Recognize custom file extensions

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JDTUtils.java

@@ -257,10 +257,13 @@ public static ICompilationUnit getFakeCompilationUnit(String uri) {
 	}
 
 	static ICompilationUnit getFakeCompilationUnit(URI uri, IProgressMonitor monitor) {
-		if (uri == null || !"file".equals(uri.getScheme()) || !uri.getPath().endsWith(".java")) {
+		if (uri == null || !"file".equals(uri.getScheme())) {
 			return null;
 		}
 		java.nio.file.Path path = Paths.get(uri);
+		if (!isJavaFile(path)) {
+			return null;
+		}
 		//Only support existing standalone java files
 		if (!java.nio.file.Files.isReadable(path)) {
 			return null;
@@ -275,7 +278,7 @@ static ICompilationUnit getFakeCompilationUnit(URI uri, IProgressMonitor monitor
 		IProject project = JavaLanguageServerPlugin.getProjectsManager().getDefaultProject();
 		if (project == null || !project.isAccessible()) {
 			String fileName = path.getFileName().toString();
-			if (fileName.endsWith(".java") || fileName.endsWith(".class")) {
+			if (JDTUtils.isJavaFile(fileName) || fileName.endsWith(".class")) {
 				fileName = fileName.substring(0, fileName.lastIndexOf('.'));
 			}
 			WorkingCopyOwner owner = new WorkingCopyOwner() {
@@ -657,6 +660,23 @@ private boolean find(IJavaElement element, final ASTNode[] nodes, SimpleName nod
 		}
 	}
 
+	public static boolean isJavaFile(java.nio.file.Path path) {
+		try {
+			return path != null && isJavaFile(path.toFile().getName());
+		} catch (Exception e) {
+			JavaLanguageServerPlugin.logException(e.getMessage(), e);
+		}
+		return false;
+	}
+
+	public static boolean isJavaFile(IPath path) {
+		return path != null && isJavaFile(path.lastSegment());
+	}
+
+	public static boolean isJavaFile(String name) {
+		return name != null && org.eclipse.jdt.internal.core.util.Util.isJavaLikeFileName(name);
+	}
+
 	/**
 	 * Enumeration for determining the location of a Java element. Either returns
 	 * with the name range only, or the extended source range around the name of the

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/framework/protobuf/ProtobufSupport.java

@@ -39,6 +39,7 @@
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.JavaModelException;
 import org.eclipse.jdt.ls.core.internal.ActionableNotification;
+import org.eclipse.jdt.ls.core.internal.JDTUtils;
 import org.eclipse.jdt.ls.core.internal.JavaClientConnection.JavaLanguageClient;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
 import org.eclipse.jdt.ls.core.internal.ProgressReport;
@@ -94,7 +95,7 @@ public void onDidProjectsImported(IProgressMonitor monitor) {
 			JavaLanguageServerPlugin.getProjectsManager().getConnection().sendActionableNotification(notification);
 		}
 	}
-	
+
 	/**
 	 * Find all the Protobuf source output directories of the given project.
 	 * @param project project.
@@ -133,7 +134,7 @@ private boolean containsJavaFiles(Set<File> generatedDirectories) {
 
 			try (Stream<Path> walkStream = Files.walk(dir.toPath())) {
 				boolean containsJavaFile = walkStream.filter(p -> p.toFile().isFile()).anyMatch(f -> {
-					return f.toString().endsWith(".java");
+					return JDTUtils.isJavaFile(f);
 				});
 
 				if (containsJavaFile) {
@@ -194,7 +195,7 @@ private static void runGenerateProtobufTasks(String projectName, IProgressMonito
 		try {
 			build.get().withConnection(connection -> {
 				connection.newBuild().forTasks("generateProto", "generateTestProto").run();
-				return null; 
+				return null;
 			}, monitor);
 		} catch (Exception e) {
 			JavaLanguageServerPlugin.logException(e);

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/BaseInitHandler.java

@@ -19,13 +19,18 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IPath;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.core.runtime.preferences.InstanceScope;
+import org.eclipse.jdt.core.JavaCore;
+import org.eclipse.jdt.internal.compiler.util.SuffixConstants;
 import org.eclipse.jdt.ls.core.internal.IConstants;
 import org.eclipse.jdt.ls.core.internal.JSONUtility;
 import org.eclipse.jdt.ls.core.internal.JVMConfigurator;
@@ -57,7 +62,6 @@ public BaseInitHandler(ProjectsManager projectsManager, PreferenceManager prefer
 		this.projectsManager = projectsManager;
 	}
 
