org.eclipse.ui.intro/src/org/eclipse/ui/internal/intro/impl/model/IntroPartPresentation.java - platform/eclipse.platform.ua - Git at Google

 /*******************************************************************************
  * Copyright (c) 2004, 2016 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.intro.impl.model;

 import java.util.ArrayList;
 import java.util.Map;
 import java.util.StringTokenizer;
 import java.util.Vector;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IRegistryChangeEvent;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.swt.SWTError;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.ui.IMemento;
 import org.eclipse.ui.internal.intro.impl.IntroPlugin;
 import org.eclipse.ui.internal.intro.impl.model.loader.ModelLoaderUtil;
 import org.eclipse.ui.internal.intro.impl.model.util.ModelUtil;
 import org.eclipse.ui.internal.intro.impl.presentations.BrowserIntroPartImplementation;
 import org.eclipse.ui.internal.intro.impl.presentations.FormIntroPartImplementation;
 import org.eclipse.ui.internal.intro.impl.presentations.TextIntroPartImplementation;
 import org.eclipse.ui.internal.intro.impl.util.Log;
 import org.eclipse.ui.internal.intro.impl.util.StringUtil;
 import org.eclipse.ui.intro.IIntroPart;

 /**
  * This class models the presentation element contributed to a config extension point. The
  * Presentation class delegates UI creation to the actual Implementation class, and passes the
  * IntroPart along to this implementation class. Also, dynamic awarness is honored here.
  * <p>
  * Rules:
  * <ul>
  * <li>There is no model class for the "implementation" markup element. This presentation class
  * inherits information from the implementation class that is picked (based on OS, ...).</li>
  * <li>ID attribute of this model class is the id of the picked implementation element.</li>
  * <li>Style attribute in this model class is the style of the picked implementation element.</li>
  * <li>HTMLHeadContent in this model class is the HEAD element under the picked implementation
  * element, only if the implementation element is a Browser implmenetation.</li>
  * <li>The UI model class, AbstractIntroPartImplementation, that represents the IntroPart
  * implementation is cached here for quick access. It is used by intro url actions for manipulation
  * of UI.<br>
  * INTRO:This really should be in a UI model class.
  * <ul>
  */
 public class IntroPartPresentation extends AbstractIntroElement {

 	protected static final String TAG_PRESENTATION = "presentation"; //$NON-NLS-1$
 	private static final String TAG_IMPLEMENTATION = "implementation"; //$NON-NLS-1$

 	private static final String ATT_KIND = "kind"; //$NON-NLS-1$
 	private static final String ATT_STYLE = "style"; //$NON-NLS-1$
 	private static final String ATT_OS = "os"; //$NON-NLS-1$
 	private static final String ATT_WS = "ws"; //$NON-NLS-1$
 	protected static final String ATT_HOME_PAGE_ID = "home-page-id"; //$NON-NLS-1$
 	protected static final String ATT_STANDBY_PAGE_ID = "standby-page-id"; //$NON-NLS-1$

 	public static final String BROWSER_IMPL_KIND = "html"; //$NON-NLS-1$
 	public static final String FORMS_IMPL_KIND = "swt"; //$NON-NLS-1$
 	// this implementation kind if not public api. Only used internally for
 	// debugging.
 	private static final String TEXT_IMPL_KIND = "text"; //$NON-NLS-1$


 	// private String title;
 	private String [] implementationStyles;
 	private String implementationKind;
 	private String homePageId;
 	private String standbyPageId;

 	// The Head contributions to this preentation (inherited from child
 	// implementation).
 	private IntroHead head;

 	private AbstractIntroPartImplementation implementation;

 	private IntroLaunchBarElement launchBar;

 	// CustomizableIntroPart and memento instances. Passed to the Implementation
 	// classes.
 	private IIntroPart introPart;
 	private IMemento memento;

