org.eclipse.jface.text/src/org/eclipse/jface/text/information/InformationPresenter.java - platform/eclipse.platform.text - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jface.text.information;

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

 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.events.ControlEvent;
 import org.eclipse.swt.events.ControlListener;
 import org.eclipse.swt.events.FocusEvent;
 import org.eclipse.swt.events.FocusListener;
 import org.eclipse.swt.events.KeyEvent;
 import org.eclipse.swt.events.KeyListener;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.MouseListener;
 import org.eclipse.swt.graphics.GC;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;

 import org.eclipse.jface.text.AbstractInformationControlManager;
 import org.eclipse.jface.text.Assert;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.IDocumentExtension3;
 import org.eclipse.jface.text.IInformationControl;
 import org.eclipse.jface.text.IInformationControlCreator;
 import org.eclipse.jface.text.IRegion;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.ITextViewerExtension5;
 import org.eclipse.jface.text.IViewportListener;
 import org.eclipse.jface.text.IWidgetTokenKeeper;
 import org.eclipse.jface.text.IWidgetTokenKeeperExtension;
 import org.eclipse.jface.text.IWidgetTokenOwner;
 import org.eclipse.jface.text.IWidgetTokenOwnerExtension;
 import org.eclipse.jface.text.Region;
 import org.eclipse.jface.text.TextUtilities;


 /**
  * Standard implementation of <code>IInformationPresenter</code>.
  * This implementation extends <code>AbstractInformationControlManager</code>.
  * The information control is made visible on request by calling
  * <code>showInformation</code>.<p>
  * Usually, clients instantiate this class and configure it before using it. The configuration
  * must be consistent: This means the used <code>IInformationControlCreator</code>
  * must create an information control expecting information in the same format the configured
  * <code>IInformationProvider</code>s  use to encode the information they provide.
  *
  * @since 2.0
  */
 public class InformationPresenter extends AbstractInformationControlManager implements IInformationPresenter, IInformationPresenterExtension, IWidgetTokenKeeper, IWidgetTokenKeeperExtension {


 	/**
 	 * Priority of the info controls managed by this information presenter.
 	 * Default value: <code>5</code> in order to beat the hovers of <code>TextViewerHoverManager</code>
 	 * @since 3.0
 	 */
 	public static final int WIDGET_PRIORITY= 5;


 	/**
 	 * Internal information control closer. Listens to several events issued by its subject control
 	 * and closes the information control when necessary.
 	 */
 	class Closer implements IInformationControlCloser, ControlListener, MouseListener, FocusListener, IViewportListener, KeyListener {

 		/** The subject control */
 		private Control fSubjectControl;
 		/** The information control */
 		private IInformationControl fInformationControl;
 		/** Indicates whether this closer is active */
 		private boolean fIsActive= false;

 		/*
 		 * @see IInformationControlCloser#setSubjectControl(Control)
 		 */
 		public void setSubjectControl(Control control) {
 			fSubjectControl= control;
 		}

 		/*
 		 * @see IInformationControlCloser#setInformationControl(IInformationControl)
 		 */
 		public void setInformationControl(IInformationControl control) {
 			fInformationControl= control;
 		}

 		/*
 		 * @see IInformationControlCloser#start(Rectangle)
 		 */
 		public void start(Rectangle informationArea) {

 			if (fIsActive)
 				return;
 			fIsActive= true;

 			if (fSubjectControl != null && ! fSubjectControl.isDisposed()) {
 				fSubjectControl.addControlListener(this);
 				fSubjectControl.addMouseListener(this);
 				fSubjectControl.addFocusListener(this);
 				fSubjectControl.addKeyListener(this);
 			}

 			if (fInformationControl != null)
 				fInformationControl.addFocusListener(this);

 			fTextViewer.addViewportListener(this);
 		}

 		/*
 		 * @see IInformationControlCloser#stop()
 		 */
 		public void stop() {

 			if (!fIsActive)
 				return;
 			fIsActive= false;

 			fTextViewer.removeViewportListener(this);

 			if (fInformationControl != null)
 				fInformationControl.removeFocusListener(this);

 			hideInformationControl();

 			if (fSubjectControl != null && !fSubjectControl.isDisposed()) {
 				fSubjectControl.removeControlListener(this);
 				fSubjectControl.removeMouseListener(this);
 				fSubjectControl.removeFocusListener(this);
 				fSubjectControl.removeKeyListener(this);
 			}
 		}

