r/org.eclipse.statet.r.ui/src/org/eclipse/statet/internal/r/ui/rhelp/RHelpPreferencePage.java - statet/org.eclipse.statet-r - Git at Google

 /*=============================================================================#
  # Copyright (c) 2010, 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.internal.r.ui.rhelp;

 import java.util.HashMap;
 import java.util.Map;

 import org.eclipse.core.databinding.UpdateValueStrategy;
 import org.eclipse.core.databinding.observable.Diffs;
 import org.eclipse.core.databinding.observable.Realm;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.jface.databinding.swt.typed.WidgetProperties;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.ModifyEvent;
 import org.eclipse.swt.events.ModifyListener;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Group;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Link;
 import org.eclipse.swt.widgets.Text;

 import org.eclipse.statet.jcommons.lang.NonNullByDefault;
 import org.eclipse.statet.jcommons.lang.Nullable;

 import org.eclipse.statet.ecommons.databinding.core.validation.IntegerValidator;
 import org.eclipse.statet.ecommons.databinding.jface.AbstractSWTObservableValue;
 import org.eclipse.statet.ecommons.databinding.jface.DataBindingSupport;
 import org.eclipse.statet.ecommons.preferences.core.Preference;
 import org.eclipse.statet.ecommons.preferences.ui.ConfigurationBlock;
 import org.eclipse.statet.ecommons.preferences.ui.ConfigurationBlockPreferencePage;
 import org.eclipse.statet.ecommons.preferences.ui.ManagedConfigurationBlock;
 import org.eclipse.statet.ecommons.runtime.core.StatusChangeListener;
 import org.eclipse.statet.ecommons.ui.util.LayoutUtils;

 import org.eclipse.statet.r.core.RCore;


 @NonNullByDefault
 public class RHelpPreferencePage extends ConfigurationBlockPreferencePage {


 	public RHelpPreferencePage() {
 	}


 	@Override
 	protected ConfigurationBlock createConfigurationBlock() throws CoreException {
 		return new RHelpConfigurationBlock(createStatusChangedListener());
 	}

 }


 @NonNullByDefault
 class RHelpConfigurationBlock extends ManagedConfigurationBlock {


 	class HomeObservable extends AbstractSWTObservableValue<String>
 			implements SelectionListener, ModifyListener {


 		private boolean isCustom;
 		private String url;
 		private String lastCustom= "http://"; //$NON-NLS-1$

 		private boolean isUpdating;


 		public HomeObservable(final Realm realm) {
 			super(realm, RHelpConfigurationBlock.this.homeUrlControl);
 			RHelpConfigurationBlock.this.homeUrlControl.addModifyListener(this);
 			RHelpConfigurationBlock.this.homeBlankControl.addSelectionListener(this);
 			RHelpConfigurationBlock.this.homeREnvControl.addSelectionListener(this);
 			RHelpConfigurationBlock.this.homeCustomControl.addSelectionListener(this);
 			this.url= ""; //$NON-NLS-1$
 		}

 		@Override
 		public Object getValueType() {
 			return String.class;
 		}

 		@Override
 		protected String doGetValue() {
 			if (!this.isUpdating) {
 				this.isUpdating= true;
 				try {
 					updateUrl();
 				}
 				finally {
 					this.isUpdating= false;
 				}
 			}
 			return this.url;
 		}

 		@Override
 		protected void doSetValue(final @Nullable String value) {
 			this.isUpdating= true;
 			this.url= (value != null) ? value : "about:blank"; //$NON-NLS-1$
 			try {
 				if (this.url.equals("about:blank")) { //$NON-NLS-1$
 					RHelpConfigurationBlock.this.homeBlankControl.setSelection(true);
 					RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
 					RHelpConfigurationBlock.this.homeCustomControl.setSelection(false);
 					this.isCustom= false;
 				}
 				else if (this.url.equals(RCore.DEFAULT_RHELP_BROWSE_URL)) {
 					RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
 					RHelpConfigurationBlock.this.homeREnvControl.setSelection(true);
 					RHelpConfigurationBlock.this.homeCustomControl.setSelection(false);
 					this.isCustom= false;
 				}
 				else {
 					RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
 					RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
 					RHelpConfigurationBlock.this.homeCustomControl.setSelection(true);
 					this.isCustom= true;
 					this.lastCustom= this.url;
 				}
 				RHelpConfigurationBlock.this.homeUrlControl.setText(this.url);
 			}
 			finally {
 				this.isUpdating= false;
 			}
 		}

