apache · asfgit · Apr 5, 2022 · Sep 30, 2021
diff --git a/maven-core/src/main/java/org/apache/maven/ReactorReader.java b/maven-core/src/main/java/org/apache/maven/ReactorReader.java
@@ -24,20 +24,20 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import javax.inject.Inject;
-import javax.inject.Named;
-
 import org.apache.maven.artifact.ArtifactUtils;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.model.Model;
@@ -49,6 +49,13 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import javax.inject.Inject;
+import javax.inject.Named;
+
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.groupingBy;
+import static java.util.stream.Collectors.toMap;
+
 /**
  * An implementation of a workspace reader that knows how to search the Maven reactor for artifacts, either as packaged
  * jar if it has been built, or only compile output directory if packaging hasn't happened yet.
@@ -72,26 +79,22 @@ class ReactorReader
     private final Map<String, List<MavenProject>> projectsByGA;
     private final WorkspaceRepository repository;
 
+    private Function<MavenProject, String> projectIntoKey =
+            s -> ArtifactUtils.key( s.getGroupId(), s.getArtifactId(), s.getVersion() );
+
+    private Function<MavenProject, String> projectIntoVersionlessKey =
+            s -> ArtifactUtils.versionlessKey( s.getGroupId(), s.getArtifactId() );
+
     @Inject
     ReactorReader( MavenSession session )
     {
         this.session = session;
-        this.projectsByGAV = new HashMap<>( session.getAllProjects().size() * 2 );
-        session.getAllProjects().forEach( project ->
-        {
-            String projectId = ArtifactUtils.key( project.getGroupId(), project.getArtifactId(), project.getVersion() );
-            this.projectsByGAV.put( projectId, project );
-        } );
-
-        projectsByGA = new HashMap<>( projectsByGAV.size() * 2 );
-        for ( MavenProject project : projectsByGAV.values() )
-        {
-            String key = ArtifactUtils.versionlessKey( project.getGroupId(), project.getArtifactId() );
-
-            List<MavenProject> projects = projectsByGA.computeIfAbsent( key, k -> new ArrayList<>( 1 ) );
+        this.projectsByGAV =
+                session.getAllProjects().stream()
+                        .collect( toMap( projectIntoKey, identity() ) );
 
-            projects.add( project );
-        }
+        this.projectsByGA = projectsByGAV.values().stream()
+                .collect( groupingBy( projectIntoVersionlessKey ) );
 
         repository = new WorkspaceRepository( "reactor", new HashSet<>( projectsByGAV.keySet() ) );
     }
@@ -128,23 +131,11 @@ public List<String> findVersions( Artifact artifact )
     {
         String key = ArtifactUtils.versionlessKey( artifact.getGroupId(), artifact.getArtifactId() );
 
-        List<MavenProject> projects = projectsByGA.get( key );
-        if ( projects == null || projects.isEmpty() )
-        {
-            return Collections.emptyList();
-        }
-
-        List<String> versions = new ArrayList<>();
-
-        for ( MavenProject project : projects )
-        {
-            if ( find( project, artifact ) != null )
-            {
-                versions.add( project.getVersion() );
-            }
-        }
-
-        return Collections.unmodifiableList( versions );
+        return Optional.ofNullable( projectsByGA.get( key ) )
+                .orElse( Collections.emptyList() ).stream()
+                .filter( s -> Objects.nonNull( find( s, artifact ) ) )
+                .map( MavenProject::getVersion )
+                .collect( Collectors.collectingAndThen( Collectors.toList(), Collections::unmodifiableList ) );
     }
 
     @Override
@@ -334,28 +325,27 @@ private Artifact findMatchingArtifact( MavenProject project, Artifact requestedA
             return mainArtifact;
         }
 
-        for ( Artifact attachedArtifact : RepositoryUtils.toArtifacts( project.getAttachedArtifacts() ) )
-        {
-            if ( attachedArtifactComparison( requestedArtifact, attachedArtifact ) )
-            {
-                return attachedArtifact;
-            }
-        }
-
-        return null;
+        return RepositoryUtils.toArtifacts( project.getAttachedArtifacts() ).stream()
+                .filter( isRequestedArtifact( requestedArtifact ) )
+                .findFirst()
+                .orElse( null );
     }
 