 		/*
 		 * @see ControlListener#controlResized(ControlEvent)
 		 */
 		 public void controlResized(ControlEvent e) {
 			stop();
 		}

 		/*
 		 * @see ControlListener#controlMoved(ControlEvent)
 		 */
 		 public void controlMoved(ControlEvent e) {
 			stop();
 		}

 		/*
 		 * @see MouseListener#mouseDown(MouseEvent)
 		 */
 		 public void mouseDown(MouseEvent e) {
 			stop();
 		}

 		/*
 		 * @see MouseListener#mouseUp(MouseEvent)
 		 */
 		public void mouseUp(MouseEvent e) {
 		}

 		/*
 		 * @see MouseListener#mouseDoubleClick(MouseEvent)
 		 */
 		public void mouseDoubleClick(MouseEvent e) {
 			stop();
 		}

 		/*
 		 * @see FocusListener#focusGained(FocusEvent)
 		 */
 		public void focusGained(FocusEvent e) {
 		}

 		/*
 		 * @see FocusListener#focusLost(FocusEvent)
 		 */
 		 public void focusLost(FocusEvent e) {
 			Display d= fSubjectControl.getDisplay();
 			d.asyncExec(new Runnable() {
 				public void run() {
 					if (fInformationControl == null || !fInformationControl.isFocusControl())
 						stop();
 				}
 			});
 		}

 		/*
 		 * @see IViewportListenerListener#viewportChanged(int)
 		 */
 		public void viewportChanged(int topIndex) {
 			stop();
 		}

 		/*
 		 * @see KeyListener#keyPressed(KeyEvent)
 		 */
 		public void keyPressed(KeyEvent e) {
 			stop();
 		}

 		/*
 		 * @see KeyListener#keyReleased(KeyEvent)
 		 */
 		public void keyReleased(KeyEvent e) {
 		}
 	}


 	/** The text viewer this information presenter works on */
 	private ITextViewer fTextViewer;
 	/** The map of <code>IInformationProvider</code> objects */
 	private Map fProviders;
 	/** The offset to override selection. */
 	private int fOffset= -1;
 	/**
 	 * The document partitioning for this information presenter.
 	 * @since 3.0
 	 */
 	private String fPartitioning;

 	/**
 	 * Creates a new information presenter that uses the given information control creator.
 	 * The presenter is not installed on any text viewer yet. By default, an information
 	 * control closer is set that closes the information control in the event of key strokes,
 	 * resizing, moves, focus changes, mouse clicks, and disposal - all of those applied to
 	 * the information control's parent control. Also, the setup ensures that the information
 	 * control when made visible will request thel focus. By default, the default document
 	 * partitioning <code>IDocumentExtension3.DEFAULT_PARTITIONING</code> is used.
 	 *
 	 * @param creator the information control creator to be used
 	 */
 	public InformationPresenter(IInformationControlCreator creator) {
 		super(creator);
 		setCloser(new Closer());
 		takesFocusWhenVisible(true);
 		fPartitioning= IDocumentExtension3.DEFAULT_PARTITIONING;
 	}

 	/**
 	 * Sets the document partitioning to be used by this information presenter.
 	 *
 	 * @param partitioning the document partitioning to be used by this information presenter
 	 * @since 3.0
 	 */
 	public void setDocumentPartitioning(String partitioning) {
 		Assert.isNotNull(partitioning);
 		fPartitioning= partitioning;
 	}

 	/*
 	 * @see org.eclipse.jface.text.information.IInformationPresenterExtension#getDocumentPartitioning()
 	 * @since 3.0
 	 */
 	public String getDocumentPartitioning() {
 		return fPartitioning;
 	}

 	/**
 	 * Registers a given information provider for a particular content type.
 	 * If there is already a provider registered for this type, the new provider
 	 * is registered instead of the old one.
 	 *
 	 * @param provider the information provider to register, or <code>null</code> to remove an existing one
 	 * @param contentType the content type under which to register
 	 */
 	 public void setInformationProvider(IInformationProvider provider, String contentType) {

 		Assert.isNotNull(contentType);

 		if (fProviders == null)
 			fProviders= new HashMap();

 		if (provider == null)
 			fProviders.remove(contentType);
 		else
 			fProviders.put(contentType, provider);
 	}

