Project documentation infrastructure

This commit adds support for an `HelpDocument` that can be generated
alongside the project. Such document can hold an arbitrary number of
sections with pre-defined sections such as "Getting Started" and "Next
Steps".

A default contributor retrieves the links for requested dependencies
and add them to the document.

Closes gh-353

Co-authored-by: Madhura Bhave <mbhave@pivotal.io>

initializr-generator-spring/pom.xml

@@ -19,6 +19,11 @@
 			<artifactId>initializr-metadata</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>com.samskivert</groupId>
+			<artifactId>jmustache</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>io.spring.initializr</groupId>
 			<artifactId>initializr-generator</artifactId>

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/GettingStartedSection.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import io.spring.initializr.generator.io.text.BulletedSection;
+import io.spring.initializr.generator.io.text.Section;
+
+/**
+ * Section that provides links and other important references to get started.
+ *
+ * @author Madhura Bhave
+ * @author Stephane Nicoll
+ */
+public final class GettingStartedSection extends PreDefinedSection {
+
+	private final BulletedSection<Link> referenceDocs;
+
+	private final BulletedSection<Link> guides;
+
+	private final BulletedSection<Link> additionalLinks;
+
+	GettingStartedSection(MustacheTemplateRenderer templateRenderer) {
+		super("Getting Started");
+		this.referenceDocs = new BulletedSection<>(templateRenderer,
+				"documentation/reference-documentation");
+		this.guides = new BulletedSection<>(templateRenderer, "documentation/guides");
+		this.additionalLinks = new BulletedSection<>(templateRenderer,
+				"documentation/additional-links");
+	}
+
+	@Override
+	public boolean isEmpty() {
+		return referenceDocs().isEmpty() && guides().isEmpty()
+				&& additionalLinks().isEmpty() && super.isEmpty();
+	}
+
+	@Override
+	protected List<Section> resolveSubSections(List<Section> sections) {
+		List<Section> allSections = new ArrayList<>();
+		allSections.add(this.referenceDocs);
+		allSections.add(this.guides);
+		allSections.add(this.additionalLinks);
+		allSections.addAll(sections);
+		return allSections;
+	}
+
+	public GettingStartedSection addReferenceDocLink(String href, String description) {
+		this.referenceDocs.addItem(new Link(href, description));
+		return this;
+	}
+
+	public BulletedSection<Link> referenceDocs() {
+		return this.referenceDocs;
+	}
+
+	public GettingStartedSection addGuideLink(String href, String description) {
+		this.guides.addItem(new Link(href, description));
+		return this;
+	}
+
+	public BulletedSection<Link> guides() {
+		return this.guides;
+	}
+
+	public GettingStartedSection addAdditionalLink(String href, String description) {
+		this.additionalLinks.addItem(new Link(href, description));
+		return this;
+	}
+
+	public BulletedSection<Link> additionalLinks() {
+		return this.additionalLinks;
+	}
+
+	/**
+	 * Internal representation of a link.
+	 */
+	public static class Link {
+
+		private final String href;
+
+		private final String description;
+
+		Link(String href, String description) {
+			this.href = href;
+			this.description = description;
+		}
+
+		public String getHref() {
+			return this.href;
+		}
+
+		public String getDescription() {
+			return this.description;
+		}
+
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/HelpDocument.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import io.spring.initializr.generator.io.text.MustacheSection;
+import io.spring.initializr.generator.io.text.Section;
+
+/**
+ * Project's help document intended to give additional references to the users. Contains a
+ * getting started section, additional sections and a next steps section.
+ *
+ * @author Stephane Nicoll
+ * @author Madhura Bhave
+ */
+public class HelpDocument {
+
+	private final MustacheTemplateRenderer templateRenderer;
+
+	private final GettingStartedSection gettingStarted;
+
+	private final PreDefinedSection nextSteps;
+
+	private final LinkedList<Section> sections = new LinkedList<>();
+
+	public HelpDocument(MustacheTemplateRenderer templateRenderer) {
+		this.templateRenderer = templateRenderer;
+		this.gettingStarted = new GettingStartedSection(templateRenderer);
+		this.nextSteps = new PreDefinedSection("Next Steps");
+	}
+
+	public GettingStartedSection gettingStarted() {
+		return this.gettingStarted;
+	}
+
+	public PreDefinedSection nextSteps() {
+		return this.nextSteps;
+	}
+
+	public HelpDocument addSection(Section section) {
+		this.sections.add(section);
+		return this;
+	}
+
+	/**
+	 * Add a section rendered by the specified mustache template and model.
+	 * @param templateName the name of the mustache template to render
+	 * @param model the model that should be used for the rendering
+	 * @return this document
+	 */
+	public HelpDocument addSection(String templateName, Map<String, Object> model) {
+		return addSection(
+				new MustacheSection(this.templateRenderer, templateName, model));
+	}
+
+	public List<Section> getSections() {
+		return Collections.unmodifiableList(this.sections);
+	}
+
+	public void write(PrintWriter writer) throws IOException {
+		LinkedList<Section> allSections = new LinkedList<>(this.sections);
+		allSections.addFirst(this.gettingStarted);
+		allSections.addLast(this.nextSteps);
+		for (Section section : allSections) {
+			section.write(writer);
+		}
+	}
+
+	public boolean isEmpty() {
+		return gettingStarted().isEmpty() && this.sections.isEmpty()
+				&& nextSteps().isEmpty();
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/HelpDocumentCustomizer.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import org.springframework.core.Ordered;
+
+/**
+ * Callback for customizing a project's {@link HelpDocument}. Invoked with an
+ * {@link Ordered order} of {@code 0} by default, considering overriding
+ * {@link #getOrder()} to customize this behaviour.
+ *
+ * @author Stephane Nicoll
+ */
+@FunctionalInterface
+public interface HelpDocumentCustomizer extends Ordered {
+
+	void customize(HelpDocument document);
+
+	@Override
+	default int getOrder() {
+		return 0;
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/HelpDocumentProjectContributor.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import io.spring.initializr.generator.project.contributor.ProjectContributor;
