add update transaction and paginated fetch endpoints

src/main/java/com/SkillsForge/expensetracker/app/filter/TransactionFilter.java

@@ -0,0 +1,13 @@
+package com.SkillsForge.expensetracker.app.filter;
+
+import com.SkillsForge.expensetracker.app.enums.TransactionCategory;
+import com.SkillsForge.expensetracker.app.enums.TransactionType;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class TransactionFilter {
+    private TransactionCategory category;
+    private TransactionType type;
+}

src/main/java/com/SkillsForge/expensetracker/controller/TransactionController.java

@@ -2,18 +2,22 @@
 
 import com.SkillsForge.expensetracker.dto.CreateTransactionRequest;
 import com.SkillsForge.expensetracker.dto.TransactionDto;
+import com.SkillsForge.expensetracker.app.filter.TransactionFilter;
+import com.SkillsForge.expensetracker.dto.TransactionUpdateRequest;
 import com.SkillsForge.expensetracker.service.TransactionService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.web.bind.annotation.*;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
-@Slf4j
 @RequiredArgsConstructor
 @RestController
-@RequestMapping(value = "/api/v1/transaction")
+@RequestMapping("/api/v1/transactions")
 public class TransactionController {
   private final TransactionService transactionService;
 
@@ -29,4 +33,20 @@ public ResponseEntity<TransactionDto> getTransactionById(@PathVariable Long id)
     TransactionDto response = transactionService.getTransactionById(id);
     return ResponseEntity.ok(response);
   }
+
+  @PutMapping("/{id}")
+  public TransactionDto updateTransaction(
+          @PathVariable Long id,
+          @RequestBody TransactionUpdateRequest request
+  ) {
+    return transactionService.updateTransaction(id, request);
+  }
+
+  @GetMapping
+  public Page<TransactionDto> getAllTransactions(
+          @ModelAttribute TransactionFilter filter,
+          Pageable pageable
+  ) {
+    return transactionService.getAllTransactions(filter, pageable);
+  }
 }

src/main/java/com/SkillsForge/expensetracker/dto/TransactionUpdateRequest.java

@@ -0,0 +1,19 @@
+package com.SkillsForge.expensetracker.dto;
+
+import com.SkillsForge.expensetracker.app.enums.TransactionCategory;
+import com.SkillsForge.expensetracker.app.enums.TransactionType;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDate;
+
+@Getter
+@Setter
+public class TransactionUpdateRequest {
+
+    private String description;
+    private TransactionCategory category;
+    private TransactionType type;
+    private Long amount;
+    private LocalDate date;
+}

src/main/java/com/SkillsForge/expensetracker/persistence/repository/TransactionRepository.java

@@ -2,5 +2,9 @@
 
 import com.SkillsForge.expensetracker.persistence.entity.Transaction;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
 
-public interface TransactionRepository extends JpaRepository<Transaction, Long> {}
+public interface TransactionRepository
+        extends JpaRepository<Transaction, Long>,
+        JpaSpecificationExecutor<Transaction> {
+}

src/main/java/com/SkillsForge/expensetracker/service/TransactionService.java

@@ -1,10 +1,21 @@
 package com.SkillsForge.expensetracker.service;
 
-import com.SkillsForge.expensetracker.dto.CreateTransactionRequest;
 import com.SkillsForge.expensetracker.dto.TransactionDto;
+import com.SkillsForge.expensetracker.dto.TransactionUpdateRequest;
+import com.SkillsForge.expensetracker.app.filter.TransactionFilter;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+import com.SkillsForge.expensetracker.dto.CreateTransactionRequest;
 
 public interface TransactionService {
   TransactionDto createTransaction(CreateTransactionRequest request);
 
   TransactionDto getTransactionById(Long id);
+
+  TransactionDto updateTransaction(Long id, TransactionUpdateRequest request);
+
+  Page<TransactionDto> getAllTransactions(TransactionFilter filter, Pageable pageable);
+
+
 }

src/main/java/com/SkillsForge/expensetracker/service/TransactionServiceImpl.java

@@ -1,49 +1,104 @@
 package com.SkillsForge.expensetracker.service;
 