 	/*
 	 * @see IInformationPresenter#getInformationProvider(String)
 	 */
 	public IInformationProvider getInformationProvider(String contentType) {
 		if (fProviders == null)
 			return null;

 		return (IInformationProvider) fProviders.get(contentType);
 	}

 	/**
 	 * Sets a offset to override the selection. Setting the value to <code>-1</code> will disable
 	 * overriding.
 	 *
 	 * @param offset the offset to override selection or <code>-1</code>
 	 */
 	public void setOffset(int offset) {
 		fOffset= offset;
 	}

 	/*
 	 * @see AbstractInformationControlManager#computeInformation()
 	 */
 	protected void computeInformation() {

 		int offset= fOffset < 0 ? fTextViewer.getSelectedRange().x : fOffset;
 		if (offset == -1)
 			return;

 		fOffset= -1;

 		IInformationProvider provider= null;
 		try {
 			String contentType= TextUtilities.getContentType(fTextViewer.getDocument(), getDocumentPartitioning(), offset, true);
 			provider= getInformationProvider(contentType);
 		} catch (BadLocationException x) {
 		}
 		if (provider == null)
 			return;

 		IRegion subject= provider.getSubject(fTextViewer, offset);
 		if (subject == null)
 			return;

 		if (provider instanceof IInformationProviderExtension2)
 			setCustomInformationControlCreator(((IInformationProviderExtension2) provider).getInformationPresenterControlCreator());
 		else
 			setCustomInformationControlCreator(null);

 		if (provider instanceof IInformationProviderExtension) {
 			IInformationProviderExtension extension= (IInformationProviderExtension) provider;
 			setInformation(extension.getInformation2(fTextViewer, subject), computeArea(subject));
 		} else
 			setInformation(provider.getInformation(fTextViewer, subject), computeArea(subject));
 	}

 	/**
 	 * Determines the graphical area covered by the given text region.
 	 *
 	 * @param region the region whose graphical extend must be computed
 	 * @return the graphical extend of the given region
 	 */
 	private Rectangle computeArea(IRegion region) {

 		IRegion widgetRegion= modelRange2WidgetRange(region);
 		int start= widgetRegion.getOffset();
 		int end= widgetRegion.getOffset() + widgetRegion.getLength();

 		StyledText styledText= fTextViewer.getTextWidget();
 		Point upperLeft= styledText.getLocationAtOffset(start);
 		Point lowerRight= new Point(upperLeft.x, upperLeft.y);

 		for (int i= start +1; i < end; i++) {

 			Point p= styledText.getLocationAtOffset(i);

 			if (upperLeft.x > p.x)
 				upperLeft.x= p.x;

 			if (upperLeft.y > p.y)
 				upperLeft.y= p.y;

 			if (lowerRight.x  < p.x)
 				lowerRight.x= p.x;

 			if (lowerRight.y < p.y)
 				lowerRight.y= p.y;
 		}

 		GC gc= new GC(styledText);
 		lowerRight.x +=  gc.getFontMetrics().getAverageCharWidth();
 		lowerRight.y += styledText.getLineHeight();
 		gc.dispose();

 		int width= lowerRight.x - upperLeft.x;
 		int height= lowerRight.y - upperLeft.y;
 		return new Rectangle(upperLeft.x, upperLeft.y, width, height);
 	}

 	/**
 	 * Translated the given range in the viewer's document into the corresponding
 	 * range of the viewer's widget.
 	 *
 	 * @param region the range in the viewer's document
 	 * @return the corresponding widget range
 	 * @since 2.1
 	 */
 	private IRegion modelRange2WidgetRange(IRegion region) {
 		if (fTextViewer instanceof ITextViewerExtension5) {
 			ITextViewerExtension5 extension= (ITextViewerExtension5) fTextViewer;
 			return extension.modelRange2WidgetRange(region);
 		}

 		IRegion visibleRegion= fTextViewer.getVisibleRegion();
 		int start= region.getOffset() - visibleRegion.getOffset();
 		int end= start + region.getLength();
 		if (end > visibleRegion.getLength())
 			end= visibleRegion.getLength();

 		return new Region(start, end - start);
 	}

 	/*
 	 * @see IInformationPresenter#install(ITextViewer)
 	 */
 	public void install(ITextViewer textViewer) {
 		fTextViewer= textViewer;
 		install(fTextViewer.getTextWidget());
 	}

