Ability to ask for integer

diff --git a/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java b/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java
index fe00e70..e86c58b 100755 (executable)
--- a/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java
+++ b/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java
@@ -172,6 +172,64 @@ public class CLIHelper {
         }
     }
 
+    /**
+     * Asks the user for an integer value using the specified prompt on the command line.
+     * The user is prompted until a valid integer (within optional ranges) is provided.
+     * <ul>
+     *   <li>If {@code defaultValue} is specified and user presses Enter, that default is returned.</li>
+     *   <li>If {@code defaultValue} is {@code null} and user presses Enter, returns {@code null}.</li>
+     *   <li>If {@code min} is not {@code null}, we enforce that the entered integer is {@code >= min}.</li>
+     *   <li>If {@code max} is not {@code null}, we enforce that the entered integer is {@code <= max}.</li>
+     * </ul>
+     *
+     * @param prompt       The prompt displayed to the user
+     * @param defaultValue The default long if user simply presses Enter (may be null)
+     * @param min          The minimum acceptable value (inclusive), or null if no lower bound
+     * @param max          The maximum acceptable value (inclusive), or null if no upper bound
+     * @return An integer value that the user entered, or the defaultValue, or null if no defaultValue was given
+     */
+    public Integer askInteger(String prompt, Integer defaultValue, Integer min, Integer max) {
+        while (true) {
+            // If we have a defaultValue, display it in brackets; otherwise display no default
+            String displayPrompt = prompt
+                    + (defaultValue != null ? " [" + defaultValue + "]" : "")
+                    + ": ";
+
+            // Read user input
+            System.out.print(displayPrompt);
+            String input = new Scanner(System.in).nextLine().trim();
+
+            // If user just pressed Enter:
+            if (input.isEmpty()) {
+                // If a defaultValue was supplied, return it; else return null
+                return defaultValue;
+            }
+
+            // Parse long value
+            try {
+                int parsedValue = Integer.parseInt(input);
+
+                // Check against min if specified
+                if (min != null && parsedValue < min) {
+                    System.out.println("Value must be at least " + min + ".");
+                    continue;
+                }
+
+                // Check against max if specified
+                if (max != null && parsedValue > max) {
+                    System.out.println("Value must be at most " + max + ".");
+                    continue;
+                }
+
+                // Parsed successfully within optional bounds
+                return parsedValue;
+
+            } catch (NumberFormatException e) {
+                System.out.println("Invalid number format. Try again.");
+            }
+        }
+    }
+
     /**
      * Asks the user for a string value using the specified prompt on the command line.
      * If the user presses ENTER without typing anything and {@code defaultValue} is non-null,