public SignatureHelp getSignatureHelp(IProgressMonitor monitor) {
	SignatureHelp signatureHelp = new SignatureHelp();
	response.setProposals(proposals);
	CompletionResponses.store(response);

	List<SignatureInformation> infos = new ArrayList<>();
	for (int i = 0; i < proposals.size(); i++) {
		if (!monitor.isCanceled()) {
			CompletionProposal proposal = proposals.get(i);
			SignatureInformation signatureInformation = this.toSignatureInformation(proposal);
			infoProposals.put(signatureInformation, proposal);
			infos.add(signatureInformation);
		} else {
			return signatureHelp;
		}
	}
	infos.sort((SignatureInformation a, SignatureInformation b) -> a.getParameters().size() - b.getParameters().size());
	signatureHelp.getSignatures().addAll(infos);

	return signatureHelp;
}
 

@Test
public void testSignatureHelp_javadocOriginal() throws JavaModelException {
	IPackageFragment pack1 = sourceFolder.createPackageFragment("test1", false, null);
	StringBuilder buf = new StringBuilder();
	buf.append("package test1;\n");
	buf.append("import java.util.LinkedList;\n");
	buf.append("import org.sample.MyList;\n");
	buf.append("public class E {\n\n");
	buf.append("	void test() {\n");
	buf.append("		MyList<String> l = new LinkedList<>();\n");
	buf.append("		l.add(\n");
	buf.append("	}\n");
	buf.append("}\n");
	ICompilationUnit cu = pack1.createCompilationUnit("E.java", buf.toString(), false, null);
	int[] loc = findCompletionLocation(cu, "l.add(");
	SignatureHelp help = getSignatureHelp(cu, loc[0], loc[1]);
	assertNotNull(help);
	assertEquals(2, help.getSignatures().size());
	SignatureInformation signature = help.getSignatures().get(help.getActiveSignature());
	assertTrue(signature.getLabel().equals("add(String e) : boolean"));
	String documentation = signature.getDocumentation().getLeft();
	assertEquals(" Test ", documentation);
}
 

private String extractLabel(SignatureInformation signatureInformation, Either<String, Tuple.Two<Integer, Integer>> label) {
    if (label.isLeft()) {
        return label.getLeft();
    } else if (label.isRight()) {
        return signatureInformation.getLabel().substring(label.getRight().getFirst(), label.getRight().getSecond());
    } else {
        return "";
    }
}
 

@Test
void testSignatureHelpOnMethod() throws Exception {
	Path filePath = srcRoot.resolve("Completion.groovy");
	String uri = filePath.toUri().toString();
	StringBuilder contents = new StringBuilder();
	contents.append("class SignatureHelp {\n");
	contents.append("  public SignatureHelp() {\n");
	contents.append("    method(\n");
	contents.append("  }\n");
	contents.append("  public void method(int param0) {}\n");
	contents.append("}");
	TextDocumentItem textDocumentItem = new TextDocumentItem(uri, LANGUAGE_GROOVY, 1, contents.toString());
	services.didOpen(new DidOpenTextDocumentParams(textDocumentItem));
	TextDocumentIdentifier textDocument = new TextDocumentIdentifier(uri);
	Position position = new Position(2, 11);
	SignatureHelp signatureHelp = services.signatureHelp(new TextDocumentPositionParams(textDocument, position))
			.get();
	List<SignatureInformation> signatures = signatureHelp.getSignatures();
	Assertions.assertEquals(1, signatures.size());
	SignatureInformation signature = signatures.get(0);
	Assertions.assertEquals("public void method(int param0)", signature.getLabel());
	List<ParameterInformation> params = signature.getParameters();
	Assertions.assertEquals(1, params.size());
	ParameterInformation param0 = params.get(0);
	Assertions.assertEquals("int param0", param0.getLabel().get());
	Assertions.assertEquals((int) 0, (int) signatureHelp.getActiveSignature());
	Assertions.assertEquals((int) 0, (int) signatureHelp.getActiveParameter());
}
 

@Test
void testSignatureHelpOnMethodWithMultipleParameters() throws Exception {
	Path filePath = srcRoot.resolve("Completion.groovy");
	String uri = filePath.toUri().toString();
	StringBuilder contents = new StringBuilder();
	contents.append("class SignatureHelp {\n");
	contents.append("  public SignatureHelp() {\n");
	contents.append("    method(\n");
	contents.append("  }\n");
	contents.append("  public void method(int param0, String param1) {}\n");
	contents.append("}");
	TextDocumentItem textDocumentItem = new TextDocumentItem(uri, LANGUAGE_GROOVY, 1, contents.toString());
	services.didOpen(new DidOpenTextDocumentParams(textDocumentItem));
	TextDocumentIdentifier textDocument = new TextDocumentIdentifier(uri);
	Position position = new Position(2, 11);
	SignatureHelp signatureHelp = services.signatureHelp(new TextDocumentPositionParams(textDocument, position))
			.get();
	List<SignatureInformation> signatures = signatureHelp.getSignatures();
	Assertions.assertEquals(1, signatures.size());
	SignatureInformation signature = signatures.get(0);
	Assertions.assertEquals("public void method(int param0, String param1)", signature.getLabel());
	List<ParameterInformation> params = signature.getParameters();
	Assertions.assertEquals(2, params.size());
	ParameterInformation param0 = params.get(0);
	Assertions.assertEquals("int param0", param0.getLabel().get());
	ParameterInformation param1 = params.get(1);
	Assertions.assertEquals("String param1", param1.getLabel().get());
	Assertions.assertEquals((int) 0, (int) signatureHelp.getActiveSignature());
	Assertions.assertEquals((int) 0, (int) signatureHelp.getActiveParameter());
}
 