 	/*
 	 * @see IInformationPresenter#uninstall()
 	 */
 	public void uninstall() {
 		dispose();
 	}

 	/*
 	 * @see AbstractInformationControlManager#showInformationControl(Rectangle)
 	 */
 	protected void showInformationControl(Rectangle subjectArea) {
 		if (fTextViewer instanceof IWidgetTokenOwnerExtension) {
 			IWidgetTokenOwnerExtension extension= (IWidgetTokenOwnerExtension) fTextViewer;
 			if (extension.requestWidgetToken(this, WIDGET_PRIORITY))
 				super.showInformationControl(subjectArea);
 		} else if (fTextViewer instanceof IWidgetTokenOwner) {
 			IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
 			if (owner.requestWidgetToken(this))
 				super.showInformationControl(subjectArea);

 		}
 	}

 	/*
 	 * @see AbstractInformationControlManager#hideInformationControl()
 	 */
 	protected void hideInformationControl() {
 		try {
 			super.hideInformationControl();
 		} finally {
 			if (fTextViewer instanceof IWidgetTokenOwner) {
 				IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
 				owner.releaseWidgetToken(this);
 			}
 		}
 	}

 	/*
 	 * @see AbstractInformationControlManager#handleInformationControlDisposed()
 	 */
 	protected void handleInformationControlDisposed() {
 		try {
 			super.handleInformationControlDisposed();
 		} finally {
 			if (fTextViewer instanceof IWidgetTokenOwner) {
 				IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
 				owner.releaseWidgetToken(this);
 			}
 		}
 	}

 	/*
 	 * @see org.eclipse.jface.text.IWidgetTokenKeeper#requestWidgetToken(IWidgetTokenOwner)
 	 */
 	public boolean requestWidgetToken(IWidgetTokenOwner owner) {
 		return false;
 	}

 	/*
 	 * @see org.eclipse.jface.text.IWidgetTokenKeeperExtension#requestWidgetToken(org.eclipse.jface.text.IWidgetTokenOwner, int)
 	 * @since 3.0
 	 */
 	public boolean requestWidgetToken(IWidgetTokenOwner owner, int priority) {
 		return false;
 	}

 	/*
 	 * @see org.eclipse.jface.text.IWidgetTokenKeeperExtension#setFocus(org.eclipse.jface.text.IWidgetTokenOwner)
 	 * @since 3.0
 	 */
 	public boolean setFocus(IWidgetTokenOwner owner) {
 		return false;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2003 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jface.text.information;

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

	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.events.ControlEvent;
	import org.eclipse.swt.events.ControlListener;
	import org.eclipse.swt.events.FocusEvent;
	import org.eclipse.swt.events.FocusListener;
	import org.eclipse.swt.events.KeyEvent;
	import org.eclipse.swt.events.KeyListener;
	import org.eclipse.swt.events.MouseEvent;
	import org.eclipse.swt.events.MouseListener;
	import org.eclipse.swt.graphics.GC;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;

	import org.eclipse.jface.text.AbstractInformationControlManager;
	import org.eclipse.jface.text.Assert;
	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.IDocumentExtension3;
	import org.eclipse.jface.text.IInformationControl;
	import org.eclipse.jface.text.IInformationControlCreator;
	import org.eclipse.jface.text.IRegion;
	import org.eclipse.jface.text.ITextViewer;
	import org.eclipse.jface.text.ITextViewerExtension5;
	import org.eclipse.jface.text.IViewportListener;
	import org.eclipse.jface.text.IWidgetTokenKeeper;
	import org.eclipse.jface.text.IWidgetTokenKeeperExtension;
	import org.eclipse.jface.text.IWidgetTokenOwner;
	import org.eclipse.jface.text.IWidgetTokenOwnerExtension;
	import org.eclipse.jface.text.Region;
	import org.eclipse.jface.text.TextUtilities;


