feat: add InvalidSortFieldException and update GlobalExceptionHandler

src/main/java/com/libraryman_api/exception/GlobalExceptionHandler.java

@@ -31,4 +31,20 @@ public ResponseEntity<?> resourceNotFoundException(ResourceNotFoundException ex,
         ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(), request.getDescription(false));
         return new ResponseEntity<>(errorDetails, HttpStatus.NOT_FOUND);
     }
+
+    /**
+     * Handles {@link InvalidSortFieldException} exceptions.
+     * This method is triggered when an {@code InvalidSortFieldException} is thrown in the application.
+     * It constructs an {@link ErrorDetails} object containing the exception details and returns
+     * a {@link ResponseEntity} with an HTTP status of {@code 400 Bad Request}.
+     *
+     * @param ex      the exception that was thrown.
+     * @param request the current web request in which the exception was thrown.
+     * @return a {@link ResponseEntity} containing the {@link ErrorDetails} and an HTTP status of {@code 400 Bad Request}.
+     */
+    @ExceptionHandler(InvalidSortFieldException.class)
+    public ResponseEntity<?> invalidSortFieldException(InvalidSortFieldException ex, WebRequest request) {
+        ErrorDetails errorDetails = new ErrorDetails(new Date(), ex.getMessage(), request.getDescription(false));
+        return new ResponseEntity<>(errorDetails, HttpStatus.BAD_REQUEST);
+    }
 }

src/main/java/com/libraryman_api/exception/InvalidSortFieldException.java

@@ -0,0 +1,51 @@
+package com.libraryman_api.exception;
+
+import java.io.Serial;
+
+/**
+ * Custom exception class to handle scenarios where an invalid sort field
+ * is provided for API requests in the Library Management System.
+ * This exception is thrown when a sorting operation is attempted
+ * using a field that does not exist or is not supported.
+ */
+public class InvalidSortFieldException extends RuntimeException {
+
+    /**
+     * The {@code serialVersionUID} is a unique identifier for each version of a serializable class.
+     * It is used during the deserialization process to verify that the sender and receiver of a
+     * serialized object have loaded classes for that object that are compatible with each other.
+     *
+     * The {@code serialVersionUID} field is important for ensuring that a serialized class
+     * (especially when transmitted over a network or saved to disk) can be successfully deserialized,
+     * even if the class definition changes in later versions. If the {@code serialVersionUID} does not
+     * match during deserialization, an {@code InvalidClassException} is thrown.
+     *
+     * This field is optional, but it is good practice to explicitly declare it to prevent
+     * automatic generation, which could lead to compatibility issues when the class structure changes.
+     *
+     * The {@code @Serial} annotation is used here to indicate that this field is related to
+     * serialization. This annotation is available starting from Java 14 and helps improve clarity
+     * regarding the purpose of this field.
+     */
+    @Serial
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * Constructs a new {@code InvalidSortFieldException} with the specified detail message.
+     *
+     * @param message the detail message explaining the reason for the exception
+     */
+    public InvalidSortFieldException(String message) {
+        super(message);
+    }
+
+    /**
+     * Constructs a new {@code InvalidSortFieldException} with the specified detail message and cause.
+     *
+     * @param message the detail message explaining the reason for the exception
+     * @param cause   the cause of the exception (which is saved for later retrieval by the {@link #getCause()} method)
+     */
+    public InvalidSortFieldException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}