JarCastingjStyleParser
jStyleParser is a Java library for parsing CSS style sheets and assigning styles to the HTML or XML document elements according to the CSS 3 specifications. It allows parsing the individual CSS files as well as computing the efficient style of the DOM elements.
See the project page for more information: http://cssbox.sourceforge.net/jstyleparser
Installation
With Maven, use the following dependency:
<dependency>
<groupId>net.sf.cssbox</groupId>
<artifactId>jstyleparser</artifactId>
<version>4.0.0</version>
</dependency>
Parsing CSS
The basic CSSFactory interface provides functions parsing CSS strings, files or URLs. The parsed style sheet is represented by the corresponding data structures that allow accessing all parts of the style sheet in a type-safe way.
String css = "div { background-color: red; width: 12px; }";
//parse the style sheet
StyleSheet sheet = CSSFactory.parseString(css, new URL("http://base.url"));
//access the rules and declarations
RuleSet rule = (RuleSet) sheet.get(0); //get the first rule
CombinedSelector selector = rule.getSelectors()[0]; //read the 'div' selector
Declaration bgDecl = rule.get(0); //read the 'background-color' declaration
String bgProperty = bgDecl.getProperty(); //read the property name
TermColor color = (TermColor) bgDecl.get(0); //read the color
//print the results
System.out.println(selector); //prints 'div'
System.out.println(bgProperty); //prints 'background-color'
System.out.println(color); //prints '#ff0000'
//or even print the entire style sheet (formatted)
System.out.println(sheet);
See the details in the documentation.
Computing style for DOM elements
jStyleParser allows to map the style rules to the individual elements in a DOM tree based on their selectors. This allows obtaining the exact style for any HTML element.
org.w3c.dom.Document doc = ... //source DOM
MediaSpec media = new MediaSpecAll(); //use styles for all media
//create the style map
StyleMap map = CSSFactory.assignDOM(doc, "UTF-8", new URL("https://base.url/"), media, true);
//get the style of a single element
Element div = doc.getElementById("searchelement"); //choose a DOM element
NodeData style = map.get(div); //get the style map for the element
//get the type of the assigned value
CSSProperty.Margin mm = style.getProperty("margin-top");
System.out.println("margin-top=" + mm);
//if a length is specified, obtain the exact value
if (mm == Margin.length) {
TermLength mtop = style.getValue(TermLength.class, "margin-top");
System.out.println("value=" + mtop);
}
Multi-value properties
Some properties (e.g. background) allow multiple values. In that case, the NodeData interface includes the getListSize() method for getting the number of values specified and the getProperty() and getValue() functions with an index argument:
//get the style of a single element
Element div = doc.getElementById("searchelement"); //choose a DOM element
NodeData style = map.get(div); //get the style map for the element
//get the number of background images specified for the element
int bgcnt = style.getListSize("background-image", true);
//read all images
for (int index = 0; index < bgcnt; index++>) {
CSSProperty.BackgroundImage image = style.getProperty("background-image", index);
if (image == CSSProperty.BackgroundImage.uri) { //if the image is specified by its url
TermURI urlstring = style.getValue(TermURI.class, "background-image", index);
//... do something with the image url
}
}
See the details in the documentation.
License
All the source code of jStyleParser itself is licensed under the GNU Lesser General Public License (LGPL), version 3. A copy of the LGPL can be found in the LICENSE file.