[Feature] implement getting pending enrollment requests

src/main/java/com/itasocialacademy/oitassist/participation/controller/ApplicationController.java

@@ -1,7 +1,10 @@
 package com.itasocialacademy.oitassist.participation.controller;
 
+import com.itasocialacademy.oitassist.core.dao.dto.response.PageResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.CreateApplicationRequest;
+import com.itasocialacademy.oitassist.participation.dao.dto.request.EnrollmentRequestsFilter;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.RejectEnrollmentRequest;
+import com.itasocialacademy.oitassist.participation.dao.dto.response.ApplicationListItemResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.CreateApplicationResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.ProcessApplicationResponse;
 import com.itasocialacademy.oitassist.participation.service.interfaces.ApplicationService;
@@ -11,8 +14,10 @@
 import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
-import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
+import org.springdoc.core.annotations.ParameterObject;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.access.prepost.PreAuthorize;
@@ -21,7 +26,7 @@
 
 @RestController
 @RequiredArgsConstructor
-@RequestMapping("/api/v1/competitions/applications")
+@RequestMapping("/api/v1")
 @Tag(name = "Application Manager v1", description = "Operations related to competition applications")
 public class ApplicationController {
     private final ApplicationService applicationService;
@@ -51,11 +56,14 @@ public class ApplicationController {
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('USER')")
-    @PostMapping
+    @PostMapping("/competitions/{competitionId}/stages/{stageId}/applications")
     public ResponseEntity<CreateApplicationResponse> apply(
-        @Valid @RequestBody CreateApplicationRequest createApplicationRequest) {
+        @PathVariable Long competitionId,
+        @PathVariable Long stageId) {
+        CreateApplicationRequest request = CreateApplicationRequest.builder()
+            .competitionId(competitionId).stageId(stageId).build();
         return ResponseEntity.status(HttpStatus.CREATED)
-            .body((CreateApplicationResponse) applicationService.sendEnrollmentRequest(createApplicationRequest));
+            .body((CreateApplicationResponse) applicationService.sendEnrollmentRequest(request));
     }
 
     @Operation(
@@ -74,7 +82,7 @@ public ResponseEntity<CreateApplicationResponse> apply(
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('ORG')")
-    @PostMapping("/accept/{id}")
+    @PostMapping("/enrollment/applications/{id}/accept")
     public ResponseEntity<ProcessApplicationResponse> acceptRequest(@PathVariable Long id) {
         return ResponseEntity.status(HttpStatus.CREATED)
             .body((ProcessApplicationResponse) applicationService.acceptRequest(id));
@@ -95,7 +103,7 @@ public ResponseEntity<ProcessApplicationResponse> acceptRequest(@PathVariable Lo
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('ORG')")
-    @PatchMapping("/reject/{id}")
+    @PatchMapping("/enrollment/applications/{id}/reject")
     public ResponseEntity<ProcessApplicationResponse> rejectRequest(
         @PathVariable Long id,
         @RequestBody RejectEnrollmentRequest rejectEnrollmentRequest) {
@@ -111,7 +119,7 @@ public ResponseEntity<ProcessApplicationResponse> rejectRequest(
             content = @Content(mediaType = "application/json",
                 schema = @Schema(implementation = ProcessApplicationResponse.class))),
         @ApiResponse(responseCode = "400", description = """
-            User is unable to apply. Possible reasons:\s
+            User is unable to cancel the request. Possible reasons:\s
             - The user is not the owner of the application.\s
             - The application request's status is not PENDING.""",
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))),
@@ -121,9 +129,42 @@ public ResponseEntity<ProcessApplicationResponse> rejectRequest(
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('USER')")
-    @PatchMapping("/cancel/{id}")
+    @PatchMapping("/enrollment/applications/{id}/cancel")
     public ResponseEntity<ProcessApplicationResponse> cancelRequest(@PathVariable Long id) {
         return ResponseEntity.status(HttpStatus.OK)
             .body((ProcessApplicationResponse) applicationService.cancelRequest(id));
     }
+
+    @Operation(
+        summary = "Get users' application requests",
+        description = "Retrieves a paginated list of application requests "
+            + "for a specific competition stage.")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200", description = "Applications retrieved successfully",
+            content = @Content(mediaType = "application/json",
+                schema = @Schema(implementation = ApplicationListItemResponse.class))),
+        @ApiResponse(responseCode = "400", description = """
+            The competition and stage info error. The reason: \s
+            specified stage ID does not belong to the competition ID.""",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))),
+        @ApiResponse(responseCode = "403", description = "Access denied (requires ORG role)",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))),
+        @ApiResponse(responseCode = "404", description = """
+            Resource missing. Possible reasons:\s
+            - The requested competition does not exist.\s
+            - The requested stage does not exist.""",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
+    })
+    @PreAuthorize("hasRole('ORG')")
+    @GetMapping("/competitions/{competitionId}/stages/{stageId}/applications")
+    public ResponseEntity<PageResponse<ApplicationListItemResponse>> getRequests(
+        @PathVariable Long competitionId,
+        @PathVariable Long stageId,
+        @RequestParam(required = false) String search,
+        @ParameterObject @PageableDefault(size = 20, sort = "issuedAt") Pageable pageable) {
+        EnrollmentRequestsFilter request = EnrollmentRequestsFilter.builder()
+            .competitionId(competitionId).stageId(stageId).build();
+        return ResponseEntity.status(HttpStatus.OK)
+            .body(PageResponse.from(applicationService.getEnrollmentRequests(request, search, pageable)));
+    }
 }