	/**
	* Standard implementation of <code>IInformationPresenter</code>.
	* This implementation extends <code>AbstractInformationControlManager</code>.
	* The information control is made visible on request by calling
	* <code>showInformation</code>.<p>
	* Usually, clients instantiate this class and configure it before using it. The configuration
	* must be consistent: This means the used <code>IInformationControlCreator</code>
	* must create an information control expecting information in the same format the configured
	* <code>IInformationProvider</code>s use to encode the information they provide.
	*
	* @since 2.0
	*/
	public class InformationPresenter extends AbstractInformationControlManager implements IInformationPresenter, IInformationPresenterExtension, IWidgetTokenKeeper, IWidgetTokenKeeperExtension {


	/**
	* Priority of the info controls managed by this information presenter.
	* Default value: <code>5</code> in order to beat the hovers of <code>TextViewerHoverManager</code>
	* @since 3.0
	*/
	public static final int WIDGET_PRIORITY= 5;


	/**
	* Internal information control closer. Listens to several events issued by its subject control
	* and closes the information control when necessary.
	*/
	class Closer implements IInformationControlCloser, ControlListener, MouseListener, FocusListener, IViewportListener, KeyListener {

	/** The subject control */
	private Control fSubjectControl;
	/** The information control */
	private IInformationControl fInformationControl;
	/** Indicates whether this closer is active */
	private boolean fIsActive= false;

	/*
	* @see IInformationControlCloser#setSubjectControl(Control)
	*/
	public void setSubjectControl(Control control) {
	fSubjectControl= control;
	}

	/*
	* @see IInformationControlCloser#setInformationControl(IInformationControl)
	*/
	public void setInformationControl(IInformationControl control) {
	fInformationControl= control;
	}

	/*
	* @see IInformationControlCloser#start(Rectangle)
	*/
	public void start(Rectangle informationArea) {

	if (fIsActive)
	return;
	fIsActive= true;

	if (fSubjectControl != null && ! fSubjectControl.isDisposed()) {
	fSubjectControl.addControlListener(this);
	fSubjectControl.addMouseListener(this);
	fSubjectControl.addFocusListener(this);
	fSubjectControl.addKeyListener(this);
	}

	if (fInformationControl != null)
	fInformationControl.addFocusListener(this);

	fTextViewer.addViewportListener(this);
	}

	/*
	* @see IInformationControlCloser#stop()
	*/
	public void stop() {

	if (!fIsActive)
	return;
	fIsActive= false;

	fTextViewer.removeViewportListener(this);

	if (fInformationControl != null)
	fInformationControl.removeFocusListener(this);

	hideInformationControl();

	if (fSubjectControl != null && !fSubjectControl.isDisposed()) {
	fSubjectControl.removeControlListener(this);
	fSubjectControl.removeMouseListener(this);
	fSubjectControl.removeFocusListener(this);
	fSubjectControl.removeKeyListener(this);
	}
	}

	/*
	* @see ControlListener#controlResized(ControlEvent)
	*/
	public void controlResized(ControlEvent e) {
	stop();
	}

	/*
	* @see ControlListener#controlMoved(ControlEvent)
	*/
	public void controlMoved(ControlEvent e) {
	stop();
	}

	/*
	* @see MouseListener#mouseDown(MouseEvent)
	*/
	public void mouseDown(MouseEvent e) {
	stop();
	}

	/*
	* @see MouseListener#mouseUp(MouseEvent)
	*/
	public void mouseUp(MouseEvent e) {
	}

	/*
	* @see MouseListener#mouseDoubleClick(MouseEvent)
	*/
	public void mouseDoubleClick(MouseEvent e) {
	stop();
	}

	/*
	* @see FocusListener#focusGained(FocusEvent)
	*/
	public void focusGained(FocusEvent e) {
	}

	/*
	* @see FocusListener#focusLost(FocusEvent)
	*/
	public void focusLost(FocusEvent e) {
	Display d= fSubjectControl.getDisplay();
	d.asyncExec(new Runnable() {
	public void run() {
	if (fInformationControl == null \|\| !fInformationControl.isFocusControl())
	stop();
	}
	});
	}

	/*
	* @see IViewportListenerListener#viewportChanged(int)
	*/
	public void viewportChanged(int topIndex) {
	stop();
	}

	/*
	* @see KeyListener#keyPressed(KeyEvent)
	*/
	public void keyPressed(KeyEvent e) {
	stop();
	}

	/*
	* @see KeyListener#keyReleased(KeyEvent)
	*/
	public void keyReleased(KeyEvent e) {
	}
	}


