eclipse-jdtls · trancexpress · Mar 12, 2026
diff --git a/org.eclipse.jdt.ls.core/plugin.xml b/org.eclipse.jdt.ls.core/plugin.xml
@@ -5,6 +5,7 @@
    <extension-point id="org.eclipse.jdt.ls.core.importers" name="JDT LS Project Importer" schema="schema/org.eclipse.jdt.ls.core.importers.exsd"/>
    <extension-point id="org.eclipse.jdt.ls.core.contentProvider" name="contentProvider" schema="schema/org.eclipse.jdt.ls.core.contentProvider.exsd"/>
    <extension-point id="org.eclipse.jdt.ls.core.buildSupport" name="Build Support" schema="schema/org.eclipse.jdt.ls.core.buildSupport.exsd"/>
+   <extension-point id="org.eclipse.jdt.ls.core.completionHandler" name="Code Completion" schema="schema/org.eclipse.jdt.ls.core.completionHandler.exsd"/>
    <extension
          id="id1"
          point="org.eclipse.core.runtime.applications">
@@ -225,7 +226,6 @@
          id="org.eclipse.jdt.core.javanature">
       </requires-nature>
    </extension>
-
    <extension point="org.eclipse.core.contenttype.contentTypes">
       <file-association
          content-type="org.eclipse.jdt.core.javaDerivedSource"

diff --git a/org.eclipse.jdt.ls.core/schema/org.eclipse.jdt.ls.core.completionHandler.exsd b/org.eclipse.jdt.ls.core/schema/org.eclipse.jdt.ls.core.completionHandler.exsd
@@ -0,0 +1,93 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- Schema file written by PDE -->
+<schema targetNamespace="org.eclipse.jdt.ls.core" xmlns="http://www.w3.org/2001/XMLSchema">
+<annotation>
+      <appinfo>
+         <meta.schema plugin="org.eclipse.jdt.ls.core" id="org.eclipse.jdt.ls.core.codeCompletion" name="Code Completion"/>
+      </appinfo>
+      <documentation>
+         This extension point represents different kinds of code completion handlers for the JDT LS.
+Each extension must implement &lt;code&gt;org.eclipse.jdt.ls.core.internal.handlers.ICompletionHandler&lt;/code&gt;.
+      </documentation>
+   </annotation>
+
+   <element name="extension">
+      <annotation>
+         <appinfo>
+            <meta.element />
+         </appinfo>
+      </annotation>
+      <complexType>
+         <sequence>
+            <element ref="completionHandler" minOccurs="0" maxOccurs="unbounded"/>
+         </sequence>
+         <attribute name="point" type="string" use="required">
+            <annotation>
+               <documentation>
+                  a fully qualified identifier of the target extension point
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="id" type="string">
+            <annotation>
+               <documentation>
+                  an optional identifier of the extension instance
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="name" type="string">
+            <annotation>
+               <documentation>
+                  an optional name of the extension instance
+               </documentation>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+   <element name="completionHandler">
+      <complexType>
+         <attribute name="id" type="string" use="required">
+            <annotation>
+               <documentation>
+                  A unique identifier that can be used to reference this ICompletionHandler.
+               </documentation>
+            </annotation>
+         </attribute>
+         <attribute name="class" type="string" use="required">
+            <annotation>
+               <documentation>
+                  The class that implements this completion handler.  The class must implement ICompletionHandler.
+               </documentation>
+               <appinfo>
+                  <meta.attribute kind="java" basedOn=":org.eclipse.jdt.ls.core.internal.handlers.ICompletionHandler"/>
+               </appinfo>
+            </annotation>
+         </attribute>
+      </complexType>
+   </element>
+
+
+   <annotation>
+      <appinfo>
+         <meta.section type="examples"/>
+      </appinfo>
+      <documentation>
+         The following is an example of a language server content provider extension:
+
+&lt;pre&gt;
+   &lt;extension
+      id=&quot;completionHandler&quot;
+         point=&quot;org.eclipse.jdt.ls.core.completionHandler&quot;&gt;
+         &lt;completionHandler
+          id=&quot;someCompletionHandler&quot;
+          class=&quot;com.example.SomeCompletionHandler&quot; /&gt;
+   &lt;/extension&gt;
+&lt;/pre&gt;
+      </documentation>
+   </annotation>
+
+
+
+
+</schema>
diff --git a/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JDTDelegateCommandHandler.java b/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JDTDelegateCommandHandler.java
@@ -35,7 +35,7 @@
 import org.eclipse.jdt.ls.core.internal.commands.VmCommand;
 import org.eclipse.jdt.ls.core.internal.framework.protobuf.ProtobufSupport;
 import org.eclipse.jdt.ls.core.internal.handlers.BundleUtils;
-import org.eclipse.jdt.ls.core.internal.handlers.CompletionHandler;
+import org.eclipse.jdt.ls.core.internal.handlers.CompletionHandlers;
 import org.eclipse.jdt.ls.core.internal.handlers.CreateModuleInfoHandler;
 import org.eclipse.jdt.ls.core.internal.handlers.FormatterHandler;
 import org.eclipse.jdt.ls.core.internal.handlers.PasteEventHandler;
@@ -191,10 +191,10 @@ public Object executeCommand(String commandId, List<Object> arguments, IProgress
 						return false;
 					}
 				case "java.completion.onDidSelect":
-					CompletionHandler completionHandler = new CompletionHandler(JavaLanguageServerPlugin.getPreferencesManager());
+					CompletionHandlers completionHandlers = JavaLanguageServerPlugin.getInstance().getCompletionHandlers();
 					String requestId = (String) arguments.get(0);
 					String proposalId = (String) arguments.get(1);
-					completionHandler.onDidCompletionItemSelect(requestId, proposalId);
+					completionHandlers.onDidCompletionItemSelect(requestId, proposalId);
 					return new Object();
 				case "java.decompile":
 					String uri = (String) arguments.get(0);