src/main/java/com/itasocialacademy/oitassist/participation/controller/InvitationController.java

@@ -1,8 +1,11 @@
 package com.itasocialacademy.oitassist.participation.controller;
 
+import com.itasocialacademy.oitassist.core.dao.dto.response.PageResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.CreateInvitationRequest;
+import com.itasocialacademy.oitassist.participation.dao.dto.request.EnrollmentRequestsFilter;
 import com.itasocialacademy.oitassist.participation.dao.dto.request.RejectEnrollmentRequest;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.CreateInvitationResponse;
+import com.itasocialacademy.oitassist.participation.dao.dto.response.InvitationListItemResponse;
 import com.itasocialacademy.oitassist.participation.dao.dto.response.ProcessInvitationResponse;
 import com.itasocialacademy.oitassist.participation.service.interfaces.InvitationService;
 import io.swagger.v3.oas.annotations.Operation;
@@ -13,6 +16,9 @@
 import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
+import org.springdoc.core.annotations.ParameterObject;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.access.prepost.PreAuthorize;
@@ -21,7 +27,7 @@
 
 @RestController
 @RequiredArgsConstructor
-@RequestMapping("/api/v1/competitions/invitations")
+@RequestMapping("/api/v1")
 @Tag(name = "Invitation Manager v1", description = "Operations related to competition invitations")
 public class InvitationController {
     private final InvitationService invitationService;
@@ -54,8 +60,10 @@ public class InvitationController {
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('ORG')")
-    @PostMapping
+    @PostMapping("/competitions/{competitionId}/stages/{stageId}/invitations")
     public ResponseEntity<CreateInvitationResponse> invite(
+        @PathVariable Long competitionId,
+        @PathVariable Long stageId,
         @Valid @RequestBody CreateInvitationRequest createInvitationRequest) {
         return ResponseEntity.status(HttpStatus.CREATED)
             .body((CreateInvitationResponse) invitationService.sendEnrollmentRequest(createInvitationRequest));
@@ -77,7 +85,7 @@ public ResponseEntity<CreateInvitationResponse> invite(
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('USER')")
-    @PostMapping("/accept/{id}")
+    @PostMapping("/enrollment/invitations/{id}/accept")
     public ResponseEntity<ProcessInvitationResponse> acceptRequest(@PathVariable Long id) {
         return ResponseEntity.status(HttpStatus.CREATED)
             .body((ProcessInvitationResponse) invitationService.acceptRequest(id));
@@ -98,7 +106,7 @@ public ResponseEntity<ProcessInvitationResponse> acceptRequest(@PathVariable Lon
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('USER')")
-    @PatchMapping("/reject/{id}")
+    @PatchMapping("/enrollment/invitations/{id}/reject")
     public ResponseEntity<ProcessInvitationResponse> rejectRequest(
         @PathVariable Long id,
         @RequestBody RejectEnrollmentRequest rejectEnrollmentRequest) {
@@ -124,9 +132,42 @@ public ResponseEntity<ProcessInvitationResponse> rejectRequest(
             content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
     })
     @PreAuthorize("hasRole('ORG')")
-    @PatchMapping("/cancel/{id}")
+    @PatchMapping("/enrollment/invitations/{id}/cancel")
     public ResponseEntity<ProcessInvitationResponse> cancelRequest(@PathVariable Long id) {
         return ResponseEntity.status(HttpStatus.OK)
             .body((ProcessInvitationResponse) invitationService.cancelRequest(id));
     }
+