+
+/**
+ * {@link ProjectContributor} for the project's {@code HELP.md} file.
+ *
+ * @author Stephane Nicoll
+ * @author Madhura Bhave
+ */
+public class HelpDocumentProjectContributor implements ProjectContributor {
+
+	private final HelpDocument helpDocument;
+
+	public HelpDocumentProjectContributor(HelpDocument helpDocument) {
+		this.helpDocument = helpDocument;
+	}
+
+	@Override
+	public void contribute(Path projectRoot) throws IOException {
+		if (this.helpDocument.isEmpty()) {
+			return;
+		}
+		Path file = Files.createFile(projectRoot.resolve("HELP.md"));
+		try (PrintWriter writer = new PrintWriter(Files.newBufferedWriter(file))) {
+			this.helpDocument.write(writer);
+		}
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/HelpDocumentProjectGenerationConfiguration.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import io.spring.initializr.generator.project.ProjectGenerationConfiguration;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Import;
+
+/**
+ * Configuration for contributions specific to the help documentation of a project.
+ *
+ * @author Stephane Nicoll
+ */
+@ProjectGenerationConfiguration
+@Import(HelpDocumentProjectGenerationDefaultContributorsConfiguration.class)
+public class HelpDocumentProjectGenerationConfiguration {
+
+	@Bean
+	public HelpDocumentProjectContributor helpDocumentProjectContributor(
+			MustacheTemplateRenderer templateRenderer,
+			ObjectProvider<HelpDocumentCustomizer> helpDocumentCustomizers) {
+		HelpDocument helpDocument = new HelpDocument(templateRenderer);
+		helpDocumentCustomizers.orderedStream()
+				.forEach((customizer) -> customizer.customize(helpDocument));
+		return new HelpDocumentProjectContributor(helpDocument);
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/HelpDocumentProjectGenerationDefaultContributorsConfiguration.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import io.spring.initializr.generator.project.ResolvedProjectDescription;
+import io.spring.initializr.metadata.InitializrMetadata;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Default {@link HelpDocument} contributors.
+ *
+ * @author Stephane Nicoll
+ */
+@Configuration
+public class HelpDocumentProjectGenerationDefaultContributorsConfiguration {
+
+	@Bean
+	public RequestedDependenciesHelpDocumentCustomizer dependenciesHelpDocumentCustomizer(
+			ResolvedProjectDescription description, InitializrMetadata metadata) {
+		return new RequestedDependenciesHelpDocumentCustomizer(description, metadata);
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/PreDefinedSection.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.List;
+
+import io.spring.initializr.generator.io.text.Section;
+
+/**
+ * Section that is pre-defined and always present in the document. You can only add
+ * additional sections to pre-defined sections.
+ *
+ * @author Madhura Bhave
+ */
+public class PreDefinedSection implements Section {
+
+	private final String title;
+
+	private final List<Section> subSections = new ArrayList<>();
+
+	public PreDefinedSection(String title) {
+		this.title = title;
+	}
+
+	public PreDefinedSection addSection(Section section) {
+		this.subSections.add(section);
+		return this;
+	}
+
+	@Override
+	public void write(PrintWriter writer) throws IOException {
+		if (!isEmpty()) {
+			writer.println("# " + this.title);
+			writer.println("");
+			for (Section section : resolveSubSections(this.subSections)) {
+				section.write(writer);
+			}
+		}
+	}
+
+	public boolean isEmpty() {
+		return this.subSections.isEmpty();
+	}
+
+	/**
+	 * Resolve the sections to render based on the current registered sections.
+	 * @param sections the registered sections
+	 * @return the sections to render
+	 */
+	protected List<Section> resolveSubSections(List<Section> sections) {
+		return sections;
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/RequestedDependenciesHelpDocumentCustomizer.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import io.spring.initializr.generator.project.ResolvedProjectDescription;
+import io.spring.initializr.metadata.Dependency;
+import io.spring.initializr.metadata.InitializrMetadata;
+
+import org.springframework.core.Ordered;
+
+/**
+ * A {@link HelpDocumentCustomizer} that register links for selected dependencies.
+ *
+ * @author Stephane Nicoll
+ */
+public class RequestedDependenciesHelpDocumentCustomizer
+		implements HelpDocumentCustomizer {
+
+	private final ResolvedProjectDescription projectDescription;
+
+	private final InitializrMetadata metadata;
+
+	public RequestedDependenciesHelpDocumentCustomizer(
+			ResolvedProjectDescription projectDescription, InitializrMetadata metadata) {
+		this.projectDescription = projectDescription;
+		this.metadata = metadata;
+	}
+
+	@Override
+	public void customize(HelpDocument document) {
+		this.projectDescription.getRequestedDependencies().forEach((id, dependency) -> {
+			Dependency dependencyMetadata = this.metadata.getDependencies().get(id);
+			if (dependencyMetadata != null) {
+				handleDependency(document, dependencyMetadata);
+			}
+		});
+	}
+
+	@Override
+	public int getOrder() {
+		return Ordered.LOWEST_PRECEDENCE;
+	}
+
+	private void handleDependency(HelpDocument document, Dependency dependency) {
+		GettingStartedSection gettingStartedSection = document.gettingStarted();
+		dependency.getLinks().forEach((link) -> {
+			if (link.getDescription() != null && link.getRel() != null) {
+				if ("reference".equals(link.getRel())) {
+					gettingStartedSection.addReferenceDocLink(link.getHref(),
+							link.getDescription());
+				}
+				else if ("guide".equals(link.getRel())) {
+					gettingStartedSection.addGuideLink(link.getHref(),
+							link.getDescription());
+				}
+				else {
+					gettingStartedSection.addAdditionalLink(link.getHref(),
+							link.getDescription());
+				}
+			}
+		});
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/documentation/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2012-2019 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.
+ */
+
+/**
+ * Documentation contributors. Generate a {@code HELP.md} at the root of the project with
+ * additional information based on requested dependencies.
+ */
+package io.spring.initializr.generator.spring.documentation;

