feat: added the possibility to list distributions

src/main/java/dev/jbang/devkitman/JdkDistroQuery.java

@@ -0,0 +1,39 @@
+package dev.jbang.devkitman;
+
+import java.util.List;
+import java.util.Objects;
+
+public interface JdkDistroQuery {
+	List<JdkDistro> listDistros();
+
+	class JdkDistro {
+		private final String name;
+
+		public JdkDistro(String name) {
+			this.name = name;
+		}
+
+		public String name() {
+			return name;
+		}
+
+		@Override
+		public final boolean equals(Object o) {
+			if (!(o instanceof JdkDistro))
+				return false;
+
+			JdkDistro jdkDistro = (JdkDistro) o;
+			return Objects.equals(name, jdkDistro.name);
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hashCode(name);
+		}
+
+		@Override
+		public String toString() {
+			return name;
+		}
+	}
+}

src/main/java/dev/jbang/devkitman/JdkInstaller.java

@@ -11,7 +11,7 @@
  * JDKs on the user's system. They should be able to install and uninstall them
  * at the user's request.
  */
-public interface JdkInstaller {
+public interface JdkInstaller extends JdkDistroQuery {
 
 	/**
 	 * This method returns a set of JDKs that are available for installation.

src/main/java/dev/jbang/devkitman/JdkManager.java

@@ -18,7 +18,7 @@
 import dev.jbang.devkitman.jdkproviders.LinkedJdkProvider;
 import dev.jbang.devkitman.util.JavaUtils;
 
-public class JdkManager {
+public class JdkManager implements JdkDistroQuery {
 	public static final int DEFAULT_JAVA_VERSION = 21;
 	public final int defaultJavaVersion;
 
@@ -765,4 +765,12 @@ public boolean isCurrentJdkManaged() {
 		return providers(JdkProvider.Predicates.canUpdate)
 			.anyMatch(p -> p.getInstalledByPath(currentJdk) != null);
 	}
+
+	@Override
+	public List<JdkDistroQuery.JdkDistro> listDistros() {
+		return providers(JdkProvider.Predicates.canInstall)
+			.flatMap(p -> p instanceof JdkDistroQuery ? ((JdkDistroQuery) p).listDistros().stream() : Stream.empty())
+			.distinct()
+			.collect(Collectors.toList());
+	}
 }

src/main/java/dev/jbang/devkitman/jdkinstallers/FoojayJdkInstaller.java

@@ -29,11 +29,12 @@ public class FoojayJdkInstaller implements JdkInstaller {
 	protected final JdkProvider jdkProvider;
 	protected final Function<JdkResult, String> jdkId;
 	protected RemoteAccessProvider remoteAccessProvider;
-	protected String distro = DEFAULT_DISTRO;
+	protected String distros = DEFAULT_DISTROS;
 
 	public static final String FOOJAY_JDK_VERSIONS_URL = "https://api.foojay.io/disco/v3.0/packages?";
+	public static final String FOOJAY_JDK_DISTROS_URL = "https://api.foojay.io/disco/v3.0/distributions?include_versions=false&include_synonyms=false";
 
-	public static final String DEFAULT_DISTRO = "temurin,aoj";
+	public static final String DEFAULT_DISTROS = "temurin,aoj";
 
 	private static final Logger LOGGER = Logger.getLogger(FoojayJdkInstaller.class.getName());
 
@@ -55,6 +56,15 @@ public static class VersionsResponse {
 		public List<JdkResult> result;
 	}
 
+	public static class DistroResult {
+		public String name;
+		public String api_parameter;
+	}
+
+	public static class DistrosResponse {
+		public List<DistroResult> result;
+	}
+
 	public FoojayJdkInstaller(@NonNull JdkProvider jdkProvider) {
 		this.jdkProvider = jdkProvider;
 		this.jdkId = jdk -> determineId(jdk) + "-" + jdkProvider.name();
@@ -77,8 +87,8 @@ public FoojayJdkInstaller(@NonNull JdkProvider jdkProvider, @NonNull Function<Jd
 		return this;
 	}
 
