ltk/org.eclipse.statet.ltk.ui/src/org/eclipse/statet/ltk/ui/sourceediting/assist/TemplateProposal.java - gerrit/statet/org.eclipse.statet-ltk - Git at Google

 /*=============================================================================#
  # Copyright (c) 2005, 2021 Stephan Wahlbrink and others.
  #
  # This program and the accompanying materials are made available under the
  # terms of the Eclipse Public License 2.0 which is available at
  # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
  # which is available at https://www.apache.org/licenses/LICENSE-2.0.
  #
  # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
  #
  # Contributors:
  #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
  #=============================================================================*/

 package org.eclipse.statet.ltk.ui.sourceediting.assist;

 import static org.eclipse.statet.jcommons.lang.ObjectUtils.nonNullAssert;

 import static org.eclipse.statet.ltk.ui.LtkUI.BUNDLE_ID;

 import java.util.Comparator;

 import com.ibm.icu.text.Collator;

 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.BadPositionCategoryException;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.Position;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 import org.eclipse.jface.text.contentassist.ICompletionProposalExtension5;
 import org.eclipse.jface.text.link.ILinkedModeListener;
 import org.eclipse.jface.text.link.InclusivePositionUpdater;
 import org.eclipse.jface.text.link.LinkedModeModel;
 import org.eclipse.jface.text.link.LinkedModeUI;
 import org.eclipse.jface.text.link.LinkedPosition;
 import org.eclipse.jface.text.link.LinkedPositionGroup;
 import org.eclipse.jface.text.link.ProposalPosition;
 import org.eclipse.jface.text.templates.DocumentTemplateContext;
 import org.eclipse.jface.text.templates.GlobalTemplateVariables;
 import org.eclipse.jface.text.templates.Template;
 import org.eclipse.jface.text.templates.TemplateBuffer;
 import org.eclipse.jface.text.templates.TemplateContext;
 import org.eclipse.jface.text.templates.TemplateException;
 import org.eclipse.jface.text.templates.TemplateVariable;
 import org.eclipse.jface.viewers.StyledString;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.ui.statushandlers.StatusManager;

 import org.eclipse.statet.jcommons.lang.NonNull;
 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;
 import org.eclipse.statet.jcommons.text.core.SearchPattern;
 import org.eclipse.statet.jcommons.text.core.TextRegion;

 import org.eclipse.statet.ecommons.text.ui.DefaultBrowserInformationInput;
 import org.eclipse.statet.ecommons.text.ui.PositionBasedCompletionProposal;

 import org.eclipse.statet.internal.ltk.ui.LtkUIPlugin;
 import org.eclipse.statet.ltk.ui.LtkUI;
 import org.eclipse.statet.ltk.ui.sourceediting.TextEditToolSynchronizer;
 import org.eclipse.statet.ltk.ui.templates.IWorkbenchTemplateContext;
 import org.eclipse.statet.ltk.ui.util.LTKSelectionUtils;


 /**
  * Like default {@link org.eclipse.jface.text.templates.TemplateProposal}, but
  * <ul>
  *   <li>supports substring matching
  *   <li>supports {@link TextEditToolSynchronizer}</li>
  * </ul>
  */
 @NonNullByDefault
 public class TemplateProposal extends SourceProposal implements ICompletionProposalExtension5 {

 	public static class TemplateComparator implements Comparator<TemplateProposal> {


 		private final Collator collator= Collator.getInstance();


 		public TemplateComparator() {
 		}


 		@Override
 		public int compare(final TemplateProposal arg0, final TemplateProposal arg1) {
 			final int result= this.collator.compare(arg0.getTemplate().getName(), arg1.getTemplate().getName());
 			if (result != 0) {
 				return result;
 			}
 			return this.collator.compare(arg0.getDisplayString(), arg1.getDisplayString());
 		}

 	}

 	public static class TemplateProposalParameters<TContext extends AssistInvocationContext>
 			extends ProposalParameters<TContext> {


 		public final DocumentTemplateContext templateContext;

 		public final TextRegion region;

 		public Template template;