 		private void updateUrl() {
 			final String oldUrl= this.url;
 			if (RHelpConfigurationBlock.this.homeBlankControl.getSelection()) {
 				if (this.isCustom) {
 					this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
 				}
 				this.isCustom= false;
 				this.url= "about:blank"; //$NON-NLS-1$
 			}
 			else if (RHelpConfigurationBlock.this.homeREnvControl.getSelection()) {
 				if (this.isCustom) {
 					this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
 				}
 				this.isCustom= false;
 				this.url= RCore.DEFAULT_RHELP_BROWSE_URL;
 			}
 			else {
 				this.isCustom= true;
 				this.url= (this.lastCustom != null) ? this.lastCustom : ""; //$NON-NLS-1$
 			}
 			if (!this.url.equals(RHelpConfigurationBlock.this.homeUrlControl.getText())) {
 				RHelpConfigurationBlock.this.homeUrlControl.setText(this.url);
 			}
 			if (!this.url.equals(oldUrl)) {
 				fireValueChange(Diffs.createValueDiff(oldUrl, this.url));
 			}
 		}

 		@Override
 		public void widgetSelected(final SelectionEvent e) {
 			if (this.isUpdating) {
 				return;
 			}
 			this.isUpdating= true;
 			try {
 				updateUrl();
 			}
 			finally {
 				this.isUpdating= false;
 			}
 		}

 		@Override
 		public void widgetDefaultSelected(final SelectionEvent e) {
 		}

 		@Override
 		public void modifyText(final ModifyEvent e) {
 			if (this.isUpdating) {
 				return;
 			}
 			this.isUpdating= true;
 			try {
 				RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
 				RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
 				RHelpConfigurationBlock.this.homeCustomControl.setSelection(true);
 				this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
 				updateUrl();
 			}
 			finally {
 				this.isUpdating= false;
 			}
 		}

 	}


 	private Button homeBlankControl;
 	private Button homeREnvControl;
 	private Button homeCustomControl;
 	private Text homeUrlControl;

 	private Button searchReusePageControl;
 	private Text searchMaxFragmentsControl;


 	protected RHelpConfigurationBlock(final @Nullable StatusChangeListener statusListener) {
 		super(null, statusListener);
 	}

 	@Override
 	protected void createBlockArea(final Composite pageComposite) {
 		final Map<Preference<?>, @Nullable String> prefs= new HashMap<>();

 		prefs.put(RHelpPreferences.HOMEPAGE_URL_PREF, null);
 		prefs.put(RHelpPreferences.SEARCH_REUSE_PAGE_ENABLED_PREF, null);
 		prefs.put(RHelpPreferences.SEARCH_PREVIEW_FRAGMENTS_MAX_PREF, null);

 		setupPreferenceManager(prefs);

 		final Composite appearanceOptions= createAppearanceOptions(pageComposite);
 		appearanceOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		final Composite homeOptions= createHomeOptions(pageComposite);
 		homeOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		final Composite searchOptions= createSearchOptions(pageComposite);
 		searchOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		initBindings();
 		updateControls();
 	}

 	private Composite createAppearanceOptions(final Composite pageComposite) {
 		final Group group= new Group(pageComposite, SWT.NONE);
 		group.setText("Appearance" + ':');
 		group.setLayout(LayoutUtils.newGroupGrid(3));

 		final Link control= addLinkControl(group,
 				"See also settings for StatET > Documentation in <a href=\"org.eclipse.ui.preferencePages.ColorsAndFonts\">Color and Fonts</a>.");
 		control.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

 		return group;
 	}

 	private Composite createHomeOptions(final Composite pageComposite) {
 		final Group group= new Group(pageComposite, SWT.NONE);
 		group.setText("Home Page" + ':');
 		group.setLayout(LayoutUtils.newGroupGrid(3));

