package org.apache.maven.api.services;

import org.apache.maven.api.annotations.Nonnull;

/**
 * Describes a problem that was encountered during model building. A problem can either be an exception that was thrown
 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 */
public interface ModelProblem extends BuilderProblem {

    /**

        results.add(result);

        ProjectBuildingException exception = new ProjectBuildingException(results);
        String message = exception.getMessage();

        assertTrue(
                message.contains("1 problem was encountered while processing the POMs"),
                "Message should use singular form for single problem");

        assertTrue(

     *
     * @return The assembled toolchains, never {@code null}.
     */
    PersistedToolchains getEffectiveToolchains();

    /**
     * Return a list of problems, if any.
     *
     * @return a list of problems, never {@code null}.
     */
    List<Problem> getProblems();

     * @param severity The severity level of the problem, may be {@code null} to default to
     *            {@link org.apache.maven.building.Problem.Severity#ERROR}.
     * @param source A hint about the source of the problem like a file path, may be {@code null}.
     * @param lineNumber The one-based index of the line containing the problem or {@code -1} if unknown.

        assertEquals(
                "1 problem was encountered while building the effective toolchains" + LS
                        + "[ERROR] MESSAGE @ line 3, column 5" + LS,
                e.getMessage());
    }

    @Test
    void testUnknownPositionAndSource() {
        ProblemCollector problemCollector = ProblemCollectorFactory.newInstance(null);
        problemCollector.add(Problem.Severity.ERROR, "MESSAGE", -1, -1, new Exception());

                        (problemsCount == 1) ? "problem was" : "problems were",
                        result.getProjectId());

                if (request.isShowErrors()) { // this means -e or -X (as -X enables -e as well)
                    for (ModelProblem problem : result.getProblems()) {
                        String loc = ModelProblemUtils.formatLocation(problem, result.getProjectId());

    private List<Problem> problems;

    /**
     * Default constructor
     *
     * @param effectiveToolchains the merged toolchains, may not be {@code null}
     * @param problems the problems while building the effectiveToolchains, if any.
     */
    public DefaultToolchainsBuildingResult(PersistedToolchains effectiveToolchains, List<Problem> problems) {
        this.effectiveToolchains = effectiveToolchains;

     */
    Exception getException();

    /**
     * Gets the message that describes this problem.
     *
     * @return The message describing this problem, never {@code null}.
     */
    String getMessage();

    /**
     * Gets the severity level of this problem.
     *
     * @return The severity level of this problem, never {@code null}.
     */

import org.apache.maven.api.model.Model;

/**
 * Collects problems that are encountered during model building. The primary purpose of this component is to account for
 * the fact that the problem reporter has/should not have information about the calling context and hence cannot provide
 * an expressive source hint for the model problem. Instead, the source hint is configured by the model builder before

        writer.print(problems.size());
        writer.print((problems.size() == 1) ? " problem was " : " problems were ");
        writer.print("encountered while building the effective settings");
        writer.println();

        for (SettingsProblem problem : problems) {
            writer.print("[");
            writer.print(problem.getSeverity());
            writer.print("] ");
            writer.print(problem.getMessage());