Package org.jline.terminal

Class TerminalBuilder

  • public final class TerminalBuilder
extends java.lang.Object
    Builder class to create Terminal instances with flexible configuration options.

    TerminalBuilder provides a fluent API for creating and configuring terminals with various characteristics. It supports multiple implementation providers and handles the complexities of terminal creation across different platforms and environments.

    Terminal Providers

    JLine supports multiple terminal provider implementations:

    • FFM - Foreign Function Memory (Java 22+) based implementation
    • JNI - Java Native Interface based implementation
    • Jansi - Implementation based on the Jansi library
    • JNA - Java Native Access based implementation
    • Exec - Implementation using external commands
    • Dumb - Fallback implementation with limited capabilities

    The provider selection can be controlled using the provider(String) method or the org.jline.terminal.provider system property. By default, providers are tried in the order: FFM, JNI, Jansi, JNA, Exec.

    Native Library Support

    When using providers that require native libraries (such as JNI, JNA, or Jansi), the appropriate native library will be loaded automatically. The loading of these libraries is handled by JLineNativeLoader for the JNI provider.

    The native library loading can be configured using system properties as documented in JLineNativeLoader.

    System vs. Non-System Terminals

    TerminalBuilder can create two types of terminals:

    • System terminals - Connected to the actual system input/output streams
    • Non-system terminals - Connected to custom input/output streams

    System terminals are created using system(boolean) with a value of true, while non-system terminals require specifying input and output streams using streams(InputStream, OutputStream).

    Usage Examples

    Creating a default system terminal:

     Terminal terminal = TerminalBuilder.builder()
     .system(true)
     .build();

    Creating a terminal with custom streams:

     Terminal terminal = TerminalBuilder.builder()
     .name("CustomTerminal")
     .streams(inputStream, outputStream)
     .encoding(StandardCharsets.UTF_8)
     .build();

    Creating a terminal with a specific provider:

     Terminal terminal = TerminalBuilder.builder()
     .system(true)
     .provider("jni")
     .build();

    Creating a dumb terminal (with limited capabilities):

     Terminal terminal = TerminalBuilder.builder()
     .dumb(true)
     .build();
    See Also:
    Terminal, JLineNativeLoader, TerminalProvider

    • Field Detail

      • PROP_STDIN_ENCODING

        public static final java.lang.String PROP_STDIN_ENCODING
        See Also:
        Constant Field Values

      • PROP_STDOUT_ENCODING

        public static final java.lang.String PROP_STDOUT_ENCODING
        See Also:
        Constant Field Values

      • PROP_STDERR_ENCODING

        public static final java.lang.String PROP_STDERR_ENCODING
        See Also:
        Constant Field Values

      • PROP_PROVIDER_FFM

        public static final java.lang.String PROP_PROVIDER_FFM
        See Also:
        Constant Field Values

      • PROP_PROVIDER_JNI

        public static final java.lang.String PROP_PROVIDER_JNI
        See Also:
        Constant Field Values

      • PROP_PROVIDER_JANSI

        public static final java.lang.String PROP_PROVIDER_JANSI
        See Also:
        Constant Field Values

      • PROP_PROVIDER_JNA

        public static final java.lang.String PROP_PROVIDER_JNA
        See Also:
        Constant Field Values

      • PROP_PROVIDER_EXEC

        public static final java.lang.String PROP_PROVIDER_EXEC
        See Also:
        Constant Field Values

      • PROP_PROVIDER_DUMB

        public static final java.lang.String PROP_PROVIDER_DUMB
        See Also:
        Constant Field Values

      • PROP_PROVIDERS_DEFAULT

        public static final java.lang.String PROP_PROVIDERS_DEFAULT

      • PROP_OUTPUT_OUT_ERR

        public static final java.lang.String PROP_OUTPUT_OUT_ERR
        See Also:
        Constant Field Values

      • PROP_OUTPUT_ERR_OUT

        public static final java.lang.String PROP_OUTPUT_ERR_OUT
        See Also:
        Constant Field Values

      • PROP_OUTPUT_FORCED_OUT

        public static final java.lang.String PROP_OUTPUT_FORCED_OUT
        See Also:
        Constant Field Values

      • PROP_OUTPUT_FORCED_ERR

        public static final java.lang.String PROP_OUTPUT_FORCED_ERR
        See Also:
        Constant Field Values

      • PROP_NON_BLOCKING_READS

        public static final java.lang.String PROP_NON_BLOCKING_READS
        See Also:
        Constant Field Values

      • PROP_COLOR_DISTANCE

        public static final java.lang.String PROP_COLOR_DISTANCE
        See Also:
        Constant Field Values

      • PROP_DISABLE_ALTERNATE_CHARSET

        public static final java.lang.String PROP_DISABLE_ALTERNATE_CHARSET
        See Also:
        Constant Field Values

      • PROP_CLOSE_MODE

        public static final java.lang.String PROP_CLOSE_MODE
        System property to control terminal stream closure behavior.

