[MNG-7447] - Several Improvements by using Stream API

maven-core/src/main/java/org/apache/maven/ReactorReader.java

@@ -20,17 +20,17 @@ package org.apache.maven;
  */
 
 import java.io.File;
-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.List;
 import java.util.Map;
-
+import java.util.Objects;
-import javax.inject.Inject;
+import java.util.Optional;
-import javax.inject.Named;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 import org.apache.maven.artifact.ArtifactUtils;
 import org.apache.maven.execution.MavenSession;
@@ -41,6 +41,13 @@ import org.eclipse.aether.artifact.Artifact;
 import org.eclipse.aether.repository.WorkspaceRepository;
 import org.eclipse.aether.util.artifact.ArtifactIdUtils;
 
+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.
@@ -57,32 +64,27 @@ class ReactorReader
     private static final Collection<String> COMPILE_PHASE_TYPES =
         Arrays.asList( "jar", "ejb-client", "war", "rar", "ejb3", "par", "sar", "wsr", "har", "app-client" );
 
-    private Map<String, MavenProject> projectsByGAV;
+    private final MavenSession session;
+    private final Map<String, MavenProject> projectsByGAV;
+    private final Map<String, List<MavenProject>> projectsByGA;
+    private final WorkspaceRepository repository;
 
-    private Map<String, List<MavenProject>> projectsByGA;
+    private Function<MavenProject, String> projectIntoKey =
+            s -> ArtifactUtils.key( s.getGroupId(), s.getArtifactId(), s.getVersion() );
 
-    private WorkspaceRepository repository;
+    private Function<MavenProject, String> projectIntoVersionlessKey =
+            s -> ArtifactUtils.versionlessKey( s.getGroupId(), s.getArtifactId() );
 
     @Inject
     ReactorReader( MavenSession session )
     {
-        projectsByGAV = session.getProjectMap();
+        this.session = session;
+        this.projectsByGAV =
+                session.getAllProjects().stream()
+                        .collect( toMap( projectIntoKey, identity() ) );
 
-        projectsByGA = new HashMap<>( projectsByGAV.size() * 2 );
+        this.projectsByGA = projectsByGAV.values().stream()
-        for ( MavenProject project : projectsByGAV.values() )
+                .collect( groupingBy( projectIntoVersionlessKey ) );
-        {
-            String key = ArtifactUtils.versionlessKey( project.getGroupId(), project.getArtifactId() );
-
-            List<MavenProject> projects = projectsByGA.get( key );
-
-            if ( projects == null )
-            {
-                projects = new ArrayList<>( 1 );
-                projectsByGA.put( key, projects );
-            }
-
-            projects.add( project );
-        }
 
         repository = new WorkspaceRepository( "reactor", new HashSet<>( projectsByGAV.keySet() ) );
     }
@@ -119,23 +121,11 @@ class ReactorReader
     {
         String key = ArtifactUtils.versionlessKey( artifact.getGroupId(), artifact.getArtifactId() );
 
-        List<MavenProject> projects = projectsByGA.get( key );
+        return Optional.ofNullable( projectsByGA.get( key ) )
-        if ( projects == null || projects.isEmpty() )
+                .orElse( Collections.emptyList() ).stream()
-        {
+                .filter( s -> Objects.nonNull( find( s, artifact ) ) )
-            return Collections.emptyList();
+                .map( MavenProject::getVersion )
-        }
+                .collect( Collectors.collectingAndThen( Collectors.toList(), Collections::unmodifiableList ) );
-
-        List<String> versions = new ArrayList<>();
-
-        for ( MavenProject project : projects )
-        {
-            if ( find( project, artifact ) != null )
-            {
-                versions.add( project.getVersion() );
-            }
-        }
-
-        return Collections.unmodifiableList( versions );
     }
 
     @Override
@@ -190,6 +180,17 @@ class ReactorReader
         return null;
     }
 
+    private File determinePreviouslyPackagedArtifactFile( MavenProject project, Artifact artifact )
+    {
+        if ( artifact == null )
+        {
+            return null;
+        }
+
+        String fileName = String.format( "%s.%s", project.getBuild().getFinalName(), artifact.getExtension() );
+        return new File( project.getBuild().getDirectory(), fileName );
+    }
+
     private boolean hasArtifactFileFromPackagePhase( Artifact projectArtifact )
     {
         return projectArtifact != null && projectArtifact.getFile() != null && projectArtifact.getFile().exists();
@@ -218,28 +219,27 @@ class ReactorReader
             return mainArtifact;
         }
 
