/**
 */
abstract class AbstractVersionTest {

    protected static final int X_LT_Y = -1;

    protected static final int X_EQ_Y = 0;

    protected static final int X_GT_Y = 1;

    protected abstract Version newVersion(String version);

    protected void assertOrder(int expected, String version1, String version2) {
        Version v1 = newVersion(version1);

 * the problem.
 *
 */
public class DefaultModelProblem implements ModelProblem {

    private final String source;

    private final int lineNumber;

    private final int columnNumber;

    private final String modelId;

    private final String message;

    private final Exception exception;

    private final Severity severity;

    }

    public int getPosition() {
        return position;
    }

    public boolean setPosition(int position) {
        this.position = position;
        filterChildren(position);
        child = (position > 0 && position <= filteredChildren.size()) ? filteredChildren.get(position - 1) : null;
        return child != null;
    }

    private void filterChildren(int position) {

        public MessageBuilder append(CharSequence cs, int start, int end) {
            builder.append(cs, start, end);
            return this;
        }

        @Override
        public MessageBuilder append(char c) {
            builder.append(c);
            return this;
        }

        @Override
        public MessageBuilder setLength(int length) {
            builder.setLength(length);

    }

    @Override
    public MessageBuilder append(CharSequence cs, int start, int end) {
        buffer.append(cs, start, end);
        return this;
    }

    @Override
    public MessageBuilder append(char c) {
        buffer.append(c);
        return this;
    }

    @Override
    public MessageBuilder setLength(int length) {
        buffer.setLength(length);
        return this;
    }

    /** */
    private List<String> messages;

    public ModelValidationResult() {
        messages = new ArrayList<>();
    }

    public int getMessageCount() {
        return messages.size();
    }

    public String getMessage(int i) {
        return messages.get(i);
    }

    public List<String> getMessages() {
        return Collections.unmodifiableList(messages);
    }

     * returns -1 if none is available.
     * @return the current line number
     */
    int getLineNumber();

    /**
     * Return the column number where the current event ends,
     * returns -1 if none is available.
     * @return the current column number
     */
    int getColumnNumber();

    /**
     * Return the byte or character offset into the input source this location

        return versionRangeViolations != null;
    }

    /**
     * TODO this needs to accept a {@link OverConstrainedVersionException} as returned by
     *       {@link #getVersionRangeViolation(int)} but it's not used like that in
     *       {@link org.apache.maven.repository.legacy.resolver.DefaultLegacyArtifactCollector}
     */
    public MetadataResolutionResult addVersionRangeViolation(Exception e) {

    }

    static class GavCacheKey {

        private final String gav;

        private final String tag;

        private final int hash;

        GavCacheKey(String groupId, String artifactId, String version, String tag) {
            this(gav(groupId, artifactId, version), tag);
        }

        GavCacheKey(String gav, String tag) {

            return false;
        }
        Key<?> that = (Key<?>) o;
        return type.equals(that.type) && Objects.equals(qualifier, that.qualifier);
    }

    @Override
    public int hashCode() {
        int hashCode = hash;
        if (hashCode == 0) {
            hash = 31 * type.hashCode() + (qualifier == null ? 0 : qualifier.hashCode());
        }
        return hash;
    }

    @Override