Add support for transforming the chosen platform version

This commit improves the ProjectRequest converter to invoke a
ProjectRequestPlatformVersionTransformer. A default implementation does
the conversion based on configurable ranges for the V1 and V2 format
respectively.

This complement our backward compatible support with 2.1 metadata on an
instance using the new version format. All that is required is to
configure which versions are using which format.

See gh-1092

initializr-metadata/src/main/java/io/spring/initializr/metadata/InitializrConfiguration.java

@@ -30,6 +30,7 @@ import javax.lang.model.SourceVersion;
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import io.spring.initializr.generator.version.InvalidVersionException;
 import io.spring.initializr.generator.version.Version;
+import io.spring.initializr.generator.version.Version.Format;
 import io.spring.initializr.generator.version.VersionParser;
 import io.spring.initializr.generator.version.VersionRange;
 
@@ -210,16 +211,6 @@ public class InitializrConfiguration {
 		 */
 		private boolean forceSsl;
 
-		/**
-		 * Compatibility range of supported platform versions. Requesting metadata or
-		 * project generation with a platform version that does not match this range is
-		 * not supported.
-		 */
-		private String platformCompatibilityRange;
-
-		@JsonIgnore
-		private VersionRange compatibilityRange;
-
 		/**
 		 * The "BillOfMaterials" that are referenced in this instance, identified by an
 		 * arbitrary identifier that can be used in the dependencies definition.
@@ -250,6 +241,12 @@ public class InitializrConfiguration {
 		@NestedConfigurationProperty
 		private final Maven maven = new Maven();
 
+		/**
+		 * Platform-specific settings.
+		 */
+		@NestedConfigurationProperty
+		private final Platform platform = new Platform();
+
 		public Env() {
 			try {
 				this.repositories.put("spring-snapshots",
@@ -310,14 +307,6 @@ public class InitializrConfiguration {
 			this.forceSsl = forceSsl;
 		}
 
-		public String getPlatformCompatibilityRange() {
-			return this.platformCompatibilityRange;
-		}
-
-		public void setPlatformCompatibilityRange(String platformCompatibilityRange) {
-			this.platformCompatibilityRange = platformCompatibilityRange;
-		}
-
 		public String getArtifactRepository() {
 			return this.artifactRepository;
 		}
@@ -342,6 +331,10 @@ public class InitializrConfiguration {
 			return this.maven;
 		}
 
+		public Platform getPlatform() {
+			return this.platform;
+		}
+
 		public void setArtifactRepository(String artifactRepository) {
 			if (!artifactRepository.endsWith("/")) {
 				artifactRepository = artifactRepository + "/";
@@ -359,8 +352,7 @@ public class InitializrConfiguration {
 		public void updateCompatibilityRange(VersionParser versionParser) {
 			this.getBoms().values().forEach((it) -> it.updateCompatibilityRange(versionParser));
 			this.getKotlin().updateCompatibilityRange(versionParser);
-			this.compatibilityRange = (this.platformCompatibilityRange != null)
-					? versionParser.parseRange(this.platformCompatibilityRange) : null;
+			this.getPlatform().updateCompatibilityRange(versionParser);
 		}
 
 		public void merge(Env other) {
@@ -370,29 +362,14 @@ public class InitializrConfiguration {
 			this.fallbackApplicationName = other.fallbackApplicationName;
 			this.invalidApplicationNames = other.invalidApplicationNames;
 			this.forceSsl = other.forceSsl;
-			this.platformCompatibilityRange = other.platformCompatibilityRange;
-			this.compatibilityRange = other.compatibilityRange;
 			this.gradle.merge(other.gradle);
 			this.kotlin.merge(other.kotlin);
 			this.maven.merge(other.maven);
+			this.platform.merge(other.platform);
 			other.boms.forEach(this.boms::putIfAbsent);
 			other.repositories.forEach(this.repositories::putIfAbsent);
 		}
 