@Test
void testSignatureHelpOnMethodWithActiveParameter() throws Exception {
	Path filePath = srcRoot.resolve("Completion.groovy");
	String uri = filePath.toUri().toString();
	StringBuilder contents = new StringBuilder();
	contents.append("class SignatureHelp {\n");
	contents.append("  public SignatureHelp() {\n");
	contents.append("    method(123,\n");
	contents.append("  }\n");
	contents.append("  public void method(int param0, String param1) {}\n");
	contents.append("}");
	TextDocumentItem textDocumentItem = new TextDocumentItem(uri, LANGUAGE_GROOVY, 1, contents.toString());
	services.didOpen(new DidOpenTextDocumentParams(textDocumentItem));
	TextDocumentIdentifier textDocument = new TextDocumentIdentifier(uri);
	Position position = new Position(2, 15);
	SignatureHelp signatureHelp = services.signatureHelp(new TextDocumentPositionParams(textDocument, position))
			.get();
	List<SignatureInformation> signatures = signatureHelp.getSignatures();
	Assertions.assertEquals(1, signatures.size());
	SignatureInformation signature = signatures.get(0);
	Assertions.assertEquals("public void method(int param0, String param1)", signature.getLabel());
	List<ParameterInformation> params = signature.getParameters();
	Assertions.assertEquals(2, params.size());
	ParameterInformation param0 = params.get(0);
	Assertions.assertEquals("int param0", param0.getLabel().get());
	ParameterInformation param1 = params.get(1);
	Assertions.assertEquals("String param1", param1.getLabel().get());
	Assertions.assertEquals((int) 0, (int) signatureHelp.getActiveSignature());
	Assertions.assertEquals((int) 1, (int) signatureHelp.getActiveParameter());
}
 

/** @return string for given element */
public String toString(SignatureInformation sigInfo) {
	if (sigInfo == null) {
		return "";
	}
	String str = Strings.join(", ",
			sigInfo.getLabel(),
			Strings.toString(this::toString, sigInfo.getParameters()),
			toString7(sigInfo.getDocumentation()));

	return "(" + str + ")";
}
 

public SignatureInformation toSignatureInformation(CompletionProposal methodProposal) {
	SignatureInformation $ = new SignatureInformation();
	StringBuilder desription = descriptionProvider.createMethodProposalDescription(methodProposal);
	$.setLabel(desription.toString());
	$.setDocumentation(this.computeJavaDoc(methodProposal));

	char[] signature = SignatureUtil.fix83600(methodProposal.getSignature());
	char[][] parameterNames = methodProposal.findParameterNames(null);
	char[][] parameterTypes = Signature.getParameterTypes(signature);

	for (int i = 0; i < parameterTypes.length; i++) {
		parameterTypes[i] = Signature.getSimpleName(Signature.toCharArray(SignatureUtil.getLowerBound(parameterTypes[i])));
	}

	if (Flags.isVarargs(methodProposal.getFlags())) {
		int index = parameterTypes.length - 1;
		parameterTypes[index] = convertToVararg(parameterTypes[index]);
	}

	List<ParameterInformation> parameterInfos = new LinkedList<>();
	for (int i = 0; i < parameterTypes.length; i++) {
		StringBuilder builder = new StringBuilder();
		builder.append(parameterTypes[i]);
		builder.append(' ');
		builder.append(parameterNames[i]);

		parameterInfos.add(new ParameterInformation(builder.toString()));
	}

	$.setParameters(parameterInfos);

	return $;
}
 

private boolean isSameParameters(IMethod m, SignatureHelp help, SignatureHelpRequestor collector, IJavaProject javaProject) throws JavaModelException {
	if (m == null || help == null || javaProject == null) {
		return false;
	}
	List<SignatureInformation> infos = help.getSignatures();
	for (int i = 0; i < infos.size(); i++) {
		CompletionProposal proposal = collector.getInfoProposals().get(infos.get(i));
		IMethod method = JDTUtils.resolveMethod(proposal, javaProject);
		if (isSameParameters(method, m)) {
			return true;
		}
	}
	return false;
}
 

