Introduce conditional configuration file format support

Author: YangSiJun528

initializr-generator/src/main/java/io/spring/initializr/generator/condition/ConditionalOnConfigurationFileFormat.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012 - present 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.condition;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import io.spring.initializr.generator.configuration.format.ConfigurationFileFormat;
+
+import org.springframework.context.annotation.Conditional;
+
+/**
+ * Condition that matches when a generated project uses a particular
+ * {@link ConfigurationFileFormat}.
+ *
+ * @author Sijun Yang
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@Documented
+@Conditional(OnConfigurationFileFormatCondition.class)
+public @interface ConditionalOnConfigurationFileFormat {
+
+	String value();
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/condition/OnConfigurationFileFormatCondition.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012 - present 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.condition;
+
+import io.spring.initializr.generator.configuration.format.ConfigurationFileFormat;
+import io.spring.initializr.generator.project.ProjectDescription;
+
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+
+/**
+ * {@link ProjectGenerationCondition Condition} implementation for
+ * {@link ConditionalOnConfigurationFileFormat}.
+ *
+ * @author Sijun Yang
+ */
+class OnConfigurationFileFormatCondition extends ProjectGenerationCondition {
+
+	@Override
+	protected boolean matches(ProjectDescription description, ConditionContext context,
+			AnnotatedTypeMetadata metadata) {
+		if (description.getConfigurationFileFormat() == null) {
+			return false;
+		}
+		String configurationFileFormatId = (String) metadata
+			.getAllAnnotationAttributes(ConditionalOnConfigurationFileFormat.class.getName())
+			.getFirst("value");
+		ConfigurationFileFormat configurationFileFormat = ConfigurationFileFormat.forId(configurationFileFormatId);
+		return description.getConfigurationFileFormat().id().equals(configurationFileFormat.id());
+	}
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/configuration/format/ConfigurationFileFormat.java

@@ -16,12 +16,33 @@
 
 package io.spring.initializr.generator.configuration.format;
 
+import java.util.Objects;
+
+import org.springframework.core.io.support.SpringFactoriesLoader;
+
 public interface ConfigurationFileFormat {
 
 	/**
-	 * Return the id of the packaging.
+	 * Return the id of the configuration file format.
 	 * @return the id
 	 */
 	String id();
 
+	/**
+	 * Creates the configuration file format for the given id.
+	 * @param id the id
+	 * @return the configuration file format
+	 * @throws IllegalStateException if the configuration file format with the given id
+	 * can't be found
+	 */
+	static ConfigurationFileFormat forId(String id) {
+		return SpringFactoriesLoader
+			.loadFactories(ConfigurationFileFormatFactory.class, ConfigurationFileFormat.class.getClassLoader())
+			.stream()
+			.map((factory) -> factory.createConfigurationFileFormat(id))
+			.filter(Objects::nonNull)
+			.findFirst()
+			.orElseThrow(() -> new IllegalStateException("Unrecognized configuration file format id '" + id + "'"));
+	}
+
 }