Example project that shows a possible use-case for Markdom

This example illustrates a possible use-case, where an application needs to minimal support rich-text in different contexts. Different contexts allow different forms of rich-text. One context could, for instance, allow links, while another context doesn't. This is achieved by parsing rich-text as Commonmark text, representing the parsed Commonmark document internally as a Markdom document and using different Markdom handlers to produce various representations of that Markdom document.

Specifically, this example provides the following operations:

• Reading rich-text in form of Commonmark text.
• Creating a normalized version of that Commonmark text (e.g., one that always uses the same symbols for emphasises and so on) that keeps any undesired parts.
• Creating a list of warnings for all forms of undesired rich-text that occur in the read Commonmark text.
• Creating a HTML text snippet representation of the rich-text that doesn't contain the undesired parts.
• Creating a XHTML document representation of the rich-text that doesn't contain the undesired parts (e.g. to be transformed into a PDF-file using a Flying Saucer).

The last three operations are provided by a RichtextProvider. The first operation is provided by the RichtextProviderFactory which reads Commonmark text and constructs corresponding instances of RichtextProvider.

A specific set of undesired forms of rich-text is represented as a RichtextContext.

A MarkdomRichtextProviderFactory is constructed with such a RichtextContext and constructs instances of MarkdomRichtextProvider. A MarkdomRichtextProvider internally holds a MarkdomDocument and uses different implementatiojns of MarkdomHandler to perform its functionality.

Creating RichtextProvider:

RichtextProviderFactory factory = new MarkdomRichtextProviderFactory(RichtextContext.DETAILS);
RichtextProvider provider = factory.fromCommonmark(getCommonmarkTextAsInputStream()));

Creating normalized Commonmark text:

System.out.println(provider.toCommonmarkText());

Creating a list of warning:

System.out.println(String.join("\n", provider.toWarnings()));

Creating a HTML text snippet (with abbr-tags):

Map<String, String> abbreviations = new HashMap<>();
abbreviations.put("js", "JavaScript");
abbreviations.put("mm", "millimeter");

System.out.println(provider.toHtmlElementsText(abbreviations, true));

Creating a PDF document (via XHTML):

ITextRenderer renderer = new ITextRenderer();
DocumentBuilder documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
renderer.setDocument(provider.toXhtmlDocument(documentBuilder, "test.md"), null);
renderer.layout();

renderer.createPDF(new FileOutputStream("test.pdf"));