protected String _toExpectation(final SignatureHelp it) {
  String _xblockexpression = null;
  {
    int _size = it.getSignatures().size();
    boolean _tripleEquals = (_size == 0);
    if (_tripleEquals) {
      StringConcatenation _builder = new StringConcatenation();
      _builder.append("Signature index is expected to be null when no signatures are available. Was: ");
      Integer _activeSignature = it.getActiveSignature();
      _builder.append(_activeSignature);
      _builder.append(".");
      Assert.assertNull(_builder.toString(), 
        it.getActiveSignature());
      return "<empty>";
    }
    Assert.assertNotNull("Active signature index must not be null when signatures are available.", it.getActiveSignature());
    String _xifexpression = null;
    Integer _activeParameter = it.getActiveParameter();
    boolean _tripleEquals_1 = (_activeParameter == null);
    if (_tripleEquals_1) {
      _xifexpression = "<empty>";
    } else {
      _xifexpression = it.getSignatures().get((it.getActiveSignature()).intValue()).getParameters().get(
        (it.getActiveParameter()).intValue()).getLabel().getLeft();
    }
    final String param = _xifexpression;
    StringConcatenation _builder_1 = new StringConcatenation();
    final Function1<SignatureInformation, String> _function = (SignatureInformation it_1) -> {
      return it_1.getLabel();
    };
    String _join = IterableExtensions.join(ListExtensions.<SignatureInformation, String>map(it.getSignatures(), _function), " | ");
    _builder_1.append(_join);
    _builder_1.append(" | ");
    _builder_1.append(param);
    _xblockexpression = _builder_1.toString();
  }
  return _xblockexpression;
}
 

public CompletableFuture<SignatureHelp> provideSignatureHelp(TextDocumentIdentifier textDocument,
		Position position) {
	if (ast == null) {
		//this shouldn't happen, but let's avoid an exception if something
		//goes terribly wrong.
		return CompletableFuture.completedFuture(new SignatureHelp(Collections.emptyList(), -1, -1));
	}
	URI uri = URI.create(textDocument.getUri());
	ASTNode offsetNode = ast.getNodeAtLineAndColumn(uri, position.getLine(), position.getCharacter());
	if (offsetNode == null) {
		return CompletableFuture.completedFuture(new SignatureHelp(Collections.emptyList(), -1, -1));
	}
	int activeParamIndex = -1;
	MethodCall methodCall = null;
	ASTNode parentNode = ast.getParent(offsetNode);

	if (offsetNode instanceof ArgumentListExpression) {
		methodCall = (MethodCall) parentNode;

		ArgumentListExpression argsList = (ArgumentListExpression) offsetNode;
		List<Expression> expressions = argsList.getExpressions();
		activeParamIndex = getActiveParameter(position, expressions);
	}

	if (methodCall == null) {
		return CompletableFuture.completedFuture(new SignatureHelp(Collections.emptyList(), -1, -1));
	}

	List<MethodNode> methods = GroovyASTUtils.getMethodOverloadsFromCallExpression(methodCall, ast);
	if (methods.isEmpty()) {
		return CompletableFuture.completedFuture(new SignatureHelp(Collections.emptyList(), -1, -1));
	}

	List<SignatureInformation> sigInfos = new ArrayList<>();
	for (MethodNode method : methods) {
		List<ParameterInformation> parameters = new ArrayList<>();
		Parameter[] methodParams = method.getParameters();
		for (int i = 0; i < methodParams.length; i++) {
			Parameter methodParam = methodParams[i];

			ParameterInformation paramInfo = new ParameterInformation();
			paramInfo.setLabel(GroovyNodeToStringUtils.variableToString(methodParam, ast));
			parameters.add(paramInfo);
		}
		SignatureInformation sigInfo = new SignatureInformation();
		sigInfo.setLabel(GroovyNodeToStringUtils.methodToString(method, ast));
		sigInfo.setParameters(parameters);
		sigInfos.add(sigInfo);
	}

	MethodNode bestMethod = GroovyASTUtils.getMethodFromCallExpression(methodCall, ast, activeParamIndex);
	int activeSignature = methods.indexOf(bestMethod);

	return CompletableFuture.completedFuture(new SignatureHelp(sigInfos, activeSignature, activeParamIndex));
}
 

public Map<SignatureInformation, CompletionProposal> getInfoProposals() {
	return infoProposals;
}
 

public SignatureHelp() {
  ArrayList<SignatureInformation> _arrayList = new ArrayList<SignatureInformation>();
  this.signatures = _arrayList;
}
 

public SignatureHelp(@NonNull final List<SignatureInformation> signatures, final Integer activeSignature, final Integer activeParameter) {
  this.signatures = Preconditions.<List<SignatureInformation>>checkNotNull(signatures, "signatures");
  this.activeSignature = activeSignature;
  this.activeParameter = activeParameter;
}
 

/**
 * One or more signatures.
 */
@Pure
@NonNull
public List<SignatureInformation> getSignatures() {
  return this.signatures;
}
 

/**
 * One or more signatures.
 */
public void setSignatures(@NonNull final List<SignatureInformation> signatures) {
  this.signatures = Preconditions.checkNotNull(signatures, "signatures");
}