javax.swing.text.html
Class StyleSheet

java.lang.Object
  |
  +--javax.swing.text.StyleContext
        |
        +--javax.swing.text.html.StyleSheet

public class StyleSheet

extends StyleContext

Support for defining the visual characteristics of html views being rendered. The StyleSheet is used to translate the html model into visual characteristics. This enables views to be customized by a look-and-feel, multiple views over the same model can be rendered differently, etc. This can be thought of as a CSS rule repository. The key for CSS attributes is an object of type CSS.Attribute. The type of the value is up to the StyleSheet implementation, but the toString method is required to return a string representation of CSS value.

The primary entry point for HTML View implementations to get their attributes is the getViewAttributes method. This should be implemented to establish the desired policy used to associate attributes with the view. Each HTMLEditorKit (i.e. and therefore each associated JEditorPane) can have its own StyleSheet, but by default one sheet will be shared by all of the HTMLEditorKit instances. HTMLDocument instance can also have a StyleSheet, which holds the document-specific CSS specifications.

In order for Views to store less state and therefore be more lightweight, the StyleSheet can act as a factory for painters that handle some of the rendering tasks. This allows implementations to determine what they want to cache and have the sharing potentially at the level that a selector is common to multiple views. Since the StyleSheet may be used by views over multiple documents and typically the html attributes don't effect the selector being used, the potential for sharing is significant.

The rules are stored as named styles, and other information is stored to translate the context of an element to a rule quickly. The following code fragment will display the named styles, and therefore the CSS rules contained.

import java.util.*;
import javax.swing.text.*;
import javax.swing.text.html.*;

public class ShowStyles {

public static void main(String[] args) {
HTMLEditorKit kit = new HTMLEditorKit();
HTMLDocument doc = (HTMLDocument) kit.createDefaultDocument();
StyleSheet styles = doc.getStyleSheet();

Enumeration rules = styles.getStyleNames();
while (rules.hasMoreElements()) {
String name = (String) rules.nextElement();
Style rule = styles.getStyle(name);
System.out.println(rule.toString());
}
System.exit(0);
}
}

 

Note: This implementation is currently incomplete. It can be replaced with alternative implementations that are complete. Future versions of this class will provide better CSS support.

See Also:

Serialized Form

Inner Class Summary

static class	StyleSheet.BoxPainter Class to carry out some of the duties of css formatting.
static class	StyleSheet.ListPainter class to carry out some of the duties of css list formatting.

Inner classes inherited from class javax.swing.text.StyleContext

StyleContext.NamedStyle, StyleContext.SmallAttributeSet

Fields inherited from class javax.swing.text.StyleContext

DEFAULT_STYLE

Constructor Summary

StyleSheet()
Construct a StyleSheet

Method Summary

void	addRule(String rule) Add a set of rules to the sheet.
Color	getBackground(AttributeSet a) Takes a set of attributes and turn it into a background color specification.
StyleSheet.BoxPainter	getBoxPainter(AttributeSet a) Fetch the box formatter to use for the given set of css attributes.
AttributeSet	getDeclaration(String decl) Translate a CSS declaration to an AttributeSet that represents the CSS declaration.
Font	getFont(AttributeSet a) Fetch the font to use for the given set of attributes.
Color	getForeground(AttributeSet a) Takes a set of attributes and turn it into a foreground color specification.
static int	getIndexOfSize(float pt)
StyleSheet.ListPainter	getListPainter(AttributeSet a) Fetch the list formatter to use for the given set of css attributes.
float	getPointSize(int index) Return the point size, given a size index.
float	getPointSize(String size) Given a string "+2", "-2", "2".
Style	getRule(HTML.Tag t, Element e) Fetch the style to use to render the given type of html tag.
Style	getRule(String selector) Fetch the rule that best matches the selector given in string form.
AttributeSet	getViewAttributes(View v) Fetch a set of attributes to use in the view for displaying.
void	loadRules(Reader in, URL ref) Load a set of rules that have been specified in terms of CSS1 grammar.
void	setBaseFontSize(int sz)
void	setBaseFontSize(String size)
Color	stringToColor(String str) Convert a color string "RED" or "#NNNNNN" to a Color.
AttributeSet	translateHTMLToCSS(AttributeSet htmlAttrSet) Convert a set of html attributes to an equivalent set of css attributes.