-	@SuppressWarnings("unchecked")
 	public InitializeResult initialize(InitializeParams param) {
 		logInfo("Initializing Java Language Server " + JavaLanguageServerPlugin.getVersion());
 		InitializeResult result = new InitializeResult();
@@ -70,6 +74,7 @@ public InitializeResult initialize(InitializeParams param) {
 		return result;
 	}
 
+	@SuppressWarnings("unchecked")
 	public Map<?, ?> handleInitializationOptions(InitializeParams param) {
 		Map<?, ?> initializationOptions = this.getInitializationOptions(param);
 		Map<String, Object> extendedClientCapabilities = getInitializationOption(initializationOptions, "extendedClientCapabilities", Map.class);
@@ -109,7 +114,6 @@ public InitializeResult initialize(InitializeParams param) {
 			rootPaths.add(workspaceLocation);
 		}
 		if (initializationOptions.get(SETTINGS_KEY) instanceof Map<?, ?> settings) {
-			@SuppressWarnings("unchecked")
 			Preferences prefs = Preferences.createFrom((Map<String, Object>) settings);
 			prefs.setRootPaths(rootPaths);
 			preferenceManager.update(prefs);

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/FileEventHandler.java

@@ -305,7 +305,7 @@ private static boolean isFileNameRenameEvent(FileRename event) {
 		}
 
 		return (oldPath.toFile().isFile() || newPath.toFile().isFile())
-			&& oldPath.lastSegment().endsWith(".java") && newPath.lastSegment().endsWith(".java")
+				&& JDTUtils.isJavaFile(oldPath.lastSegment()) && JDTUtils.isJavaFile(newPath.lastSegment())
 			&& Objects.equals(oldPath.removeLastSegments(1), newPath.removeLastSegments(1));
 	}
 
@@ -331,7 +331,7 @@ private static boolean isMoveEvent(FileRename event) {
 			return false;
 		}
 
-		return oldPath.toFile().isFile() && oldPath.lastSegment().endsWith(".java")
+		return oldPath.toFile().isFile() && JDTUtils.isJavaFile(oldPath.lastSegment())
 			&& Objects.equals(oldPath.lastSegment(), newPath.lastSegment());
 	}
 

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/WorkspaceEventsHandler.java

@@ -174,7 +174,7 @@ private void cleanUpDiagnostics(String uri) {
 
 	private void discardWorkingCopies(String parentUri) {
 		IPath parentPath = ResourceUtils.filePathFromURI(parentUri);
-		if (parentPath != null && !parentPath.lastSegment().endsWith(".java")) {
+		if (parentPath != null && !JDTUtils.isJavaFile(parentPath)) {
 			ICompilationUnit[] workingCopies = JavaCore.getWorkingCopies(null);
 			for (ICompilationUnit workingCopy : workingCopies) {
 				IResource resource = workingCopy.getResource();

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/managers/InvisibleProjectImporter.java

@@ -520,7 +520,7 @@ private static File findNearbyNonEmptyFile(File nioFile) throws IOException {
 		try (Stream<java.nio.file.Path> walk = Files.walk(directory, 1)) {
 			Optional<java.nio.file.Path> found = walk.filter(Files::isRegularFile).filter(file -> {
 				try {
-					return file.toString().endsWith(".java") && !Objects.equals(nioFile.getName(), file.toFile().getName()) && Files.size(file) > 0;
+					return JDTUtils.isJavaFile(file) && !Objects.equals(nioFile.getName(), file.toFile().getName()) && Files.size(file) > 0;
 				} catch (IOException e) {
 					return false;
 				}
@@ -672,7 +672,7 @@ public FileVisitResult preVisitDirectory(java.nio.file.Path dirPath, BasicFileAt
 					return FileVisitResult.TERMINATE;
 				}
 
-				if (javaFile == null && f.getName().endsWith(".java")) {
+				if (javaFile == null && JDTUtils.isJavaFile(f.getName())) {
 					javaFile = f;
 				}
 			}

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/preferences/PreferenceManager.java

@@ -12,13 +12,11 @@
  *******************************************************************************/
 package org.eclipse.jdt.ls.core.internal.preferences;
 
