Package org.openjdk.nashorn.api.tree

package org.openjdk.nashorn.api.tree

Nashorn parser API provides interfaces to represent ECMAScript source code as abstract syntax trees (AST) and Parser to parse ECMAScript source scripts.

Using parser API user can write Java code to access parse tree representation of ECMAScript source. Script source may be a file, a URL or a String. Unless stated otherwise null argument in methods of this package result in NullPointerException being thrown. 


import org.openjdk.nashorn.api.tree.*;
import java.io.File;

// Simple example that prints warning on 'with' statements
public class Main {
    public static void main(String[] args) throws Exception {
        // Create a new parser instance
        Parser parser = Parser.create();
        File sourceFile = new File(args[0]);

        // Parse given source File using parse method.
        // Pass a diagnostic listener to print error messages.
        CompilationUnitTree cut = parser.parse(sourceFile,
            (d) -> { System.out.println(d); });

        if (cut != null) {
            // call Tree.accept method passing a SimpleTreeVisitor
            cut.accept(new SimpleTreeVisitor<Void, Void>() {
                // visit method for 'with' statement
                public Void visitWith(WithTree wt, Void v) {
                    // print warning on 'with' statement
                    System.out.println("Warning: using 'with' statement!");
                    return null;
                }
            }, null);
        }
    }
}
Since:
9