 	/**
 	 *
 	 */
 	IntroPartPresentation(IConfigurationElement element) {
 		super(element);
 		homePageId = element.getAttribute(ATT_HOME_PAGE_ID);
 		standbyPageId = element.getAttribute(ATT_STANDBY_PAGE_ID);
 	}

 	private void updatePresentationAttributes(IConfigurationElement element) {
 		if (element != null) {
 			// reset (ie: inherit) type and style to be implementation type and
 			// style. Then handle HEAD content for the case of HTML Browser.
 			String value = element.getAttribute(ATT_STYLE);
 			if (value!=null) {
 				IntroModelRoot root = getModelRoot();
 				ArrayList<String> list = new ArrayList<>();
 				StringTokenizer stok = new StringTokenizer(value, ","); //$NON-NLS-1$
 				for (;stok.hasMoreTokens();) {
 					String oneStyle = stok.nextToken().trim();
 					if (root!=null)
 						oneStyle = root.resolveVariables(oneStyle);
 					list.add(oneStyle);
 				}
 				implementationStyles = (String[])list.toArray(new String[list.size()]);
 			}
 			implementationKind = element.getAttribute(ATT_KIND);
 			// get Head contribution, regardless of implementation class.
 			// Implementation class is created lazily by UI.
 			head = getHead(element);
 			// Resolve.
 			if (implementationStyles!=null) {
 				for (int i=0; i<implementationStyles.length; i++) {
 					implementationStyles[i] = ModelUtil.resolveURL(implementationStyles[i], element);
 				}
 			}
 		}
 	}

 	/**
 	 * Returns the styles associated with the Presentation. May be null if no shared presentation
 	 * style is needed, or in the case of static HTML OOBE.
 	 *
 	 * @return Returns the array of styles or null if not defined.
 	 */
 	public String[] getImplementationStyles() {
 		return implementationStyles;
 	}

 	/**
 	 * Returns the type attribute of the implementation picked by this presentation.
 	 *
 	 * @return Returns the implementationKind.
 	 */
 	public String getImplementationKind() {
 		return implementationKind;
 	}

 	public AbstractIntroPartImplementation getIntroPartImplementation() {
 		return implementation;
 	}


 	/**
 	 * Returns the model class for the Head element under an implementation. Returns null if there
 	 * is no head contribution.
 	 *
 	 * @param element
 	 * @return
 	 */
 	private IntroHead getHead(IConfigurationElement element) {
 		try {
 			// There should only be one head element. Since elements where
 			// obtained by name, no point validating name.
 			IConfigurationElement[] headElements = element.getChildren(IntroHead.TAG_HEAD);
 			if (headElements.length == 0)
 				// no contributions. done.
 				return null;
 			IntroHead head = new IntroHead(headElements[0]);
 			head.setParent(this);
 			return head;
 		} catch (Exception e) {
 			Log.error(e.getMessage(), e);
 			return null;
 		}
 	}

 	/**
 	 * Returns the launch bar element if defined in this presentation, or <code>null</code>
 	 * otherwise.
 	 *
 	 * @since 3.1
 	 * @return
 	 */

 	public IntroLaunchBarElement getLaunchBarElement() {
 		if (launchBar != null)
 			return launchBar;
 		IConfigurationElement[] children = getCfgElement().getChildren("launchBar"); //$NON-NLS-1$
 		if (children.length > 0) {
 			launchBar = new IntroLaunchBarElement(children[0]);
 			launchBar.setParent(this);
 			if (children.length > 1)
 				Log
 						.warning("Mutiple Intro Launch bars defined when only one is allowed. Only first one was loaded. "); //$NON-NLS-1$
 		}
 		return launchBar;
 	}

 	/**
 	 * @param introPart
 	 */
 	public void init(IIntroPart introPart, IMemento memento) {
 		// REVISIT: Called when the actual UI needs to be created. Incomplete
 		// separation of model / UI. Will change later. should not get here if
 		// there is no valid implementation.
 		this.introPart = introPart;
 		this.memento = memento;
 	}

 	/**
 	 * Creates the UI based on the implementation class.
 	 *
 	 * @see org.eclipse.ui.IWorkbenchPart#createPartControl(org.eclipse.swt.widgets.Composite)
 	 */
 	public void createPartControl(Composite parent) {
 		Vector validImplementations = getValidImplementationElements(getCfgElement());
 		IConfigurationElement implementationElement = null;
 		for (int i = 0; i < validImplementations.size(); i++) {
 			implementationElement = (IConfigurationElement) validImplementations.elementAt(i);
 			// you want to pass primed model.
 			updatePresentationAttributes(implementationElement);
 			try {
 				implementation = createIntroPartImplementation(getImplementationKind());
 				if (implementation == null)
 					// failed to create executable.
 					continue;