 		@SuppressWarnings("null")
 		public TemplateProposalParameters(
 				final TContext context, final TextRegion region,
 				final SearchPattern namePattern,
 				final DocumentTemplateContext templateContext) {
 			super(context, region.getStartOffset(), namePattern);

 			this.templateContext= templateContext;
 			this.region= region;
 		}

 		public TemplateProposalParameters(
 				final TContext context, final TextRegion region,
 				final DocumentTemplateContext templateContext, final Template template) {
 			super(context, region.getStartOffset(), 0);

 			this.templateContext= templateContext;
 			this.region= region;

 			this.template= template;
 		}

 	}


 	private final Template template;
 	private final DocumentTemplateContext templateContext;

 	private final Image image;

 	private TextRegion region;

 	private @Nullable InclusivePositionUpdater updater;


 	public TemplateProposal(final TemplateProposalParameters<?> parameters,
 			final Image image) {
 		super(parameters);

 		this.template= nonNullAssert(parameters.template);
 		this.templateContext= nonNullAssert(parameters.templateContext);
 		this.image= nonNullAssert(image);
 		this.region= nonNullAssert(parameters.region);
 	}

 	public TemplateProposal(final TemplateProposalParameters<?> parameters) {
 		this(parameters,
 				LtkUIPlugin.getInstance().getImageRegistry().get(LtkUI.OBJ_TEXT_TEMPLATE_IMAGE_ID) );
 	}


 	protected TemplateContext getContext() {
 		return this.templateContext;
 	}

 	protected Template getTemplate() {
 		return this.template;
 	}

 	protected boolean isSelectionTemplate() {
 		if (this.templateContext instanceof DocumentTemplateContext) {
 			final DocumentTemplateContext docContext= this.templateContext;
 			if (docContext.getCompletionLength() > 0) {
 				return true;
 			}
 		}
 		return false;
 	}


 	@Override
 	protected String getName() {
 		return this.template.getName();
 	}


 	@Override
 	public String getSortingString() {
 		return this.template.getName();
 	}


 	@Override
 	public String getDisplayString() {
 		return getStyledDisplayString().getString();
 	}

 	@Override
 	public StyledString computeStyledText() {
 		final StyledString styledText= new StyledString(this.template.getName());
 		if (!this.template.getDescription().isEmpty()) {
 			styledText.append(QUALIFIER_SEPARATOR, StyledString.QUALIFIER_STYLER);
 			styledText.append(this.template.getDescription(), StyledString.QUALIFIER_STYLER);
 		}
 		return styledText;
 	}

 	@Override
 	public Image getImage() {
 		return this.image;
 	}


 	@Override
 	public @Nullable Object getAdditionalProposalInfo(final IProgressMonitor monitor) {
 		try {
 			final TemplateContext context= getContext();
 			context.setReadOnly(true);
 			final String preview;
 			if (context instanceof IWorkbenchTemplateContext) {
 				preview= ((IWorkbenchTemplateContext)context).evaluateInfo(getTemplate());
 			}
 			else {
 				final TemplateBuffer templateBuffer= context.evaluate(getTemplate());
 				preview= (templateBuffer != null) ? templateBuffer.toString() : null;
 			}

 			if (preview != null) {
 				return new DefaultBrowserInformationInput(getDisplayString(),
 						preview, DefaultBrowserInformationInput.FORMAT_SOURCE_INPUT,
 						getInvocationContext().getTabSize() );
 			}
 		}
 		catch (final TemplateException | BadLocationException e) {}
 		return null;
 	}


 	@Override
 	public boolean isAutoInsertable() {
 		if (isSelectionTemplate()) {
 			return false;
 		}
 		return this.template.isAutoInsertable();
 	}


 	@Override
 	public @Nullable CharSequence getPrefixCompletionText(final IDocument document, final int offset) {
 		if (isSelectionTemplate()) {
 			return null;
 		}
 		return super.getPrefixCompletionText(document, offset);
 	}


