Improve default value handling

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 fcdd8e9..041a50a 100755 (executable)
--- a/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java
+++ b/src/main/java/eu/svjatoslav/commons/cli_helper/CLIHelper.java
@@ -33,18 +33,31 @@ public class CLIHelper {
      *         {@code false} if they answered negatively,
      *         or {@code defaultValue} if input was empty
      */
-    public static boolean askBoolean(final String prompt, final Boolean defaultValue) {
+    public static Boolean askBoolean(final String prompt, final Boolean defaultValue, boolean allowEmpty) {
         while (true) {
 
-            String finalPrompt = prompt;
-            if (defaultValue != null){
-                // Show the user something like "Continue? [Y/n]: " or "Continue? [y/N]: "
-                finalPrompt = prompt + " [" + (defaultValue ? "Y/n" : "y/N") + "]: ";
-            }
-            String line = askString(finalPrompt);
+            // 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 line = new Scanner(System.in).nextLine().trim();
+            // If user just pressed Enter:
+            if (line.isEmpty()){
+
+                // If a defaultValue was supplied, return it
+                if (defaultValue != null) {
+                    return defaultValue;
+                }
 
-            if ((defaultValue != null) && (line == null)) {
-                return defaultValue;
+                if (allowEmpty) {
+                    return null;
+                } else {
+                    System.out.println("Input cannot be empty. Please enter y/yes/true or n/no/false.");
+                    continue;
+                }
             }
 
             final String userInput = line.toLowerCase();
@@ -76,7 +89,7 @@ public class CLIHelper {
      * @param max          The maximum acceptable value (inclusive), or null if no upper bound
      * @return A Float value that the user entered, or the defaultValue, or null if no defaultValue was given
      */
-    public static Float askFloat(String prompt, Float defaultValue, Float min, Float max) {
+    public static Float askFloat(String prompt, Float defaultValue, Float min, Float max, boolean allowEmpty) {
         while (true) {
             // If we have a defaultValue, display it in brackets; otherwise display no default
             String displayPrompt = prompt
@@ -87,12 +100,21 @@ public class CLIHelper {
             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;
+            if (input.isEmpty()){
+                // If a defaultValue was supplied, return it
+                if (defaultValue != null) {
+                    return defaultValue;
+                }
+
+                if (allowEmpty) {
+                    return null;
+                } else {
+                    System.out.println("Input cannot be empty. Please enter a valid float.");
+                    continue;
+                }
             }
 
+
             // Parse float value
             try {
                 float parsedValue = Float.parseFloat(input);
@@ -134,7 +156,7 @@ public class CLIHelper {
      * @param max          The maximum acceptable value (inclusive), or null if no upper bound
      * @return A Long value that the user entered, or the defaultValue, or null if no defaultValue was given
      */
-    public static Long askLong(String prompt, Long defaultValue, Long min, Long max) {
+    public static Long askLong(String prompt, Long defaultValue, Long min, Long max, boolean allowEmpty) {
         while (true) {
             // If we have a defaultValue, display it in brackets; otherwise display no default
             String displayPrompt = prompt
@@ -145,10 +167,19 @@ public class CLIHelper {
             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;
+            if (input.isEmpty()){
+
+                // If a defaultValue was supplied, return it
+                if (defaultValue != null) {
+                    return defaultValue;
+                }
+
+                if (allowEmpty) {
+                    return null;
+                } else {
+                    System.out.println("Input cannot be empty. Please enter a valid long.");
+                    continue;
+                }
             }
 
             // Parse long value
@@ -186,13 +217,14 @@ public class CLIHelper {
      *   <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
+     * @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.
+     * @param allowEmpty   If <code>true</code>, empty input is acceptable. Otherwise keep asking user.
+     * @return An integer value that the user entered, or the defaultValue, or null if no defaultValue was given.
      */
-    public static Integer askInteger(String prompt, Integer defaultValue, Integer min, Integer max) {
+    public static Integer askInteger(String prompt, Integer defaultValue, Integer min, Integer max, boolean allowEmpty) {
         while (true) {
             // If we have a defaultValue, display it in brackets; otherwise display no default
             String displayPrompt = prompt
@@ -204,9 +236,19 @@ public class CLIHelper {
             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;
+            if (input.isEmpty()){
+
+                // If a defaultValue was supplied, return it
+                if (defaultValue != null) {
+                    return defaultValue;
+                }
+
+                if (allowEmpty) {
+                    return null;
+                } else {
+                    System.out.println("Input cannot be empty. Please enter a valid integer.");
+                    continue;
+                }
             }
 
             // Parse long value
@@ -243,23 +285,34 @@ public class CLIHelper {
      * @param defaultValue the value to return if the user provides no input
      * @return the value typed by the user, or {@code defaultValue} if empty input
      */
-    public static String askString(String prompt, String defaultValue) {
-        Scanner scanner = new Scanner(System.in);
-        System.out.print(prompt + (defaultValue != null ? " [" + defaultValue + "]" : "") + ": ");
-        String input = scanner.nextLine().trim();
+    public static String askString(String prompt, String defaultValue, boolean allowEmpty) {
+        while (true) {
+            // If we have a defaultValue, display it in brackets; otherwise display no default
+            String displayPrompt = prompt
+                    + (defaultValue != null ? " [" + defaultValue + "]" : "")
+                    + ": ";
 
-        // Return the default if user just pressed ENTER
-        return input.isEmpty() ? defaultValue : input;
-    }
+            // Read user input
+            System.out.print(displayPrompt);
+            String input = new Scanner(System.in).nextLine().trim();
+
+            if (input.isEmpty()){
+
+                // If a defaultValue was supplied, return it
+                if (defaultValue != null) {
+                    return defaultValue;
+                }
+
+                if (allowEmpty) {
+                    return null;
+                } else {
+                    System.out.println("Input cannot be empty. Please enter a valid string.");
+                    continue;
+                }
+            }
+
+            return input;
+        }
 
-    /**
-     * Asks the user for a string value using the specified prompt on the command line.
-     * If the user presses ENTER without typing anything, {@code null} is returned.
-     *
-     * @param prompt the message to display to the user
-     * @return the value typed by the user, or {@code null} if empty input
-     */
-    public static String askString(String prompt) {
-        return askString(prompt, null);
     }
 }