diff --git a/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JavaLanguageServerPlugin.java b/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JavaLanguageServerPlugin.java
@@ -55,6 +55,7 @@
 import org.eclipse.jdt.ls.core.internal.corext.template.java.JavaLanguageServerTemplateStore;
 import org.eclipse.jdt.ls.core.internal.handlers.BundleUtils;
 import org.eclipse.jdt.ls.core.internal.handlers.CompletionContributionService;
+import org.eclipse.jdt.ls.core.internal.handlers.CompletionHandlers;
 import org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer;
 import org.eclipse.jdt.ls.core.internal.handlers.LogHandler;
 import org.eclipse.jdt.ls.core.internal.managers.ContentProviderManager;
@@ -137,6 +138,8 @@ public class JavaLanguageServerPlugin extends Plugin {
 	private CompletionContributionService completionContributionService;
 	private LogHandler logHandler;
 
+	private CompletionHandlers completionHandlers;
+
 	public static LanguageServerApplication getLanguageServer() {
 		return pluginInstance == null ? null : pluginInstance.languageServer;
 	}
@@ -167,6 +170,7 @@ public void start(BundleContext bundleContext) throws Exception {
 			preferenceManager = new StandardPreferenceManager();
 			projectsManager = new StandardProjectsManager(preferenceManager);
 		}
+		completionHandlers = new CompletionHandlers(preferenceManager);
 		digestStore = new DigestStore(getStateLocation().toFile());
 		try {
 			ResourcesPlugin.getWorkspace().addSaveParticipant(IConstants.PLUGIN_ID, projectsManager);
@@ -427,6 +431,10 @@ public WorkingCopyOwner getWorkingCopyOwner() {
 		return this.protocol.getWorkingCopyOwner();
 	}
 