 	@Override
 	public void apply(final ITextViewer viewer, final char trigger, final int stateMask, final int offset) {
 		final IDocument document= viewer.getDocument();
 		final ApplyData applyData= getApplyData();

 		final Position regionPosition= new Position(this.region.getStartOffset(), this.region.getLength());
 		final Position offsetPosition= new Position(offset, 0);
 		try {
 			document.addPosition(regionPosition);
 			document.addPosition(offsetPosition);
 			this.templateContext.setReadOnly(false);
 			TemplateBuffer templateBuffer;
 			try {
 				templateBuffer= nonNullAssert(this.templateContext.evaluate(this.template));
 			}
 			catch (final TemplateException | NullPointerException e) {
 				applyData.setSelection(this.region);
 				return;
 			}

 			this.region= LTKSelectionUtils.toTextRegion(regionPosition);
 			final int start= getReplaceOffset();
 			final int end= Math.max(getReplaceEndOffset(), offsetPosition.getOffset());

 			// insert template string
 			final String templateString= templateBuffer.getString();
 			document.replace(start, end - start, templateString);

 			// translate positions
 			final LinkedModeModel model= new LinkedModeModel();
 			final TemplateVariable[] variables= templateBuffer.getVariables();
 			boolean hasPositions= false;
 			for (int i= 0; i != variables.length; i++) {
 				final TemplateVariable variable= variables[i];

 				if (variable.isUnambiguous()) {
 					continue;
 				}

 				final LinkedPositionGroup group= new LinkedPositionGroup();

 				final int[] offsets= variable.getOffsets();
 				final int length= variable.getLength();

 				final String[] values= variable.getValues();
 				final ICompletionProposal[] proposals= new @NonNull ICompletionProposal[values.length];
 				for (int j= 0; j < values.length; j++) {
 					ensurePositionCategoryInstalled(document, model);
 					final Position pos= new Position(offsets[0] + start, length);
 					document.addPosition(getCategory(), pos);
 					proposals[j]= new PositionBasedCompletionProposal(values[j], pos, length);
 				}

 				for (int j= 0; j < offsets.length; j++) {
 					if (j == 0 && proposals.length > 1) {
 						group.addPosition(new ProposalPosition(document, offsets[j] + start, length, proposals));
 					}
 					else {
 						group.addPosition(new LinkedPosition(document, offsets[j] + start, length));
 					}
 				}

 				model.addGroup(group);
 				hasPositions= true;
 			}

 			if (hasPositions) {
 				model.forceInstall();

 				final TextEditToolSynchronizer toolSynchronizer= getInvocationContext().getEditor()
 						.getTextEditToolSynchronizer();
 				if (toolSynchronizer != null) {
 					toolSynchronizer.install(model);
 				}

 				final LinkedModeUI ui= new LinkedModeUI(model, viewer);
 				ui.setExitPosition(viewer, getCaretOffset(templateBuffer) + start, 0, Integer.MAX_VALUE);
 				ui.enter();

 				applyData.setSelection(LTKSelectionUtils.toTextRegion(ui.getSelectedRegion()));
 			}
 			else {
 				ensurePositionCategoryRemoved(document);
 				applyData.setSelection(getCaretOffset(templateBuffer) + start);
 			}
 		}
 		catch (final BadLocationException | BadPositionCategoryException e) {
 			StatusManager.getManager().handle(new Status(IStatus.ERROR, BUNDLE_ID, 0,
 					"Template Evaluation Error",
 					e ));
 			applyData.clearSelection();
 		}
 		finally {
 			document.removePosition(regionPosition);
 			document.removePosition(offsetPosition);
 		}
 	}


 	private String getCategory() {
 		return "TemplateProposalCategory_" + toString(); //$NON-NLS-1$
 	}

 	private void ensurePositionCategoryInstalled(final IDocument document, final LinkedModeModel model) {
 		if (!document.containsPositionCategory(getCategory())) {
 			document.addPositionCategory(getCategory());
 			this.updater= new InclusivePositionUpdater(getCategory());
 			document.addPositionUpdater(this.updater);

 			model.addLinkingListener(new ILinkedModeListener() {

 				@Override
 				public void left(final LinkedModeModel environment, final int flags) {
 					ensurePositionCategoryRemoved(document);
 				}

