/*******************************************************************************
* Copyright (c) 2008, 2015 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.jface.viewers;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.viewers.StyledString.Styler;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Image;
/**
* A {@link DecoratingStyledCellLabelProvider} is a
* {@link DelegatingStyledCellLabelProvider} that uses a nested
* {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider} to compute
* styled text label and image and takes a {@link ILabelDecorator} to decorate
* the label.
*
* <p>
* Use this label provider as a replacement for the
* {@link DecoratingLabelProvider} when decorating styled text labels.
* </p>
*
* <p>
* The {@link DecoratingStyledCellLabelProvider} will try to evaluate the text
* decoration added by the {@link ILabelDecorator} and will apply the style
* returned by {@link #getDecorationStyle(Object)}
* </p>
* <p>
* The {@link ILabelDecorator} can optionally implement {@link IColorDecorator}
* and {@link IFontDecorator} to provide foreground and background color and
* font decoration.
* </p>
*
* @since 3.4
*/
public class DecoratingStyledCellLabelProvider extends
DelegatingStyledCellLabelProvider {
private ILabelDecorator decorator;
private IDecorationContext decorationContext= DecorationContext.DEFAULT_CONTEXT;
private ILabelProviderListener labelProviderListener;
/**
* Creates a {@link DecoratingStyledCellLabelProvider} that delegates the
* requests for styled labels and for images to a
* {@link DelegatingStyledCellLabelProvider.IStyledLabelProvider}.
*
* @param labelProvider
* the styled label provider
* @param decorator
* a label decorator or <code>null</code> to not decorate the
* label
* @param decorationContext
* a decoration context or <code>null</code> if the no
* decorator is configured or the default decorator should be
* used
*/
public DecoratingStyledCellLabelProvider(
IStyledLabelProvider labelProvider, ILabelDecorator decorator,
IDecorationContext decorationContext) {
super(labelProvider);
this.decorator = decorator;
this.decorationContext = decorationContext != null ? decorationContext
: DecorationContext.DEFAULT_CONTEXT;
this.labelProviderListener = event -> fireLabelProviderChanged(event);
labelProvider.addListener(this.labelProviderListener);
if (decorator != null)
decorator.addListener(this.labelProviderListener);
}
/**
* Returns the decoration context associated with this label provider. It
* will be passed to the decorator if the decorator is an instance of
* {@link LabelDecorator}.
*
* @return the decoration context associated with this label provider
*/
public IDecorationContext getDecorationContext() {
return this.decorationContext;
}
/**
* Set the decoration context that will be based to the decorator for this
* label provider if that decorator implements {@link LabelDecorator}.
*
* @param decorationContext
* the decoration context.
*/
public void setDecorationContext(IDecorationContext decorationContext) {
Assert.isNotNull(decorationContext);
this.decorationContext = decorationContext;
}
private boolean waitForPendingDecoration(ViewerCell cell) {
if (this.decorator == null)
return false;
Object element = cell.getElement();
String oldText = cell.getText();
boolean isDecorationPending = false;
if (this.decorator instanceof LabelDecorator) {
isDecorationPending = !((LabelDecorator) this.decorator)
.prepareDecoration(element, oldText, getDecorationContext());
} else if (this.decorator instanceof IDelayedLabelDecorator) {
isDecorationPending = !((IDelayedLabelDecorator) this.decorator)
.prepareDecoration(element, oldText);
}
if (isDecorationPending && oldText.length() == 0) {
// item is empty: is shown for the first time: don't wait
return false;
}
return isDecorationPending;
}
@Override
public void update(ViewerCell cell) {
if (waitForPendingDecoration(cell)) {
return; // wait until the decoration is ready
}
super.update(cell);
}
@Override
public Color getForeground(Object element) {
if (this.decorator instanceof IColorDecorator) {
Color foreground = ((IColorDecorator) this.decorator)
.decorateForeground(element);
if (foreground != null)
return foreground;
}
return super.getForeground(element);
}
@Override
public Color getBackground(Object element) {
if (this.decorator instanceof IColorDecorator) {
Color color = ((IColorDecorator) this.decorator)
.decorateBackground(element);
if (color != null)
return color;
}
return super.getBackground(element);
}
@Override
public Font getFont(Object element) {
if (this.decorator instanceof IFontDecorator) {
Font font = ((IFontDecorator) this.decorator).decorateFont(element);
if (font != null)
return font;
}
return super.getFont(element);
}
@Override
public Image getImage(Object element) {
Image image = super.getImage(element);
if (this.decorator == null) {
return image;
}
Image decorated = null;
if (this.decorator instanceof LabelDecorator) {
decorated = ((LabelDecorator) this.decorator).decorateImage(image,
element, getDecorationContext());
} else {
decorated = this.decorator.decorateImage(image, element);
}
if (decorated != null)
return decorated;
return image;
}
/**
* Returns the styled text for the label of the given element.