 				implementation.init(introPart, memento);
 				implementation.createPartControl(parent);
 				IntroModelRoot model = getModelRoot();
 				if (model != null && model.getConfigurer() != null) {
 					IntroTheme theme = model.getTheme();
 					Map<String, String> properties = theme != null ? theme.getProperties() : null;
 					model.getConfigurer().init(introPart.getIntroSite(), properties);
 				}
 				if (Log.logInfo)
 					Log.info("Loading Intro UI implementation from: " //$NON-NLS-1$
 							+ ModelLoaderUtil.getLogString(implementationElement, "kind")); //$NON-NLS-1$
 				break;
 			} catch (SWTError e) {
 				Log.warning("Failed to create Intro UI implementation from: " //$NON-NLS-1$
 						+ ModelLoaderUtil.getLogString(implementationElement, "kind") + e.getMessage()); //$NON-NLS-1$
 				implementation = null;
 				implementationElement = null;
 			} catch (Exception e) {
 				Log.error("Failed to create Intro UI implementation from: " //$NON-NLS-1$
 						+ ModelLoaderUtil.getLogString(implementationElement, "kind"), e); //$NON-NLS-1$
 				implementation = null;
 				implementationElement = null;
 			}
 		}

 		if (implementationElement == null) {
 			// worst case scenario. We failed in all cases.
 			implementation = new FormIntroPartImplementation();
 			try {
 				implementation.init(introPart, memento);
 				// simply set the presentation kind since all other attributes
 				// will be null.
 				implementationKind = FORMS_IMPL_KIND;
 			} catch (Exception e) {
 				// should never be here.
 				Log.error(e.getMessage(), e);
 				return;
 			}
 			implementation.createPartControl(parent);
 			Log.warning("Loaded UI Forms implementation as a default UI implementation."); //$NON-NLS-1$
 		}
 	}

 	/**
 	 * Retruns a list of valid implementation elements of the config. Choose correct implementation
 	 * element based on os atrributes. Rules: get current OS, choose first contributrion, with os
 	 * that matches OS. Otherwise, choose first contribution with no os. Returns null if no valid
 	 * implementation is found.
 	 */
 	private Vector getValidImplementationElements(IConfigurationElement configElement) {

 		Vector<IConfigurationElement> validList = new Vector<>();

 		// There can be more than one implementation contribution. Add each
 		// valid one. First start with OS, then WS then no OS.
 		IConfigurationElement[] implementationElements = configElement.getChildren(TAG_IMPLEMENTATION);
 		// IConfigurationElement implementationElement = null;

 		if (implementationElements.length == 0)
 			// no contributions. done.
 			return validList;

 		String currentOS = Platform.getOS();
 		String currentWS = Platform.getWS();

 		// first loop through all to find one with matching OS, with or
 		// without WS.
 		for (int i = 0; i < implementationElements.length; i++) {
 			String os = implementationElements[i].getAttribute(ATT_OS);
 			if (os == null)
 				// no os, no match.
 				continue;

 			if (listValueHasValue(os, currentOS)) {
 				// found implementation with correct OS. Now try if WS
 				// matches.
 				String ws = implementationElements[i].getAttribute(ATT_WS);
 				if (ws == null) {
 					// good OS, and they do not care about WS. we have a
 					// match.
 					validList.add(implementationElements[i]);
 				} else {
 					// good OS, and we have WS.
 					if (listValueHasValue(ws, currentWS))
 						validList.add(implementationElements[i]);
 				}
 			}
 		}

 		// now loop through all to find one with no OS defined, but with a
 		// matching WS.
 		for (int i = 0; i < implementationElements.length; i++) {
 			String os = implementationElements[i].getAttribute(ATT_OS);
 			if (os == null) {
 				// found implementation with no OS. Now try if WS
 				// matches.
 				String ws = implementationElements[i].getAttribute(ATT_WS);
 				if (ws == null) {
 					// no OS, and they do not care about WS. we have a
 					// match.
 					validList.add(implementationElements[i]);
 				} else {
 					// no OS, and we have WS.
 					if (listValueHasValue(ws, currentWS))
 						validList.add(implementationElements[i]);
 				}

 			}
 		}

 		return validList;