 				@Override
 				public void suspend(final LinkedModeModel environment) {}
 				@Override
 				public void resume(final LinkedModeModel environment, final int flags) {}
 			});
 		}
 	}

 	private void ensurePositionCategoryRemoved(final IDocument document) {
 		if (document.containsPositionCategory(getCategory())) {
 			try {
 				document.removePositionCategory(getCategory());
 			} catch (final BadPositionCategoryException e) {
 				// ignore
 			}
 			document.removePositionUpdater(this.updater);
 		}
 	}

 	private int getCaretOffset(final TemplateBuffer buffer) {
 		final TemplateVariable[] variables= buffer.getVariables();
 		for (int i= 0; i != variables.length; i++) {
 			final TemplateVariable variable= variables[i];
 			if (variable.getType().equals(GlobalTemplateVariables.Cursor.NAME)) {
 				return variable.getOffsets()[0];
 			}
 		}
 		return buffer.getString().length();
 	}

 	/**
 	 * Returns the offset of the range in the document that will be replaced by
 	 * applying this template.
 	 *
 	 * @return the offset of the range in the document that will be replaced by
 	 *     applying this template
 	 */
 	protected final int getReplaceOffset() {
 		int start;
 		if (this.templateContext instanceof DocumentTemplateContext) {
 			final DocumentTemplateContext docContext= this.templateContext;
 			start= docContext.getStart();
 		}
 		else {
 			start= this.region.getStartOffset();
 		}
 		return start;
 	}

 	/**
 	 * Returns the end offset of the range in the document that will be replaced
 	 * by applying this template.
 	 *
 	 * @return the end offset of the range in the document that will be replaced
 	 *     by applying this template
 	 */
 	protected final int getReplaceEndOffset() {
 		int end;
 		if (this.templateContext instanceof DocumentTemplateContext) {
 			final DocumentTemplateContext docContext= this.templateContext;
 			end= docContext.getEnd();
 		}
 		else {
 			end= this.region.getEndOffset();
 		}
 		return end;
 	}

 	@Override
 	public int getContextInformationPosition() {
 		return this.region.getStartOffset();
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2005, 2021 Stephan Wahlbrink and others.
	#
	# This program and the accompanying materials are made available under the
	# terms of the Eclipse Public License 2.0 which is available at
	# https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
	# which is available at https://www.apache.org/licenses/LICENSE-2.0.
	#
	# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
	#
	# Contributors:
	# Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
	#=============================================================================*/

	package org.eclipse.statet.ltk.ui.sourceediting.assist;

	import static org.eclipse.statet.jcommons.lang.ObjectUtils.nonNullAssert;

	import static org.eclipse.statet.ltk.ui.LtkUI.BUNDLE_ID;

	import java.util.Comparator;

	import com.ibm.icu.text.Collator;

	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.BadPositionCategoryException;
	import org.eclipse.jface.text.IDocument;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.Position;
	import org.eclipse.jface.text.contentassist.ICompletionProposal;
	import org.eclipse.jface.text.contentassist.ICompletionProposalExtension5;
	import org.eclipse.jface.text.link.ILinkedModeListener;
	import org.eclipse.jface.text.link.InclusivePositionUpdater;
	import org.eclipse.jface.text.link.LinkedModeModel;
	import org.eclipse.jface.text.link.LinkedModeUI;
	import org.eclipse.jface.text.link.LinkedPosition;
	import org.eclipse.jface.text.link.LinkedPositionGroup;
	import org.eclipse.jface.text.link.ProposalPosition;
	import org.eclipse.jface.text.templates.DocumentTemplateContext;
	import org.eclipse.jface.text.templates.GlobalTemplateVariables;
	import org.eclipse.jface.text.templates.Template;
	import org.eclipse.jface.text.templates.TemplateBuffer;
	import org.eclipse.jface.text.templates.TemplateContext;
	import org.eclipse.jface.text.templates.TemplateException;
	import org.eclipse.jface.text.templates.TemplateVariable;
	import org.eclipse.jface.viewers.StyledString;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.ui.statushandlers.StatusManager;