-        for ( Artifact attachedArtifact : RepositoryUtils.toArtifacts( project.getAttachedArtifacts() ) )
+        return RepositoryUtils.toArtifacts( project.getAttachedArtifacts() ).stream()
-        {
+                .filter( isRequestedArtifact( requestedArtifact ) )
-            if ( attachedArtifactComparison( requestedArtifact, attachedArtifact ) )
+                .findFirst()
-            {
+                .orElse( null );
-                return attachedArtifact;
-            }
-        }
-
-        return 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 )
     {
-        //
+        return s -> s.getArtifactId().equals( requestArtifact.getArtifactId() )
-        // We are taking as much as we can from the DefaultArtifact.equals(). The requested artifact has no file so
+                && s.getGroupId().equals( requestArtifact.getGroupId() )
-        // we want to remove that from the comparison.
+                && s.getVersion().equals( requestArtifact.getVersion() )
-        //
+                && s.getExtension().equals( requestArtifact.getExtension() )
-        return requested.getArtifactId().equals( attached.getArtifactId() )
+                && s.getClassifier().equals( requestArtifact.getClassifier() );
-            && requested.getGroupId().equals( attached.getGroupId() )
+
-            && requested.getVersion().equals( attached.getVersion() )
-            && requested.getExtension().equals( attached.getExtension() )
-            && requested.getClassifier().equals( attached.getClassifier() );
     }
 
     /**

maven-core/src/main/java/org/apache/maven/RepositoryUtils.java

@@ -26,6 +26,8 @@ import java.util.Iterator;
 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 class RepositoryUtils
 
         Artifact result = toArtifact( artifact );
 
-        List<Exclusion> excl = null;
+        List<Exclusion> excl = Optional.ofNullable( exclusions )
-        if ( exclusions != null )
+                .orElse( Collections.emptyList() )
-        {
+                .stream()
-            excl = new ArrayList<>( exclusions.size() );
+                .map( RepositoryUtils::toExclusion )
-            for ( org.apache.maven.model.Exclusion exclusion : exclusions )
+                .collect( Collectors.toList() );
-            {
-                excl.add( toExclusion( exclusion ) );
-            }
-        }
-
         return new Dependency( result, artifact.getScope(), artifact.isOptional(), excl );
     }
 
     public static List<RemoteRepository> toRepos( List<ArtifactRepository> repos )
     {
-        if ( repos == null )
+        return Optional.ofNullable( repos )
-        {
+                .orElse( Collections.emptyList() )
-            return null;
+                .stream()
-        }
+                .map( RepositoryUtils::toRepo )
-
+                .collect( Collectors.toList() );
-        List<RemoteRepository> results = new ArrayList<>( repos.size() );
-        for ( ArtifactRepository repo : repos )
-        {
-            results.add( toRepo( repo ) );
-        }
-        return results;
     }
 
     public static RemoteRepository toRepo( ArtifactRepository repo )
@@ -316,11 +307,8 @@ public class RepositoryUtils
             new DefaultArtifact( dependency.getGroupId(), dependency.getArtifactId(), dependency.getClassifier(), null,
                                  dependency.getVersion(), props, stereotype );
 
-        List<Exclusion> exclusions = new ArrayList<>( dependency.getExclusions().size() );
+        List<Exclusion> exclusions =
-        for ( org.apache.maven.model.Exclusion exclusion : dependency.getExclusions() )
+                dependency.getExclusions().stream().map( RepositoryUtils::toExclusion ).collect( Collectors.toList() );
-        {
-            exclusions.add( toExclusion( exclusion ) );
-        }
 
         Dependency result = new Dependency( artifact,
                                             dependency.getScope(),
@@ -363,12 +351,7 @@ public class RepositoryUtils
 
     public static Collection<Artifact> toArtifacts( Collection<org.apache.maven.artifact.Artifact> artifactsToConvert )
     {
-        List<Artifact> artifacts = new ArrayList<>();
+        return artifactsToConvert.stream().map( RepositoryUtils::toArtifact ).collect( Collectors.toList() );
-        for ( org.apache.maven.artifact.Artifact a : artifactsToConvert )
-        {
-            artifacts.add( toArtifact( a ) );
-        }
-        return artifacts;
     }
 
     public static WorkspaceRepository getWorkspace( RepositorySystemSession session )

maven-core/src/main/java/org/apache/maven/artifact/resolver/filter/ExclusionArtifactFilter.java