-	public @NonNull FoojayJdkInstaller distro(String distro) {
-		this.distro = distro != null && !distro.isEmpty() ? distro : DEFAULT_DISTRO;
+	public @NonNull FoojayJdkInstaller distros(String distros) {
+		this.distros = distros != null && !distros.isEmpty() ? distros : DEFAULT_DISTROS;
 		return this;
 	}
 
@@ -95,8 +105,8 @@ public Stream<Jdk.AvailableJdk> listAvailable() {
 	}
 
 	private VersionsResponse readPackagesForList() throws IOException {
-		return readJsonFromUrl(
-				getVersionsUrl(0, true, OsUtils.getOS(), OsUtils.getArch(), distro, "ga,ea"));
+		return readVersionsFromUrl(
+				getVersionsUrl(0, true, OsUtils.getOS(), OsUtils.getArch(), distros, "ga,ea"));
 	}
 
 	@Override
@@ -129,11 +139,11 @@ private VersionsResponse readPackagesForList() throws IOException {
 	}
 
 	private VersionsResponse readPackagesForVersion(Integer minVersion, boolean openVersion) throws IOException {
-		VersionsResponse res = readJsonFromUrl(
-				getVersionsUrl(minVersion, openVersion, OsUtils.getOS(), OsUtils.getArch(), distro, "ga"));
+		VersionsResponse res = readVersionsFromUrl(
+				getVersionsUrl(minVersion, openVersion, OsUtils.getOS(), OsUtils.getArch(), distros, "ga"));
 		if (res.result.isEmpty()) {
-			res = readJsonFromUrl(
-					getVersionsUrl(minVersion, openVersion, OsUtils.getOS(), OsUtils.getArch(), distro, "ea"));
+			res = readVersionsFromUrl(
+					getVersionsUrl(minVersion, openVersion, OsUtils.getOS(), OsUtils.getArch(), distros, "ea"));
 		}
 		return res;
 	}
@@ -176,7 +186,7 @@ private Stream<Jdk.AvailableJdk> processPackages(List<JdkResult> jdks, Comparato
 		return tags;
 	}
 
-	private VersionsResponse readJsonFromUrl(String url) throws IOException {
+	private VersionsResponse readVersionsFromUrl(String url) throws IOException {
 		return RemoteAccessProvider.readJsonFromUrl(remoteAccessProvider(), url, VersionsResponse.class);
 	}
 
@@ -209,7 +219,7 @@ private List<JdkResult> filterEA(List<JdkResult> jdks) {
 		.compare(o1.java_version, o2.java_version);
 
 	private Comparator<JdkResult> majorVersionSort() {
-		List<String> ds = Arrays.asList(distro.split(","));
+		List<String> ds = Arrays.asList(distros.split(","));
 		Comparator<JdkResult> jdkResultDistroComparator = Comparator.comparingInt(o -> ds.indexOf(o.distribution));
 		return Comparator
 			.comparingInt((JdkResult jdk) -> -jdk.major_version)
@@ -256,13 +266,27 @@ public void uninstall(Jdk.@NonNull InstalledJdk jdk) {
 		JavaUtils.safeDeleteJdk(jdk.home());
 	}
 
+	@Override
+	public List<JdkDistro> listDistros() {
+		try {
+			DistrosResponse response = RemoteAccessProvider.readJsonFromUrl(remoteAccessProvider(),
+					FOOJAY_JDK_DISTROS_URL, DistrosResponse.class);
+			return response.result.stream()
+				.map(d -> new JdkDistro(d.api_parameter))
+				.collect(Collectors.toList());
+		} catch (IOException e) {
+			LOGGER.log(Level.FINE, "Couldn't list available JDKs", e);
+			return Collections.emptyList();
+		}
+	}
+
 	private static String getVersionsUrl(int minVersion, boolean openVersion, OsUtils.OS os, OsUtils.Arch arch,
-			String distro, String status) {
-		return FOOJAY_JDK_VERSIONS_URL + getUrlParams(minVersion, openVersion, os, arch, distro, status);
+			String distros, String status) {
+		return FOOJAY_JDK_VERSIONS_URL + getUrlParams(minVersion, openVersion, os, arch, distros, status);
 	}
 
 	private static String getUrlParams(int version, boolean openVersion, OsUtils.OS os, OsUtils.Arch arch,
-			String distro, String status) {
+			String distros, String status) {
 		Map<String, String> params = new HashMap<>();
 		if (version > 0) {
 			String v = String.valueOf(version);
@@ -272,14 +296,14 @@ private static String getUrlParams(int version, boolean openVersion, OsUtils.OS
 			params.put("version", v);
 		}
 