initializr-generator-spring/src/main/resources/META-INF/spring.factories

@@ -7,4 +7,5 @@ io.spring.initializr.generator.spring.code.groovy.GroovyProjectGenerationConfigu
 io.spring.initializr.generator.spring.code.java.JavaProjectGenerationConfiguration,\
 io.spring.initializr.generator.spring.code.kotlin.KotlinProjectGenerationConfiguration,\
 io.spring.initializr.generator.spring.configuration.ApplicationConfigurationProjectGenerationConfiguration,\
+io.spring.initializr.generator.spring.documentation.HelpDocumentProjectGenerationConfiguration,\
 io.spring.initializr.generator.spring.scm.git.GitProjectGenerationConfiguration

initializr-generator-spring/src/main/resources/templates/documentation/additional-links.mustache

@@ -0,0 +1,6 @@
+### Additional Links
+These additional references should also help you:
+
+{{#items}}
+* [{{description}}]({{href}})
+{{/items}}

initializr-generator-spring/src/main/resources/templates/documentation/guides.mustache

@@ -0,0 +1,6 @@
+### Guides
+The following guides illustrates how to use certain features concretely:
+
+{{#items}}
+* [{{description}}]({{href}})
+{{/items}}

initializr-generator-spring/src/main/resources/templates/documentation/reference-documentation.mustache