        This property controls what happens when code attempts to read from or write to terminal streams (reader, writer, input, output) after the terminal has been closed.

        Two levels of closure enforcement:

        1. Terminal-level: Calling methods on the terminal itself after close() always throws IllegalStateException, regardless of this property.
        2. Stream-level: Using held references to streams obtained before close() is controlled by this property.

        Property values:

        • "strict" - Accessing closed streams throws ClosedException
        • "warn" (default in JLine 3.x) - Accessing closed streams logs a warning but continues to operate
        • "lenient" - Accessing closed streams is silently allowed (no warning, no exception)

        Example: 

        
 Terminal terminal = TerminalBuilder.terminal();
 NonBlockingReader reader = terminal.reader();  // Get reference before close
 terminal.close();

 // This always throws IllegalStateException (terminal-level):
 terminal.reader();  // throws IllegalStateException

 // This behavior depends on jline.terminal.closeMode (stream-level):
 reader.read();  // throws ClosedException in strict, logs warning in warn, silent in lenient
        Since:
        3.28.0
        See Also:
        ClosedException, NonBlockingInputStream, NonBlockingReader, Constant Field Values

      • PROP_FILE_DESCRIPTOR_CREATION_MODE

        public static final java.lang.String PROP_FILE_DESCRIPTOR_CREATION_MODE
        See Also:
        Constant Field Values

      • PROP_FILE_DESCRIPTOR_CREATION_MODE_NATIVE

        public static final java.lang.String PROP_FILE_DESCRIPTOR_CREATION_MODE_NATIVE
        See Also:
        Constant Field Values

      • PROP_FILE_DESCRIPTOR_CREATION_MODE_REFLECTION

        public static final java.lang.String PROP_FILE_DESCRIPTOR_CREATION_MODE_REFLECTION
        See Also:
        Constant Field Values

      • PROP_FILE_DESCRIPTOR_CREATION_MODE_DEFAULT

        public static final java.lang.String PROP_FILE_DESCRIPTOR_CREATION_MODE_DEFAULT

      • PROP_REDIRECT_PIPE_CREATION_MODE

        public static final java.lang.String PROP_REDIRECT_PIPE_CREATION_MODE
        See Also:
        Constant Field Values

      • PROP_REDIRECT_PIPE_CREATION_MODE_NATIVE

        public static final java.lang.String PROP_REDIRECT_PIPE_CREATION_MODE_NATIVE
        See Also:
        Constant Field Values

      • PROP_REDIRECT_PIPE_CREATION_MODE_REFLECTION

        public static final java.lang.String PROP_REDIRECT_PIPE_CREATION_MODE_REFLECTION
        See Also:
        Constant Field Values

      • PROP_REDIRECT_PIPE_CREATION_MODE_DEFAULT

        public static final java.lang.String PROP_REDIRECT_PIPE_CREATION_MODE_DEFAULT

      • DEPRECATED_PROVIDERS

        public static final java.util.Set<java.lang.String> DEPRECATED_PROVIDERS

      • PROP_DISABLE_DEPRECATED_PROVIDER_WARNING

        public static final java.lang.String PROP_DISABLE_DEPRECATED_PROVIDER_WARNING
        See Also:
        Constant Field Values

    • Method Detail

      • terminal

        public static Terminal terminal()
                         throws java.io.IOException
        Returns the default system terminal with automatic configuration.

        This method creates a terminal connected to the system's standard input and output streams, automatically detecting the appropriate terminal type and capabilities for the current environment. It's the simplest way to get a working terminal instance for most applications.

        The terminal is created with default settings, which include:

        • System streams for input and output
        • Auto-detected terminal type
        • System default encoding
        • Native signal handling

        This call is equivalent to: builder().build()

        Important: Terminals should be closed properly using the Closeable.close() method when they are no longer needed in order to restore the original terminal state.

        Example usage:

         try (Terminal terminal = TerminalBuilder.terminal()) {
     terminal.writer().println("Hello, terminal!");
     terminal.flush();
     // Use terminal...
 }
        Returns:
        the default system terminal, never null
        Throws:
        java.io.IOException - if an error occurs during terminal creation
        See Also:
        builder()

      • builder

        public static TerminalBuilder builder()
        Creates a new terminal builder instance for configuring and creating terminals.

        This method returns a builder that can be used to configure various aspects of the terminal before creating it. The builder provides a fluent API for setting terminal properties such as name, type, encoding, input/output streams, and more.