+    @Operation(
+        summary = "Get users' pending invitations",
+        description = "Retrieves a paginated list of invitations "
+            + "for a specific competition stage.")
+    @ApiResponses(value = {
+        @ApiResponse(responseCode = "200", description = "Invitations retrieved successfully",
+            content = @Content(mediaType = "application/json",
+                schema = @Schema(implementation = InvitationListItemResponse.class))),
+        @ApiResponse(responseCode = "400", description = """
+            The competition and stage info error. The reason: \s
+            specified stage ID does not belong to the competition ID.""",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))),
+        @ApiResponse(responseCode = "403", description = "Access denied (requires ORG role)",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class))),
+        @ApiResponse(responseCode = "404", description = """
+            Resource missing. Possible reasons:\s
+            - The requested competition does not exist.\s
+            - The requested stage does not exist.""",
+            content = @Content(mediaType = "application/json", schema = @Schema(implementation = ErrorResponse.class)))
+    })
+    @PreAuthorize("hasRole('ORG')")
+    @GetMapping("/competitions/{competitionId}/stages/{stageId}/invitations")
+    public ResponseEntity<PageResponse<InvitationListItemResponse>> getRequests(
+        @PathVariable Long competitionId,
+        @PathVariable Long stageId,
+        @RequestParam(required = false) String search,
+        @ParameterObject @PageableDefault(size = 20, sort = "issuedAt") Pageable pageable) {
+        EnrollmentRequestsFilter request = EnrollmentRequestsFilter.builder()
+            .competitionId(competitionId).stageId(stageId).build();
+        return ResponseEntity.status(HttpStatus.OK)
+            .body(PageResponse.from(invitationService.getEnrollmentRequests(request, search, pageable)));
+    }
 }

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/request/AbstractEnrollmentFilter.java

@@ -0,0 +1,29 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.request;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import jakarta.validation.constraints.NotNull;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import lombok.experimental.SuperBuilder;
+
+@SuperBuilder
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public abstract class AbstractEnrollmentFilter {
+    @Schema(
+        description = "Unique identifier of the competition",
+        example = "1",
+        requiredMode = Schema.RequiredMode.REQUIRED)
+    @NotNull
+    private Long competitionId;
+    @Schema(
+        description = "Unique identifier of the stage",
+        example = "2",
+        requiredMode = Schema.RequiredMode.REQUIRED)
+    @NotNull
+    private Long stageId;
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/request/EnrollmentRequestsFilter.java

@@ -0,0 +1,17 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.request;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.AllArgsConstructor;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.Setter;
+import lombok.experimental.SuperBuilder;
+
+@Getter
+@Setter
+@AllArgsConstructor
+@EqualsAndHashCode(callSuper = true)
+@SuperBuilder
+@Schema(description = "DTO for getting the enrollment requests list.")
+public class EnrollmentRequestsFilter extends AbstractEnrollmentFilter {
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/response/ApplicationListItemResponse.java