-import java.io.File;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
-import java.net.URI;
+import java.util.ArrayList;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.Hashtable;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -28,13 +26,13 @@
 import java.util.stream.Collectors;
 
 import org.apache.commons.lang3.StringUtils;
-import org.eclipse.core.resources.IMarker;
-import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.ISafeRunnable;
 import org.eclipse.core.runtime.ListenerList;
+import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.SafeRunner;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.core.runtime.preferences.DefaultScope;
 import org.eclipse.core.runtime.preferences.IEclipsePreferences;
 import org.eclipse.core.runtime.preferences.InstanceScope;
@@ -43,6 +41,7 @@
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.manipulation.CodeStyleConfiguration;
 import org.eclipse.jdt.core.manipulation.JavaManipulation;
+import org.eclipse.jdt.internal.compiler.util.SuffixConstants;
 import org.eclipse.jdt.internal.core.manipulation.CodeTemplateContextType;
 import org.eclipse.jdt.internal.core.manipulation.CodeTemplateContextType.CodeTemplateVariableResolver;
 import org.eclipse.jdt.internal.core.manipulation.JavaManipulationMessages;
@@ -54,7 +53,6 @@
 import org.eclipse.jdt.internal.corext.util.CodeFormatterUtil;
 import org.eclipse.jdt.ls.core.internal.IConstants;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
-import org.eclipse.jdt.ls.core.internal.ProjectUtils;
 import org.eclipse.jdt.ls.core.internal.ResourceUtils;
 import org.eclipse.jdt.ls.core.internal.StatusFactory;
 import org.eclipse.jdt.ls.core.internal.handlers.BaseDiagnosticsHandler;
@@ -258,6 +256,49 @@ public void update(Preferences preferences) {
 				JavaLanguageServerPlugin.getInstance().getClientConnection().publishDiagnostics(diagnostics);
 			}
 		}
+		if (!oldPreferences.getFilesAssociations().equals(preferences.getFilesAssociations())) {
+			configureContentTypes(preferences);
+		}
+	}
+
+	// only for test purpose
+	public static void configureContentTypes(Preferences preferences) {
+		if (preferences != null && preferences.getFilesAssociations() != null) {
+			IContentType javaSourceContentType = Platform.getContentTypeManager().getContentType(JavaCore.JAVA_SOURCE_CONTENT_TYPE);
+			if (javaSourceContentType != null) {
+				List<String> toRemove = new ArrayList<>();
+				String[] specs = javaSourceContentType.getFileSpecs(IContentType.FILE_EXTENSION_SPEC);
+				for (String spec : specs) {
+					if (!SuffixConstants.EXTENSION_java.equals(spec)) {
+						toRemove.add(spec);
+					}
+				}
+				List<String> toAdd = new ArrayList<>();
+				for (String spec : preferences.getFilesAssociations()) {
+					if (toRemove.contains(spec)) {
+						toRemove.remove(spec);
+					} else {
+						toAdd.add(spec);
+					}
+				}
+				for (String spec : toRemove) {
+					try {
+						javaSourceContentType.removeFileSpec(spec, IContentType.FILE_EXTENSION_SPEC);
+					} catch (CoreException e) {
+						JavaLanguageServerPlugin.logException(e);
+					}
+				}
+				for (String spec : toAdd) {
+					try {
+						javaSourceContentType.addFileSpec(spec, IContentType.FILE_EXTENSION_SPEC);
+					} catch (CoreException e) {
+						JavaLanguageServerPlugin.logException(e);
+					}
+				}
+			} else {
+				JavaLanguageServerPlugin.logInfo("There is not java source content type");
+			}
+		}
 	}
 
 	private void preferencesChanged(Preferences oldPreferences, Preferences newPreferences) {

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/preferences/Preferences.java

@@ -120,6 +120,11 @@ public class Preferences {
 	 * Tab Size
 	 */
 	public static final String JAVA_CONFIGURATION_TABSIZE = "java.format.tabSize";
+
+	/**
+	 * Files associations to languages
+	 */
+	public static final String JAVA_CONFIGURATION_ASSOCIATIONS = "java.associations";
 	/**
 	 * Specifies Java Execution Environments.
 	 */
@@ -589,6 +594,7 @@ public class Preferences {
 	private static Map<String, List<String>> nonnullClasspathStorage = new HashMap<>();
 	private static Map<String, List<String>> nullableClasspathStorage = new HashMap<>();
 	private static Map<String, List<String>> nonnullbydefaultClasspathStorage = new HashMap<>();
+	private List<String> filesAssociations = new ArrayList<>();
 
