Recognize custom file extensions

Author: snjeza

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;
@@ -57,19 +62,59 @@ 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();
 		handleInitializationOptions(param);
 		registerCapabilities(result);
+		configureContentTypes();
 
 		// At the end of the InitHandler, trigger a job to import the workspace. This is used to ensure ServiceStatus notification
 		// is not sent before the initialize response. See the bug https://github.com/redhat-developer/vscode-java/issues/1056
 		triggerInitialization(preferenceManager.getPreferences().getRootPaths());
 		return result;
 	}
 
+	private void configureContentTypes() {
+		if (preferenceManager.getPreferences().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 : preferenceManager.getPreferences().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");
+			}
+		}
+	}
+
+	@SuppressWarnings("unchecked")
 	public Map<?, ?> handleInitializationOptions(InitializeParams param) {
 		Map<?, ?> initializationOptions = this.getInitializationOptions(param);
 		Map<String, Object> extendedClientCapabilities = getInitializationOption(initializationOptions, "extendedClientCapabilities", Map.class);
@@ -109,7 +154,6 @@ 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/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;
@@ -1330,6 +1336,22 @@ 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 associations = getValue(configuration, JAVA_CONFIGURATION_ASSOCIATIONS);
+		List<String> filesAssociations = new ArrayList<>();
+		if (associations instanceof Map map) {
+			try {
+				Map<String, String> element = map;
+				element.forEach((k, v) -> {
+					// Java LS only recognizes *.<extension>
+					if ("java".equals(v) && k.startsWith("*.") && k.length() > 2) {
+						filesAssociations.add(k.substring(2));
+					}
+				});
+			} catch (Exception e) {
+				JavaLanguageServerPlugin.logException(e);
+			}
+		}
+		prefs.setFilesAssociations(filesAssociations);
 		return prefs;
 	}
 
@@ -2582,4 +2604,12 @@ 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;
@@ -462,6 +463,24 @@ 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);
+			initialize(false);
+			assertTrue(Util.isJavaLikeFileName("Test.maxj"));
+		} finally {
+			preferences.getFilesAssociations().clear();
+			initialize(false);
+			assertFalse(Util.isJavaLikeFileName("Test.maxj"));
+		}
+	}
+
 	private void removeExclusionPattern(IJavaProject javaProject) throws JavaModelException {
 		IClasspathEntry[] classpath = javaProject.getRawClasspath();
 		for (int i = 0; i < classpath.length; i++) {