JLine is a Java library for handling console input. It is similar in functionality to BSD editline and GNU readline. People familiar with the readline/editline capabilities for modern shells (such as bash and tcsh) will find most of the command editing features of JLine to be familiar.
JLine is distributed under the BSD license, meaning that you are completely free to redistribute, modify, or sell it with almost no restrictins. For more information on the BSD license, see http://www.opensource.org/licenses/bsd-license.php.
For information on obtaining the software under another license, contact the copyright holder: email@example.com.
JLine is hosted on SourceForge, and is located at http://jline.sf.net. The latest release can be downloaded from http://sourceforge.net/project/showfiles.php?group_id=64033. API documentation can be found in the apidocs/ directory.
JLine has no library dependencies, aside from a JVM of version 1.2 or higher. To install JLine, download the jline.jar file, and either place it in the system-wide java extensions directory, or manually add it to your CLASSPATH. The extensions directory is dependent on your operating system. Some few examples are:
JLine is not 100% pure Java. On Windows, it relies on a .dll file to initialize the terminal to be able to accept unbuffered input. However, no installation is necessary for this: when initialized, JLine will dynamically extract the DLL to a temporary directory and load it. For more details, see the documentation for the jline.WindowsTerminal class.
On UNIX systems (including Macintosh OS X), JLine will execute the stty command to initialize the terminal to allow unbuffered input. For more details, see the documentation for the jline.UnixTerminal class.
For both Windows and UNIX systems, JLine will fail to initialize if it is run inside a strict security manager that does not allow the loading of libraries, writing to the file system, or executing external programs. However, for most console applications, this is usually not the case.
JLine should work on any Windows system, or any minimally compliant POSIX system (includling Linux and Macintosh OS X).
The platforms on which JLine has been confirmed to work are:
Please report successes or failures to the author: firstname.lastname@example.org.
This section discusses some common usages of the JLine API. For in-depth usage of the JLine API, see the apidocs.
A common task that console applications need to do is read in a password. While it is standard for software to not echo password strings as they are typed, the Java core APIs surprisingly do not provide any means to do this.
JLine can read a password with the following code:
String password = new jline.ConsoleReader().readLine(new Character('*'));
Alternately, you can have it not echo password character at all:
String password = new jline.ConsoleReader().readLine(new Character(0));
The jline-demo.jar file contains a sample application that reads the password. To run the sample, execute:
java -cp jline-demo.jar jline.example.PasswordReader "*"
You can disable JLine by setting the System property "jline.terminal" to "jline.UnsupportedTerminal". For example:
java -Djline.terminal=jline.UnsupportedTerminal jline.example.Example simple
You can create your own keybindings by creating a HOME/.jlinebindings.properties" file. You can override the location of this file with the "jline.keybindings" system property. To examine the format to use, see the src/jline/keybindings.properties file in the source distribution.
No, but you can use the jline.ConsoleRunner application to set up the system input stream and continue on the launch another program. For example, to use JLine as the input handler for the popular BeanShell console application, you can run:
java jline.ConsoleRunner bsh.Interpreter
Yes. Try running:
java jline.ConsoleRunner com.sun.tools.example.debug.tty.TTY args
No: JLine uses a couple small native methods in the Windows platform. On Unix, it is technically pure java, but relies on the execution of external (non-java) programs. See the installation section for more details.
No: JLine has no ability to position the cursor on the console. It might someday evolve into a plausible Java curses implementation.
The following people have contributed to improving JLine over the years: