Implement trackhasartist relationship management

Add complete implementation for track-artist relationship management,
  following the established albumhasgenre pattern. This enables tracking
  which artists are associated with each track in the media library.

  Changes:
  - Fix TrackHasArtist model: Rename from TrackHasArtistt.java (typo)
    and correct table name from "trackhasgenre" to "trackhasartist"
  - Implement TrackHasArtistRepository with full CRUD operations
  - Implement TrackHasArtistService with business logic and validation
  - Add TrackHasArtistMapper for entity/protobuf conversion
  - Create action handlers:
    * CreateTrackHasArtistHandler (trackhasartist.create)
    * DeleteTrackHasArtistHandler (trackhasartist.delete)
    * GetTrackHasArtistByIdHandler (trackhasartist.getById)
    * GetTrackHasArtistHandler (trackhasartist.getAll)
  - Register TrackHasArtistService in DelegateActionManager for
    automatic handler discovery and dependency injection
  - Proto file (trackhasartist.proto) was already correct

  The implementation validates track and artist existence before creating
  relationships and provides proper error handling with appropriate HTTP
  status codes.

  🤖 Generated with [Claude Code](https://claude.com/claude-code)

  Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/main/java/com/mediamanager/mapper/TrackHasArtistMapper.java

@@ -0,0 +1,47 @@
+package com.mediamanager.mapper;
+
+import com.mediamanager.model.TrackHasArtist;
+import com.mediamanager.protocol.messages.TrackHasArtistMessages;
+
+public class TrackHasArtistMapper {
+    public static TrackHasArtistMessages.TrackHasArtist toProtobuf(TrackHasArtist entity) {
+        if (entity == null) {
+            return null;
+        }
+
+        TrackHasArtistMessages.TrackHasArtist.Builder builder = TrackHasArtistMessages.TrackHasArtist.newBuilder();
+
+        Integer id = entity.getId();
+        if (id != null) {
+            builder.setId(id);
+        }
+
+        // Map Track foreign key
+        if (entity.getTrack() != null && entity.getTrack().getId() != null) {
+            builder.setFkTrackId(entity.getTrack().getId());
+        }
+
+        // Map Artist foreign key
+        if (entity.getArtist() != null && entity.getArtist().getId() != null) {
+            builder.setFkArtistId(entity.getArtist().getId());
+        }
+
+        return builder.build();
+    }
+
+    public static TrackHasArtist toEntity(TrackHasArtistMessages.TrackHasArtist protobuf) {
+        if (protobuf == null) {
+            return null;
+        }
+
+        TrackHasArtist entity = new TrackHasArtist();
+
+        if (protobuf.getId() > 0) {
+            entity.setId(protobuf.getId());
+        }
+
+        // Note: Foreign key relationships (Track, Artist) are handled in the service layer
+
+        return entity;
+    }
+}

src/main/java/com/mediamanager/model/TrackHasArtist.java

@@ -0,0 +1,55 @@
+package com.mediamanager.model;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name = "trackhasartist")
+public class TrackHasArtist {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "fk_track_id", nullable = false)
+    private Track track;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "fk_artist_id", nullable = false)
+    private Artist artist;
+
+    public TrackHasArtist() {}
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public Track getTrack() {
+        return track;
+    }
+
+    public void setTrack(Track track) {
+        this.track = track;
+    }
+
+    public Artist getArtist() {
+        return artist;
+    }
+
+    public void setArtist(Artist artist) {
+        this.artist = artist;
+    }
+
+    @Override
+    public String toString() {
+        return "TrackHasArtist{" +
+                "id=" + id +
+                ", trackId=" + (track != null ? track.getId() : null) +
+                ", artistId=" + (artist != null ? artist.getId() : null) +
+                '}';
+    }
+}

src/main/java/com/mediamanager/repository/TrackHasArtistRepository.java

@@ -0,0 +1,85 @@
+package com.mediamanager.repository;
+
+
+import com.mediamanager.model.TrackHasArtist;
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+
+import java.util.List;
+import java.util.Optional;
+
+public class TrackHasArtistRepository {
+    private static final Logger logger = LogManager.getLogger(TrackHasArtistRepository.class);
+
+    private final EntityManagerFactory entityManagerFactory;
+
+    public TrackHasArtistRepository(EntityManagerFactory entityManagerFactory) {
+        this.entityManagerFactory = entityManagerFactory;
+    }
+
+    public TrackHasArtist save(TrackHasArtist trackHasArtist) {
+        logger.debug("Saving TrackHasArtist: {}", trackHasArtist);
+        EntityManager em = entityManagerFactory.createEntityManager();
+        em.getTransaction().begin();
+        try {
+            em.persist(trackHasArtist);
+            em.getTransaction().commit();
+            logger.debug("TrackHasArtist has been saved successfully");
+            return trackHasArtist;
+        } catch (Exception e) {
+            em.getTransaction().rollback();
+            logger.error("Error while saving TrackHasArtist: {}", e.getMessage());
+            throw e;
+        } finally {
+            if (em.isOpen()) em.close();
+        }
+    }
+
+    public List<TrackHasArtist> findAll() {
+        logger.debug("Finding All TrackHasArtist");
+        EntityManager em = entityManagerFactory.createEntityManager();
+        try{
+            return em.createQuery("select t from TrackHasArtist t", TrackHasArtist.class).getResultList();
+        }finally {
+            if (em.isOpen()) em.close();
+        }
+    }
+
+    public Optional<TrackHasArtist> findById(Integer id) {
+        logger.debug("Finding TrackHasArtist with id: {}", id);
+        EntityManager em = entityManagerFactory.createEntityManager();
+        try{
+            TrackHasArtist trackHasArtist = em.find(TrackHasArtist.class, id);
+            return Optional.ofNullable(trackHasArtist);
+        }finally {
+            if (em.isOpen()) em.close();
+        }
+    }
+
+    public boolean deleteById(Integer id){
+        logger.debug("Deleting TrackHasArtist with id: {}", id);
+        EntityManager em = entityManagerFactory.createEntityManager();
+        em.getTransaction().begin();
+        try{
+            TrackHasArtist trackHasArtist = em.find(TrackHasArtist.class, id);
+            if (trackHasArtist == null) {
+                em.getTransaction().rollback();
+                return false;
+            }
+            em.remove(trackHasArtist);
+            em.getTransaction().commit();
+            logger.debug("TrackHasArtist has been deleted successfully");
+            return true;
+        } catch (Exception e) {
+            em.getTransaction().rollback();
+            logger.error("Error while deleting TrackHasArtist: {}", e.getMessage());
+            throw e;
+        } finally {
+            if (em.isOpen()) em.close();
+        }
+    }
+
+}

src/main/java/com/mediamanager/service/delegate/DelegateActionManager.java

@@ -13,6 +13,7 @@ import com.mediamanager.service.bitdepth.BitDepthService;
 import com.mediamanager.service.bitrate.BitRateService;
 import com.mediamanager.service.composer.ComposerService;
 import com.mediamanager.service.trackhasgenre.TrackHasGenreService;
+import com.mediamanager.service.trackhasartist.TrackHasArtistService;
 
 import com.mediamanager.repository.GenreRepository;
 import com.mediamanager.service.artist.ArtistService;
@@ -117,6 +118,10 @@ public class DelegateActionManager {
         TrackHasGenreService trackHasGenreService = new TrackHasGenreService(trackHasGenreRepository, trackRepository, genreRepository);
         serviceLocator.register(TrackHasGenreService.class, trackHasGenreService);
 
+        TrackHasArtistRepository trackHasArtistRepository = new TrackHasArtistRepository(entityManagerFactory);
+        TrackHasArtistService trackHasArtistService = new TrackHasArtistService(trackHasArtistRepository, trackRepository, artistRepository);
+        serviceLocator.register(TrackHasArtistService.class, trackHasArtistService);
+
         serviceLocator.logRegisteredServices();
 
         logger.info("Services initialized successfully");

src/main/java/com/mediamanager/service/delegate/handler/trackhasartist/CreateTrackHasArtistHandler.java

@@ -0,0 +1,54 @@
+package com.mediamanager.service.delegate.handler.trackhasartist;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.mediamanager.mapper.TrackHasArtistMapper;
+import com.mediamanager.model.TrackHasArtist;
+import com.mediamanager.protocol.TransportProtocol;
+import com.mediamanager.protocol.messages.TrackHasArtistMessages;
+import com.mediamanager.service.delegate.ActionHandler;
+import com.mediamanager.service.delegate.annotation.Action;
+import com.mediamanager.service.trackhasartist.TrackHasArtistService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+@Action("trackhasartist.create")
+public class CreateTrackHasArtistHandler implements ActionHandler {
+    private static final Logger logger = LogManager.getLogger(CreateTrackHasArtistHandler.class);
+    private final TrackHasArtistService trackHasArtistService;
+
+    public CreateTrackHasArtistHandler(TrackHasArtistService trackHasArtistService) {
+        this.trackHasArtistService = trackHasArtistService;
+    }
+
+    @Override
+    public TransportProtocol.Response.Builder handle(ByteString requestPayload) throws InvalidProtocolBufferException {
+        try{
+            TrackHasArtistMessages.CreateTrackHasArtistRequest createRequest =
+                    TrackHasArtistMessages.CreateTrackHasArtistRequest.parseFrom(requestPayload);
+
+            TrackHasArtist trackHasArtist = trackHasArtistService.createTrackHasArtist(
+                    createRequest.getFkTrackId() > 0 ? createRequest.getFkTrackId() : null,
+                    createRequest.getFkArtistId() > 0 ? createRequest.getFkArtistId() : null
+            );
+
+            TrackHasArtistMessages.TrackHasArtist trackHasArtistProto = TrackHasArtistMapper.toProtobuf(trackHasArtist);
+            TrackHasArtistMessages.CreateTrackHasArtistResponse createTrackHasArtistResponse = TrackHasArtistMessages.CreateTrackHasArtistResponse.newBuilder()
+                    .setTrackhasartist(trackHasArtistProto)
+                    .build();
+            return TransportProtocol.Response.newBuilder()
+                    .setPayload(createTrackHasArtistResponse.toByteString());
+        } catch (IllegalArgumentException e) {
+            logger.error("Validation error", e);
+            return TransportProtocol.Response.newBuilder()
+                    .setStatusCode(400)
+                    .setPayload(ByteString.copyFromUtf8("Validation error: " + e.getMessage()));
+
+        } catch (Exception e) {
+            logger.error("Error creating track has artist", e);
+            return TransportProtocol.Response.newBuilder()
+                    .setStatusCode(500)
+                    .setPayload(ByteString.copyFromUtf8("Error: " + e.getMessage()));
+        }
+    }
+}

src/main/java/com/mediamanager/service/delegate/handler/trackhasartist/DeleteTrackHasArtistHandler.java

@@ -0,0 +1,62 @@
+package com.mediamanager.service.delegate.handler.trackhasartist;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.mediamanager.protocol.TransportProtocol;
+import com.mediamanager.protocol.messages.TrackHasArtistMessages;
+import com.mediamanager.service.delegate.ActionHandler;
+import com.mediamanager.service.delegate.annotation.Action;
+import com.mediamanager.service.trackhasartist.TrackHasArtistService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+@Action("trackhasartist.delete")
+public class DeleteTrackHasArtistHandler implements ActionHandler {
+    private static final Logger logger = LogManager.getLogger(DeleteTrackHasArtistHandler.class);
+
+    private final TrackHasArtistService trackHasArtistService;
+
+    public DeleteTrackHasArtistHandler(TrackHasArtistService trackHasArtistService) {
+        this.trackHasArtistService = trackHasArtistService;
+    }
+
+    @Override
+    public TransportProtocol.Response.Builder handle(ByteString requestPayload)
+            throws InvalidProtocolBufferException {
+
+        try {
+            TrackHasArtistMessages.DeleteTrackHasArtistRequest deleteRequest =
+                    TrackHasArtistMessages.DeleteTrackHasArtistRequest.parseFrom(requestPayload);
+            int id = deleteRequest.getId();
+            boolean success = trackHasArtistService.deleteTrackHasArtist(id);
+            TrackHasArtistMessages.DeleteTrackHasArtistResponse deleteResponse;
+            if (success) {
+                deleteResponse = TrackHasArtistMessages.DeleteTrackHasArtistResponse.newBuilder()
+                        .setSuccess(true)
+                        .setMessage("Track has artist deleted successfully")
+                        .build();
+                return TransportProtocol.Response.newBuilder()
+                        .setPayload(deleteResponse.toByteString());
+            } else {
+                deleteResponse = TrackHasArtistMessages.DeleteTrackHasArtistResponse.newBuilder()
+                        .setSuccess(false)
+                        .setMessage("Track has artist not found")
+                        .build();
+
+                return TransportProtocol.Response.newBuilder()
+                        .setStatusCode(404)
+                        .setPayload(deleteResponse.toByteString());
+            }
+        } catch (Exception e) {
+            logger.error("Error deleting track has artist", e);
+            TrackHasArtistMessages.DeleteTrackHasArtistResponse deleteResponse =
+                    TrackHasArtistMessages.DeleteTrackHasArtistResponse.newBuilder()
+                            .setSuccess(false)
+                            .setMessage("Error: " + e.getMessage())
+                            .build();
+            return TransportProtocol.Response.newBuilder()
+                    .setStatusCode(500)
+                    .setPayload(deleteResponse.toByteString());
+        }
+    }
+    }

src/main/java/com/mediamanager/service/delegate/handler/trackhasartist/GetTrackHasArtistByIdHandler.java

@@ -0,0 +1,56 @@
+package com.mediamanager.service.delegate.handler.trackhasartist;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.mediamanager.mapper.TrackHasArtistMapper;
+import com.mediamanager.model.TrackHasArtist;
+import com.mediamanager.protocol.TransportProtocol;
+import com.mediamanager.protocol.messages.TrackHasArtistMessages;
+import com.mediamanager.service.delegate.ActionHandler;
+import com.mediamanager.service.delegate.annotation.Action;
+import com.mediamanager.service.trackhasartist.TrackHasArtistService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Optional;
+
+@Action(value = "trackhasartist.getById")
+public class GetTrackHasArtistByIdHandler implements ActionHandler {
+    private static final Logger logger = LogManager.getLogger(GetTrackHasArtistByIdHandler.class);
+    private final TrackHasArtistService trackHasArtistService;
+
+    public GetTrackHasArtistByIdHandler(TrackHasArtistService trackHasArtistService) {
+        this.trackHasArtistService = trackHasArtistService;
+    }
+
+    @Override
+    public TransportProtocol.Response.Builder handle(ByteString requestPayload)
+        throws InvalidProtocolBufferException{
+
+        try{
+            TrackHasArtistMessages.GetTrackHasArtistByIdRequest getByIdRequest =
+                    TrackHasArtistMessages.GetTrackHasArtistByIdRequest.parseFrom(requestPayload);
+            int id = getByIdRequest.getId();
+
+            Optional<TrackHasArtist> trackHasArtistOpt = trackHasArtistService.getTrackHasArtistById(id);
+
+            if (trackHasArtistOpt.isEmpty()){
+                logger.warn("TrackHasArtist not found with ID: {}", id);
+                return TransportProtocol.Response.newBuilder()
+                        .setStatusCode(404)
+                        .setPayload(ByteString.copyFromUtf8("TrackHasArtist not found"));
+            }
+            TrackHasArtistMessages.TrackHasArtist trackHasArtistProto = TrackHasArtistMapper.toProtobuf(trackHasArtistOpt.get());
+            TrackHasArtistMessages.GetTrackHasArtistByIdResponse getByIdResponse = TrackHasArtistMessages.GetTrackHasArtistByIdResponse.newBuilder()
+                    .setTrackhasartist(trackHasArtistProto)
+                    .build();
+            return TransportProtocol.Response.newBuilder()
+                    .setPayload(getByIdResponse.toByteString());
+        } catch (Exception e) {
+            logger.error("Error getting track has artist by ID", e);
+            return TransportProtocol.Response.newBuilder()
+                    .setStatusCode(500)
+                    .setPayload(ByteString.copyFromUtf8("Error: "+ e.getMessage()));
+        }
+    }
+}

src/main/java/com/mediamanager/service/delegate/handler/trackhasartist/GetTrackHasArtistHandler.java

@@ -0,0 +1,48 @@
+package com.mediamanager.service.delegate.handler.trackhasartist;
+
+import com.google.protobuf.ByteString;
+import com.google.protobuf.InvalidProtocolBufferException;
+import com.mediamanager.mapper.TrackHasArtistMapper;
+import com.mediamanager.model.TrackHasArtist;
+import com.mediamanager.protocol.TransportProtocol;
+import com.mediamanager.protocol.messages.TrackHasArtistMessages;
+import com.mediamanager.service.delegate.ActionHandler;
+import com.mediamanager.service.delegate.annotation.Action;
+import com.mediamanager.service.trackhasartist.TrackHasArtistService;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.List;
+
+
+@Action("trackhasartist.getAll")
+public class GetTrackHasArtistHandler implements ActionHandler {
+    private static final Logger logger = LogManager.getLogger(GetTrackHasArtistHandler.class);
+
+    private final TrackHasArtistService trackHasArtistService;
+
+    public GetTrackHasArtistHandler(TrackHasArtistService trackHasArtistService){this.trackHasArtistService = trackHasArtistService;}
+
+    @Override
+    public TransportProtocol.Response.Builder handle(ByteString requestPayload) throws InvalidProtocolBufferException {
+        try{
+            List<TrackHasArtist> trackHasArtists = trackHasArtistService.getAllTrackHasArtists();
+            TrackHasArtistMessages.GetTrackHasArtistsResponse.Builder responseBuilder = TrackHasArtistMessages.GetTrackHasArtistsResponse.newBuilder();
+
+            for (TrackHasArtist trackHasArtist : trackHasArtists) {
+                TrackHasArtistMessages.TrackHasArtist trackHasArtistProto = TrackHasArtistMapper.toProtobuf(trackHasArtist);
+                responseBuilder.addTrackhasartist(trackHasArtistProto);
+            }
+            TrackHasArtistMessages.GetTrackHasArtistsResponse getTrackHasArtistsResponse = responseBuilder.build();
+
+            return TransportProtocol.Response.newBuilder()
+                    .setPayload(getTrackHasArtistsResponse.toByteString());
+
+        }catch (Exception e){
+            logger.error("Error getting track has artists", e);
+            return TransportProtocol.Response.newBuilder()
+                    .setStatusCode(500)
+                    .setPayload(ByteString.copyFromUtf8("Error: " + e.getMessage()));
+        }
+    }
+}

src/main/java/com/mediamanager/service/trackhasartist/TrackHasArtistService.java

@@ -0,0 +1,77 @@
+package com.mediamanager.service.trackhasartist;
+
+import com.mediamanager.model.Track;
+import com.mediamanager.model.TrackHasArtist;
+import com.mediamanager.model.Artist;
+import com.mediamanager.repository.TrackHasArtistRepository;
+import com.mediamanager.repository.TrackRepository;
+import com.mediamanager.repository.ArtistRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.List;
+import java.util.Optional;
+
+public class TrackHasArtistService {
+    private static final Logger logger = LogManager.getLogger(TrackHasArtistService.class);
+    private final TrackHasArtistRepository repository;
+    private final TrackRepository trackRepository;
+    private final ArtistRepository artistRepository;
+
+    public TrackHasArtistService(TrackHasArtistRepository repository, TrackRepository trackRepository, ArtistRepository artistRepository) {
+        this.repository = repository;
+        this.trackRepository = trackRepository;
+        this.artistRepository = artistRepository;
+    }
+
+    public TrackHasArtist createTrackHasArtist(Integer trackId, Integer artistId) {
+        logger.debug("Creating track has artist relationship - trackId:{}, artistId:{}", trackId, artistId);
+
+        if (trackId == null || trackId <= 0) {
+            throw new IllegalArgumentException("Track ID cannot be null or invalid");
+        }
+        if (artistId == null || artistId <= 0) {
+            throw new IllegalArgumentException("Artist ID cannot be null or invalid");
+        }
+
+        // Verify Track exists
+        Optional<Track> track = trackRepository.findById(trackId);
+        if (track.isEmpty()) {
+            throw new IllegalArgumentException("Track not found with id: " + trackId);
+        }
+
+        // Verify Artist exists
+        Optional<Artist> artist = artistRepository.findById(artistId);
+        if (artist.isEmpty()) {
+            throw new IllegalArgumentException("Artist not found with id: " + artistId);
+        }
+
+        TrackHasArtist trackHasArtist = new TrackHasArtist();
+        trackHasArtist.setTrack(track.get());
+        trackHasArtist.setArtist(artist.get());
+
+        return repository.save(trackHasArtist);
+    }
+
+    public List<TrackHasArtist> getAllTrackHasArtists() {
+        logger.info("Getting all track has artist relationships");
+        return repository.findAll();
+    }
+
+    public Optional<TrackHasArtist> getTrackHasArtistById(Integer id) {
+        if (id == null) {
+            throw new IllegalArgumentException("ID cannot be null");
+        }
+        logger.info("Getting track has artist by id:{}", id);
+        return repository.findById(id);
+    }
+
+    public boolean deleteTrackHasArtist(Integer id) {
+        if (id == null) {
+            throw new IllegalArgumentException("Track has artist id cannot be null");
+        }
+        logger.info("Deleting track has artist:{}", id);
+        return repository.deleteById(id);
+    }
+
+}

src/main/proto/trackhasartist.proto

@@ -0,0 +1,46 @@
+syntax = "proto3";
+
+option java_package = "com.mediamanager.protocol.messages";
+option java_outer_classname = "TrackHasArtistMessages";
+
+package mediamanager.messages;
+
+message TrackHasArtist{
+  int32 id = 1;
+  int32 fk_track_id = 2;
+  int32 fk_artist_id =3;
+}
+
+message CreateTrackHasArtistRequest {
+  int32 fk_track_id = 1;
+  int32 fk_artist_id = 2;
+}
+
+message CreateTrackHasArtistResponse {
+  TrackHasArtist trackhasartist = 1;
+}
+
+message GetTrackHasArtistsRequest {
+
+}
+
+message GetTrackHasArtistsResponse {
+  repeated TrackHasArtist trackhasartist = 1;
+}
+
+message GetTrackHasArtistByIdRequest {
+  int32 id = 1;
+}
+
+message GetTrackHasArtistByIdResponse {
+  TrackHasArtist trackhasartist = 1;
+}
+
+message DeleteTrackHasArtistRequest {
+  int32 id = 1;
+}
+
+message DeleteTrackHasArtistResponse {
+  bool success = 1;
+  string message = 2;
+}