-		/**
-		 * Specify whether the specified {@linkplain Version platform version} is
-		 * supported.
-		 * @param platformVersion the platform version to check
-		 * @return {@code true} if this version is supported, {@code false} otherwise
-		 */
-		public boolean isCompatiblePlatformVersion(Version platformVersion) {
-			return (this.compatibilityRange == null || this.compatibilityRange.match(platformVersion));
-		}
-
-		public String determinePlatformCompatibilityRangeRequirement() {
-			return this.compatibilityRange.toString();
-		}
-
 		/**
 		 * Gradle details.
 		 */
@@ -662,4 +639,112 @@ public class InitializrConfiguration {
 
 	}
 
+	/**
+	 * Platform-specific settings.
+	 */
+	public static class Platform {
+
+		/**
+		 * Compatibility range of supported platform versions. Requesting metadata or
+		 * project generation with a platform version that does not match this range is
+		 * not supported.
+		 */
+		private String compatibilityRange;
+
+		@JsonIgnore
+		private VersionRange range;
+
+		/**
+		 * Compatibility range of platform versions using the first version format.
+		 */
+		private String v1FormatCompatibilityRange;
+
+		@JsonIgnore
+		private VersionRange v1FormatRange;
+
+		/**
+		 * Compatibility range of platform versions using the second version format.
+		 */
+		private String v2FormatCompatibilityRange;
+
+		@JsonIgnore
+		private VersionRange v2FormatRange;
+
+		public void updateCompatibilityRange(VersionParser versionParser) {
+			this.range = (this.compatibilityRange != null) ? versionParser.parseRange(this.compatibilityRange) : null;
+			this.v1FormatRange = (this.v1FormatCompatibilityRange != null)
+					? versionParser.parseRange(this.v1FormatCompatibilityRange) : null;
+			this.v2FormatRange = (this.v2FormatCompatibilityRange != null)
+					? versionParser.parseRange(this.v2FormatCompatibilityRange) : null;
+		}
+
+		private void merge(Platform other) {
+			this.compatibilityRange = other.compatibilityRange;
+			this.range = other.range;
+			this.v1FormatCompatibilityRange = other.v1FormatCompatibilityRange;
+			this.v1FormatRange = other.v1FormatRange;
+			this.v2FormatCompatibilityRange = other.v2FormatCompatibilityRange;
+			this.v2FormatRange = other.v2FormatRange;
+		}
+
+		/**
+		 * Specify whether the specified {@linkplain Version platform version} is
+		 * supported.
+		 * @param platformVersion the platform version to check
+		 * @return {@code true} if this version is supported, {@code false} otherwise
+		 */
+		public boolean isCompatibleVersion(Version platformVersion) {
+			return (this.range == null || this.range.match(platformVersion));
+		}
+
+		public String determineCompatibilityRangeRequirement() {
+			return this.range.toString();
+		}
+
+		/**
+		 * Format the expected {@link Version platform version}.
+		 * @param platformVersion a platform version
+		 * @return a platform version in the suitable format
+		 */
+		public Version formatPlatformVersion(Version platformVersion) {
+			Format format = getExpectedVersionFormat(platformVersion);
+			return platformVersion.format(format);
+		}
+
+		private Format getExpectedVersionFormat(Version version) {
+			if (this.v2FormatRange != null && this.v2FormatRange.match(version)) {
+				return Format.V2;
+			}
+			if (this.v1FormatRange != null && this.v1FormatRange.match(version)) {
+				return Format.V1;
+			}
+			return version.getFormat();
+		}
+
+		public String getCompatibilityRange() {
+			return this.compatibilityRange;
+		}
+
+		public void setCompatibilityRange(String compatibilityRange) {
+			this.compatibilityRange = compatibilityRange;
+		}
+
+		public String getV1FormatCompatibilityRange() {
+			return this.v1FormatCompatibilityRange;
+		}
+
+		public void setV1FormatCompatibilityRange(String v1FormatCompatibilityRange) {
+			this.v1FormatCompatibilityRange = v1FormatCompatibilityRange;
+		}
+
+		public String getV2FormatCompatibilityRange() {
+			return this.v2FormatCompatibilityRange;
+		}
+
+		public void setV2FormatCompatibilityRange(String v2FormatCompatibilityRange) {
+			this.v2FormatCompatibilityRange = v2FormatCompatibilityRange;
+		}
+
+	}
+
 }