 		{	final Button button= new Button(group, SWT.RADIO);
 			button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
 			button.setText("&Blank page");
 			this.homeBlankControl= button;
 		}
 		{	final Button button= new Button(group, SWT.RADIO);
 			button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
 			button.setText("Default &R environment");
 			this.homeREnvControl= button;
 		}
 		{	final Button button= new Button(group, SWT.RADIO);
 			button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
 			button.setText("C&ustom");
 			this.homeCustomControl= button;
 		}
 		{	final Text text= new Text(group, SWT.BORDER);
 			text.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 3, 1));
 			text.setText(""); //$NON-NLS-1$
 			this.homeUrlControl= text;
 		}

 		return group;
 	}

 	private Composite createSearchOptions(final Composite pageComposite) {
 		final Group group= new Group(pageComposite, SWT.NONE);
 		group.setText("Search" + ':');
 		group.setLayout(LayoutUtils.newGroupGrid(2));

 		this.searchReusePageControl= new Button(group, SWT.CHECK);
 		this.searchReusePageControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
 		this.searchReusePageControl.setText("Reuse &page in R Help view to show matches.");

 		{	final Label label= new Label(group, SWT.NONE);
 			label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
 			label.setText("Maximum preview &fragments:");

 			final Text text= new Text(group, SWT.BORDER | SWT.RIGHT);
 			final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
 			gd.widthHint= LayoutUtils.hintWidth(text, 5);
 			text.setLayoutData(gd);

 			this.searchMaxFragmentsControl= text;
 		}

 		return group;
 	}

 	@Override
 	protected void addBindings(final DataBindingSupport db) {
 		db.getContext().bindValue(
 				new HomeObservable(db.getRealm()),
 				createObservable(RHelpPreferences.HOMEPAGE_URL_PREF) );
 		db.getContext().bindValue(
 				WidgetProperties.buttonSelection()
 						.observe(this.searchReusePageControl),
 				createObservable(RHelpPreferences.SEARCH_REUSE_PAGE_ENABLED_PREF) );
 		db.getContext().bindValue(
 				WidgetProperties.text(SWT.Modify)
 						.observe(this.searchMaxFragmentsControl),
 				createObservable(RHelpPreferences.SEARCH_PREVIEW_FRAGMENTS_MAX_PREF),
 				new UpdateValueStrategy<String, Integer>()
 						.setAfterGetValidator(new IntegerValidator(1, 1000,
 								"Invalid maximum for preview fragments specified (1-1000).")),
 				null );
 	}

 }
	/*=============================================================================#
	# Copyright (c) 2010, 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.internal.r.ui.rhelp;

	import java.util.HashMap;
	import java.util.Map;

	import org.eclipse.core.databinding.UpdateValueStrategy;
	import org.eclipse.core.databinding.observable.Diffs;
	import org.eclipse.core.databinding.observable.Realm;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.jface.databinding.swt.typed.WidgetProperties;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.ModifyEvent;
	import org.eclipse.swt.events.ModifyListener;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Group;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Link;
	import org.eclipse.swt.widgets.Text;

	import org.eclipse.statet.jcommons.lang.NonNullByDefault;
	import org.eclipse.statet.jcommons.lang.Nullable;

	import org.eclipse.statet.ecommons.databinding.core.validation.IntegerValidator;
	import org.eclipse.statet.ecommons.databinding.jface.AbstractSWTObservableValue;
	import org.eclipse.statet.ecommons.databinding.jface.DataBindingSupport;
	import org.eclipse.statet.ecommons.preferences.core.Preference;
	import org.eclipse.statet.ecommons.preferences.ui.ConfigurationBlock;
	import org.eclipse.statet.ecommons.preferences.ui.ConfigurationBlockPreferencePage;
	import org.eclipse.statet.ecommons.preferences.ui.ManagedConfigurationBlock;
	import org.eclipse.statet.ecommons.runtime.core.StatusChangeListener;
	import org.eclipse.statet.ecommons.ui.util.LayoutUtils;

	import org.eclipse.statet.r.core.RCore;


	@NonNullByDefault
	public class RHelpPreferencePage extends ConfigurationBlockPreferencePage {


	public RHelpPreferencePage() {
	}


	@Override
	protected ConfigurationBlock createConfigurationBlock() throws CoreException {
	return new RHelpConfigurationBlock(createStatusChangedListener());
	}