@@ -0,0 +1,6 @@
+### Reference Documentation
+For further reference, please consider the following sections:
+
+{{#items}}
+* [{{description}}]({{href}})
+{{/items}}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/documentation/GettingStartedSectionTests.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link GettingStartedSection}.
+ *
+ * @author Stephane Nicoll
+ */
+class GettingStartedSectionTests {
+
+	private final MustacheTemplateRenderer renderer = new MustacheTemplateRenderer("");
+
+	@Test
+	void gettingStartedEmpty() {
+		GettingStartedSection gettingStarted = newGettingStartedSection();
+		assertThat(gettingStarted.isEmpty()).isTrue();
+	}
+
+	@Test
+	void gettingStartedWithGuideLinkIsNotEmpty() {
+		GettingStartedSection gettingStarted = newGettingStartedSection();
+		gettingStarted.addGuideLink("https://example.com", "Test");
+		assertThat(gettingStarted.isEmpty()).isFalse();
+	}
+
+	@Test
+	void gettingStartedWithReferenceDocLinkIsNotEmpty() {
+		GettingStartedSection gettingStarted = newGettingStartedSection();
+		gettingStarted.addReferenceDocLink("https://example.com", "Test");
+		assertThat(gettingStarted.isEmpty()).isFalse();
+	}
+
+	@Test
+	void gettingStartedWithAdditionalLinkIsNotEmpty() {
+		GettingStartedSection gettingStarted = newGettingStartedSection();
+		gettingStarted.addAdditionalLink("https://example.com", "Test");
+		assertThat(gettingStarted.isEmpty()).isFalse();
+	}
+
+	@Test
+	void gettingStartedWithSubSectionIsNotEmpty() {
+		GettingStartedSection gettingStarted = newGettingStartedSection();
+		gettingStarted.addSection((writer) -> writer.println("test"));
+		assertThat(gettingStarted.isEmpty()).isFalse();
+	}
+
+	private GettingStartedSection newGettingStartedSection() {
+		return new GettingStartedSection(this.renderer);
+	}
+
+}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/documentation/HelpDocumentProjectContributorTests.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link HelpDocumentProjectContributor}.
+ *
+ * @author Stephane Nicoll
+ */
+class HelpDocumentProjectContributorTests {
+
+	private Path directory;
+
+	private MustacheTemplateRenderer templateRenderer;
+
+	@BeforeEach
+	void setup(@TempDir Path directory) {
+		this.directory = directory;
+		this.templateRenderer = new MustacheTemplateRenderer("classpath:/templates");
+	}
+
+	@Test
+	void helpDocumentEmptyDoesNotCreateFile() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		assertThat(document.isEmpty()).isTrue();
+		Path projectDir = Files.createTempDirectory(this.directory, "project-");
+		new HelpDocumentProjectContributor(document).contribute(projectDir);
+		Path helpDocument = projectDir.resolve("HELP.md");
+		assertThat(helpDocument).doesNotExist();
+	}
+
+	@Test
+	void helpDocumentWithLinksToGuide() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addGuideLink("https://test.example.com", "test")
+				.addGuideLink("https://test2.example.com", "test2");
+		List<String> lines = generateDocument(document);
+		assertThat(lines).containsExactly("# Getting Started", "", "### Guides",
+				"The following guides illustrates how to use certain features concretely:",
+				"", "* [test](https://test.example.com)",
+				"* [test2](https://test2.example.com)", "");
+	}
+
+	@Test
+	void helpDocumentWithLinksToReferenceDoc() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addReferenceDocLink("https://test.example.com", "doc")
+				.addReferenceDocLink("https://test2.example.com", "doc2");
+		List<String> lines = generateDocument(document);
+		assertThat(lines).containsExactly("# Getting Started", "",
+				"### Reference Documentation",
+				"For further reference, please consider the following sections:", "",
+				"* [doc](https://test.example.com)",
+				"* [doc2](https://test2.example.com)", "");
+	}
+
+	@Test
+	void helpDocumentWithLinksToOtherLinks() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addAdditionalLink("https://test.example.com",
+				"Something");
+		List<String> lines = generateDocument(document);
+		assertThat(lines).containsExactly("# Getting Started", "", "### Additional Links",
+				"These additional references should also help you:", "",
+				"* [Something](https://test.example.com)", "");
+	}
+
+	@Test
+	void helpDocumentWithSimpleSection() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.addSection((writer) -> writer
+				.println(String.format("# My test section%n%n    * Test")));
+		List<String> lines = generateDocument(document);
+		assertThat(lines).containsExactly("# My test section", "", "    * Test");
+	}
+
+	@Test
+	void helpDocumentWithLinksAndSimpleSection() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addGuideLink("https://test.example.com", "test")
+				.addSection((writer) -> writer
+						.println(String.format("# My test section%n%n    * Test")));
+		List<String> lines = generateDocument(document);
+		assertThat(lines).containsExactly("# Getting Started", "", "### Guides",
+				"The following guides illustrates how to use certain features concretely:",
+				"", "* [test](https://test.example.com)", "", "# My test section", "",
+				"    * Test");
+	}
+
+	private List<String> generateDocument(HelpDocument document) throws IOException {
+		Path projectDir = Files.createTempDirectory(this.directory, "project-");
+		new HelpDocumentProjectContributor(document).contribute(projectDir);
+		Path helpDocument = projectDir.resolve("HELP.md");
+		assertThat(helpDocument).isRegularFile();
+		return Files.readAllLines(helpDocument);
+	}
+
+}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/documentation/HelpDocumentProjectGenerationConfigurationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.nio.file.Path;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import io.spring.initializr.generator.project.ProjectDescription;
+import io.spring.initializr.generator.spring.test.InitializrMetadataTestBuilder;
+import io.spring.initializr.generator.test.project.ProjectAssetTester;
+import io.spring.initializr.metadata.Dependency;
+import io.spring.initializr.metadata.InitializrMetadata;
+import io.spring.initializr.metadata.Link;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link HelpDocumentProjectGenerationConfiguration}.
+ *
+ * @author Stephane Nicoll
+ */
+class HelpDocumentProjectGenerationConfigurationTests {
+
+	private ProjectAssetTester projectTester;
+
+	private InitializrMetadataTestBuilder metadataBuilder = InitializrMetadataTestBuilder
+			.withDefaults();
+
+	@BeforeEach
+	void setup(@TempDir Path directory) {
+		this.projectTester = new ProjectAssetTester()
+				.withConfiguration(HelpDocumentProjectGenerationConfiguration.class)
+				.withBean(MustacheTemplateRenderer.class,
+						() -> new MustacheTemplateRenderer("classpath:/templates"))
+				.withBean(InitializrMetadata.class, () -> this.metadataBuilder.build())
+				.withDirectory(directory);
+	}
+
+	@Test
+	void helpDocumentIsNotContributedWithoutLinks() {
+		assertThat(this.projectTester.generate(new ProjectDescription())
+				.getRelativePathsOfProjectFiles()).isEmpty();
+	}
+
+	@Test
+	void helpDocumentIsContributedWithLinks() {
+		Dependency dependency = Dependency.withId("example", "com.example", "example");
+		dependency.getLinks().add(
+				Link.create("guide", "https://example.com/how-to", "How-to example"));
+		dependency.getLinks().add(Link.create("reference", "https://example.com/doc",
+				"Reference doc example"));
+		this.metadataBuilder.addDependencyGroup("test", dependency);
+		ProjectDescription description = new ProjectDescription();
+		description.addDependency("example", null);
+		assertThat(
+				this.projectTester.generate(description).getRelativePathsOfProjectFiles())
+						.containsOnly("HELP.md");
+	}
+
+}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/documentation/HelpDocumentTests.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
+/**
+ * Tests for {@link HelpDocument}.
+ *
+ * @author Stephane Nicoll
+ */
+class HelpDocumentTests {
+
+	private final MustacheTemplateRenderer templateRenderer = new MustacheTemplateRenderer(
+			"classpath:/templates");
+
+	@Test
+	void renderEmptyDocumentDoesNotCallWriter() throws IOException {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		PrintWriter out = mock(PrintWriter.class);
+		document.write(out);
+		verifyZeroInteractions(out);
+	}
+
+	@Test
+	void renderSingleSection() {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.addSection((writer) -> writer.println("# Test"));
+		String out = write(document);
+		assertThat(out).contains("# Test", "");
+	}
+
+	@Test
+	void renderLinks() {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addReferenceDocLink("https://example.com/doc", "Doc");
+		document.gettingStarted().addGuideLink("https://example.com/guide-1", "Guide 1");
+		document.gettingStarted().addGuideLink("https://example.com/guide-2", "Guide 2");
+		String out = write(document);
+		assertThat(out).contains("# Getting Started", "", "### Reference Documentation",
+				"For further reference, please consider the following sections:", "",
+				"* [Doc](https://example.com/doc)", "", "### Guides",
+				"The following guides illustrates how to use certain features concretely:",
+				"", "* [Guide 1](https://example.com/guide-1)",
+				"* [Guide 2](https://example.com/guide-2)", "");
+	}
+
+	@Test
+	void renderOnlyAdditionalLink() {
+		HelpDocument document = new HelpDocument(this.templateRenderer);
+		document.gettingStarted().addAdditionalLink("https://example.com/app",
+				"Test App");
+		String out = write(document);
+		assertThat(out).contains("# Getting Started", "", "### Additional Links",
+				"These additional references should also help you:", "",
+				"* [Test App](https://example.com/app)", "");
+	}
+
+	private String write(HelpDocument document) {
+		try {
+			StringWriter out = new StringWriter();
+			document.write(new PrintWriter(out));
+			return out.toString();
+		}
+		catch (IOException ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+}