 	}

 	/**
 	 * Util method that searches for the given value in a comma separated list of values. The list
 	 * is retrieved as an attribute value of OS, WS.
 	 *
 	 */
 	private boolean listValueHasValue(String stringValue, String value) {
 		String[] attributeValues = StringUtil.split(stringValue, ","); //$NON-NLS-1$
 		for (int i = 0; i < attributeValues.length; i++) {
 			if (attributeValues[i].equalsIgnoreCase(value))
 				return true;
 		}
 		return false;
 	}

 	/**
 	 * Util method to load shared style from given kind.
 	 */
 	public String getSharedStyle(String kind) {
 		// There can be more than one implementation contribution.
 		IConfigurationElement[] implementationElements = getCfgElement().getChildren(TAG_IMPLEMENTATION);
 		// IConfigurationElement implementationElement = null;

 		if (implementationElements.length == 0)
 			// no implementations. done.
 			return null;

 		// loop through all to find one with matching kind.
 		for (int i = 0; i < implementationElements.length; i++) {
 			String aKind = implementationElements[i].getAttribute(ATT_KIND);
 			if (aKind.equals(kind)) {
 				// found implementation with matching kind.
 				String style = implementationElements[i].getAttribute(ATT_STYLE);
 				return ModelUtil.resolveURL(style, getCfgElement());
 			}
 		}
 		return null;
 	}


 	/**
 	 * Creates the actual implementation class. Returns null on failure.
 	 *
 	 */
 	private AbstractIntroPartImplementation createIntroPartImplementation(String implementationType) {
 		// quick exits
 		if (implementationType == null)
 			return null;
 		if (!implementationType.equals(BROWSER_IMPL_KIND) && !implementationType.equals(FORMS_IMPL_KIND)
 				&& !implementationType.equals(TEXT_IMPL_KIND))
 			return null;
 		if (implementationType.equals(BROWSER_IMPL_KIND) && IntroPlugin.DEBUG_NO_BROWSER)
 			return null;

 		AbstractIntroPartImplementation implementation = null;
 		try {
 			if (implementationType.equals(BROWSER_IMPL_KIND))
 				implementation = //null;
 			      new BrowserIntroPartImplementation();
 			else if (implementationType.equals(FORMS_IMPL_KIND))
 				implementation = new FormIntroPartImplementation();
 			else
 				implementation = new TextIntroPartImplementation();
 		} catch (Exception e) {
 			Log.error("Could not instantiate implementation " //$NON-NLS-1$
 					+ implementationType, e);
 		}
 		return implementation;
 	}

 	/**
 	 * Returns the the Customizable Intro Part. may return null if init() has not been called yet on
 	 * the presentation.
 	 *
 	 * @return Returns the introPart.
 	 */
 	public IIntroPart getIntroPart() {
 		return introPart;
 	}

 	/**
 	 * Save the current state of the intro. Delegate to the implementation to do the work, as
 	 * different implementations may have different requirements.
 	 *
 	 * @param memento
 	 *            the memento in which to store state information
 	 */
 	public void saveState(IMemento memento) {
 		if (implementation != null)
 			implementation.saveState(memento);
 	}


 	public void setFocus() {
 		if (implementation != null)
 			implementation.setFocus();
 	}

 	public void standbyStateChanged(boolean standby, boolean isStandbyPartNeeded) {
 		if (implementation != null)
 			implementation.standbyStateChanged(standby, isStandbyPartNeeded);
 	}

 	public void updateHistory(AbstractIntroPage page) {
 		if (implementation != null)
 			implementation.updateHistory(page);
 	}


 	public boolean navigateForward() {
 		if (implementation != null)
 			return implementation.navigateForward();
 		return false;
 	}

 	public boolean navigateBackward() {
 		if (implementation != null)
 			return implementation.navigateBackward();
 		return false;
 	}

 	public boolean navigateHome() {
 		if (implementation != null)
 			return implementation.navigateHome();
 		return false;
 	}


 	/**
 	 * Called when the IntroPart is disposed. Forwards the call to the implementation class.
 	 */
 	public void dispose() {
 		if (implementation != null)
 			implementation.dispose();
 	}

 	/**
 	 * Support dynamic awarness. Clear cached models first, then update UI by delegating to
 	 * implementation.
 	 *
 	 * @see org.eclipse.core.runtime.IRegistryChangeListener#registryChanged(org.eclipse.core.runtime.IRegistryChangeEvent)
 	 */
 	public void registryChanged(IRegistryChangeEvent event) {
 		if (implementation != null)
 			implementation.registryChanged(event);
 	}

