*
     * @param dir the directory to locate the pom for, never {@code null}
     * @return a {@code Source} pointing to the located pom or an empty {@code Optional} if none was found by this parser
     */
    @Nonnull
    Optional<Source> locate(@Nonnull Path dir);

    /**
     * Parse the model obtained previously by a previous call to {@link #locate(Path)}.
     *

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.lifecycle;

/**
 * Signals a failure to locate a lifecycle.
 *
 */
public class LifecycleNotFoundException extends Exception {

    private final String lifecycleId;

    /**
     * Creates a new exception to indicate that the specified lifecycle is unknown.

 */
package org.apache.maven.api.services.model;

import java.nio.file.Path;

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

/**
 * Interface used to locate the root directory for a given project.
 *
 * The root locator is usually looked up from the plexus container.
 * One notable exception is the computation of the early {@code session.rootDirectory}

        // Alright, here's the justification for all the regexp wizardry below...
        //
        // Continuum and other server-like apps may need to locate the user-level and
        // global-level settings somewhere other than ${user.home} and ${maven.home},
        // respectively. Using a simple replacement of these patterns will allow them

        // Note that the ModelProcessor#locatePom never returns null
        // while the ModelParser#locatePom needs to return an existing path!
        Path pom = modelParsers.stream()
                .map(m -> m.locate(projectDirectory)
                        .map(org.apache.maven.api.services.Source::getPath)
                        .orElse(null))
                .filter(Objects::nonNull)
                .findFirst()

        Path pomPath = pomFile.resolveSibling(relativePath).normalize();
        if (Files.isDirectory(pomPath)) {
            pomPath = context.locate(pomPath);
        }

        if (pomPath == null || !Files.isRegularFile(pomPath)) {
            return Optional.empty();
        }

        DefaultModelProblemCollector problems = (DefaultModelProblemCollector) collector;
        return new ModelTransformerContext() {

            @Override
            public Path locate(Path path) {
                return context.locate(path);
            }

            @Override
            public String getUserProperty(String key) {
                return context.userProperties.computeIfAbsent(

    @Override
    public Model getRawModel(Path from, String groupId, String artifactId) {
        return Holder.deref(modelByGA.get(new GAKey(groupId, artifactId)));
    }

    @Override
    public Path locate(Path path) {
        return modelLocator.locateExistingPom(path);
    }

    static class GAKey {
        private final String groupId;
        private final String artifactId;

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.lifecycle;

/**
 * Signals a failure to locate the lifecycle for some phase.
 *
 */
public class LifecyclePhaseNotFoundException extends Exception {

    private final String lifecyclePhase;

    /**

        }

        @Override
        public Model getRawModel(Path from, Path p) {
            throw new UnsupportedOperationException();
        }

        @Override
        public Path locate(Path path) {
            throw new UnsupportedOperationException();
        }
    }