Module org.jline.prompt
Package org.jline.prompt

Interface InputBuilder

All Superinterfaces:
BaseBuilder<InputBuilder>
All Known Implementing Classes:
DefaultInputBuilder
public interface InputBuilder extends BaseBuilder<InputBuilder>
Builder for creating text input prompts with advanced features.

InputBuilder creates prompts that allow users to enter free-form text input. It supports various advanced features including input masking (for passwords), auto-completion, validation, and custom line readers.

Features

  • Text Input - Free-form text entry with full editing capabilities
  • Input Masking - Hide sensitive input like passwords
  • Auto-completion - Provide completion suggestions as user types
  • Validation - Validate input before accepting
  • Default Values - Pre-populate input with default text
  • Custom Line Readers - Use specialized line readers for advanced scenarios

Basic Usage


 builder.createInputPrompt()
     .name("username")
     .message("Enter your username:")
     .defaultValue("admin")
     .addPrompt();

Password Input


 builder.createInputPrompt()
     .name("password")
     .message("Enter your password:")
     .mask('*')  // Hide input with asterisks
     .addPrompt();

Input with Validation


 builder.createInputPrompt()
     .name("email")
     .message("Enter your email address:")
     .validator(input -> input.contains("@") && input.contains("."))
     .addPrompt();

Input with Completion


 Completer fileCompleter = new FileNameCompleter();

 builder.createInputPrompt()
     .name("filepath")
     .message("Enter file path:")
     .completer(fileCompleter)
     .addPrompt();
Since:
3.30.0
See Also:

  • Method Details

    • defaultValue

      InputBuilder defaultValue(String defaultValue)
      Set the default value that will be pre-filled in the input field.

      The default value appears in the input field when the prompt is displayed, allowing users to accept it by pressing Enter or modify it as needed. This is useful for providing sensible defaults or previously entered values.

      Example:

      
 builder.createInputPrompt()
     .name("port")
     .message("Enter port number:")
     .defaultValue("8080")  // User can accept or change this
     .addPrompt();
      Parameters:
      defaultValue - the default text to pre-fill (may be null for no default)
      Returns:
      this builder instance for method chaining

    • mask

      InputBuilder mask(Character mask)
      Set the character used to mask input for sensitive data.

      When a mask character is set, the actual input characters are hidden and replaced with the mask character in the display. This is essential for password input and other sensitive data entry.

      Common Mask Characters:

      • '*' - Traditional asterisk masking
      • '?' - Bullet point (modern style)
      • '?' - Filled circle
      • ' ' - Space (completely hidden)

      Example:

      
 builder.createInputPrompt()
     .name("password")
     .message("Enter password:")
     .mask('*')  // Input appears as: ****
     .addPrompt();
      Parameters:
      mask - the character to display instead of actual input, or null to disable masking
      Returns:
      this builder instance for method chaining

    • completer

      InputBuilder completer(org.jline.reader.Completer completer)
      Set the completer to provide auto-completion suggestions.

      The completer is invoked as the user types to provide completion suggestions. Users can typically press Tab to trigger completion or navigate through suggestions. JLine provides several built-in completers for common use cases.

      Built-in Completers:

      • FileNameCompleter - File and directory completion
      • StringsCompleter - Completion from a predefined list
      • ArgumentCompleter - Multi-argument completion
      • AggregateCompleter - Combines multiple completers

      Example:

      
 Completer completer = new StringsCompleter("option1", "option2", "option3");

 builder.createInputPrompt()
     .name("choice")
     .message("Enter option:")
     .completer(completer)
     .addPrompt();
      Parameters:
      completer - the completer to use for auto-completion (may be null for no completion)
      Returns:
      this builder instance for method chaining
      See Also:
      • invalid reference 
        org.jline.reader.impl.completer.FileNameCompleter
      • StringsCompleter

    • lineReader

      InputBuilder lineReader(org.jline.reader.LineReader lineReader)
      Set a custom line reader for advanced input handling.

      By default, the prompter uses its own line reader configuration. This method allows you to provide a custom line reader with specific settings, key bindings, or behaviors that differ from the default configuration.

      Use Cases:

      • Custom key bindings for specific input scenarios
      • Specialized editing modes (vi vs emacs)
      • Custom history management
      • Integration with existing line reader configurations

      Example:

      
 LineReader customReader = LineReaderBuilder.builder()
     .terminal(terminal)
     .option(LineReader.Option.DISABLE_EVENT_EXPANSION, true)
     .build();

 builder.createInputPrompt()
     .name("command")
     .message("Enter command:")
     .lineReader(customReader)
     .addPrompt();
      Parameters:
      lineReader - the custom line reader to use (may be null to use default)
      Returns:
      this builder instance for method chaining
      See Also:
      • LineReaderBuilder

    • validator

      InputBuilder validator(Function<String,Boolean> validator)
      Set a validator function to validate user input before accepting it.

      The validator function is called with the user's input and should return true if the input is valid, false otherwise. If validation fails, the user is prompted to enter the input again.

      Validation Examples:

      
 // Email validation
 builder.createInputPrompt()
     .name("email")
     .message("Enter email:")
     .validator(input -> input.matches("^[^@]+@[^@]+\\.[^@]+$"))
     .addPrompt();

 // Number validation
 builder.createInputPrompt()
     .name("port")
     .message("Enter port (1-65535):")
     .validator(input -> {
         try {
             int port = Integer.parseInt(input);
             return port >= 1 && port <= 65535;
         } catch (NumberFormatException e) {
             return false;
         }
     })
     .addPrompt();

 // Non-empty validation
 builder.createInputPrompt()
     .name("name")
     .message("Enter your name:")
     .validator(input -> !input.trim().isEmpty())
     .addPrompt();
      Parameters:
      validator - function that returns true for valid input, false otherwise
      Returns:
      this builder instance for method chaining