@@ -19,11 +19,12 @@ package org.apache.maven.artifact.resolver.filter;
  * 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 class ExclusionArtifactFilter implements ArtifactFilter
         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 )
+        return !exclusions.stream().anyMatch( exclude( artifact ) );
-        {
-            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;
     }
 }

maven-core/src/main/java/org/apache/maven/execution/MavenSession.java

@@ -84,15 +84,9 @@ public class MavenSession
         if ( !projects.isEmpty() )
         {
             this.currentProject = projects.get( 0 );
-            this.topLevelProject = currentProject;
+            this.topLevelProject =
-            for ( MavenProject project : projects )
+                    projects.stream().filter( project -> project.isExecutionRoot() ).findFirst()
-            {
+                            .orElse( currentProject );
-                if ( project.isExecutionRoot() )
-                {
-                    topLevelProject = project;
-                    break;
-                }
-            }
         }
         else
         {

maven-core/src/main/java/org/apache/maven/extension/internal/CoreExports.java

@@ -20,14 +20,16 @@ package org.apache.maven.extension.internal;
  */
 
 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 class CoreExports
 
     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 ) );
     }
 
     /**

maven-core/src/main/java/org/apache/maven/lifecycle/mapping/DefaultLifecycleMapping.java

@@ -19,10 +19,14 @@ package org.apache.maven.lifecycle.mapping;
  * under the License.
  */
 
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.toMap;
+
 /**
  * DefaultLifecycleMapping
  */
@@ -38,7 +42,28 @@ public class DefaultLifecycleMapping
     private Map<String, LifecyclePhase> phases;
 
     /**
-     * Populates the lifecycle map from the injected list of lifecycle mappings (if not already done).
+     * Default ctor for plexus compatibility: lifecycles are most commonly defined in Plexus XML, that does field
+     * injection. Still, for Plexus to be able to instantiate this class, default ctor is needed.
+     *
+     * @deprecated Should not be used in Java code.
+     */
+    @Deprecated
+    public DefaultLifecycleMapping()
+    {
+    }
+
+    /**
+     * Ctor to be used in Java code/providers.
+     */
+    public DefaultLifecycleMapping( final List<Lifecycle> lifecycles )
+    {
+        this.lifecycleMap = Collections.unmodifiableMap(
+                lifecycles.stream().collect( toMap( Lifecycle::getId, identity() ) )
+        );
+    }
+
+    /**
+     * Plexus: Populates the lifecycle map from the injected list of lifecycle mappings (if not already done).
      */
     private void initLifecycleMap()
     {
@@ -79,6 +104,7 @@ public class DefaultLifecycleMapping
         }
     }
 
+    @Override
     public Map<String, Lifecycle> getLifecycles()
     {
         initLifecycleMap();
@@ -86,6 +112,8 @@ public class DefaultLifecycleMapping
         return lifecycleMap;
     }
 
+    @Deprecated
+    @Override
     public List<String> getOptionalMojos( String lifecycle )
     {
         return null;
@@ -110,7 +138,7 @@ public class DefaultLifecycleMapping
             return null;
         }
     }
-    
+
     @Deprecated
     public Map<String, String> getPhases( String lifecycle )
     {

maven-model-builder/src/main/java/org/apache/maven/model/profile/DefaultProfileActivationContext.java

@@ -21,12 +21,13 @@ package org.apache.maven.model.profile;
 
 import java.io.File;
 import java.util.Collections;
-import java.util.Enumeration;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 
+import static java.util.stream.Collectors.collectingAndThen;
+import static java.util.stream.Collectors.toMap;
+
 /**
  * Describes the environmental context used to determine the activation status of profiles.
  *
@@ -230,8 +231,11 @@ public class DefaultProfileActivationContext
     {
         if ( projectProperties != null )
         {
-
+            this.projectProperties = projectProperties.entrySet().stream()
-            this.projectProperties = Collections.unmodifiableMap( toMap( projectProperties ) );
+                    .collect(
+                            collectingAndThen(
+                                    toMap( k -> String.valueOf( k.getKey() ), v -> String.valueOf( v ) ),
+                                    Collections::unmodifiableMap ) );
         }
         else
         {
@@ -241,19 +245,4 @@ public class DefaultProfileActivationContext
         return this;
     }
 
-    private Map<String, String> toMap( Properties properties )
-    {
-        if ( properties == null )
-        {
-            return Collections.emptyMap();
-        }
-        Map<String, String> map = new HashMap<>();
-        Enumeration keys = properties.keys();
-        while ( keys.hasMoreElements() )
-        {
-            String key = (String) keys.nextElement();
-            map.put( key, properties.getProperty( key ) );
-        }
-        return map;
-    }
 }