@@ -0,0 +1,13 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.response;
+
+import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.time.Instant;
+
+@Schema(description = "DTO representing the each application request's details in the list.")
+public record ApplicationListItemResponse(
+    @Schema(description = "Unique identifier of the request", example = "1") Long applicationId,
+    @Schema(description = "Request creation date", example = "2026-06-07T09:50:30Z") Instant issuedAt,
+    @Schema(description = "Current request status", example = "PENDING") RequestStatus status,
+    UserSummary user) {
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/response/InvitationListItemResponse.java

@@ -0,0 +1,13 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.response;
+
+import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.time.Instant;
+
+@Schema(description = "DTO representing the each invitation's details in the list.")
+public record InvitationListItemResponse(
+    @Schema(description = "Unique identifier of the request", example = "1") Long invitationId,
+    @Schema(description = "Request creation date", example = "2026-06-07T09:50:30Z") Instant issuedAt,
+    @Schema(description = "Current request status", example = "PENDING") RequestStatus status,
+    UserSummary user) {
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/dto/response/UserSummary.java

@@ -0,0 +1,10 @@
+package com.itasocialacademy.oitassist.participation.dao.dto.response;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+
+@Schema(description = "DTO representing the each user's details of each enrollment request in the list.")
+public record UserSummary(
+    @Schema(description = "User's first name", example = "Ivan") String firstName,
+    @Schema(description = "User's surname", example = "Petrenko") String surname,
+    @Schema(description = "User's email address", example = "ivapetr@gmail.com") String email) {
+}

src/main/java/com/itasocialacademy/oitassist/participation/dao/repository/ApplicationRepository.java

@@ -3,10 +3,11 @@
 import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
 import com.itasocialacademy.oitassist.participation.dao.model.Application;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.stereotype.Repository;
 
 @Repository
-public interface ApplicationRepository extends JpaRepository<Application, Long> {
+public interface ApplicationRepository extends JpaRepository<Application, Long>, JpaSpecificationExecutor<Application> {
     boolean existsByIssuedByAndCompetitionIdAndStageIdAndStatus(
         Long studentId,
         Long competitionId,

src/main/java/com/itasocialacademy/oitassist/participation/dao/repository/InvitationRepository.java

@@ -3,11 +3,12 @@
 import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
 import com.itasocialacademy.oitassist.participation.dao.model.Invitation;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 import org.springframework.stereotype.Repository;
 import java.util.List;
 
 @Repository
-public interface InvitationRepository extends JpaRepository<Invitation, Long> {
+public interface InvitationRepository extends JpaRepository<Invitation, Long>, JpaSpecificationExecutor<Invitation> {
     List<Invitation> findByStudentIdInAndCompetitionIdAndStageIdAndStatus(
         List<Long> studentId,
         Long competitionId,

src/main/java/com/itasocialacademy/oitassist/participation/dao/specification/ApplicationSpecification.java

@@ -0,0 +1,28 @@
+package com.itasocialacademy.oitassist.participation.dao.specification;
+
+import com.itasocialacademy.oitassist.participation.dao.enums.RequestStatus;
+import com.itasocialacademy.oitassist.participation.dao.model.Application;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import org.springframework.data.jpa.domain.Specification;
+import java.util.List;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class ApplicationSpecification {
+    public static Specification<Application> hasCompetitionAndStage(Long competitionId, Long stageId) {
+        return (root, query, cb) -> cb.and(
+            cb.equal(root.get("competitionId"), competitionId),
+            cb.equal(root.get("stageId"), stageId));
+    }
+
+    public static Specification<Application> userIdIn(List<Long> userIds) {
+        return (root, query, cb) -> userIds == null
+            ? cb.conjunction()
+            : root.get("issuedBy").in(userIds);
+    }
+
+    public static Specification<Application> hasStatus(RequestStatus status) {
+        return (root, query, cb) -> cb.and(
+            cb.equal(root.get("status"), status));
+    }
+}