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

/**
 * A container for data that is specific to a session.
 * All components may use this storage to associate arbitrary data with a session.
 * <p>
 * Unlike a cache, this session data is not subject to purging. For this same reason, session data should also not be
 * abused as a cache (i.e. for storing values that can be re-calculated) to avoid memory exhaustion.

        return (T) computeIfAbsent(new GavCacheKey(groupId, artifactId, version, tag), data);
    }

    @Override
    @SuppressWarnings({"unchecked"})
    public <T> T computeIfAbsent(Source path, String tag, Supplier<T> data) {
        return (T) computeIfAbsent(new SourceCacheKey(path, tag), data);
    }

     */
    @Nonnull
    Map<ChecksumAlgorithm, String> calculate(@Nonnull byte[] data, @Nonnull Collection<ChecksumAlgorithm> algorithms);

    /**
     * Calculates checksums for specified data.
     *
     * @param data        The content for which to calculate checksums, must not be {@code null}.
     * @param algorithms  The checksum algorithms to use, must not be {@code null}.

        }
    }

    @Override
    public Map<ChecksumAlgorithm, String> calculate(byte[] data, Collection<ChecksumAlgorithm> algorithms) {
        nonNull(data, "data");
        nonNull(algorithms, "algorithms");
        try {
            return calculate(new ByteArrayInputStream(data), algorithms);
        } catch (IOException e) {
            throw new UncheckedIOException(e); // really unexpected
        }

        }
    }

    @Override
    public Map<ChecksumAlgorithm, String> calculate(byte[] data, Collection<ChecksumAlgorithm> algorithms) {
        nonNull(data, "data");
        nonNull(algorithms, "algorithms");
        try {
            return calculate(new ByteArrayInputStream(data), algorithms);
        } catch (IOException e) {
            throw new UncheckedIOException(e); // really unexpected
        }

 * identity of a model. The tag allows for further classification of the associated data on the sole discretion of the
 * model builder.
 *
 */
public interface ModelCache {

    <T> T computeIfAbsent(String groupId, String artifactId, String version, String tag, Supplier<T> data);

    <T> T computeIfAbsent(Source path, String tag, Supplier<T> data);

import org.apache.maven.api.services.ModelBuilderRequest;
import org.apache.maven.api.services.ModelProblemCollector;
import org.apache.maven.api.services.model.ModelBuildingEvent;

/**
 * Holds data relevant for a model building event.
 */
record DefaultModelBuildingEvent(
        Model model, Consumer<Model> update, ModelBuilderRequest request, ModelProblemCollector problems)

EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING

 * under the License.
 */
package org.apache.maven.execution;

import org.apache.maven.plugin.MojoExecution;
import org.apache.maven.project.MavenProject;

/**
 * Holds data relevant for an execution event.
 *
 */
public interface ExecutionEvent {

    /**
     * The possible types of execution events.
     */
    enum Type {
        ProjectDiscoveryStarted,

            mojos.remove(Thread.currentThread());
        }

        private OwnerReentrantLock getProjectLock(MavenSession session) {
            SessionData data = session.getSession().getData();
            Map<MavenProject, OwnerReentrantLock> locks = data.computeIfAbsent(PROJECT_LOCKS, ConcurrentHashMap::new);
            return locks.computeIfAbsent(session.getCurrentProject(), p -> new OwnerReentrantLock());
        }
    }