Methods inherited from class javax.swing.text.StyleContext

addAttribute, addAttributes, addChangeListener, addStyle, createLargeAttributeSet, createSmallAttributeSet, getCompressionThreshold, getDefaultStyleContext, getEmptySet, getFont, getFontMetrics, getStaticAttribute, getStaticAttributeKey, getStyle, getStyleNames, readAttributes, readAttributeSet, reclaim, registerStaticAttributeKey, removeAttribute, removeAttributes, removeAttributes, removeChangeListener, removeStyle, toString, writeAttributes, writeAttributeSet

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

StyleSheet

public StyleSheet()

Construct a StyleSheet

Method Detail

getRule

public Style getRule(HTML.Tag t,
                     Element e)

Fetch the style to use to render the given type of html tag. The element given is representing the tag and can be used to determine the nesting for situations where the attributes will differ if nesting inside of elements.

Parameters:

t - the type to translate to visual attributes.

e - the element representing the tag. The element can be used to determine the nesting for situations where the attributes will differ if nested inside of other elements.

getRule

public Style getRule(String selector)

Fetch the rule that best matches the selector given in string form.

addRule

public void addRule(String rule)

Add a set of rules to the sheet. The rules are expected to be in valid CSS format. Typically this would be called as a result of parsing a <style> tag.

getDeclaration

public AttributeSet getDeclaration(String decl)

Translate a CSS declaration to an AttributeSet that represents the CSS declaration. Typically this would be called as a result of encountering an HTML style attribute.

loadRules

public void loadRules(Reader in,
                      URL ref)
               throws IOException

Load a set of rules that have been specified in terms of CSS1 grammar. If there are collisions with existing rules, the newly specified rule will win.

Parameters:

in - the stream to read the css grammar from.

ref - the reference url. This value represents the location of the stream and may be null. All relative urls specified in the stream will be based upon this parameter.

getViewAttributes

public AttributeSet getViewAttributes(View v)

Fetch a set of attributes to use in the view for displaying. This is basically a set of attributes that can be used for View.getAttributes.

getFont

public Font getFont(AttributeSet a)

Fetch the font to use for the given set of attributes.

Overrides:

getFont in class StyleContext

getForeground

public Color getForeground(AttributeSet a)

Takes a set of attributes and turn it into a foreground color specification. This might be used to specify things like brighter, more hue, etc.

Parameters:

a - the set of attributes

Returns:

the color

Overrides:

getForeground in class StyleContext

getBackground

public Color getBackground(AttributeSet a)

Takes a set of attributes and turn it into a background color specification. This might be used to specify things like brighter, more hue, etc.

Parameters:

attr - the set of attributes

Returns:

the color

Overrides:

getBackground in class StyleContext

getBoxPainter

public StyleSheet.BoxPainter getBoxPainter(AttributeSet a)

Fetch the box formatter to use for the given set of css attributes.

getListPainter

public StyleSheet.ListPainter getListPainter(AttributeSet a)

Fetch the list formatter to use for the given set of css attributes.

stringToColor

public Color stringToColor(String str)

Convert a color string "RED" or "#NNNNNN" to a Color. Note: This will only convert the HTML3.2 colors strings or string of length 7 otherwise, it will return null.

setBaseFontSize

public void setBaseFontSize(int sz)

setBaseFontSize

public void setBaseFontSize(String size)

getIndexOfSize

public static int getIndexOfSize(float pt)

getPointSize

public float getPointSize(int index)

Return the point size, given a size index.

getPointSize

public float getPointSize(String size)

Given a string "+2", "-2", "2". returns a point size value

translateHTMLToCSS

public AttributeSet translateHTMLToCSS(AttributeSet htmlAttrSet)

Convert a set of html attributes to an equivalent set of css attributes.

Parameters:

AttributeSet - containing the HTML attributes.

AttributeSet - containing the corresponding CSS attributes. The AttributeSet will be empty if there are no mapping CSS attributes.