        Example usage:

         Terminal terminal = TerminalBuilder.builder()
     .name("MyTerminal")
     .system(true)
     .encoding(StandardCharsets.UTF_8)
     .build();
        Returns:
        a new terminal builder instance, never null
        See Also:
        terminal()

      • streams

        public TerminalBuilder streams​(java.io.InputStream in,
                               java.io.OutputStream out)

      • systemOutput

        public TerminalBuilder systemOutput​(TerminalBuilder.SystemOutput systemOutput)
        Indicates which standard stream should be used when displaying to the terminal. The default is to use the system output stream. Building a system terminal will fail if one of the stream specified is not linked to the controlling terminal.
        Parameters:
        systemOutput - The mode to choose the output stream.
        Returns:
        The builder.

      • provider

        public TerminalBuilder provider​(java.lang.String provider)
        Forces the usage of the give terminal provider.
        Parameters:
        provider - The TerminalProvider's name to use when creating the Terminal.
        Returns:
        The builder.

      • providers

        public TerminalBuilder providers​(java.lang.String providers)
        Sets the list of providers to try when creating the terminal. If not specified, the system property PROP_PROVIDERS will be used if set. Else, the value PROP_PROVIDERS_DEFAULT will be used.
        Parameters:
        providers - The list of TerminalProvider's names to check when creating the Terminal.
        Returns:
        The builder.

      • jna

        public TerminalBuilder jna​(boolean jna)
        Enables or disables the PROP_PROVIDER_JNA/jna terminal provider. If not specified, the system property PROP_JNA will be used if set. If not specified, the provider will be checked.

      • jansi

        public TerminalBuilder jansi​(boolean jansi)
        Enables or disables the PROP_PROVIDER_JANSI/jansi terminal provider. If not specified, the system property PROP_JANSI will be used if set. If not specified, the provider will be checked.

      • jni

        public TerminalBuilder jni​(boolean jni)
        Enables or disables the PROP_PROVIDER_JNI/jni terminal provider.

        The JNI provider uses the JLine native library loaded by JLineNativeLoader to access low-level terminal functionality. This provider generally offers the best performance and most complete terminal support.

        If not specified, the system property PROP_JNI will be used if set. If not specified, the provider will be checked for availability.

        The native library loading can be configured using system properties as documented in JLineNativeLoader.

        Parameters:
        jni - true to enable the JNI provider, false to disable it
        Returns:
        this builder
        See Also:
        JLineNativeLoader

      • exec

        public TerminalBuilder exec​(boolean exec)
        Enables or disables the PROP_PROVIDER_EXEC/exec terminal provider. If not specified, the system property PROP_EXEC will be used if set. If not specified, the provider will be checked.

      • ffm

        public TerminalBuilder ffm​(boolean ffm)
        Enables or disables the PROP_PROVIDER_FFM/ffm terminal provider. If not specified, the system property PROP_FFM will be used if set. If not specified, the provider will be checked.

      • dumb

        public TerminalBuilder dumb​(boolean dumb)
        Enables or disables the PROP_PROVIDER_DUMB/dumb terminal provider. If not specified, the system property PROP_DUMB will be used if set. If not specified, the provider will be checked.

      • encoding

        public TerminalBuilder encoding​(java.lang.String encoding)
                         throws java.nio.charset.UnsupportedCharsetException
        Set the encoding to use for reading/writing from the console. If null (the default value), JLine will automatically select a Charset, usually the default system encoding. However, on some platforms (e.g. Windows) it may use a different one depending on the Terminal implementation.

        Use Terminal.encoding() to get the Charset that should be used for a Terminal.

        This method sets a single encoding for all streams (stdin, stdout, stderr). To set separate encodings for each stream, use stdinEncoding(Charset), stdoutEncoding(Charset), and stderrEncoding(Charset).

        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        Throws:
        java.nio.charset.UnsupportedCharsetException - If the given encoding is not supported
        See Also:
        Terminal.encoding()

      • encoding

        public TerminalBuilder encoding​(java.nio.charset.Charset encoding)
        Set the Charset to use for reading/writing from the console. If null (the default value), JLine will automatically select a Charset, usually the default system encoding. However, on some platforms (e.g. Windows) it may use a different one depending on the Terminal implementation.

        Use Terminal.encoding() to get the Charset that should be used to read/write from a Terminal.

        This method sets a single encoding for all streams (stdin, stdout, stderr). To set separate encodings for each stream, use stdinEncoding(Charset), stdoutEncoding(Charset), and stderrEncoding(Charset).

