import java.util.List;

import org.apache.maven.project.MavenProject;

/**
 * Describes the interdependencies between projects in the reactor.
 *
 * @since 3.0-alpha
 */
public interface ProjectDependencyGraph {

    /**
     * Gets all collected projects.
     *
     * @return All collected projects.
     *
     * @since 3.5.0
     */
    List<MavenProject> getAllProjects();

    /**

    private final ProjectDependencyGraph projectDependencyGraph;

    private final Set<MavenProject> finishedProjects = new HashSet<>();

    private final SmartProjectComparator projectComparator;

    public ConcurrencyDependencyGraph(ProjectBuildList projectBuilds, ProjectDependencyGraph projectDependencyGraph) {
        this.projectDependencyGraph = projectDependencyGraph;
        this.projectBuilds = projectBuilds;

    private volatile boolean halted = false;

    public ReactorBuildStatus(ProjectDependencyGraph projectDependencyGraph) {
        this.projectDependencyGraph = projectDependencyGraph;
    }

    public boolean isBlackListed(MavenProject project) {
        return blackListedProjects.contains(BuilderCommon.getKey(project));
    }

    public void blackList(MavenProject project) {

import java.util.concurrent.ConcurrentHashMap;

import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.project.MavenProject;

/**
 * Provides a sub view of another dependency graph.
 *
 */
class FilteredProjectDependencyGraph implements ProjectDependencyGraph {

    private final ProjectDependencyGraph projectDependencyGraph;

    private final Map<MavenProject, ?> whiteList;

        if (activeProjects.size() != projectDependencyGraph.getSortedProjects().size()) {
            projectDependencyGraph = new FilteredProjectDependencyGraph(projectDependencyGraph, activeProjects);
        }

        return Result.success(projectDependencyGraph);
    }

    private List<MavenProject> trimProjectsToRequest(

                new FilteredProjectDependencyGraph(projectDependencyGraph, List.of(aProject));

        when(projectDependencyGraph.getDownstreamProjects(bProject, transitive)).thenReturn(List.of(cProject));

        graph.getDownstreamProjects(bProject, transitive);
        graph.getDownstreamProjects(bProject, transitive);

        verify(projectDependencyGraph).getDownstreamProjects(bProject, transitive);
    }

                ProjectDependencyGraphStub.getProjectBuildList(ProjectDependencyGraphStub.getMavenSession());

        ProjectDependencyGraph projectDependencyGraph = new ProjectDependencyGraphStub();

        ConcurrencyDependencyGraph graph = new ConcurrencyDependencyGraph(projectBuildList, projectDependencyGraph);

        // start
        assertEquals(0, graph.getFinishedProjects().size());

import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.model.building.Result;

/**
 * Builds the {@link ProjectDependencyGraph inter-dependencies graph} between projects in the reactor.
 *
 * @since 3.0-alpha
 */
public interface GraphBuilder {
    String HINT = "graphBuilder";

    Result<? extends ProjectDependencyGraph> build(MavenSession session);

import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Collectors;

import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.project.CycleDetectedException;
import org.apache.maven.project.DuplicateProjectException;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.ProjectSorter;

/**

 * under the License.
 */
package org.apache.maven.lifecycle.internal;

import java.util.List;

import org.apache.maven.execution.MavenSession;
import org.apache.maven.execution.ProjectDependencyGraph;
import org.apache.maven.lifecycle.LifecycleNotFoundException;
import org.apache.maven.lifecycle.LifecyclePhaseNotFoundException;
import org.apache.maven.lifecycle.internal.builder.multithreaded.ConcurrencyDependencyGraph;