	/** The text viewer this information presenter works on */
	private ITextViewer fTextViewer;
	/** The map of <code>IInformationProvider</code> objects */
	private Map fProviders;
	/** The offset to override selection. */
	private int fOffset= -1;
	/**
	* The document partitioning for this information presenter.
	* @since 3.0
	*/
	private String fPartitioning;

	/**
	* Creates a new information presenter that uses the given information control creator.
	* The presenter is not installed on any text viewer yet. By default, an information
	* control closer is set that closes the information control in the event of key strokes,
	* resizing, moves, focus changes, mouse clicks, and disposal - all of those applied to
	* the information control's parent control. Also, the setup ensures that the information
	* control when made visible will request thel focus. By default, the default document
	* partitioning <code>IDocumentExtension3.DEFAULT_PARTITIONING</code> is used.
	*
	* @param creator the information control creator to be used
	*/
	public InformationPresenter(IInformationControlCreator creator) {
	super(creator);
	setCloser(new Closer());
	takesFocusWhenVisible(true);
	fPartitioning= IDocumentExtension3.DEFAULT_PARTITIONING;
	}

	/**
	* Sets the document partitioning to be used by this information presenter.
	*
	* @param partitioning the document partitioning to be used by this information presenter
	* @since 3.0
	*/
	public void setDocumentPartitioning(String partitioning) {
	Assert.isNotNull(partitioning);
	fPartitioning= partitioning;
	}

	/*
	* @see org.eclipse.jface.text.information.IInformationPresenterExtension#getDocumentPartitioning()
	* @since 3.0
	*/
	public String getDocumentPartitioning() {
	return fPartitioning;
	}

	/**
	* Registers a given information provider for a particular content type.
	* If there is already a provider registered for this type, the new provider
	* is registered instead of the old one.
	*
	* @param provider the information provider to register, or <code>null</code> to remove an existing one
	* @param contentType the content type under which to register
	*/
	public void setInformationProvider(IInformationProvider provider, String contentType) {

	Assert.isNotNull(contentType);

	if (fProviders == null)
	fProviders= new HashMap();

	if (provider == null)
	fProviders.remove(contentType);
	else
	fProviders.put(contentType, provider);
	}

	/*
	* @see IInformationPresenter#getInformationProvider(String)
	*/
	public IInformationProvider getInformationProvider(String contentType) {
	if (fProviders == null)
	return null;

	return (IInformationProvider) fProviders.get(contentType);
	}

	/**
	* Sets a offset to override the selection. Setting the value to <code>-1</code> will disable
	* overriding.
	*
	* @param offset the offset to override selection or <code>-1</code>
	*/
	public void setOffset(int offset) {
	fOffset= offset;
	}

	/*
	* @see AbstractInformationControlManager#computeInformation()
	*/
	protected void computeInformation() {

	int offset= fOffset < 0 ? fTextViewer.getSelectedRange().x : fOffset;
	if (offset == -1)
	return;

	fOffset= -1;

	IInformationProvider provider= null;
	try {
	String contentType= TextUtilities.getContentType(fTextViewer.getDocument(), getDocumentPartitioning(), offset, true);
	provider= getInformationProvider(contentType);
	} catch (BadLocationException x) {
	}
	if (provider == null)
	return;

	IRegion subject= provider.getSubject(fTextViewer, offset);
	if (subject == null)
	return;

	if (provider instanceof IInformationProviderExtension2)
	setCustomInformationControlCreator(((IInformationProviderExtension2) provider).getInformationPresenterControlCreator());
	else
	setCustomInformationControlCreator(null);

	if (provider instanceof IInformationProviderExtension) {
	IInformationProviderExtension extension= (IInformationProviderExtension) provider;
	setInformation(extension.getInformation2(fTextViewer, subject), computeArea(subject));
	} else
	setInformation(provider.getInformation(fTextViewer, subject), computeArea(subject));
	}

	/**
	* Determines the graphical area covered by the given text region.
	*
	* @param region the region whose graphical extend must be computed
	* @return the graphical extend of the given region
	*/
	private Rectangle computeArea(IRegion region) {

	IRegion widgetRegion= modelRange2WidgetRange(region);
	int start= widgetRegion.getOffset();
	int end= widgetRegion.getOffset() + widgetRegion.getLength();