-    private boolean attachedArtifactComparison( Artifact requested, Artifact attached )
+    /**
+     * We are taking as much as we can from the DefaultArtifact.equals(). The requested artifact has no file, so we want
+     * to remove that from the comparison.
+     *
+     * @param requestArtifact checked against the given artifact.
+     * @return true if equals, false otherwise.
+     */
+    private Predicate<Artifact> isRequestedArtifact( Artifact requestArtifact )
     {
-        //
-        // We are taking as much as we can from the DefaultArtifact.equals(). The requested artifact has no file so
-        // we want to remove that from the comparison.
-        //
-        return requested.getArtifactId().equals( attached.getArtifactId() )
-            && requested.getGroupId().equals( attached.getGroupId() )
-            && requested.getVersion().equals( attached.getVersion() )
-            && requested.getExtension().equals( attached.getExtension() )
-            && requested.getClassifier().equals( attached.getClassifier() );
+        return s -> s.getArtifactId().equals( requestArtifact.getArtifactId() )
+                && s.getGroupId().equals( requestArtifact.getGroupId() )
+                && s.getVersion().equals( requestArtifact.getVersion() )
+                && s.getExtension().equals( requestArtifact.getExtension() )
+                && s.getClassifier().equals( requestArtifact.getClassifier() );
+
     }
 
     /**

diff --git a/maven-core/src/main/java/org/apache/maven/RepositoryUtils.java b/maven-core/src/main/java/org/apache/maven/RepositoryUtils.java
@@ -26,6 +26,8 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
+import java.util.stream.Collectors;
 
 import org.apache.maven.artifact.handler.ArtifactHandler;
 import org.apache.maven.artifact.handler.DefaultArtifactHandler;
@@ -170,32 +172,21 @@ public static Dependency toDependency( org.apache.maven.artifact.Artifact artifa
 
         Artifact result = toArtifact( artifact );
 
-        List<Exclusion> excl = null;
-        if ( exclusions != null )
-        {
-            excl = new ArrayList<>( exclusions.size() );
-            for ( org.apache.maven.model.Exclusion exclusion : exclusions )
-            {
-                excl.add( toExclusion( exclusion ) );
-            }
-        }
-
+        List<Exclusion> excl = Optional.ofNullable( exclusions )
+                .orElse( Collections.emptyList() )
+                .stream()
+                .map( RepositoryUtils::toExclusion )
+                .collect( Collectors.toList() );
         return new Dependency( result, artifact.getScope(), artifact.isOptional(), excl );
     }
 
     public static List<RemoteRepository> toRepos( List<ArtifactRepository> repos )
     {
-        if ( repos == null )
-        {
-            return null;
-        }
-
-        List<RemoteRepository> results = new ArrayList<>( repos.size() );
-        for ( ArtifactRepository repo : repos )
-        {
-            results.add( toRepo( repo ) );
-        }
-        return results;
+        return Optional.ofNullable( repos )
+                .orElse( Collections.emptyList() )
+                .stream()
+                .map( RepositoryUtils::toRepo )
+                .collect( Collectors.toList() );
     }
 
     public static RemoteRepository toRepo( ArtifactRepository repo )
@@ -318,11 +309,8 @@ public static Dependency toDependency( org.apache.maven.model.Dependency depende
             new DefaultArtifact( dependency.getGroupId(), dependency.getArtifactId(), dependency.getClassifier(), null,
                                  dependency.getVersion(), props, stereotype );
 
-        List<Exclusion> exclusions = new ArrayList<>( dependency.getExclusions().size() );
-        for ( org.apache.maven.model.Exclusion exclusion : dependency.getExclusions() )
-        {
-            exclusions.add( toExclusion( exclusion ) );
-        }
+        List<Exclusion> exclusions =
+                dependency.getExclusions().stream().map( RepositoryUtils::toExclusion ).collect( Collectors.toList() );
 
         return new Dependency( artifact,
                                             dependency.getScope(),
@@ -363,12 +351,7 @@ public ArtifactType get( String stereotypeId )
 
     public static Collection<Artifact> toArtifacts( Collection<org.apache.maven.artifact.Artifact> artifactsToConvert )
     {
-        List<Artifact> artifacts = new ArrayList<>();
-        for ( org.apache.maven.artifact.Artifact a : artifactsToConvert )
-        {
-            artifacts.add( toArtifact( a ) );
-        }
-        return artifacts;
+        return artifactsToConvert.stream().map( RepositoryUtils::toArtifact ).collect( Collectors.toList() );
     }
 
     public static WorkspaceRepository getWorkspace( RepositorySystemSession session )

diff --git a/...core/src/main/java/org/apache/maven/artifact/resolver/filter/ExclusionArtifactFilter.java b/...core/src/main/java/org/apache/maven/artifact/resolver/filter/ExclusionArtifactFilter.java
@@ -19,11 +19,12 @@
  * under the License.
  */
 
+import java.util.List;
+import java.util.function.Predicate;
+
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.model.Exclusion;
 
-import java.util.List;
-
 /**
  * Filter to exclude from a list of artifact patterns.
  */
@@ -38,31 +39,33 @@ public ExclusionArtifactFilter( List<Exclusion> exclusions )
         this.exclusions = exclusions;
     }
 
