A Java Parser implemented in JavaScript using the Chevrotain Parsing ToolKit. It outputs a Concrete Syntax Tree, rather than an Abstract Syntax Tree.
Currently the main focus of this project is to be used in implementing a prettier Java plugin. But it could also be used as the basis for other Java related tools in the JavaScript ecosystem.
npm install java-parser --save-dev
or
yarn add java-parser --dev
const { parse } = require("java-parser"); const javaText = ` public class HelloWorldExample{ public static void main(String args[]){ System.out.println("Hello World !"); } } `; const cst = parse(javaText); // explore the CST
See relevant Chevrotain documentation on CST Traversal.
const { BaseJavaCstVisitor, BaseJavaCstVisitorWithDefaults } = require("java-parser"); // Use "BaseJavaCstVisitor" if you need to implement all the visitor methods yourself. class LambdaArrowsPositionCollector extends BaseJavaCstVisitorWithDefaults { constructor() { super(); this.customResult = []; this.validateVisitor(); } lambdaExpression(ctx) { // Collects all the starting offsets of lambda arrows in lambdas with short (no parenthesis) // single argument lists: e.g: // - n -> n*n (will be collected) // - (n) -> n*n (not collected) if (ctx.lambdaParameters[0].children.Identifier) { this.customResult.push(ctx.Arrow[0].startOffset); } } } const lambdaArrowsCollector = new LambdaArrowsPositionCollector(); // The CST result from the previous code snippet lambdaArrowsCollector.visit(cst); lambdaArrowsCollector.customResult.forEach(arrowOffset => { console.log(arrowOffset); });