	}


	@NonNullByDefault
	class RHelpConfigurationBlock extends ManagedConfigurationBlock {


	class HomeObservable extends AbstractSWTObservableValue<String>
	implements SelectionListener, ModifyListener {


	private boolean isCustom;
	private String url;
	private String lastCustom= "http://"; //$NON-NLS-1$

	private boolean isUpdating;


	public HomeObservable(final Realm realm) {
	super(realm, RHelpConfigurationBlock.this.homeUrlControl);
	RHelpConfigurationBlock.this.homeUrlControl.addModifyListener(this);
	RHelpConfigurationBlock.this.homeBlankControl.addSelectionListener(this);
	RHelpConfigurationBlock.this.homeREnvControl.addSelectionListener(this);
	RHelpConfigurationBlock.this.homeCustomControl.addSelectionListener(this);
	this.url= ""; //$NON-NLS-1$
	}

	@Override
	public Object getValueType() {
	return String.class;
	}

	@Override
	protected String doGetValue() {
	if (!this.isUpdating) {
	this.isUpdating= true;
	try {
	updateUrl();
	}
	finally {
	this.isUpdating= false;
	}
	}
	return this.url;
	}

	@Override
	protected void doSetValue(final @Nullable String value) {
	this.isUpdating= true;
	this.url= (value != null) ? value : "about:blank"; //$NON-NLS-1$
	try {
	if (this.url.equals("about:blank")) { //$NON-NLS-1$
	RHelpConfigurationBlock.this.homeBlankControl.setSelection(true);
	RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
	RHelpConfigurationBlock.this.homeCustomControl.setSelection(false);
	this.isCustom= false;
	}
	else if (this.url.equals(RCore.DEFAULT_RHELP_BROWSE_URL)) {
	RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
	RHelpConfigurationBlock.this.homeREnvControl.setSelection(true);
	RHelpConfigurationBlock.this.homeCustomControl.setSelection(false);
	this.isCustom= false;
	}
	else {
	RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
	RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
	RHelpConfigurationBlock.this.homeCustomControl.setSelection(true);
	this.isCustom= true;
	this.lastCustom= this.url;
	}
	RHelpConfigurationBlock.this.homeUrlControl.setText(this.url);
	}
	finally {
	this.isUpdating= false;
	}
	}

	private void updateUrl() {
	final String oldUrl= this.url;
	if (RHelpConfigurationBlock.this.homeBlankControl.getSelection()) {
	if (this.isCustom) {
	this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
	}
	this.isCustom= false;
	this.url= "about:blank"; //$NON-NLS-1$
	}
	else if (RHelpConfigurationBlock.this.homeREnvControl.getSelection()) {
	if (this.isCustom) {
	this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
	}
	this.isCustom= false;
	this.url= RCore.DEFAULT_RHELP_BROWSE_URL;
	}
	else {
	this.isCustom= true;
	this.url= (this.lastCustom != null) ? this.lastCustom : ""; //$NON-NLS-1$
	}
	if (!this.url.equals(RHelpConfigurationBlock.this.homeUrlControl.getText())) {
	RHelpConfigurationBlock.this.homeUrlControl.setText(this.url);
	}
	if (!this.url.equals(oldUrl)) {
	fireValueChange(Diffs.createValueDiff(oldUrl, this.url));
	}
	}

	@Override
	public void widgetSelected(final SelectionEvent e) {
	if (this.isUpdating) {
	return;
	}
	this.isUpdating= true;
	try {
	updateUrl();
	}
	finally {
	this.isUpdating= false;
	}
	}

	@Override
	public void widgetDefaultSelected(final SelectionEvent e) {
	}

	@Override
	public void modifyText(final ModifyEvent e) {
	if (this.isUpdating) {
	return;
	}
	this.isUpdating= true;
	try {
	RHelpConfigurationBlock.this.homeBlankControl.setSelection(false);
	RHelpConfigurationBlock.this.homeREnvControl.setSelection(false);
	RHelpConfigurationBlock.this.homeCustomControl.setSelection(true);
	this.lastCustom= RHelpConfigurationBlock.this.homeUrlControl.getText();
	updateUrl();
	}
	finally {
	this.isUpdating= false;
	}
	}