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/documentation/RequestedDependenciesHelpDocumentCustomizerTests.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.spring.documentation;
+
+import java.util.List;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import io.spring.initializr.generator.project.ProjectDescription;
+import io.spring.initializr.generator.project.ResolvedProjectDescription;
+import io.spring.initializr.generator.spring.test.InitializrMetadataTestBuilder;
+import io.spring.initializr.metadata.Dependency;
+import io.spring.initializr.metadata.InitializrMetadata;
+import io.spring.initializr.metadata.Link;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link RequestedDependenciesHelpDocumentCustomizer}.
+ *
+ * @author Stephane Nicoll
+ */
+class RequestedDependenciesHelpDocumentCustomizerTests {
+
+	private final InitializrMetadataTestBuilder metadataBuilder = InitializrMetadataTestBuilder
+			.withDefaults();
+
+	@Test
+	void dependencyLinkWithNoDescriptionIsIgnored() {
+		Dependency dependency = Dependency.withId("example", "com.example", "example");
+		dependency.getLinks().add(Link.create("guide", "https://example.com/how-to"));
+		this.metadataBuilder.addDependencyGroup("test", dependency);
+		HelpDocument document = customizeHelp("example");
+		assertThat(document.gettingStarted().isEmpty()).isTrue();
+	}
+
+	@Test
+	void dependencyWithReferenceDocLink() {
+		Dependency dependency = Dependency.withId("example", "com.example", "example");
+		dependency.getLinks().add(Link.create("reference", "https://example.com/doc",
+				"Reference doc example"));
+		this.metadataBuilder.addDependencyGroup("test", dependency);
+		HelpDocument document = customizeHelp("example");
+		assertThat(document.gettingStarted().isEmpty()).isFalse();
+		List<GettingStartedSection.Link> links = document.gettingStarted().referenceDocs()
+				.getItems();
+		assertThat(links).hasSize(1);
+		assertLink(links.get(0), "https://example.com/doc", "Reference doc example");
+	}
+
+	@Test
+	void dependencyWithGuideLink() {
+		Dependency dependency = Dependency.withId("example", "com.example", "example");
+		dependency.getLinks().add(
+				Link.create("guide", "https://example.com/how-to", "How-to example"));
+		this.metadataBuilder.addDependencyGroup("test", dependency);
+		HelpDocument document = customizeHelp("example");
+		assertThat(document.gettingStarted().isEmpty()).isFalse();
+		List<GettingStartedSection.Link> links = document.gettingStarted().guides()
+				.getItems();
+		assertThat(links).hasSize(1);
+		assertLink(links.get(0), "https://example.com/how-to", "How-to example");
+	}
+
+	@Test
+	void dependencyWithAdditionalLink() {
+		Dependency dependency = Dependency.withId("example", "com.example", "example");
+		dependency.getLinks()
+				.add(Link.create("something", "https://example.com/test", "Test App"));
+		this.metadataBuilder.addDependencyGroup("test", dependency);
+		HelpDocument document = customizeHelp("example");
+		assertThat(document.gettingStarted().isEmpty()).isFalse();
+		List<GettingStartedSection.Link> links = document.gettingStarted()
+				.additionalLinks().getItems();
+		assertThat(links).hasSize(1);
+		assertLink(links.get(0), "https://example.com/test", "Test App");
+	}
+
+	private void assertLink(GettingStartedSection.Link link, String href,
+			String description) {
+		assertThat(link.getHref()).isEqualTo(href);
+		assertThat(link.getDescription()).isEqualTo(description);
+	}
+
+	private HelpDocument customizeHelp(String... requestedDependencies) {
+		ProjectDescription description = new ProjectDescription();
+		for (String requestedDependency : requestedDependencies) {
+			description.addDependency(requestedDependency, null);
+		}
+		InitializrMetadata metadata = this.metadataBuilder.build();
+		HelpDocument document = new HelpDocument(
+				new MustacheTemplateRenderer("classpath:/templates"));
+		new RequestedDependenciesHelpDocumentCustomizer(
+				new ResolvedProjectDescription(description), metadata)
+						.customize(document);
+		return document;
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/io/text/BulletedSection.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.io.text;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import io.spring.initializr.generator.io.template.TemplateRenderer;
+
+/**
+ * {@link Section} for list of items using a {@link TemplateRenderer}.
+ *
+ * @param <T> the type of the item in the bullets
+ * @author Madhura Bhave
+ */
+public class BulletedSection<T> implements Section {
+
+	private final TemplateRenderer templateRenderer;
+
+	private final String templateName;
+
+	private final String itemName;
+
+	private List<T> items = new ArrayList<>();
+
+	public BulletedSection(TemplateRenderer templateRenderer, String templateName) {
+		this(templateRenderer, templateName, "items");
+	}
+
+	public BulletedSection(TemplateRenderer templateRenderer, String templateName,
+			String itemName) {
+		this.templateRenderer = templateRenderer;
+		this.templateName = templateName;
+		this.itemName = itemName;
+	}
+
+	public BulletedSection addItem(T item) {
+		this.items.add(item);
+		return this;
+	}
+
+	public boolean isEmpty() {
+		return this.items.isEmpty();
+	}
+
+	public List<T> getItems() {
+		return Collections.unmodifiableList(this.items);
+	}
+
+	@Override
+	public void write(PrintWriter writer) throws IOException {
+		if (!isEmpty()) {
+			Map<String, Object> model = new HashMap<>();
+			model.put(this.itemName, this.items);
+			writer.println(this.templateRenderer.render(this.templateName, model));
+		}
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/io/text/MustacheSection.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.io.text;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.Map;
+
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+
+/**
+ * {@link Section} that uses a {@link MustacheTemplateRenderer}. Renders the content with
+ * a newline at the end.
+ *
+ * @author Madhura Bhave
+ */
+public class MustacheSection implements Section {
+
+	private final MustacheTemplateRenderer templateRenderer;
+
+	private final String templateName;
+
+	private final Map<String, Object> model;
+
+	public MustacheSection(MustacheTemplateRenderer templateRenderer, String templateName,
+			Map<String, Object> model) {
+		this.templateRenderer = templateRenderer;
+		this.templateName = templateName;
+		this.model = model;
+	}
+
+	@Override
+	public void write(PrintWriter writer) throws IOException {
+		writer.println(this.templateRenderer.render(this.templateName,
+				resolveModel(this.model)));
+	}
+
+	/**
+	 * Resolve the {@code model} prior to render the section.
+	 * @param model the current model
+	 * @return the model to use to render this section (never null)
+	 */
+	protected Map<String, Object> resolveModel(Map<String, Object> model) {
+		return model;
+	}
+
+}

