Add support to detect installed Java versions using Mac native and SDKman.

Closes #196

release-tools/pom.xml

@@ -67,6 +67,12 @@
 			<version>1.4.7</version>
 		</dependency>
 
+		<dependency>
+			<groupId>com.googlecode.plist</groupId>
+			<artifactId>dd-plist</artifactId>
+			<version>1.23</version>
+		</dependency>
+
 		<dependency>
 			<groupId>org.apache.commons</groupId>
 			<artifactId>commons-exec</artifactId>

release-tools/src/main/java/org/springframework/data/release/io/JavaRuntimes.java

@@ -0,0 +1,244 @@
+/*
+ * Copyright 2022 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 org.springframework.data.release.io;
+
+import lombok.SneakyThrows;
+import lombok.Value;
+
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.FileFilter;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.filefilter.RegexFileFilter;
+
+import org.springframework.boot.system.SystemProperties;
+import org.springframework.data.release.model.JavaVersion;
+import org.springframework.data.release.model.Version;
+import org.springframework.data.util.Lazy;
+import org.springframework.util.StreamUtils;
+
+import com.dd.plist.NSArray;
+import com.dd.plist.NSDictionary;
+import com.dd.plist.XMLPropertyListParser;
+
+/**
+ * Utility to detect a Java runtime version.
+ *
+ * @author Mark Paluch
+ */
+public class JavaRuntimes {
+
+	private static final List<JdkDetector> DETECTORS = Arrays.asList(new SDKmanJdkDetector(), new MacNativeJdkDetector());
+	private static final Lazy<List<JdkInstallation>> JDKS = Lazy.of(() -> {
+
+		List<JdkInstallation> jdks = DETECTORS.stream().flatMap(it -> it.detect().stream()).sorted()
+				.collect(Collectors.toList());
+
+		Collections.reverse(jdks);
+
+		return Collections.unmodifiableList(jdks);
+	});
+
+	/**
+	 * Lookup a {@link JdkInstallation} by detecting installed JDKs and applying the {@link Predicate filter}. Returns the
+	 * first matching one or throws {@link NoSuchElementException}.
+	 *
+	 * @param filter
+	 * @return
+	 */
+	public static JdkInstallation getJdk(Predicate<JdkInstallation> filter) {
+		return getJdk(filter, () -> "Cannot obtain required JDK");
+	}
+
+	/**
+	 * Lookup a {@link JdkInstallation} by detecting installed JDKs and applying the {@link Predicate filter}. Returns the
+	 * first matching one or throws {@link NoSuchElementException}.
+	 *
+	 * @param filter
+	 * @param message
+	 * @return
+	 */
+	public static JdkInstallation getJdk(Predicate<JdkInstallation> filter, Supplier<String> message) {
+
+		List<JdkInstallation> jdks = JDKS.get();
+
+		return jdks.stream().filter(filter).findFirst()
+				.orElseThrow(() -> new NoSuchElementException(String.format("%s%nAvailable JDK: %s", message.get(), jdks)));
+	}
+
+	/**
+	 * JDK detection strategy.
+	 */
+	interface JdkDetector {
+
+		/**
+		 * @return {@code true} if the detector strategy is available.
+		 */
+		boolean isAvailable();
+
+		/**
+		 * @return a list of JDK installations.
+		 */
+		List<JdkInstallation> detect();
+
+	}
+
+	/**
+	 * Selector to determine a {@link JdkInstallation}.
+	 */
+	public static class Selector {
+
+		private String notFoundMessage;
+		private Predicate<JdkInstallation> predicate;
+
+		private Selector() {
+
+		}
+
+		public static Selector builder() {
+			return new Selector();
+		}
+
+		public static Selector from(JavaVersion javaVersion) {
+			return builder().and(it -> javaVersion.getVersionDetector().test(it.getVersion()))
+					.message("Cannot find Java " + javaVersion.getName());
+		}
+
+		public Selector and(Predicate<JdkInstallation> predicate) {
+			this.predicate = this.predicate == null ? predicate : this.predicate.and(predicate);
+			return this;
+		}
+
+		public Selector notGraalVM() {
+			this.notFoundMessage += " (Not GraalVM)";
+			return and(it -> !it.getName().contains("GraalVM"));
+		}
+
+		public Selector message(String notFoundMessage) {
+			this.notFoundMessage = notFoundMessage;