	StyledText styledText= fTextViewer.getTextWidget();
	Point upperLeft= styledText.getLocationAtOffset(start);
	Point lowerRight= new Point(upperLeft.x, upperLeft.y);

	for (int i= start +1; i < end; i++) {

	Point p= styledText.getLocationAtOffset(i);

	if (upperLeft.x > p.x)
	upperLeft.x= p.x;

	if (upperLeft.y > p.y)
	upperLeft.y= p.y;

	if (lowerRight.x < p.x)
	lowerRight.x= p.x;

	if (lowerRight.y < p.y)
	lowerRight.y= p.y;
	}

	GC gc= new GC(styledText);
	lowerRight.x += gc.getFontMetrics().getAverageCharWidth();
	lowerRight.y += styledText.getLineHeight();
	gc.dispose();

	int width= lowerRight.x - upperLeft.x;
	int height= lowerRight.y - upperLeft.y;
	return new Rectangle(upperLeft.x, upperLeft.y, width, height);
	}

	/**
	* Translated the given range in the viewer's document into the corresponding
	* range of the viewer's widget.
	*
	* @param region the range in the viewer's document
	* @return the corresponding widget range
	* @since 2.1
	*/
	private IRegion modelRange2WidgetRange(IRegion region) {
	if (fTextViewer instanceof ITextViewerExtension5) {
	ITextViewerExtension5 extension= (ITextViewerExtension5) fTextViewer;
	return extension.modelRange2WidgetRange(region);
	}

	IRegion visibleRegion= fTextViewer.getVisibleRegion();
	int start= region.getOffset() - visibleRegion.getOffset();
	int end= start + region.getLength();
	if (end > visibleRegion.getLength())
	end= visibleRegion.getLength();

	return new Region(start, end - start);
	}

	/*
	* @see IInformationPresenter#install(ITextViewer)
	*/
	public void install(ITextViewer textViewer) {
	fTextViewer= textViewer;
	install(fTextViewer.getTextWidget());
	}

	/*
	* @see IInformationPresenter#uninstall()
	*/
	public void uninstall() {
	dispose();
	}

	/*
	* @see AbstractInformationControlManager#showInformationControl(Rectangle)
	*/
	protected void showInformationControl(Rectangle subjectArea) {
	if (fTextViewer instanceof IWidgetTokenOwnerExtension) {
	IWidgetTokenOwnerExtension extension= (IWidgetTokenOwnerExtension) fTextViewer;
	if (extension.requestWidgetToken(this, WIDGET_PRIORITY))
	super.showInformationControl(subjectArea);
	} else if (fTextViewer instanceof IWidgetTokenOwner) {
	IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
	if (owner.requestWidgetToken(this))
	super.showInformationControl(subjectArea);

	}
	}

	/*
	* @see AbstractInformationControlManager#hideInformationControl()
	*/
	protected void hideInformationControl() {
	try {
	super.hideInformationControl();
	} finally {
	if (fTextViewer instanceof IWidgetTokenOwner) {
	IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
	owner.releaseWidgetToken(this);
	}
	}
	}

	/*
	* @see AbstractInformationControlManager#handleInformationControlDisposed()
	*/
	protected void handleInformationControlDisposed() {
	try {
	super.handleInformationControlDisposed();
	} finally {
	if (fTextViewer instanceof IWidgetTokenOwner) {
	IWidgetTokenOwner owner= (IWidgetTokenOwner) fTextViewer;
	owner.releaseWidgetToken(this);
	}
	}
	}

	/*
	* @see org.eclipse.jface.text.IWidgetTokenKeeper#requestWidgetToken(IWidgetTokenOwner)
	*/
	public boolean requestWidgetToken(IWidgetTokenOwner owner) {
	return false;
	}

	/*
	* @see org.eclipse.jface.text.IWidgetTokenKeeperExtension#requestWidgetToken(org.eclipse.jface.text.IWidgetTokenOwner, int)
	* @since 3.0
	*/
	public boolean requestWidgetToken(IWidgetTokenOwner owner, int priority) {
	return false;
	}

	/*
	* @see org.eclipse.jface.text.IWidgetTokenKeeperExtension#setFocus(org.eclipse.jface.text.IWidgetTokenOwner)
	* @since 3.0
	*/
	public boolean setFocus(IWidgetTokenOwner owner) {
	return false;
	}
	}