        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        See Also:
        Terminal.encoding()

      • stdinEncoding

        public TerminalBuilder stdinEncoding​(java.lang.String encoding)
                              throws java.nio.charset.UnsupportedCharsetException
        Set the encoding to use for reading from standard input. If null (the default value), JLine will use the value from the "stdin.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        Throws:
        java.nio.charset.UnsupportedCharsetException - If the given encoding is not supported
        See Also:
        Terminal.inputEncoding()

      • stdinEncoding

        public TerminalBuilder stdinEncoding​(java.nio.charset.Charset encoding)
        Set the Charset to use for reading from standard input. If null (the default value), JLine will use the value from the "stdin.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        See Also:
        Terminal.inputEncoding()

      • stdoutEncoding

        public TerminalBuilder stdoutEncoding​(java.lang.String encoding)
                               throws java.nio.charset.UnsupportedCharsetException
        Set the encoding to use for writing to standard output. If null (the default value), JLine will use the value from the "stdout.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        Throws:
        java.nio.charset.UnsupportedCharsetException - If the given encoding is not supported
        See Also:
        Terminal.outputEncoding()

      • stdoutEncoding

        public TerminalBuilder stdoutEncoding​(java.nio.charset.Charset encoding)
        Set the Charset to use for writing to standard output. If null (the default value), JLine will use the value from the "stdout.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        See Also:
        Terminal.outputEncoding()

      • stderrEncoding

        public TerminalBuilder stderrEncoding​(java.lang.String encoding)
                               throws java.nio.charset.UnsupportedCharsetException
        Set the encoding to use for writing to standard error. If null (the default value), JLine will use the value from the "stderr.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        Throws:
        java.nio.charset.UnsupportedCharsetException - If the given encoding is not supported
        See Also:
        Terminal.outputEncoding()

      • stderrEncoding

        public TerminalBuilder stderrEncoding​(java.nio.charset.Charset encoding)
        Set the Charset to use for writing to standard error. If null (the default value), JLine will use the value from the "stderr.encoding" system property if set, or fall back to the general encoding.
        Parameters:
        encoding - The encoding to use or null to automatically select one
        Returns:
        The builder
        See Also:
        Terminal.outputEncoding()

      • codepage

        @Deprecated
public TerminalBuilder codepage​(int codepage)
        Deprecated.
        JLine now writes Unicode output independently from the selected code page. Using this option will only make it emulate the selected code page for Terminal.input() and Terminal.output().
        Parameters:
        codepage - the codepage
        Returns:
        The builder

      • nativeSignals

        public TerminalBuilder nativeSignals​(boolean nativeSignals)

      • signalHandler

        public TerminalBuilder signalHandler​(Terminal.SignalHandler signalHandler)
        Determines the default value for signal handlers. All signals will be mapped to the given handler.
        Parameters:
        signalHandler - the default signal handler
        Returns:
        The builder

      • paused

        public TerminalBuilder paused​(boolean paused)
        Initial paused state of the terminal (defaults to false). By default, the terminal is started, but in some cases, one might want to make sure the input stream is not consumed before needed, in which case the terminal needs to be created in a paused state.
        Parameters:
        paused - the initial paused state
        Returns:
        The builder
        See Also:
        Terminal.pause()

      • build

        public Terminal build()
               throws java.io.IOException
        Builds the terminal.
        Returns:
        the newly created terminal, never null
        Throws:
        java.io.IOException - if an error occurs

      • computeType

        public java.lang.String computeType()

      • computeEncoding

        public java.nio.charset.Charset computeEncoding()

      • computeStdinEncoding

        public java.nio.charset.Charset computeStdinEncoding()

      • computeStdoutEncoding

        public java.nio.charset.Charset computeStdoutEncoding()

      • computeStderrEncoding

        public java.nio.charset.Charset computeStderrEncoding()

      • getProviders

        public java.util.List<TerminalProvider> getProviders​(java.lang.String provider,
                                                     java.lang.IllegalStateException exception)
        Get the list of available terminal providers. This list is sorted according to the PROP_PROVIDERS system property.
        Parameters:
        provider - if not null, only this provider will be checked
        exception - if a provider throws an exception, it will be added to this exception as a suppressed exception
        Returns:
        a list of terminal providers

      • setTerminalOverride

        @Deprecated
public static void setTerminalOverride​(Terminal terminal)
        Deprecated.
        Allows an application to override the result of build(). The intended use case is to allow a container or server application to control an embedded application that uses a LineReader that uses Terminal constructed with TerminalBuilder.build but provides no public api for setting the LineReader of the Terminal. For example, the sbt build tool uses a LineReader to implement an interactive shell. One of its supported commands is console which invokes the scala REPL. The scala REPL also uses a LineReader and it is necessary to override the Terminal used by the the REPL to share the same Terminal instance used by sbt.

        When this method is called with a non-null Terminal, all subsequent calls to build() will return the provided Terminal regardless of how the TerminalBuilder was constructed. The default behavior of TerminalBuilder can be restored by calling setTerminalOverride with a null Terminal

        Usage of setTerminalOverride should be restricted to cases where it isn't possible to update the api of the nested application to accept a instance.

        Parameters:
        terminal - the Terminal to globally override