return null;
-	}
-
 }