-		if (distro == null) {
+		if (distros == null) {
 			if (version == 0 || version == 8 || version == 11 || version >= 17) {
-				distro = "temurin";
+				distros = "temurin";
 			} else {
-				distro = "aoj";
+				distros = "aoj";
 			}
 		}
-		params.put("distro", distro);
+		params.put("distro", distros);
 
 		String archiveType;
 		if (os == OsUtils.OS.windows) {
@@ -357,7 +381,7 @@ public static class Discovery implements JdkInstallers.Discovery {
 		@Override
 		public @NonNull JdkInstaller create(Config config) {
 			FoojayJdkInstaller installer = new FoojayJdkInstaller(config.jdkProvider());
-			installer.distro(config.properties().getOrDefault("distro", null));
+			installer.distros(config.properties().getOrDefault("distro", null));
 			HttpClientBuilder httpClientBuilder = NetUtils.createCachingHttpClientBuilder(config.cachePath());
 			RemoteAccessProvider rap = RemoteAccessProvider.createDefaultRemoteAccessProvider(httpClientBuilder);
 			installer.remoteAccessProvider(rap);

src/main/java/dev/jbang/devkitman/jdkinstallers/MetadataJdkInstaller.java

@@ -64,6 +64,30 @@ public static class MetadataResult {
 		public Integer size;
 	}
 
+	public static final List<JdkDistro> JDK_DISTROS = Arrays.asList(
+			new JdkDistro("adoptopenjdk"),
+			new JdkDistro("bisheng"),
+			new JdkDistro("corretto"),
+			new JdkDistro("dragonwell"),
+			new JdkDistro("graalvm"),
+			new JdkDistro("graalvm-community"),
+			new JdkDistro("ibm"),
+			new JdkDistro("java-se-ri"),
+			new JdkDistro("jetbrains"),
+			new JdkDistro("kona"),
+			new JdkDistro("liberica"),
+			new JdkDistro("mandrel"),
+			new JdkDistro("microsoft"),
+			new JdkDistro("openjdk"),
+			new JdkDistro("oracle"),
+			new JdkDistro("oracle-graalvm"),
+			new JdkDistro("redhat"),
+			new JdkDistro("sapmachine"),
+			new JdkDistro("semeru"),
+			new JdkDistro("temurin"),
+			new JdkDistro("trava"),
+			new JdkDistro("zulu"));
+
 	public MetadataJdkInstaller(@NonNull JdkProvider jdkProvider) {
 		this.jdkProvider = jdkProvider;
 		this.jdkId = jdk -> determineId(jdk) + "-" + jdkProvider.name();
@@ -332,6 +356,11 @@ public void uninstall(Jdk.@NonNull InstalledJdk jdk) {
 		JavaUtils.safeDeleteJdk(jdk.home());
 	}
 
+	@Override
+	public List<JdkDistro> listDistros() {
+		return JDK_DISTROS;
+	}
+
 	/**
 	 * Constructs the metadata API URL for the given parameters Format:
 	 * /metadata/{release_type}/{os}/{arch}/{image_type}/{jvm_impl}/{vendor}.json

src/main/java/dev/jbang/devkitman/jdkproviders/JBangJdkProvider.java

@@ -2,13 +2,15 @@
 
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.List;
 import java.util.stream.Stream;
 
