[ISSUE #789] Fix java syntax highlighting

src/theme/prism-include-languages.js

@@ -0,0 +1,16 @@
+import siteConfig from '@generated/docusaurus.config';
+export default function prismIncludeLanguages(PrismObject) {
+  const {
+    themeConfig: {prism},
+  } = siteConfig;
+  const {additionalLanguages} = prism;
+  // Prism components work on the Prism instance on the window, while prism-
+  // react-renderer uses its own Prism instance. We temporarily mount the
+  // instance onto window, import components to enhance it, then remove it to
+  // avoid polluting global namespace.
+  // You can mutate PrismObject: registering plugins, deleting languages... As
+  // long as you don't re-assign it
+  globalThis.Prism = PrismObject;
+  require(`./prism-java.js`);
+  delete globalThis.Prism;
+}

src/theme/prism-java.js

@@ -0,0 +1,124 @@
+(function (Prism) {
+
+	var keywords = /\b(?:abstract|assert|boolean|break|byte|case|catch|char|class|const|continue|default|do|double|else|enum|exports|extends|final|finally|float|for|goto|if|implements|import|instanceof|int|interface|long|module|native|new|non-sealed|null|open|opens|package|permits|private|protected|provides|public|record(?!\s*[(){}[\]<>=%~.:,;?+\-*/&|^])|requires|return|sealed|short|static|strictfp|super|switch|synchronized|this|throw|throws|to|transient|transitive|try|uses|var|void|volatile|while|with|yield)\b/;
+
+	// full package (optional) + parent classes (optional)
+	var classNamePrefix = /(?:[a-z]\w*\s*\.\s*)*(?:[A-Z]\w*\s*\.\s*)*/.source;
+
+	// based on the java naming conventions
+	var className = {
+		pattern: RegExp(/(^|[^\w.])/.source + classNamePrefix + /[A-Z](?:[\d_A-Z]*[a-z]\w*)?\b/.source),
+		lookbehind: true,
+		inside: {
+			'namespace': {
+				pattern: /^[a-z]\w*(?:\s*\.\s*[a-z]\w*)*(?:\s*\.)?/,
+				inside: {
+					'punctuation': /\./
+				}
+			},
+			'punctuation': /\./
+		}
+	};
+
+	Prism.languages.java = Prism.languages.extend('clike', {
+		'string': {
+			pattern: /(^|[^\\])"(?:\\.|[^"\\\r\n])*"/,
+			lookbehind: true,
+			greedy: true
+		},
+		'class-name': [
+			className,
+			{
+				// variables, parameters, and constructor references
+				// this to support class names (or generic parameters) which do not contain a lower case letter (also works for methods)
+				pattern: RegExp(/(^|[^\w.])/.source + classNamePrefix + /[A-Z]\w*(?=\s+\w+\s*[;,=()]|\s*(?:\[[\s,]*\]\s*)?::\s*new\b)/.source),
+				lookbehind: true,
+				inside: className.inside
+			},
+			{
+				// class names based on keyword
+				// this to support class names (or generic parameters) which do not contain a lower case letter (also works for methods)
+				pattern: RegExp(/(\b(?:class|enum|extends|implements|instanceof|interface|new|record|throws)\s+)/.source + classNamePrefix + /[A-Z]\w*\b/.source),
+				lookbehind: true,
+				inside: className.inside
+			}
+		],
+		'keyword': keywords,
+		'function': [
+			Prism.languages.clike.function,
+			{
+				pattern: /(::\s*)[a-z_]\w*/,
+				lookbehind: true
+			}
+		],
+		'number': /\b0b[01][01_]*L?\b|\b0x(?:\.[\da-f_p+-]+|[\da-f_]+(?:\.[\da-f_p+-]+)?)\b|(?:\b\d[\d_]*(?:\.[\d_]*)?|\B\.\d[\d_]*)(?:e[+-]?\d[\d_]*)?[dfl]?/i,
+		'operator': {
+			pattern: /(^|[^.])(?:<<=?|>>>?=?|->|--|\+\+|&&|\|\||::|[?:~]|[-+*/%&|^!=<>]=?)/m,
+			lookbehind: true
+		},
+		'constant': /\b[A-Z][A-Z_\d]+\b/
+	});
+
+	Prism.languages.insertBefore('java', 'string', {
+		'triple-quoted-string': {
+			// http://openjdk.java.net/jeps/355#Description
+			pattern: /"""[ \t]*[\r\n](?:(?:"|"")?(?:\\.|[^"\\]))*"""/,
+			greedy: true,
+			alias: 'string'
+		},
+		'char': {
+			pattern: /'(?:\\.|[^'\\\r\n]){1,6}'/,
+			greedy: true
+		}
+	});
+
+	Prism.languages.insertBefore('java', 'class-name', {
+		'annotation': {
+			pattern: /(^|[^.])@\w+(?:\s*\.\s*\w+)*/,
+			lookbehind: true,
+			alias: 'punctuation'
+		},
+		'generics': {
+			pattern: /<(?:[\w\s,.?]|&(?!&)|<(?:[\w\s,.?]|&(?!&)|<(?:[\w\s,.?]|&(?!&)|<(?:[\w\s,.?]|&(?!&))*>)*>)*>)*>/,
+			inside: {
+				'class-name': className,
+				'keyword': keywords,
+				'punctuation': /[<>(),.:]/,
+				'operator': /[?&|]/
+			}
+		},
+		'import': [
+			{
+				pattern: RegExp(/(\bimport\s+)/.source + classNamePrefix + /(?:[A-Z]\w*|\*)(?=\s*;)/.source),
+				lookbehind: true,
+				inside: {
+					'namespace': className.inside.namespace,
+					'punctuation': /\./,
+					'operator': /\*/,
+					'class-name': /\w+/
+				}
+			},
+			{
+				pattern: RegExp(/(\bimport\s+static\s+)/.source + classNamePrefix + /(?:\w+|\*)(?=\s*;)/.source),
+				lookbehind: true,
+				alias: 'static',
+				inside: {
+					'namespace': className.inside.namespace,
+					'static': /\b\w+$/,
+					'punctuation': /\./,
+					'operator': /\*/,
+					'class-name': /\w+/
+				}
+			}
+		],
+		'namespace': {
+			pattern: RegExp(
+				/(\b(?:exports|import(?:\s+static)?|module|open|opens|package|provides|requires|to|transitive|uses|with)\s+)(?!<keyword>)[a-z]\w*(?:\.[a-z]\w*)*\.?/
+					.source.replace(/<keyword>/g, function () { return keywords.source; })),
+			lookbehind: true,
+			inside: {
+				'punctuation': /\./,
+			}
+		}
+	});
+}(Prism));