1 files changed, 145 insertions, 0 deletions
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/GenericEditorContentAssistant.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/GenericEditorContentAssistant.java
new file mode 100644
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+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/GenericEditorContentAssistant.java
@@ -0,0 +1,145 @@
+/*******************************************************************************
+ * Copyright (c) 2021 Christoph Läubrich and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ * Christoph Läubrich - Inital API and implementation
+ *******************************************************************************/
+package org.eclipse.ui.internal.genericeditor;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
+import org.eclipse.core.runtime.content.IContentType;
+import org.eclipse.jface.text.AbstractReusableInformationControlCreator;
+import org.eclipse.jface.text.DefaultInformationControl;
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.IInformationControl;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.contentassist.ContentAssistant;
+import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
+import org.eclipse.jface.text.contentassist.IContentAssistant;
+import org.eclipse.swt.widgets.Shell;
+
+/**
+ * Extension of the ContentAssistant that supports the following additional
+ * features:
+ * <ul>
+ * <li>#updateTokens refresh the registration of
+ * {@link IContentAssistProcessor}s on document changes</li>
+ * <li>Using a ContentTypeRelatedExtensionTracker to dynamically track
+ * IContentAssistProcessor in the OSGi service registry
+ * </ul>
+ * 
+ * @author christoph
+ *
+ */
+public class GenericEditorContentAssistant extends ContentAssistant {
+	private static final DefaultContentAssistProcessor DEFAULT_CONTENT_ASSIST_PROCESSOR = new DefaultContentAssistProcessor();
+	private ContentTypeRelatedExtensionTracker<IContentAssistProcessor> contentAssistProcessorTracker;
+	private Set<IContentType> types;
+	private List<IContentAssistProcessor> processors;
+
+	/**
+	 * Creates a new GenericEditorContentAssistant instance for the given content
+	 * types and contentAssistProcessorTracker
+	 * 
+	 * @param contentAssistProcessorTracker the tracker to use for tracking
+	 *                                      additional
+	 *                                      {@link IContentAssistProcessor}s in the
+	 *                                      OSGi service factory
+	 * @param processors                    the static processor list
+	 * @param types                         the {@link IContentType} that are used
+	 *                                      to filter appropriate candidates from
+	 *                                      the registry
+	 */
+	public GenericEditorContentAssistant(
+			ContentTypeRelatedExtensionTracker<IContentAssistProcessor> contentAssistProcessorTracker,
+			List<IContentAssistProcessor> processors, Set<IContentType> types) {
+		super(true);
+		this.contentAssistProcessorTracker = contentAssistProcessorTracker;
+		this.processors = Objects.requireNonNullElseGet(processors, () -> Collections.emptyList());
+		this.types = types;
+
+		setContextInformationPopupOrientation(IContentAssistant.CONTEXT_INFO_BELOW);
+		setProposalPopupOrientation(IContentAssistant.PROPOSAL_REMOVE);
+		setAutoActivationDelay(0);
+		enableColoredLabels(true);
+		enableAutoActivation(true);
+		setInformationControlCreator(new AbstractReusableInformationControlCreator() {
+			@Override
+			protected IInformationControl doCreateInformationControl(Shell parent) {
+				return new DefaultInformationControl(parent);
+			}
+		});
+	}
+
+	/**
+	 * Updates the {@link IContentAssistProcessor} registrations according to the
+	 * documents content-type tokens
+	 * 
+	 * @param document the document to use for updating the tokens
+	 */
+	public void updateTokens(IDocument document) {
+		updateProcessors(document);
+		contentAssistProcessorTracker.getTracked().stream().filter(s -> s.isPresent()).map(s -> s.get())
+				.forEach(p -> updateProcessorToken(p, document));
+	}
+
+	private void updateProcessors(IDocument iDocument) {
+		if (processors.isEmpty()) {
+			updateProcessorToken(DEFAULT_CONTENT_ASSIST_PROCESSOR, iDocument);
+		} else {
+			for (IContentAssistProcessor processor : processors) {
+				updateProcessorToken(processor, iDocument);
+			}
+		}
+	}
+
+	private void updateProcessorToken(IContentAssistProcessor processor, IDocument document) {
+		removeContentAssistProcessor(processor);
+		addContentAssistProcessor(processor, IDocument.DEFAULT_CONTENT_TYPE);
+		if (document != null) {
+			for (String contentType : document.getLegalContentTypes()) {
+				addContentAssistProcessor(processor, contentType);
+			}
+		}
+		if (processor != DEFAULT_CONTENT_ASSIST_PROCESSOR) {
+			removeContentAssistProcessor(DEFAULT_CONTENT_ASSIST_PROCESSOR);
+		}
+	}
+
+	@Override
+	public void uninstall() {
+		contentAssistProcessorTracker.stopTracking();
+		super.uninstall();
+	}
+
+	@Override
+	public void install(ITextViewer textViewer) {
+		super.install(textViewer);
+		updateProcessors(textViewer.getDocument());
+		contentAssistProcessorTracker.onAdd(added -> {
+			if (types.contains(added.getContentType())) {
+				IContentAssistProcessor processor = added.get();
+				if (processor != null) {
+					updateProcessorToken(processor, textViewer.getDocument());
+				}
+			}
+		});
+		contentAssistProcessorTracker.onRemove(removed -> {
+			if (removed.isPresent()) {
+				removeContentAssistProcessor(removed.get());
+			}
+		});
+		contentAssistProcessorTracker.startTracking();
+	}
+}