initializr-generator/src/test/java/io/spring/initializr/generator/io/text/BulletedSectionTests.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.io.text;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.Map;
+
+import io.spring.initializr.generator.io.template.TemplateRenderer;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+/**
+ * Tests for {@link BulletedSection}.
+ *
+ * @author Stephane Nicoll
+ */
+@ExtendWith(MockitoExtension.class)
+class BulletedSectionTests {
+
+	@Mock
+	private TemplateRenderer renderer;
+
+	@Captor
+	private ArgumentCaptor<Map<String, Object>> modelCaptor;
+
+	@Test
+	void bulletedSectionEmpty() {
+		assertThat(new BulletedSection<String>(this.renderer, "test").isEmpty()).isTrue();
+	}
+
+	@Test
+	void bulletedSectionEmptyDoesNotInvokeRender() throws IOException {
+		BulletedSection<String> section = new BulletedSection<>(this.renderer, "test");
+		PrintWriter writer = mock(PrintWriter.class);
+		section.write(writer);
+		verifyNoMoreInteractions(writer, this.renderer);
+	}
+
+	@Test
+	void bulletedSectionWithItem() {
+		BulletedSection<String> section = new BulletedSection<>(this.renderer, "test");
+		section.addItem("test");
+		assertThat(section.isEmpty()).isFalse();
+	}
+
+	@Test
+	void bulletedSectionWithDefaultItemName() throws IOException {
+		given(this.renderer.render(eq("template"), any())).willReturn("output");
+		BulletedSection<String> section = new BulletedSection<>(this.renderer,
+				"template");
+		section.addItem("test");
+		section.write(new PrintWriter(new StringWriter()));
+		verify(this.renderer).render(eq("template"), this.modelCaptor.capture());
+		Map<String, Object> model = this.modelCaptor.getValue();
+		assertThat(model).containsOnly(entry("items", Collections.singletonList("test")));
+	}
+
+	@Test
+	void bulletedSectionWithCustomItemName() throws IOException {
+		given(this.renderer.render(eq("template"), any())).willReturn("output");
+		BulletedSection<String> section = new BulletedSection<>(this.renderer, "template",
+				"elements");
+		section.addItem("test");
+		section.write(new PrintWriter(new StringWriter()));
+		verify(this.renderer).render(eq("template"), this.modelCaptor.capture());
+		Map<String, Object> model = this.modelCaptor.getValue();
+		assertThat(model)
+				.containsOnly(entry("elements", Collections.singletonList("test")));
+	}
+
+}