+			return this;
+		}
+
+		public JdkInstallation getRequiredJdkInstallation() {
+			return JavaRuntimes.getJdk(predicate, () -> notFoundMessage);
+		}
+
+	}
+
+	/**
+	 * Detector using the SDKman utility storing Java installations in {@code ~/.sdkman/candidates/java}.
+	 */
+	static class SDKmanJdkDetector implements JdkDetector {
+
+		private static final File sdkManJavaHome = new File(FileUtils.getUserDirectoryPath(), ".sdkman/candidates/java");
+
+		private static final Pattern CANDIDATE = Pattern.compile("(\\d+[\\.\\d+]+)[.-][-a-zA-Z]*");
+
+		@Override
+		public boolean isAvailable() {
+			return sdkManJavaHome.exists() && sdkManJavaHome.isDirectory();
+		}
+
+		@Override
+		public List<JdkInstallation> detect() {
+
+			File[] files = sdkManJavaHome.listFiles((FileFilter) new RegexFileFilter(CANDIDATE));
+
+			return Arrays.stream(files).map(it -> {
+
+				Matcher matcher = CANDIDATE.matcher(it.getName());
+				matcher.find();
+
+				return new JdkInstallation(Version.parse(matcher.group(1)), it.getName(), it);
+
+			}).collect(Collectors.toList());
+		}
+	}
+
+	/**
+	 * Detector using the {@code /usr/libexec/java_home} utility storing Java installations in {@code /Libraries/Java} on
+	 * the Mac.
+	 */
+	static class MacNativeJdkDetector implements JdkDetector {
+
+		private static final File javaHomeBinary = new File("/usr/libexec/java_home");
+
+		private static final Pattern VERSION = Pattern.compile("(\\d+(:?\\.\\d+)*)(:?_\\+.*)?");
+
+		@Override
+		public boolean isAvailable() {
+			return javaHomeBinary.exists() && SystemProperties.get("os.name").contains("Mac");
+		}
+
+		@Override
+		@SneakyThrows
+		public List<JdkInstallation> detect() {
+
+			Process process = new ProcessBuilder(javaHomeBinary.toString(), "-X").redirectOutput(ProcessBuilder.Redirect.PIPE)
+					.start();
+
+			process.waitFor(5, TimeUnit.SECONDS);
+			byte[] out = StreamUtils.copyToByteArray(process.getInputStream());
+
+			if (process.exitValue() != 0) {
+
+				throw new IllegalStateException(javaHomeBinary + " failed with: " + System.lineSeparator() + new String(out)
+						+ new String(StreamUtils.copyToByteArray(process.getErrorStream())));
+			}
+
+			NSArray array = (NSArray) XMLPropertyListParser.parse(new ByteArrayInputStream(out));
+
+			return Arrays.stream(array.getArray()).map(it -> {
+
+				NSDictionary dict = (NSDictionary) it;
+
+				String jvmHomePath = dict.get("JVMHomePath").toJavaObject(String.class);
+				String name = dict.get("JVMName").toJavaObject(String.class);
+				String version = dict.get("JVMVersion").toJavaObject(String.class).replace('_', '.');
+
+				Matcher matcher = VERSION.matcher(version);
+				matcher.find();
+
+				return new JdkInstallation(Version.parse(matcher.group(1)), name, new File(jvmHomePath));
+
+			}).collect(Collectors.toList());
+		}
+	}
+
+	@Value
+	public static class JdkInstallation implements Comparable<JdkInstallation> {
+
+		Version version;
+		String name;
+		File home;
+
+		@Override
+		public int compareTo(JdkInstallation o) {
+			return this.version.compareTo(o.version);
+		}
+	}
+}

release-tools/src/test/java/org/springframework/data/release/io/JdkUtilityTests.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 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 org.springframework.data.release.io;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.data.release.model.Version;
+
+/**
+ * Unit tests for {@link JavaRuntimes}.
+ *
+ * @author Mark Paluch
+ */
+class JdkUtilityTests {
+
+	@Test
+	void shouldDiscoverCurrentJavaVersion() {
+
+		Version currentVersion = Version.parse(System.getProperty("java.version").replace('_', '.'));
+		JavaRuntimes.JdkInstallation jdk = JavaRuntimes.getJdk(it -> it.getVersion().is(currentVersion));
+
+		assertThat(jdk).isNotNull();
+		assertThat(System.getProperty("java.home")).contains(jdk.getHome().getPath());
+	}
+}