Custom flexmark-java LinkRenderer for CWiki (not used)

CWikiLinkRenderer.java

package cwiki.extensions;

import com.vladsch.flexmark.ext.wikilink.WikiLink;
import com.vladsch.flexmark.ext.wikilink.internal.WikiLinkOptions;
import com.vladsch.flexmark.html.CustomNodeRenderer;
import com.vladsch.flexmark.html.HtmlWriter;
import com.vladsch.flexmark.html.renderer.*;
import com.vladsch.flexmark.util.options.DataHolder;
import com.vladsch.flexmark.util.sequence.BasedSequence;

import java.util.HashSet;
import java.util.Set;

import static com.vladsch.flexmark.util.sequence.CharSubSequence.of;


public class CWikiLinkRenderer implements NodeRenderer {

    // From: https://stackoverflow.com/questions/724043/http-url-address-encoding-in-java

    /**
     * Percent-encodes a string so it's suitable for use in a URL Path (not a query string / form encode, which uses + for spaces, etc)
     */
    private static String percentEncode(String encodeMe) {
        if (encodeMe == null) {
            return "";
        }
        String encoded = encodeMe.replace("%", "%25");
        encoded = encoded.replace(" ", "%20");
        encoded = encoded.replace("!", "%21");
        encoded = encoded.replace("#", "%23");
        encoded = encoded.replace("$", "%24");
        encoded = encoded.replace("&", "%26");
        encoded = encoded.replace("'", "%27");
        encoded = encoded.replace("(", "%28");
        encoded = encoded.replace(")", "%29");
        encoded = encoded.replace("*", "%2A");
        encoded = encoded.replace("+", "%2B");
        encoded = encoded.replace(",", "%2C");
        encoded = encoded.replace("/", "%2F");
        encoded = encoded.replace(":", "%3A");
        encoded = encoded.replace(";", "%3B");
        encoded = encoded.replace("=", "%3D");
        encoded = encoded.replace("?", "%3F");
        encoded = encoded.replace("@", "%40");
        encoded = encoded.replace("[", "%5B");
        encoded = encoded.replace("]", "%5D");
        return encoded;
    }

    public static class Factory implements DelegatingNodeRendererFactory {

        @Override
        public NodeRenderer create(final DataHolder options) {
            return new CWikiLinkRenderer();
        }

        @Override
        public Set<Class<? extends NodeRendererFactory>> getDelegates() {
            ///Set<Class<? extends NodeRendererFactory>> set = new HashSet<Class<? extends NodeRendererFactory>>();
            // add node renderer factory classes to which this renderer will delegate some of its rendering
            // core node renderer is assumed to have all depend it so there is no need to add it
            //set.add(WikiLinkNodeRenderer.Factory.class);
            //return set;

            // return null if renderer does not delegate or delegates only to core node renderer
            return null;
        }
    }

    @Override
    public Set<NodeRenderingHandler<?>> getNodeRenderingHandlers() {
        HashSet<NodeRenderingHandler<?>> set = new HashSet<NodeRenderingHandler<?>>();
        set.add(new NodeRenderingHandler<WikiLink>(WikiLink.class, new CustomNodeRenderer<WikiLink>() {
            @Override
            public void render(WikiLink node, NodeRendererContext context, HtmlWriter html) {
                String encodedLink = percentEncode(node.getLink().toString());
                BasedSequence newLink = of(encodedLink);
                DataHolder options = context.getOptions();
                WikiLinkOptions wlo = new WikiLinkOptions(options);
                node.setLink(newLink, wlo.allowAnchors, wlo.allowAnchorEscape);

                context.delegateRender();
            }
        }));

        return set;
    }
}

CWikiLinkRendererExtension.java

package cwiki.extensions;

import com.vladsch.flexmark.html.HtmlRenderer;
import com.vladsch.flexmark.util.options.MutableDataHolder;

public class CWikiLinkRendererExtension implements HtmlRenderer.HtmlRendererExtension {
        @Override
        public void rendererOptions(final MutableDataHolder options) {
            // add any configuration settings to options you want to apply to everything, here
        }