+	public CompletionHandlers getCompletionHandlers() {
+		return completionHandlers;
+	}
+
 	public static JavaLanguageServerPlugin getInstance() {
 		return pluginInstance;
 	}

diff --git a/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/CompletionHandler.java b/org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/CompletionHandler.java
@@ -13,16 +13,13 @@
 package org.eclipse.jdt.ls.core.internal.handlers;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
-import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.ProgressMonitorWrapper;
@@ -37,9 +34,6 @@
 import org.eclipse.jdt.core.dom.StringLiteral;
 import org.eclipse.jdt.core.manipulation.SharedASTProviderCore;
 import org.eclipse.jdt.internal.core.DefaultWorkingCopyOwner;
-import org.eclipse.jdt.ls.core.contentassist.CompletionRanking;
-import org.eclipse.jdt.ls.core.contentassist.ICompletionRankingProvider;
-import org.eclipse.jdt.ls.core.internal.ExceptionFactory;
 import org.eclipse.jdt.ls.core.internal.JDTEnvironmentUtils;
 import org.eclipse.jdt.ls.core.internal.JDTUtils;
 import org.eclipse.jdt.ls.core.internal.JavaLanguageServerPlugin;
@@ -51,7 +45,6 @@
 import org.eclipse.jdt.ls.core.internal.contentassist.SortTextHelper;
 import org.eclipse.jdt.ls.core.internal.preferences.PreferenceManager;
 import org.eclipse.jdt.ls.core.internal.syntaxserver.ModelBasedCompletionEngine;
-import org.eclipse.lsp4j.Command;
 import org.eclipse.lsp4j.CompletionItem;
 import org.eclipse.lsp4j.CompletionItemKind;
 import org.eclipse.lsp4j.CompletionItemOptions;
@@ -60,10 +53,9 @@
 import org.eclipse.lsp4j.CompletionParams;
 import org.eclipse.lsp4j.CompletionTriggerKind;
 import org.eclipse.lsp4j.Position;
-import org.eclipse.lsp4j.jsonrpc.messages.Either;
 
 
-public class CompletionHandler{
+public class CompletionHandler implements ICompletionHandler {
 
 	public final static CompletionOptions getDefaultCompletionOptions(PreferenceManager preferenceManager) {
 		CompletionOptions completionOptions = new CompletionOptions(Boolean.TRUE, List.of(".", "@", "#", "*", " "));
@@ -101,19 +93,15 @@ public int compare(CompletionItem o1, CompletionItem o2) {
 
 	};
 
-	// TODO: we can consider to cache more detailed context so that the information can also
-	// be used by features like inlay hint.
-	public static CompletionProposal selectedProposal;
-
 	private PreferenceManager manager;
 
 	public CompletionHandler(PreferenceManager manager) {
 		this.manager = manager;
 	}
 