+import com.SkillsForge.expensetracker.app.filter.TransactionFilter;
 import com.SkillsForge.expensetracker.dto.CreateTransactionRequest;
 import com.SkillsForge.expensetracker.dto.TransactionDto;
+import com.SkillsForge.expensetracker.dto.TransactionUpdateRequest;
 import com.SkillsForge.expensetracker.exception.ResourceNotFoundException;
 import com.SkillsForge.expensetracker.persistence.entity.Transaction;
 import com.SkillsForge.expensetracker.persistence.repository.TransactionRepository;
-import java.time.LocalDateTime;
+import jakarta.persistence.criteria.Predicate;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.jpa.domain.Specification;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
 @Service
 @Slf4j
 @RequiredArgsConstructor
 public class TransactionServiceImpl implements TransactionService {
 
-  private final TransactionRepository transactionRepository;
-
-  @Override
-  @Transactional
-  public TransactionDto createTransaction(CreateTransactionRequest request) {
-    LocalDateTime now = LocalDateTime.now();
-
-    Transaction transaction = new Transaction(request);
-    transaction.setCreatedAt(now);
-    transaction.setUpdatedAt(now);
-
-    Transaction savedTransaction = transactionRepository.save(transaction);
-    log.info("Transaction created successfully with ID: {}", savedTransaction.getId());
-    return TransactionDto.fromEntity(savedTransaction);
-  }
-
-  @Override
-  @Transactional(readOnly = true)
-  public TransactionDto getTransactionById(Long id) {
-    log.info("Fetching transaction with ID: {}", id);
-
-    return TransactionDto.fromEntity(
-        transactionRepository
-            .findById(id)
-            .orElseThrow(
-                () -> {
-                  log.error("Transaction not found with ID: {}", id);
-                  return new ResourceNotFoundException("Transaction not found with ID: " + id);
-                }));
-  }
+    private final TransactionRepository transactionRepository;
+
+    // ================= CREATE =================
+    @Override
+    @Transactional
+    public TransactionDto createTransaction(CreateTransactionRequest request) {
+        LocalDateTime now = LocalDateTime.now();
+
+        Transaction transaction = new Transaction(request);
+        transaction.setCreatedAt(now);
+        transaction.setUpdatedAt(now);
+
+        Transaction saved = transactionRepository.save(transaction);
+        log.info("Transaction created successfully with ID: {}", saved.getId());
+
+        return TransactionDto.fromEntity(saved);
+    }
+
+    // ================= GET BY ID =================
+    @Override
+    @Transactional(readOnly = true)
+    public TransactionDto getTransactionById(Long id) {
+        log.info("Fetching transaction with ID: {}", id);
+
+        Transaction transaction = transactionRepository.findById(id)
+                .orElseThrow(() ->
+                        new ResourceNotFoundException("Transaction not found with ID: " + id));
+
+        return TransactionDto.fromEntity(transaction);
+    }
+
+    // ================= UPDATE =================
+    @Override
+    @Transactional
+    public TransactionDto updateTransaction(Long id, TransactionUpdateRequest request) {
+
+        Transaction existing = transactionRepository.findById(id)
+                .orElseThrow(() ->
+                        new ResourceNotFoundException("Transaction not found with ID: " + id));
+
+        existing.setDescription(request.getDescription());
+        existing.setCategory(request.getCategory());
+        existing.setType(request.getType());
+        existing.setAmount(request.getAmount());
+        existing.setDate(request.getDate());
+        existing.setUpdatedAt(LocalDateTime.now());
+
+        Transaction saved = transactionRepository.save(existing);
+        log.info("Transaction updated successfully with ID: {}", saved.getId());
+
+        return TransactionDto.fromEntity(saved);
+    }
+
+    // ================= GET ALL (FILTERED) =================
+    @Override
+    @Transactional(readOnly = true)
+    public Page<TransactionDto> getAllTransactions(TransactionFilter filter, Pageable pageable) {
+
+        Specification<Transaction> spec = (root, query, cb) -> {
+            List<Predicate> predicates = new ArrayList<>();
+
+            if (filter.getCategory() != null) {
+                predicates.add(cb.equal(root.get("category"), filter.getCategory()));
+            }
+
+            if (filter.getType() != null) {
+                predicates.add(cb.equal(root.get("type"), filter.getType()));
+            }
+
+            return cb.and(predicates.toArray(new Predicate[0]));
+        };
+
+        return transactionRepository
+                .findAll(spec, pageable)
+                .map(TransactionDto::fromEntity);
+    }
 }