 	/**
 	 * @return Returns the homePageId.
 	 */
 	public String getHomePageId() {
 		return homePageId;
 	}

 	/**
 	 * @return Returns the homePageId.
 	 */
 	public String getStandbyPageId() {
 		return standbyPageId;
 	}

 	@Override
 	public int getType() {
 		return AbstractIntroElement.PRESENTATION;
 	}

 	/**
 	 * @return Returns the HTML head conttent to be added to each dynamic html page in this
 	 *         presentation..
 	 */
 	public IntroHead getHead() {
 		return head;
 	}


 }
	/*******************************************************************************
	* Copyright (c) 2004, 2016 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.ui.internal.intro.impl.model;

	import java.util.ArrayList;
	import java.util.Map;
	import java.util.StringTokenizer;
	import java.util.Vector;

	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IRegistryChangeEvent;
	import org.eclipse.core.runtime.Platform;
	import org.eclipse.swt.SWTError;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.ui.IMemento;
	import org.eclipse.ui.internal.intro.impl.IntroPlugin;
	import org.eclipse.ui.internal.intro.impl.model.loader.ModelLoaderUtil;
	import org.eclipse.ui.internal.intro.impl.model.util.ModelUtil;
	import org.eclipse.ui.internal.intro.impl.presentations.BrowserIntroPartImplementation;
	import org.eclipse.ui.internal.intro.impl.presentations.FormIntroPartImplementation;
	import org.eclipse.ui.internal.intro.impl.presentations.TextIntroPartImplementation;
	import org.eclipse.ui.internal.intro.impl.util.Log;
	import org.eclipse.ui.internal.intro.impl.util.StringUtil;
	import org.eclipse.ui.intro.IIntroPart;

	/**
	* This class models the presentation element contributed to a config extension point. The
	* Presentation class delegates UI creation to the actual Implementation class, and passes the
	* IntroPart along to this implementation class. Also, dynamic awarness is honored here.
	* <p>
	* Rules:
	* <ul>
	* <li>There is no model class for the "implementation" markup element. This presentation class
	* inherits information from the implementation class that is picked (based on OS, ...).</li>
	* <li>ID attribute of this model class is the id of the picked implementation element.</li>
	* <li>Style attribute in this model class is the style of the picked implementation element.</li>
	* <li>HTMLHeadContent in this model class is the HEAD element under the picked implementation
	* element, only if the implementation element is a Browser implmenetation.</li>
	* <li>The UI model class, AbstractIntroPartImplementation, that represents the IntroPart
	* implementation is cached here for quick access. It is used by intro url actions for manipulation
	* of UI.<br>
	* INTRO:This really should be in a UI model class.
	* <ul>
	*/
	public class IntroPartPresentation extends AbstractIntroElement {

	protected static final String TAG_PRESENTATION = "presentation"; //$NON-NLS-1$
	private static final String TAG_IMPLEMENTATION = "implementation"; //$NON-NLS-1$

	private static final String ATT_KIND = "kind"; //$NON-NLS-1$
	private static final String ATT_STYLE = "style"; //$NON-NLS-1$
	private static final String ATT_OS = "os"; //$NON-NLS-1$
	private static final String ATT_WS = "ws"; //$NON-NLS-1$
	protected static final String ATT_HOME_PAGE_ID = "home-page-id"; //$NON-NLS-1$
	protected static final String ATT_STANDBY_PAGE_ID = "standby-page-id"; //$NON-NLS-1$

	public static final String BROWSER_IMPL_KIND = "html"; //$NON-NLS-1$
	public static final String FORMS_IMPL_KIND = "swt"; //$NON-NLS-1$
	// this implementation kind if not public api. Only used internally for
	// debugging.
	private static final String TEXT_IMPL_KIND = "text"; //$NON-NLS-1$


	// private String title;
	private String [] implementationStyles;
	private String implementationKind;
	private String homePageId;
	private String standbyPageId;

	// The Head contributions to this preentation (inherited from child
	// implementation).
	private IntroHead head;

	private AbstractIntroPartImplementation implementation;

	private IntroLaunchBarElement launchBar;

	// CustomizableIntroPart and memento instances. Passed to the Implementation
	// classes.
	private IIntroPart introPart;
	private IMemento memento;