 	private Map<String, Object> configuration;
 	private Severity incompleteClasspathSeverity;
@@ -1330,9 +1336,36 @@ public static Preferences createFrom(Map<String, Object> configuration) {
 		prefs.setChainCompletionEnabled(chainCompletionEnabled);
 		List<String> diagnosticFilter = getList(configuration, JAVA_DIAGNOSTIC_FILER, Collections.emptyList());
 		prefs.setDiagnosticFilter(diagnosticFilter);
+		Object object = getValue(configuration, JAVA_CONFIGURATION_ASSOCIATIONS);
+		Set<String> associations = new HashSet<>();
+		if (object instanceof Map map) {
+			try {
+				Map<String, String> element = map;
+				element.forEach((k, v) -> {
+					// Java LS only support a small subset of the glob pattern syntax (*.xxx)
+					if ("java".equals(v) && validateFileName(k)) {
+						associations.add(k.substring(2));
+					}
+				});
+			} catch (Exception e) {
+				JavaLanguageServerPlugin.logException(e);
+			}
+		}
+		prefs.setFilesAssociations(new ArrayList<>(associations));
 		return prefs;
 	}
 
+	private static boolean validateFileName(String filename) {
+		if (filename != null && filename.startsWith("*.") && filename.length() > 2) {
+			String ext = filename.substring(2);
+			if (!ext.contains("?") && !ext.contains("*")) {
+				return true;
+			}
+		}
+		JavaLanguageServerPlugin.logInfo("Pattern '" + filename + "' is not supported.");
+		return false;
+	}
+
 	/**
 	 * Sets the new value of the enabled clean ups.
 	 *
@@ -2582,4 +2615,12 @@ public List<String> getDiagnosticFilter() {
 	public void setDiagnosticFilter(List<String> diagnosticFilter) {
 		this.diagnosticFilter = diagnosticFilter;
 	}
+
+	public List<String> getFilesAssociations() {
+		return filesAssociations;
+	}
+
+	public void setFilesAssociations(List<String> filesAssociations) {
+		this.filesAssociations = filesAssociations;
+	}
 }

org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/InitHandlerTest.java

@@ -56,6 +56,7 @@
 import org.eclipse.jdt.core.IJavaProject;
 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.JavaModelException;
+import org.eclipse.jdt.internal.core.util.Util;
 import org.eclipse.jdt.launching.IVMInstall;
 import org.eclipse.jdt.launching.IVMInstallChangedListener;
 import org.eclipse.jdt.launching.JavaRuntime;
@@ -68,6 +69,7 @@
 import org.eclipse.jdt.ls.core.internal.managers.AbstractProjectsManagerBasedTest;
 import org.eclipse.jdt.ls.core.internal.managers.ProjectsManager;
 import org.eclipse.jdt.ls.core.internal.preferences.ClientPreferences;
+import org.eclipse.jdt.ls.core.internal.preferences.PreferenceManager;
 import org.eclipse.jdt.ls.core.internal.preferences.Preferences;
 import org.eclipse.lsp4j.ClientCapabilities;
 import org.eclipse.lsp4j.DidChangeConfigurationCapabilities;
@@ -462,6 +464,24 @@ public void testMissingResourceOperations() throws Exception {
 		assertFalse(preferences.isResourceOperationSupported());
 	}
 
+	// https://github.com/eclipse-jdtls/eclipse.jdt.ls/issues/3222
+	@Test
+	public void testFilesAssociations() throws Exception {
+		try {
+			ClientPreferences mockCapabilies = mock(ClientPreferences.class);
+			when(preferenceManager.getClientPreferences()).thenReturn(mockCapabilies);
+			List<String> fileAssociations = new ArrayList<>();
+			fileAssociations.add("maxj");
+			preferences.setFilesAssociations(fileAssociations);
+			PreferenceManager.configureContentTypes(preferences);
+			assertTrue(Util.isJavaLikeFileName("Test.maxj"));
+		} finally {
+			preferences.getFilesAssociations().clear();
+			PreferenceManager.configureContentTypes(preferences);
+			assertFalse(Util.isJavaLikeFileName("Test.maxj"));
+		}
+	}
+
 	private void removeExclusionPattern(IJavaProject javaProject) throws JavaModelException {
 		IClasspathEntry[] classpath = javaProject.getRawClasspath();
 		for (int i = 0; i < classpath.length; i++) {