initializr-generator/src/test/java/io/spring/initializr/generator/io/text/MustacheSectionTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2012-2019 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 io.spring.initializr.generator.io.text;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.Map;
+
+import com.samskivert.mustache.MustacheException;
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * Tests for {@link MustacheSection}.
+ *
+ * @author Stephane Nicoll
+ */
+class MustacheSectionTests {
+
+	private final MustacheTemplateRenderer renderer = new MustacheTemplateRenderer(
+			"classpath:/templates/mustache");
+
+	@Test
+	void renderSection() throws IOException {
+		MustacheSection section = new MustacheSection(this.renderer, "test",
+				Collections.singletonMap("key", "hello"));
+		StringWriter writer = new StringWriter();
+		section.write(new PrintWriter(writer));
+		assertThat(writer.toString()).isEqualTo(String.format("hello%n"));
+	}
+
+	@Test
+	void renderSectionWithMissingKey() {
+		MustacheSection section = new MustacheSection(this.renderer, "test",
+				Collections.singletonMap("another", "hello"));
+		assertThatThrownBy(() -> section.write(new PrintWriter(new StringWriter())))
+				.isInstanceOf(MustacheException.class).hasMessageContaining("key");
+	}
+
+	@Test
+	void renderSectionWithCustomModelResolution() throws IOException {
+		MustacheSection section = new MustacheSection(this.renderer, "test",
+				Collections.emptyMap()) {
+			@Override
+			protected Map<String, Object> resolveModel(Map<String, Object> model) {
+				return Collections.singletonMap("key", "custom");
+			}
+		};
+		StringWriter writer = new StringWriter();
+		section.write(new PrintWriter(writer));
+		assertThat(writer.toString()).isEqualTo(String.format("custom%n"));
+	}
+
+}