	import org.eclipse.statet.jcommons.lang.NonNull;
	import org.eclipse.statet.jcommons.lang.NonNullByDefault;
	import org.eclipse.statet.jcommons.lang.Nullable;
	import org.eclipse.statet.jcommons.text.core.SearchPattern;
	import org.eclipse.statet.jcommons.text.core.TextRegion;

	import org.eclipse.statet.ecommons.text.ui.DefaultBrowserInformationInput;
	import org.eclipse.statet.ecommons.text.ui.PositionBasedCompletionProposal;

	import org.eclipse.statet.internal.ltk.ui.LtkUIPlugin;
	import org.eclipse.statet.ltk.ui.LtkUI;
	import org.eclipse.statet.ltk.ui.sourceediting.TextEditToolSynchronizer;
	import org.eclipse.statet.ltk.ui.templates.IWorkbenchTemplateContext;
	import org.eclipse.statet.ltk.ui.util.LTKSelectionUtils;


	/**
	* Like default {@link org.eclipse.jface.text.templates.TemplateProposal}, but
	* <ul>
	* <li>supports substring matching
	* <li>supports {@link TextEditToolSynchronizer}</li>
	* </ul>
	*/
	@NonNullByDefault
	public class TemplateProposal extends SourceProposal implements ICompletionProposalExtension5 {

	public static class TemplateComparator implements Comparator<TemplateProposal> {


	private final Collator collator= Collator.getInstance();


	public TemplateComparator() {
	}


	@Override
	public int compare(final TemplateProposal arg0, final TemplateProposal arg1) {
	final int result= this.collator.compare(arg0.getTemplate().getName(), arg1.getTemplate().getName());
	if (result != 0) {
	return result;
	}
	return this.collator.compare(arg0.getDisplayString(), arg1.getDisplayString());
	}

	}

	public static class TemplateProposalParameters<TContext extends AssistInvocationContext>
	extends ProposalParameters<TContext> {


	public final DocumentTemplateContext templateContext;

	public final TextRegion region;

	public Template template;


	@SuppressWarnings("null")
	public TemplateProposalParameters(
	final TContext context, final TextRegion region,
	final SearchPattern namePattern,
	final DocumentTemplateContext templateContext) {
	super(context, region.getStartOffset(), namePattern);

	this.templateContext= templateContext;
	this.region= region;
	}

	public TemplateProposalParameters(
	final TContext context, final TextRegion region,
	final DocumentTemplateContext templateContext, final Template template) {
	super(context, region.getStartOffset(), 0);

	this.templateContext= templateContext;
	this.region= region;

	this.template= template;
	}

	}


	private final Template template;
	private final DocumentTemplateContext templateContext;

	private final Image image;

	private TextRegion region;

	private @Nullable InclusivePositionUpdater updater;


	public TemplateProposal(final TemplateProposalParameters<?> parameters,
	final Image image) {
	super(parameters);

	this.template= nonNullAssert(parameters.template);
	this.templateContext= nonNullAssert(parameters.templateContext);
	this.image= nonNullAssert(image);
	this.region= nonNullAssert(parameters.region);
	}

	public TemplateProposal(final TemplateProposalParameters<?> parameters) {
	this(parameters,
	LtkUIPlugin.getInstance().getImageRegistry().get(LtkUI.OBJ_TEXT_TEMPLATE_IMAGE_ID) );
	}


	protected TemplateContext getContext() {
	return this.templateContext;
	}

	protected Template getTemplate() {
	return this.template;
	}

	protected boolean isSelectionTemplate() {
	if (this.templateContext instanceof DocumentTemplateContext) {
	final DocumentTemplateContext docContext= this.templateContext;
	if (docContext.getCompletionLength() > 0) {
	return true;
	}
	}
	return false;
	}