        @Override
        public void extend(final HtmlRenderer.Builder rendererBuilder, final String rendererType) {
            rendererBuilder.nodeRendererFactory(new CWikiLinkRenderer.Factory());
        }

        public static CWikiLinkRendererExtension create() {
            return new CWikiLinkRendererExtension();
        }
    }

CWikiLinkRendererTest.clj

(ns cwiki.test.extensions.CWikiLinkRendererTest
  (:require [clojure.test :refer :all])
  (:import (com.vladsch.flexmark.ext.gfm.strikethrough StrikethroughExtension)
           (com.vladsch.flexmark.ext.tables TablesExtension)
           (com.vladsch.flexmark.ext.footnotes FootnoteExtension)
           (com.vladsch.flexmark.ext.wikilink WikiLinkExtension)
           (com.vladsch.flexmark.html HtmlRenderer HtmlRenderer$Builder)
           (com.vladsch.flexmark.parser Parser Parser$Builder)
           (com.vladsch.flexmark.util KeepType)
           (com.vladsch.flexmark.util.options MutableDataSet)
           (cwiki.extensions CWikiLinkRendererExtension)
           (java.util ArrayList)))

;-------------------------------------------------------------------------------
; Test fixtures.
;-------------------------------------------------------------------------------

; All of these extensions are not really needed but are here so that the test
; environment is more similar to the actual use in the program.

(def options (-> (MutableDataSet.)
                 (.set Parser/REFERENCES_KEEP KeepType/LAST)
                 (.set HtmlRenderer/INDENT_SIZE (Integer/valueOf 2))
                 (.set HtmlRenderer/PERCENT_ENCODE_URLS true)
                 (.set TablesExtension/COLUMN_SPANS false)
                 (.set TablesExtension/MIN_HEADER_ROWS (Integer/valueOf 1))
                 (.set TablesExtension/MAX_HEADER_ROWS (Integer/valueOf 1))
                 (.set TablesExtension/APPEND_MISSING_COLUMNS true)
                 (.set TablesExtension/DISCARD_EXTRA_COLUMNS true)
                 (.set TablesExtension/WITH_CAPTION false)
                 (.set TablesExtension/HEADER_SEPARATOR_COLUMN_MATCH true)
                 (.set WikiLinkExtension/ALLOW_ANCHOR_ESCAPE true)
                 (.set WikiLinkExtension/ALLOW_ANCHORS true)
                 (.set WikiLinkExtension/LINK_FIRST_SYNTAX true)
                 (.set WikiLinkExtension/LINK_ESCAPE_CHARS "")
                 (.set Parser/EXTENSIONS (ArrayList.
                                           [(FootnoteExtension/create)
                                            (StrikethroughExtension/create)
                                            (WikiLinkExtension/create)
                                            (CWikiLinkRendererExtension/create)
                                            (TablesExtension/create)]))))

(def parser (.build ^Parser$Builder (Parser/builder options)))
(def renderer (.build ^HtmlRenderer$Builder (HtmlRenderer/builder options)))

;-------------------------------------------------------------------------------
; Utilities
;-------------------------------------------------------------------------------

(defn- convert-markdown-to-html
  "Convert the markdown formatted input string to html
  and return it."
  [mkdn]
  (->> mkdn
       (.parse parser)
       (.render renderer)))

;-------------------------------------------------------------------------------
; Tests
;-------------------------------------------------------------------------------

(deftest wikilink-encoding-test
  (testing "Testing the get-option-value function."
    (is (= "<p>some text</p>\n" (convert-markdown-to-html "some text")))
    (is (= "<p>a link to the <a href=\"Front%20Page\">Front Page</a>.</p>\n"
           (convert-markdown-to-html "a link to the [[Front Page]].")))
    (is (= "<p><a href=\"link%20part\">text part</a></p>\n"
           (convert-markdown-to-html "[[link part|text part]]")))
    (is (= "<p><a href=\"What%20is%20A%2FB%20Testing%3F\">What is A/B Testing?</a></p>\n"
           (convert-markdown-to-html "[[What is A/B Testing?]]")))))

These files are custom LinkRenderer, LinkRendererExtension, and test files for flexmark-java. They are used in conjunction with the WikiLinkExtension that already exists in the flexmark project. They were an experiment for use in a personal wiki program. They allowed page titles including punctuation characters to be used as URLs to link to the named pages.