Add support for customizable application properties

Closes gh-1516

Author: mhalbritter

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/configuration/ApplicationConfigurationProjectGenerationConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -26,17 +26,13 @@
  * Configuration for application-related contributions to a generated project.
  *
  * @author Stephane Nicoll
+ * @author Moritz Halbritter
  */
 @ProjectGenerationConfiguration
 public class ApplicationConfigurationProjectGenerationConfiguration {
 
 	@Bean
-	public ApplicationPropertiesContributor applicationPropertiesContributor() {
-		return new ApplicationPropertiesContributor();
-	}
-
-	@Bean
-	public WebFoldersContributor webFoldersContributor(Build build, InitializrMetadata metadata) {
+	WebFoldersContributor webFoldersContributor(Build build, InitializrMetadata metadata) {
 		return new WebFoldersContributor(build, metadata);
 	}
 

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/configuration/ApplicationPropertiesContributor.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2012-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.initializr.generator.spring.properties;
+
+import java.io.PrintWriter;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+
+/**
+ * Application properties.
+ *
+ * @author Moritz Halbritter
+ */
+public class ApplicationProperties {
+
+	private final Map<String, Object> properties = new HashMap<>();
+
+	/**
+	 * Adds a new property.
+	 * @param key the key of the property
+	 * @param value the value of the property
+	 */
+	public void add(String key, long value) {
+		add(key, (Object) value);
+	}
+
+	/**
+	 * Adds a new property.
+	 * @param key the key of the property
+	 * @param value the value of the property
+	 */
+	public void add(String key, boolean value) {
+		add(key, (Object) value);
+	}
+
+	/**
+	 * Adds a new property.
+	 * @param key the key of the property
+	 * @param value the value of the property
+	 */
+	public void add(String key, double value) {
+		add(key, (Object) value);
+	}
+
+	/**
+	 * Adds a new property.
+	 * @param key the key of the property
+	 * @param value the value of the property
+	 */
+	public void add(String key, String value) {
+		add(key, (Object) value);
+	}
+
+	void writeTo(PrintWriter writer) {
+		for (Map.Entry<String, Object> entry : this.properties.entrySet()) {
+			writer.printf("%s=%s%n", entry.getKey(), entry.getValue());
+		}
+	}
+
+	private void add(String key, Object value) {
+		Assert.state(!this.properties.containsKey(key), () -> "Property '%s' already exists".formatted(key));
+		this.properties.put(key, value);
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/properties/ApplicationProperties.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2012-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.initializr.generator.spring.properties;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+
+import io.spring.initializr.generator.project.contributor.ProjectContributor;
+
+/**
+ * A {@link ProjectContributor} that contributes a {@code application.properties} file to
+ * a project.
+ *
+ * @author Stephane Nicoll
+ * @author Moritz Halbritter
+ */
+public class ApplicationPropertiesContributor implements ProjectContributor {
+
+	private static final String FILE = "src/main/resources/application.properties";
+
+	private final ApplicationProperties properties;
+
+	public ApplicationPropertiesContributor(ApplicationProperties properties) {
+		this.properties = properties;
+	}
+
+	@Override
+	public void contribute(Path projectRoot) throws IOException {
+		Path output = projectRoot.resolve(FILE);
+		if (!Files.exists(output)) {
+			Files.createDirectories(output.getParent());
+			Files.createFile(output);
+		}
+		try (PrintWriter writer = new PrintWriter(Files.newOutputStream(output, StandardOpenOption.APPEND), false,
+				StandardCharsets.UTF_8)) {
+			this.properties.writeTo(writer);
+		}
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/properties/ApplicationPropertiesContributor.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2012-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.initializr.generator.spring.properties;
+
+/**
+ * Callback for customizing a project's {@link ApplicationProperties}.
+ *
+ * @author Moritz Halbritter
+ */
+@FunctionalInterface
+public interface ApplicationPropertiesCustomizer {
+
+	/**
+	 * Customizes the project's {@link ApplicationProperties}.
+	 * @param properties the properties to customize
+	 */
+	void customize(ApplicationProperties properties);
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/properties/ApplicationPropertiesCustomizer.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.initializr.generator.spring.properties;
+
+import io.spring.initializr.generator.project.ProjectGenerationConfiguration;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.context.annotation.Bean;
+
+/**
+ * Configuration for application properties related contributions to a generated project.
+ *
+ * @author Moritz Halbritter
+ */
+@ProjectGenerationConfiguration
+class ApplicationPropertiesProjectGenerationConfiguration {
+
+	@Bean
+	ApplicationProperties applicationProperties(ObjectProvider<ApplicationPropertiesCustomizer> customizers) {
+		ApplicationProperties properties = new ApplicationProperties();
+		customizers.orderedStream().forEach((customizer) -> customizer.customize(properties));
+		return properties;
+	}
+
+	@Bean
+	ApplicationPropertiesContributor applicationPropertiesContributor(ApplicationProperties applicationProperties) {
+		return new ApplicationPropertiesContributor(applicationProperties);
+	}
+
+}

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/properties/ApplicationPropertiesProjectGenerationConfiguration.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Support for application properties.
+ */
+package io.spring.initializr.generator.spring.properties;

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

@@ -8,4 +8,5 @@ io.spring.initializr.generator.spring.code.java.JavaProjectGenerationConfigurati
 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.properties.ApplicationPropertiesProjectGenerationConfiguration,\
 io.spring.initializr.generator.spring.scm.git.GitProjectGenerationConfiguration

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -14,10 +14,9 @@
  * limitations under the License.
  */
 
-package io.spring.initializr.generator.spring.configuration;
+package io.spring.initializr.generator.spring.properties;
 
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
 
 import io.spring.initializr.generator.test.project.ProjectStructure;
@@ -30,6 +29,7 @@
  * Tests for {@link ApplicationPropertiesContributor}.
  *
  * @author Stephane Nicoll
+ * @author Moritz Halbritter
  */
 class ApplicationPropertiesContributorTests {
 
@@ -38,11 +38,20 @@ class ApplicationPropertiesContributorTests {
 
 	@Test
 	void applicationConfigurationWithDefaultSettings() throws IOException {
-		Path projectDir = Files.createTempDirectory(this.directory, "project-");
-		new ApplicationPropertiesContributor().contribute(projectDir);
-		assertThat(new ProjectStructure(projectDir)).textFile("src/main/resources/application.properties")
-			.lines()
+		new ApplicationPropertiesContributor(new ApplicationProperties()).contribute(this.directory);
+		assertThat(new ProjectStructure(this.directory)).textFile("src/main/resources/application.properties")
 			.isEmpty();
 	}
 
+	@Test
+	void shouldAddStringProperty() throws IOException {
+		ApplicationProperties properties = new ApplicationProperties();
+		properties.add("spring.application.name", "test");
+		ApplicationPropertiesContributor contributor = new ApplicationPropertiesContributor(properties);
+		contributor.contribute(this.directory);
+		assertThat(new ProjectStructure(this.directory)).textFile("src/main/resources/application.properties")
+			.lines()
+			.contains("spring.application.name=test");
+	}
+
 }