	@Override
	protected String getName() {
	return this.template.getName();
	}


	@Override
	public String getSortingString() {
	return this.template.getName();
	}


	@Override
	public String getDisplayString() {
	return getStyledDisplayString().getString();
	}

	@Override
	public StyledString computeStyledText() {
	final StyledString styledText= new StyledString(this.template.getName());
	if (!this.template.getDescription().isEmpty()) {
	styledText.append(QUALIFIER_SEPARATOR, StyledString.QUALIFIER_STYLER);
	styledText.append(this.template.getDescription(), StyledString.QUALIFIER_STYLER);
	}
	return styledText;
	}

	@Override
	public Image getImage() {
	return this.image;
	}


	@Override
	public @Nullable Object getAdditionalProposalInfo(final IProgressMonitor monitor) {
	try {
	final TemplateContext context= getContext();
	context.setReadOnly(true);
	final String preview;
	if (context instanceof IWorkbenchTemplateContext) {
	preview= ((IWorkbenchTemplateContext)context).evaluateInfo(getTemplate());
	}
	else {
	final TemplateBuffer templateBuffer= context.evaluate(getTemplate());
	preview= (templateBuffer != null) ? templateBuffer.toString() : null;
	}

	if (preview != null) {
	return new DefaultBrowserInformationInput(getDisplayString(),
	preview, DefaultBrowserInformationInput.FORMAT_SOURCE_INPUT,
	getInvocationContext().getTabSize() );
	}
	}
	catch (final TemplateException \| BadLocationException e) {}
	return null;
	}


	@Override
	public boolean isAutoInsertable() {
	if (isSelectionTemplate()) {
	return false;
	}
	return this.template.isAutoInsertable();
	}


	@Override
	public @Nullable CharSequence getPrefixCompletionText(final IDocument document, final int offset) {
	if (isSelectionTemplate()) {
	return null;
	}
	return super.getPrefixCompletionText(document, offset);
	}


	@Override
	public void apply(final ITextViewer viewer, final char trigger, final int stateMask, final int offset) {
	final IDocument document= viewer.getDocument();
	final ApplyData applyData= getApplyData();

	final Position regionPosition= new Position(this.region.getStartOffset(), this.region.getLength());
	final Position offsetPosition= new Position(offset, 0);
	try {
	document.addPosition(regionPosition);
	document.addPosition(offsetPosition);
	this.templateContext.setReadOnly(false);
	TemplateBuffer templateBuffer;
	try {
	templateBuffer= nonNullAssert(this.templateContext.evaluate(this.template));
	}
	catch (final TemplateException \| NullPointerException e) {
	applyData.setSelection(this.region);
	return;
	}

	this.region= LTKSelectionUtils.toTextRegion(regionPosition);
	final int start= getReplaceOffset();
	final int end= Math.max(getReplaceEndOffset(), offsetPosition.getOffset());

	// insert template string
	final String templateString= templateBuffer.getString();
	document.replace(start, end - start, templateString);

	// translate positions
	final LinkedModeModel model= new LinkedModeModel();
	final TemplateVariable[] variables= templateBuffer.getVariables();
	boolean hasPositions= false;
	for (int i= 0; i != variables.length; i++) {
	final TemplateVariable variable= variables[i];

	if (variable.isUnambiguous()) {
	continue;
	}

	final LinkedPositionGroup group= new LinkedPositionGroup();

	final int[] offsets= variable.getOffsets();
	final int length= variable.getLength();

	final String[] values= variable.getValues();
	final ICompletionProposal[] proposals= new @NonNull ICompletionProposal[values.length];
	for (int j= 0; j < values.length; j++) {
	ensurePositionCategoryInstalled(document, model);
	final Position pos= new Position(offsets[0] + start, length);
	document.addPosition(getCategory(), pos);
	proposals[j]= new PositionBasedCompletionProposal(values[j], pos, length);
	}

