[Question] SniperJavaPrettyPrinter, add comment to method

[uvilop]

how can i add some inline-comments before a method and keep everything else unchanged, printing with SniperJavaPrettyPrinter?

i am am trying:

      CtComment cc1 = factory.createInlineComment("TEST 1");
      CtComment cc2 = factory.createInlineComment("TEST 2");
      CtComment cc3 = factory.createInlineComment("");
      method.setComments(List.of(cc1,cc2,cc3));

but this comments the method out:

 // TEST 1
 // TEST 2
 // public static void main(String[] args)

i am using 11.3.1-beta-8 and java 25.

[seintur]

Hi @uvilop

Can you give more context or provide a failing test case please?

Empty line comments are supported. As an example the following test case is passing:

	@ExtendWith(LineSeparatorExtension.class)
	@ModelTest(code = "class A { public static void main(String[] args) {} }")
	void testEmptyInlineComment(@BySimpleName("A") CtClass<?> cl, Factory factory) {
		CtComment comment1 = factory.createInlineComment("TEST 1");
		CtComment comment2 = factory.createInlineComment("TEST 2");
		CtComment comment3 = factory.createInlineComment("");
		CtMethod<?> main = cl.getMethodsByName("main").get(0);
		main.setComments(List.of(comment1, comment2, comment3));
		var sjpp = new SniperJavaPrettyPrinter(factory.getEnvironment());
		assertEquals(
			"""
				// TEST 1
				// TEST 2
				//\s
				public static void main(java.lang.String[] args) {
				}""", sjpp.printElement(main));
	}

[uvilop]

thanks. it is not a matter of empty comments. the following program applied to itself gives:

…
 // TEST 1
 // TEST 2public static void main(String[] args)
…

import java.io.*;
import java.util.*;
import spoon.*;
import spoon.support.sniper.*;
import spoon.reflect.*;
import spoon.reflect.declaration.*;
import spoon.reflect.factory.*;
import spoon.reflect.visitor.*;
import spoon.reflect.code.*;
import spoon.reflect.cu.*;
import spoon.support.reflect.cu.position.*;

public class ExperimentalSniper
{
public static void main(String[] args)
  throws Exception
{
  Launcher launcher = new Launcher();
  launcher.getEnvironment().setNoClasspath(true);
  //
  launcher.addInputResource(args[0]);
  Factory factory = launcher.getFactory();
  launcher.getEnvironment().setPrettyPrinterCreator(() -> new SniperJavaPrettyPrinter(launcher.getEnvironment()));
  //
  launcher.buildModel();
  CtModel model = launcher.getModel();
  CtCompilationUnit cu = factory.CompilationUnit().getMap().values().iterator().next();
  //
  for (CtType<?> type : model.getAllTypes()) {
    for (CtMethod<?> method: type.getMethods()) {
      CtComment cc1 = factory.createInlineComment("TEST 1");
      CtComment cc2 = factory.createInlineComment("TEST 2");
      method.setComments(List.of(cc1,cc2));
    }
  }
  PrettyPrinter printer = cu.getFactory().getEnvironment().createPrettyPrinter();
  System.out.println(printer.printCompilationUnit(cu));
}

[seintur]

The sniper mode enables to rewrite transformed AST elements, so that the rest of the code is printed identically to the origin version. This is useful to get small diffs after automated refactoring.

In the case that you report, the added comment is assigned the same source positioning as the one of the node corresponding to the main method. This explains why you get this output. I guess that the sniper mode has not been developed considering this case in mind.

Note that the problem does not occur with the default pretty printer: a newline is correctly appended to the end of the comment.