*
* @param element
* the element for which to provide the styled label text
* @return the styled text string used to label the element
*/
@Override
protected StyledString getStyledText(Object element) {
StyledString styledString = super.getStyledText(element);
if (this.decorator == null) {
return styledString;
}
String label = styledString.getString();
String decorated;
if (this.decorator instanceof LabelDecorator) {
decorated = ((LabelDecorator) this.decorator).decorateText(label,
element, getDecorationContext());
} else {
decorated = this.decorator.decorateText(label, element);
}
if (decorated == null)
return styledString;
Styler style = getDecorationStyle(element);
return StyledCellLabelProvider.styleDecoratedString(decorated, style, styledString);
}
/**
* Sets the {@link StyledString.Styler} to be used for string
* decorations. By default the
* {@link StyledString#DECORATIONS_STYLER decoration style}. Clients
* can override.
*
* Note that it is the client's responsibility to react on color changes of
* the decoration color by refreshing the view
*
* @param element
* the element that has been decorated
*
* @return return the decoration style
*/
protected Styler getDecorationStyle(Object element) {
return StyledString.DECORATIONS_STYLER;
}
/**
* Returns the decorator or <code>null</code> if no decorator is installed
*
* @return the decorator or <code>null</code> if no decorator is installed
*/
public ILabelDecorator getLabelDecorator() {
return this.decorator;
}
/**
* Sets the label decorator. Removes all known listeners from the old
* decorator, and adds all known listeners to the new decorator. The old
* decorator is not disposed. Fires a label provider changed event
* indicating that all labels should be updated. Has no effect if the given
* decorator is identical to the current one.
*
* @param newDecorator
* the label decorator, or <code>null</code> if no decorations
* are to be applied
*/
public void setLabelDecorator(ILabelDecorator newDecorator) {
ILabelDecorator oldDecorator = this.decorator;
if (oldDecorator != newDecorator) {
if (oldDecorator != null)
oldDecorator.removeListener(this.labelProviderListener);
this.decorator = newDecorator;
if (newDecorator != null) {
newDecorator.addListener(this.labelProviderListener);
}
}
fireLabelProviderChanged(new LabelProviderChangedEvent(this));
}
@Override
public void addListener(ILabelProviderListener listener) {
super.addListener(listener);
if (this.decorator != null) {
this.decorator.addListener(this.labelProviderListener);
}
}
@Override
public void removeListener(ILabelProviderListener listener) {
super.removeListener(listener);
if (this.decorator != null && !isListenerAttached()) {
this.decorator.removeListener(this.labelProviderListener);
}
}
@Override
public boolean isLabelProperty(Object element, String property) {
if (super.isLabelProperty(element, property)) {
return true;
}
return this.decorator != null
&& this.decorator.isLabelProperty(element, property);
}
@Override
public void dispose() {
super.dispose();
if (this.decorator != null) {
this.decorator.removeListener(this.labelProviderListener);
this.decorator.dispose();
this.decorator = null;
}
}
}