 import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
 
 import dev.jbang.devkitman.Jdk;
 import dev.jbang.devkitman.JdkDiscovery;
+import dev.jbang.devkitman.JdkDistroQuery;
 import dev.jbang.devkitman.JdkInstaller;
 import dev.jbang.devkitman.JdkInstallers;
 import dev.jbang.devkitman.JdkProvider;
@@ -21,7 +23,7 @@
  * provided by the Java Metadata API. They get installed in the user's JBang
  * folder.
  */
-public class JBangJdkProvider extends BaseFoldersJdkProvider {
+public class JBangJdkProvider extends BaseFoldersJdkProvider implements JdkDistroQuery {
 	protected JdkInstaller jdkInstaller;
 
 	public static final String DEFAULT_INSTALLER = "foojay";
@@ -71,6 +73,11 @@ public void uninstall(Jdk.@NonNull InstalledJdk jdk) {
 		jdkInstaller.uninstall(jdk);
 	}
 
+	@Override
+	public List<JdkDistro> listDistros() {
+		return jdkInstaller.listDistros();
+	}
+
 	@Override
 	public boolean canUpdate() {
 		return true;

src/main/java/dev/jbang/devkitman/util/RemoteAccessProvider.java

@@ -10,6 +10,7 @@
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
+import com.google.gson.Strictness;
 
 public interface RemoteAccessProvider {
 
@@ -26,7 +27,7 @@ default <T> T resultFromUrl(String url, FunctionWithError<InputStream, T> stream
 	static <T> T readJsonFromUrl(RemoteAccessProvider rap, String url, Class<T> klass) throws IOException {
 		return rap.resultFromUrl(url, is -> {
 			try (InputStream ignored = is) {
-				Gson parser = new GsonBuilder().create();
+				Gson parser = new GsonBuilder().setStrictness(Strictness.LENIENT).create();
 				return parser.fromJson(new InputStreamReader(is), klass);
 			} catch (IOException e) {
 				throw new RuntimeException(e);

src/test/java/dev/jbang/devkitman/BaseTest.java

@@ -226,6 +226,9 @@ public <T> T resultFromUrl(
 				if (url.startsWith(FoojayJdkInstaller.FOOJAY_JDK_VERSIONS_URL)) {
 					return streamToObject.apply(
 							getClass().getResourceAsStream("/testFoojayInstall.json"));
+				} else if (url.startsWith(FoojayJdkInstaller.FOOJAY_JDK_DISTROS_URL)) {
+					return streamToObject.apply(
+							getClass().getResourceAsStream("/testFoojayDistros.json"));
 				} else if (url.startsWith(MetadataJdkInstaller.METADATA_BASE_URL)) {
 					return streamToObject.apply(
 							getClass().getResourceAsStream("/testMetadataInstall.json"));
@@ -236,7 +239,7 @@ public <T> T resultFromUrl(
 
 		JBangJdkProvider jbang = new JBangJdkProvider(config.installPath());
 		FoojayJdkInstaller installer = new FoojayJdkInstaller(jbang)
-			.distro("jbang")
+			.distros("jbang")
 			.remoteAccessProvider(rap);
 		installer.remoteAccessProvider(rap);
 		jbang.installer(installer);

src/test/java/dev/jbang/devkitman/TestJdkManager.java

@@ -487,4 +487,13 @@ void testUninstallAll() {
 		jdks = jm.listInstalledJdks();
 		assertThat(jdks, empty());
 	}
+
+	@Test
+	public void testListDistros() {
+		JdkManager jm = jdkManager();
+		List<JdkDistroQuery.JdkDistro> distros = jm.listDistros();
+		assertThat(distros.size(), equalTo(30));
+		assertThat(distros.toString(), equalTo(
+				"[zulu, trava, temurin, semeru_certified, semeru, sap_machine, redhat, oracle_open_jdk, oracle, openlogic, ojdk_build, microsoft, mandrel, liberica_native, liberica, kona, jetbrains, graalvm_community, graalvm_ce8, graalvm_ce19, graalvm_ce17, graalvm_ce16, graalvm_ce11, graalvm, gluon_graalvm, dragonwell, corretto, bisheng, aoj_openj9, aoj]"));
+	}
 }