+    private Predicate<Exclusion> sameArtifactId( Artifact artifact )
+    {
+        return exclusion -> exclusion.getArtifactId().equals( artifact.getArtifactId() );
+    }
+
+    private Predicate<Exclusion> sameGroupId( Artifact artifact )
+    {
+        return exclusion -> exclusion.getGroupId().equals( artifact.getGroupId() );
+    }
+
+    private Predicate<Exclusion> groupIdIsWildcard = exclusion -> WILDCARD.equals( exclusion.getGroupId() );
+
+    private Predicate<Exclusion> artifactIdIsWildcard = exclusion -> WILDCARD.equals( exclusion.getArtifactId() );
+
+    private Predicate<Exclusion> groupIdAndArtifactIdIsWildcard = groupIdIsWildcard.and( artifactIdIsWildcard );
+
+    private Predicate<Exclusion> exclude( Artifact artifact )
+    {
+        return groupIdAndArtifactIdIsWildcard
+                .or( groupIdIsWildcard.and( sameArtifactId( artifact ) ) )
+                .or( artifactIdIsWildcard.and( sameGroupId( artifact ) ) )
+                .or( sameGroupId( artifact ).and( sameArtifactId( artifact ) ) );
+    }
+
     @Override
     public boolean include( Artifact artifact )
     {
-        for ( Exclusion exclusion : exclusions )
-        {
-            if ( WILDCARD.equals( exclusion.getGroupId() ) && WILDCARD.equals( exclusion.getArtifactId() ) )
-            {
-                return false;
-            }
-            if ( WILDCARD.equals( exclusion.getGroupId() )
-                && exclusion.getArtifactId().equals( artifact.getArtifactId() ) )
-            {
-                return false;
-            }
-            if ( WILDCARD.equals( exclusion.getArtifactId() )
-                && exclusion.getGroupId().equals( artifact.getGroupId() ) )
-            {
-                return false;
-            }
-            if ( exclusion.getGroupId().equals( artifact.getGroupId() )
-                && exclusion.getArtifactId().equals( artifact.getArtifactId() ) )
-            {
-                return false;
-            }
-        }
-        return true;
+        return !exclusions.stream().anyMatch( exclude( artifact ) );
     }
 }
diff --git a/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java b/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
@@ -91,15 +91,9 @@ public void setProjects( List<MavenProject> projects )
         if ( !projects.isEmpty() )
         {
             this.currentProject = projects.get( 0 );
-            this.topLevelProject = currentProject;
-            for ( MavenProject project : projects )
-            {
-                if ( project.isExecutionRoot() )
-                {
-                    topLevelProject = project;
-                    break;
-                }
-            }
+            this.topLevelProject =
+                    projects.stream().filter( project -> project.isExecutionRoot() ).findFirst()
+                            .orElse( currentProject );
         }
         else
         {

diff --git a/maven-core/src/main/java/org/apache/maven/extension/internal/CoreExports.java b/maven-core/src/main/java/org/apache/maven/extension/internal/CoreExports.java
@@ -20,14 +20,16 @@
  */
 
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
-import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
 
 import org.codehaus.plexus.classworlds.realm.ClassRealm;
 
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.collectingAndThen;
+import static java.util.stream.Collectors.toMap;
+
 /**
  * Provides information about artifacts (identified by groupId:artifactId string key) and classpath elements exported by
  * Maven core itself and loaded Maven core extensions.
@@ -47,13 +49,9 @@ public CoreExports( CoreExtensionEntry entry )
 
     public CoreExports( ClassRealm realm, Set<String> exportedArtifacts, Set<String> exportedPackages )
     {
-        Map<String, ClassLoader> packages = new LinkedHashMap<>();
-        for ( String pkg : exportedPackages )
-        {
-            packages.put( pkg, realm );
-        }
         this.artifacts = Collections.unmodifiableSet( new HashSet<>( exportedArtifacts ) );
-        this.packages = Collections.unmodifiableMap( new HashMap<>( packages ) );
+        this.packages = exportedPackages.stream().collect(
+                collectingAndThen( toMap( identity(), v -> realm ), Collections::unmodifiableMap ) );
     }
 
     /**

diff --git a/maven-core/src/main/java/org/apache/maven/lifecycle/mapping/DefaultLifecycleMapping.java b/maven-core/src/main/java/org/apache/maven/lifecycle/mapping/DefaultLifecycleMapping.java
@@ -24,6 +24,7 @@
 import java.util.List;
 import java.util.Map;
 
+import static java.util.function.Function.identity;
 import static java.util.stream.Collectors.toMap;
 
 /**
@@ -57,7 +58,7 @@ public DefaultLifecycleMapping()
     public DefaultLifecycleMapping( final List<Lifecycle> lifecycles )
     {
         this.lifecycleMap = Collections.unmodifiableMap(
-                lifecycles.stream().collect( toMap( Lifecycle::getId, l -> l ) )
+                lifecycles.stream().collect( toMap( Lifecycle::getId, identity() ) )
         );
     }