	/**
	*
	*/
	IntroPartPresentation(IConfigurationElement element) {
	super(element);
	homePageId = element.getAttribute(ATT_HOME_PAGE_ID);
	standbyPageId = element.getAttribute(ATT_STANDBY_PAGE_ID);
	}

	private void updatePresentationAttributes(IConfigurationElement element) {
	if (element != null) {
	// reset (ie: inherit) type and style to be implementation type and
	// style. Then handle HEAD content for the case of HTML Browser.
	String value = element.getAttribute(ATT_STYLE);
	if (value!=null) {
	IntroModelRoot root = getModelRoot();
	ArrayList<String> list = new ArrayList<>();
	StringTokenizer stok = new StringTokenizer(value, ","); //$NON-NLS-1$
	for (;stok.hasMoreTokens();) {
	String oneStyle = stok.nextToken().trim();
	if (root!=null)
	oneStyle = root.resolveVariables(oneStyle);
	list.add(oneStyle);
	}
	implementationStyles = (String[])list.toArray(new String[list.size()]);
	}
	implementationKind = element.getAttribute(ATT_KIND);
	// get Head contribution, regardless of implementation class.
	// Implementation class is created lazily by UI.
	head = getHead(element);
	// Resolve.
	if (implementationStyles!=null) {
	for (int i=0; i<implementationStyles.length; i++) {
	implementationStyles[i] = ModelUtil.resolveURL(implementationStyles[i], element);
	}
	}
	}
	}

	/**
	* Returns the styles associated with the Presentation. May be null if no shared presentation
	* style is needed, or in the case of static HTML OOBE.
	*
	* @return Returns the array of styles or null if not defined.
	*/
	public String[] getImplementationStyles() {
	return implementationStyles;
	}

	/**
	* Returns the type attribute of the implementation picked by this presentation.
	*
	* @return Returns the implementationKind.
	*/
	public String getImplementationKind() {
	return implementationKind;
	}

	public AbstractIntroPartImplementation getIntroPartImplementation() {
	return implementation;
	}


	/**
	* Returns the model class for the Head element under an implementation. Returns null if there
	* is no head contribution.
	*
	* @param element
	* @return
	*/
	private IntroHead getHead(IConfigurationElement element) {
	try {
	// There should only be one head element. Since elements where
	// obtained by name, no point validating name.
	IConfigurationElement[] headElements = element.getChildren(IntroHead.TAG_HEAD);
	if (headElements.length == 0)
	// no contributions. done.
	return null;
	IntroHead head = new IntroHead(headElements[0]);
	head.setParent(this);
	return head;
	} catch (Exception e) {
	Log.error(e.getMessage(), e);
	return null;
	}
	}

	/**
	* Returns the launch bar element if defined in this presentation, or <code>null</code>
	* otherwise.
	*
	* @since 3.1
	* @return
	*/

	public IntroLaunchBarElement getLaunchBarElement() {
	if (launchBar != null)
	return launchBar;
	IConfigurationElement[] children = getCfgElement().getChildren("launchBar"); //$NON-NLS-1$
	if (children.length > 0) {
	launchBar = new IntroLaunchBarElement(children[0]);
	launchBar.setParent(this);
	if (children.length > 1)
	Log
	.warning("Mutiple Intro Launch bars defined when only one is allowed. Only first one was loaded. "); //$NON-NLS-1$
	}
	return launchBar;
	}

	/**
	* @param introPart
	*/
	public void init(IIntroPart introPart, IMemento memento) {
	// REVISIT: Called when the actual UI needs to be created. Incomplete
	// separation of model / UI. Will change later. should not get here if
	// there is no valid implementation.
	this.introPart = introPart;
	this.memento = memento;
	}

	/**
	* Creates the UI based on the implementation class.
	*
	* @see org.eclipse.ui.IWorkbenchPart#createPartControl(org.eclipse.swt.widgets.Composite)
	*/
	public void createPartControl(Composite parent) {
	Vector validImplementations = getValidImplementationElements(getCfgElement());
	IConfigurationElement implementationElement = null;
	for (int i = 0; i < validImplementations.size(); i++) {
	implementationElement = (IConfigurationElement) validImplementations.elementAt(i);
	// you want to pass primed model.
	updatePresentationAttributes(implementationElement);
	try {
	implementation = createIntroPartImplementation(getImplementationKind());
	if (implementation == null)
	// failed to create executable.
	continue;