	for (int j= 0; j < offsets.length; j++) {
	if (j == 0 && proposals.length > 1) {
	group.addPosition(new ProposalPosition(document, offsets[j] + start, length, proposals));
	}
	else {
	group.addPosition(new LinkedPosition(document, offsets[j] + start, length));
	}
	}

	model.addGroup(group);
	hasPositions= true;
	}

	if (hasPositions) {
	model.forceInstall();

	final TextEditToolSynchronizer toolSynchronizer= getInvocationContext().getEditor()
	.getTextEditToolSynchronizer();
	if (toolSynchronizer != null) {
	toolSynchronizer.install(model);
	}

	final LinkedModeUI ui= new LinkedModeUI(model, viewer);
	ui.setExitPosition(viewer, getCaretOffset(templateBuffer) + start, 0, Integer.MAX_VALUE);
	ui.enter();

	applyData.setSelection(LTKSelectionUtils.toTextRegion(ui.getSelectedRegion()));
	}
	else {
	ensurePositionCategoryRemoved(document);
	applyData.setSelection(getCaretOffset(templateBuffer) + start);
	}
	}
	catch (final BadLocationException \| BadPositionCategoryException e) {
	StatusManager.getManager().handle(new Status(IStatus.ERROR, BUNDLE_ID, 0,
	"Template Evaluation Error",
	e ));
	applyData.clearSelection();
	}
	finally {
	document.removePosition(regionPosition);
	document.removePosition(offsetPosition);
	}
	}


	private String getCategory() {
	return "TemplateProposalCategory_" + toString(); //$NON-NLS-1$
	}

	private void ensurePositionCategoryInstalled(final IDocument document, final LinkedModeModel model) {
	if (!document.containsPositionCategory(getCategory())) {
	document.addPositionCategory(getCategory());
	this.updater= new InclusivePositionUpdater(getCategory());
	document.addPositionUpdater(this.updater);

	model.addLinkingListener(new ILinkedModeListener() {

	@Override
	public void left(final LinkedModeModel environment, final int flags) {
	ensurePositionCategoryRemoved(document);
	}

	@Override
	public void suspend(final LinkedModeModel environment) {}
	@Override
	public void resume(final LinkedModeModel environment, final int flags) {}
	});
	}
	}

	private void ensurePositionCategoryRemoved(final IDocument document) {
	if (document.containsPositionCategory(getCategory())) {
	try {
	document.removePositionCategory(getCategory());
	} catch (final BadPositionCategoryException e) {
	// ignore
	}
	document.removePositionUpdater(this.updater);
	}
	}

	private int getCaretOffset(final TemplateBuffer buffer) {
	final TemplateVariable[] variables= buffer.getVariables();
	for (int i= 0; i != variables.length; i++) {
	final TemplateVariable variable= variables[i];
	if (variable.getType().equals(GlobalTemplateVariables.Cursor.NAME)) {
	return variable.getOffsets()[0];
	}
	}
	return buffer.getString().length();
	}

	/**
	* Returns the offset of the range in the document that will be replaced by
	* applying this template.
	*
	* @return the offset of the range in the document that will be replaced by
	* applying this template
	*/
	protected final int getReplaceOffset() {
	int start;
	if (this.templateContext instanceof DocumentTemplateContext) {
	final DocumentTemplateContext docContext= this.templateContext;
	start= docContext.getStart();
	}
	else {
	start= this.region.getStartOffset();
	}
	return start;
	}

	/**
	* Returns the end offset of the range in the document that will be replaced
	* by applying this template.
	*
	* @return the end offset of the range in the document that will be replaced
	* by applying this template
	*/
	protected final int getReplaceEndOffset() {
	int end;
	if (this.templateContext instanceof DocumentTemplateContext) {
	final DocumentTemplateContext docContext= this.templateContext;
	end= docContext.getEnd();
	}
	else {
	end= this.region.getEndOffset();
	}
	return end;
	}

	@Override
	public int getContextInformationPosition() {
	return this.region.getStartOffset();
	}

	}