-	public Either<List<CompletionItem>, CompletionList> completion(CompletionParams params,
+	@Override
+	public CompletionList completion(CompletionParams params,
 			IProgressMonitor monitor) {
-		long startTime = System.currentTimeMillis();
 		CompletionList $ = null;
 		try {
 			ICompilationUnit unit = JDTUtils.resolveCompilationUnit(params.getTextDocument().getUri());
@@ -137,96 +125,7 @@ public Either<List<CompletionItem>, CompletionList> completion(CompletionParams
 		} else {
 			JavaLanguageServerPlugin.logInfo("Completion request completed");
 		}
-		long executionTime = System.currentTimeMillis() - startTime;
-		String lastRequestId = null;
-		for (CompletionItem item : $.getItems()) {
-			String requestId = "";
-			String proposalId = "";
-			@SuppressWarnings("unchecked")
-			Map<String, String> data = (Map<String, String>) item.getData();
-			if (data != null) {
-				requestId = data.getOrDefault(CompletionResolveHandler.DATA_FIELD_REQUEST_ID, "");
-				proposalId = data.getOrDefault(CompletionResolveHandler.DATA_FIELD_PROPOSAL_ID, "");
-			}
-			if (requestId.isEmpty() || proposalId.isEmpty()) {
-				continue;
-			}
-			item.setCommand(new Command("", "java.completion.onDidSelect", Arrays.asList(
-					requestId,
-					proposalId
-			)));
-
-			if (Objects.equals(requestId, lastRequestId)) {
-				continue;
-			}
-			lastRequestId = requestId;
-			int pId = Integer.parseInt(proposalId);
-			long rId = Long.parseLong(requestId);
-			CompletionResponse completionResponse = CompletionResponses.get(rId);
-			if (completionResponse == null || completionResponse.getProposals().size() <= pId) {
-				JavaLanguageServerPlugin.logError("Failed to save common data for completion items.");
-				continue;
-			}
-			completionResponse.setCommonData(CompletionRanking.COMPLETION_EXECUTION_TIME, String.valueOf(executionTime));
-		}
-		return Either.forRight($);
-	}
-
-	@SuppressWarnings("unchecked")
-	public void onDidCompletionItemSelect(String requestId, String proposalId) throws CoreException {
-		triggerSignatureHelp();
-		if (proposalId.isEmpty() || requestId.isEmpty()) {
-			return;
-		}
-		int pId = Integer.parseInt(proposalId);
-		long rId = Long.parseLong(requestId);
-		CompletionResponse completionResponse = CompletionResponses.get(rId);
-		if (completionResponse == null || completionResponse.getItems().size() <= pId
-				|| completionResponse.getProposals().size() <= pId) {
-			throw ExceptionFactory.newException("Cannot get completion responses.");
-		}
-
-		CompletionProposal proposal = completionResponse.getProposals().get(pId);
-
-		// clear the cache if failed to get the selected proposal.
-		if (proposal == null) {
-			selectedProposal = null;
-		} else if (proposal.getKind() == CompletionProposal.METHOD_REF
-				|| proposal.getKind() == CompletionProposal.CONSTRUCTOR_INVOCATION
-				|| proposal.getKind() == CompletionProposal.METHOD_REF_WITH_CASTED_RECEIVER) {
-			selectedProposal = proposal;
-		}
-		CompletionItem item = completionResponse.getItems().get(pId);
-		if (item == null) {
-			throw ExceptionFactory.newException("Cannot get the completion item.");
-		}
-
-		// get the cached completion execution time and set it to the selected item in case that providers need it.
-		String executionTime = completionResponse.getCommonData(CompletionRanking.COMPLETION_EXECUTION_TIME);
-		if (executionTime != null) {
-			((Map<String, String>)item.getData()).put(CompletionRanking.COMPLETION_EXECUTION_TIME, executionTime);
-		}
-
-		Map<String, String> contributedData = completionResponse.getCompletionItemData(pId);
-		if (contributedData != null) {
-			((Map<String, String>)item.getData()).putAll(contributedData);
-		}
-
-		List<ICompletionRankingProvider> providers =
-				((CompletionContributionService) JavaLanguageServerPlugin.getCompletionContributionService()).getRankingProviders();
-		for (ICompletionRankingProvider provider : providers) {
-			provider.onDidCompletionItemSelect(item);
-		}
-	}
-
-	private void triggerSignatureHelp() {
-		if (manager.getPreferences().isSignatureHelpEnabled()) {
-			String onSelectedCommand = manager.getClientPreferences().getCompletionItemCommand();
-			if (!onSelectedCommand.isEmpty() && manager.getClientPreferences().isExecuteClientCommandSupport()) {
-				JavaLanguageServerPlugin.getInstance().getClientConnection()
-						.executeClientCommand(onSelectedCommand);
-			}
-		}
+		return $;
 	}
 
 	private CompletionList computeContentAssist(ICompilationUnit unit, CompletionParams params, IProgressMonitor monitor) throws JavaModelException {