	implementation.init(introPart, memento);
	implementation.createPartControl(parent);
	IntroModelRoot model = getModelRoot();
	if (model != null && model.getConfigurer() != null) {
	IntroTheme theme = model.getTheme();
	Map<String, String> properties = theme != null ? theme.getProperties() : null;
	model.getConfigurer().init(introPart.getIntroSite(), properties);
	}
	if (Log.logInfo)
	Log.info("Loading Intro UI implementation from: " //$NON-NLS-1$
	+ ModelLoaderUtil.getLogString(implementationElement, "kind")); //$NON-NLS-1$
	break;
	} catch (SWTError e) {
	Log.warning("Failed to create Intro UI implementation from: " //$NON-NLS-1$
	+ ModelLoaderUtil.getLogString(implementationElement, "kind") + e.getMessage()); //$NON-NLS-1$
	implementation = null;
	implementationElement = null;
	} catch (Exception e) {
	Log.error("Failed to create Intro UI implementation from: " //$NON-NLS-1$
	+ ModelLoaderUtil.getLogString(implementationElement, "kind"), e); //$NON-NLS-1$
	implementation = null;
	implementationElement = null;
	}
	}

	if (implementationElement == null) {
	// worst case scenario. We failed in all cases.
	implementation = new FormIntroPartImplementation();
	try {
	implementation.init(introPart, memento);
	// simply set the presentation kind since all other attributes
	// will be null.
	implementationKind = FORMS_IMPL_KIND;
	} catch (Exception e) {
	// should never be here.
	Log.error(e.getMessage(), e);
	return;
	}
	implementation.createPartControl(parent);
	Log.warning("Loaded UI Forms implementation as a default UI implementation."); //$NON-NLS-1$
	}
	}

	/**
	* Retruns a list of valid implementation elements of the config. Choose correct implementation
	* element based on os atrributes. Rules: get current OS, choose first contributrion, with os
	* that matches OS. Otherwise, choose first contribution with no os. Returns null if no valid
	* implementation is found.
	*/
	private Vector getValidImplementationElements(IConfigurationElement configElement) {

	Vector<IConfigurationElement> validList = new Vector<>();

	// There can be more than one implementation contribution. Add each
	// valid one. First start with OS, then WS then no OS.
	IConfigurationElement[] implementationElements = configElement.getChildren(TAG_IMPLEMENTATION);
	// IConfigurationElement implementationElement = null;

	if (implementationElements.length == 0)
	// no contributions. done.
	return validList;

	String currentOS = Platform.getOS();
	String currentWS = Platform.getWS();

	// first loop through all to find one with matching OS, with or
	// without WS.
	for (int i = 0; i < implementationElements.length; i++) {
	String os = implementationElements[i].getAttribute(ATT_OS);
	if (os == null)
	// no os, no match.
	continue;

	if (listValueHasValue(os, currentOS)) {
	// found implementation with correct OS. Now try if WS
	// matches.
	String ws = implementationElements[i].getAttribute(ATT_WS);
	if (ws == null) {
	// good OS, and they do not care about WS. we have a
	// match.
	validList.add(implementationElements[i]);
	} else {
	// good OS, and we have WS.
	if (listValueHasValue(ws, currentWS))
	validList.add(implementationElements[i]);
	}
	}
	}

	// now loop through all to find one with no OS defined, but with a
	// matching WS.
	for (int i = 0; i < implementationElements.length; i++) {
	String os = implementationElements[i].getAttribute(ATT_OS);
	if (os == null) {
	// found implementation with no OS. Now try if WS
	// matches.
	String ws = implementationElements[i].getAttribute(ATT_WS);
	if (ws == null) {
	// no OS, and they do not care about WS. we have a
	// match.
	validList.add(implementationElements[i]);
	} else {
	// no OS, and we have WS.
	if (listValueHasValue(ws, currentWS))
	validList.add(implementationElements[i]);
	}

	}
	}

	return validList;

	}

	/**
	* Util method that searches for the given value in a comma separated list of values. The list
	* is retrieved as an attribute value of OS, WS.
	*
	*/
	private boolean listValueHasValue(String stringValue, String value) {
	String[] attributeValues = StringUtil.split(stringValue, ","); //$NON-NLS-1$
	for (int i = 0; i < attributeValues.length; i++) {
	if (attributeValues[i].equalsIgnoreCase(value))
	return true;
	}
	return false;
	}