	}


	private Button homeBlankControl;
	private Button homeREnvControl;
	private Button homeCustomControl;
	private Text homeUrlControl;

	private Button searchReusePageControl;
	private Text searchMaxFragmentsControl;


	protected RHelpConfigurationBlock(final @Nullable StatusChangeListener statusListener) {
	super(null, statusListener);
	}

	@Override
	protected void createBlockArea(final Composite pageComposite) {
	final Map<Preference<?>, @Nullable String> prefs= new HashMap<>();

	prefs.put(RHelpPreferences.HOMEPAGE_URL_PREF, null);
	prefs.put(RHelpPreferences.SEARCH_REUSE_PAGE_ENABLED_PREF, null);
	prefs.put(RHelpPreferences.SEARCH_PREVIEW_FRAGMENTS_MAX_PREF, null);

	setupPreferenceManager(prefs);

	final Composite appearanceOptions= createAppearanceOptions(pageComposite);
	appearanceOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	final Composite homeOptions= createHomeOptions(pageComposite);
	homeOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	final Composite searchOptions= createSearchOptions(pageComposite);
	searchOptions.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	initBindings();
	updateControls();
	}

	private Composite createAppearanceOptions(final Composite pageComposite) {
	final Group group= new Group(pageComposite, SWT.NONE);
	group.setText("Appearance" + ':');
	group.setLayout(LayoutUtils.newGroupGrid(3));

	final Link control= addLinkControl(group,
	"See also settings for StatET > Documentation in <a href=\"org.eclipse.ui.preferencePages.ColorsAndFonts\">Color and Fonts</a>.");
	control.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

	return group;
	}

	private Composite createHomeOptions(final Composite pageComposite) {
	final Group group= new Group(pageComposite, SWT.NONE);
	group.setText("Home Page" + ':');
	group.setLayout(LayoutUtils.newGroupGrid(3));

	{ final Button button= new Button(group, SWT.RADIO);
	button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
	button.setText("&Blank page");
	this.homeBlankControl= button;
	}
	{ final Button button= new Button(group, SWT.RADIO);
	button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
	button.setText("Default &R environment");
	this.homeREnvControl= button;
	}
	{ final Button button= new Button(group, SWT.RADIO);
	button.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false));
	button.setText("C&ustom");
	this.homeCustomControl= button;
	}
	{ final Text text= new Text(group, SWT.BORDER);
	text.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 3, 1));
	text.setText(""); //$NON-NLS-1$
	this.homeUrlControl= text;
	}

	return group;
	}

	private Composite createSearchOptions(final Composite pageComposite) {
	final Group group= new Group(pageComposite, SWT.NONE);
	group.setText("Search" + ':');
	group.setLayout(LayoutUtils.newGroupGrid(2));

	this.searchReusePageControl= new Button(group, SWT.CHECK);
	this.searchReusePageControl.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
	this.searchReusePageControl.setText("Reuse &page in R Help view to show matches.");

	{ final Label label= new Label(group, SWT.NONE);
	label.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false));
	label.setText("Maximum preview &fragments:");

	final Text text= new Text(group, SWT.BORDER \| SWT.RIGHT);
	final GridData gd= new GridData(SWT.LEFT, SWT.CENTER, false, false);
	gd.widthHint= LayoutUtils.hintWidth(text, 5);
	text.setLayoutData(gd);

	this.searchMaxFragmentsControl= text;
	}

	return group;
	}

	@Override
	protected void addBindings(final DataBindingSupport db) {
	db.getContext().bindValue(
	new HomeObservable(db.getRealm()),
	createObservable(RHelpPreferences.HOMEPAGE_URL_PREF) );
	db.getContext().bindValue(
	WidgetProperties.buttonSelection()
	.observe(this.searchReusePageControl),
	createObservable(RHelpPreferences.SEARCH_REUSE_PAGE_ENABLED_PREF) );
	db.getContext().bindValue(
	WidgetProperties.text(SWT.Modify)
	.observe(this.searchMaxFragmentsControl),
	createObservable(RHelpPreferences.SEARCH_PREVIEW_FRAGMENTS_MAX_PREF),
	new UpdateValueStrategy<String, Integer>()
	.setAfterGetValidator(new IntegerValidator(1, 1000,
	"Invalid maximum for preview fragments specified (1-1000).")),
	null );
	}

	}