initializr-generator/src/test/java/io/spring/initializr/generator/test/project/ProjectGeneratorTester.java

@@ -17,13 +17,14 @@
 package io.spring.initializr.generator.test.project;
 
 import java.nio.file.Path;
-import java.util.Collections;
+import java.util.HashMap;
 import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import io.spring.initializr.generator.io.IndentingWriterFactory;
 import io.spring.initializr.generator.io.SimpleIndentStrategy;
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
 import io.spring.initializr.generator.project.DefaultProjectAssetGenerator;
 import io.spring.initializr.generator.project.ProjectAssetGenerator;
 import io.spring.initializr.generator.project.ProjectDescription;
@@ -49,8 +50,12 @@ public class ProjectGeneratorTester
 	}
 
 	private static Map<Class<?>, Supplier<?>> defaultBeans() {
-		return Collections.singletonMap(IndentingWriterFactory.class,
+		Map<Class<?>, Supplier<?>> beans = new HashMap<>();
+		beans.put(IndentingWriterFactory.class,
 				() -> IndentingWriterFactory.create(new SimpleIndentStrategy("    ")));
+		beans.put(MustacheTemplateRenderer.class,
+				() -> new MustacheTemplateRenderer("classpath:/templates"));
+		return beans;
 	}
 
 	@Override

initializr-web/src/main/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfiguration.java

@@ -89,8 +89,8 @@ public class InitializrAutoConfiguration {
 	}
 
 	@Bean
-	@ConditionalOnMissingBean
-	public TemplateRenderer templateRenderer(Environment environment,
+	@ConditionalOnMissingBean(TemplateRenderer.class)
+	public MustacheTemplateRenderer templateRenderer(Environment environment,
 			ObjectProvider<CacheManager> cacheManager) {
 		return new MustacheTemplateRenderer("classpath:/templates",
 				determineCache(environment, cacheManager.getIfAvailable()));

initializr-web/src/test/java/io/spring/initializr/web/project/ProjectGenerationInvokerTests.java

@@ -24,6 +24,7 @@ import java.util.Map;
 
 import io.spring.initializr.generator.io.IndentingWriterFactory;
 import io.spring.initializr.generator.io.SimpleIndentStrategy;
+import io.spring.initializr.generator.io.template.MustacheTemplateRenderer;
 import io.spring.initializr.generator.project.ProjectDirectoryFactory;
 import io.spring.initializr.generator.spring.test.InitializrMetadataTestBuilder;
 import io.spring.initializr.generator.spring.test.ProjectAssert;
@@ -206,6 +207,11 @@ public class ProjectGenerationInvokerTests {
 			return IndentingWriterFactory.create(new SimpleIndentStrategy("\t"));
 		}
 
+		@Bean
+		public MustacheTemplateRenderer templateRenderer() {
+			return new MustacheTemplateRenderer("classpath:/templates");
+		}
+
 		@Bean
 		public ProjectDirectoryFactory projectDirectoryFactory() {
 			return (description) -> Files.createTempDirectory("project-");