	/**
	* Util method to load shared style from given kind.
	*/
	public String getSharedStyle(String kind) {
	// There can be more than one implementation contribution.
	IConfigurationElement[] implementationElements = getCfgElement().getChildren(TAG_IMPLEMENTATION);
	// IConfigurationElement implementationElement = null;

	if (implementationElements.length == 0)
	// no implementations. done.
	return null;

	// loop through all to find one with matching kind.
	for (int i = 0; i < implementationElements.length; i++) {
	String aKind = implementationElements[i].getAttribute(ATT_KIND);
	if (aKind.equals(kind)) {
	// found implementation with matching kind.
	String style = implementationElements[i].getAttribute(ATT_STYLE);
	return ModelUtil.resolveURL(style, getCfgElement());
	}
	}
	return null;
	}


	/**
	* Creates the actual implementation class. Returns null on failure.
	*
	*/
	private AbstractIntroPartImplementation createIntroPartImplementation(String implementationType) {
	// quick exits
	if (implementationType == null)
	return null;
	if (!implementationType.equals(BROWSER_IMPL_KIND) && !implementationType.equals(FORMS_IMPL_KIND)
	&& !implementationType.equals(TEXT_IMPL_KIND))
	return null;
	if (implementationType.equals(BROWSER_IMPL_KIND) && IntroPlugin.DEBUG_NO_BROWSER)
	return null;

	AbstractIntroPartImplementation implementation = null;
	try {
	if (implementationType.equals(BROWSER_IMPL_KIND))
	implementation = //null;
	new BrowserIntroPartImplementation();
	else if (implementationType.equals(FORMS_IMPL_KIND))
	implementation = new FormIntroPartImplementation();
	else
	implementation = new TextIntroPartImplementation();
	} catch (Exception e) {
	Log.error("Could not instantiate implementation " //$NON-NLS-1$
	+ implementationType, e);
	}
	return implementation;
	}

	/**
	* Returns the the Customizable Intro Part. may return null if init() has not been called yet on
	* the presentation.
	*
	* @return Returns the introPart.
	*/
	public IIntroPart getIntroPart() {
	return introPart;
	}

	/**
	* Save the current state of the intro. Delegate to the implementation to do the work, as
	* different implementations may have different requirements.
	*
	* @param memento
	* the memento in which to store state information
	*/
	public void saveState(IMemento memento) {
	if (implementation != null)
	implementation.saveState(memento);
	}


	public void setFocus() {
	if (implementation != null)
	implementation.setFocus();
	}

	public void standbyStateChanged(boolean standby, boolean isStandbyPartNeeded) {
	if (implementation != null)
	implementation.standbyStateChanged(standby, isStandbyPartNeeded);
	}

	public void updateHistory(AbstractIntroPage page) {
	if (implementation != null)
	implementation.updateHistory(page);
	}



	public boolean navigateForward() {
	if (implementation != null)
	return implementation.navigateForward();
	return false;
	}

	public boolean navigateBackward() {
	if (implementation != null)
	return implementation.navigateBackward();
	return false;
	}

	public boolean navigateHome() {
	if (implementation != null)
	return implementation.navigateHome();
	return false;
	}


	/**
	* Called when the IntroPart is disposed. Forwards the call to the implementation class.
	*/
	public void dispose() {
	if (implementation != null)
	implementation.dispose();
	}

	/**
	* Support dynamic awarness. Clear cached models first, then update UI by delegating to
	* implementation.
	*
	* @see org.eclipse.core.runtime.IRegistryChangeListener#registryChanged(org.eclipse.core.runtime.IRegistryChangeEvent)
	*/
	public void registryChanged(IRegistryChangeEvent event) {
	if (implementation != null)
	implementation.registryChanged(event);
	}

	/**
	* @return Returns the homePageId.
	*/
	public String getHomePageId() {
	return homePageId;
	}

	/**
	* @return Returns the homePageId.
	*/
	public String getStandbyPageId() {
	return standbyPageId;
	}

	@Override
	public int getType() {
	return AbstractIntroElement.PRESENTATION;
	}

	/**
	* @return Returns the HTML head conttent to be added to each dynamic html page in this
	* presentation..
	*/
	public IntroHead getHead() {
	return head;
	}




	}