Add LayoutFactory in spring.factories

Instead of a fixed enum of layout types, user can provide custom
layouts via implementations of LayoutFactory in spring.factories.

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2012-2015 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
+ *
+ *      http://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.loader.tools;
+
+/**
+ * Strategy for creating instances of {@link Layout}.
+ * 
+ * @author Dave Syer
+ *
+ */
+public interface LayoutFactory {
+	
+	Layout getLayout();
+	
+	String getName();
+
+}

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

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2012-2015 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
+ *
+ *      http://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.loader.tools;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
+/**
+ * Archive layout types.
+ */
+public enum LayoutType {
+
+	/**
+	 * Jar Layout.
+	 */
+	JAR(new Layouts.Jar()),
+
+	/**
+	 * War Layout.
+	 */
+	WAR(new Layouts.War()),
+
+	/**
+	 * Zip Layout.
+	 */
+	ZIP(new Layouts.Expanded()),
+
+	/**
+	 * Dir Layout.
+	 */
+	DIR(new Layouts.Expanded()),
+
+	/**
+	 * Module Layout.
+	 */
+	MODULE(new Layouts.Module()),
+
+	/**
+	 * No Layout.
+	 */
+	NONE(new Layouts.None());
+
+	private static Map<String, Layout> customTypes;
+
+	private final Layout layout;
+
+	public Layout layout() {
+		return this.layout;
+	}
+
+	LayoutType(Layout layout) {
+		this.layout = layout;
+	}
+
+	public static Layout layout(String value) {
+		try {
+			return valueOf(value).layout();
+		}
+		catch (IllegalArgumentException e) {
+			if (customTypes == null) {
+				customTypes = new HashMap<String, Layout>();
+				lookupCustomTypes();
+			}
+			Layout layout = customTypes.get(value);
+			if (layout == null) {
+				throw new IllegalArgumentException(
+						"Cannot resolve custom layout type: " + value);
+			}
+			return layout;
+		}
+	}
+
+	private static void lookupCustomTypes() {
+		ClassLoader classLoader = LayoutType.class.getClassLoader();
+		List<LayoutFactory> factories = SpringFactoriesLoader
+				.loadFactories(LayoutFactory.class, classLoader);
+		for (LayoutFactory factory : factories) {
+			customTypes.put(factory.getName(), factory.getLayout());
+		}
+	}
+
+}

spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/LayoutTypeTests.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012-2015 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
+ *
+ *      http://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.loader.tools;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class LayoutTypeTests {
+
+	@Test
+	public void standardType() {
+		assertThat(LayoutType.layout("DIR")).isEqualTo(LayoutType.valueOf("DIR").layout());
+	}
+
+	@Test
+	public void customType() {
+		assertThat(LayoutType.layout("CUSTOM")).isNotNull();
+	}
+	
+	public static class TestLayoutFactory implements LayoutFactory {
+
+		@Override
+		public Layout getLayout() {
+			return new Layouts.Jar();
+		}
+
+		@Override
+		public String getName() {
+			return "CUSTOM";
+		}}
+
+}

spring-boot-tools/spring-boot-loader-tools/src/test/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.loader.tools.LayoutFactory=\
+org.springframework.boot.loader.tools.LayoutTypeTests.TestLayoutFactory