Fril Native Library for Java

This page lists examples and documentation on calling Fril from a Java program, using the Fril native library.The software is evolving and may change before any final version is released. It is provided for educational, research or private use by an individual or organisation, and may not be sold or included in any system used commercially without prior written agreement from the authors. See the Fril Resources Page for author details and the license conditions

The Fril system is supplied as a class file (JFril.class) and a native library :

Operating System	library format	library name	Availability
Windows	dynamic link library (DLL)	JFrilLib.dll	Zip archive (also contains example code) 4.982 version (for steve and zhou if he comes looking for it )
MacOS 8/9	system extension	n/a	<not currently downloadable>
MacOS X	shared library	libJFrilLib.jnilib	gzipped tar archive unpack with gunzip macosxJFril.tar.gz tar xvf macosxJFril.tar (if it doesn't happen automatically). Move the library libJFrilLib.jnilib and JFril.class to appropriate directories
Solaris	shared library (fril version 4.983)	libJFrilLib.so	gzipped tar archive unpack with gunzip solarisJFril.tar.gz tar xvf solarisJFril.tar Move the library libJFrilLib.so and JFril.class to appropriate directories
Linux	shared library	libJFrilLib.so	<not currently downloadable>

The relevant library is loaded automatically by creating an instance of the JFril class (only one instance of this class should be created). The library must be available to java, for example by setting the LD_LIBRARY_PATH environment variable. The precise mechanism varies according to operating system and development environment - see documentation for java.lang.System.loadLibrary and/or your development environment.

Javadoc documentation for JFril is available.

Three examples illustrate the use of Fril within Java. The source files are:

and the demos also use the Fril source files:

In all cases, documentation of the examples is basically what-you-see-is-what-you-get - it's in the nature of a tutorial that you dig into the source code and find out what's going on. No guarantee that it couldn't be done better - any comments, suggestions, etc to Trevor.Martin@bris.ac.uk. It's all ongoing and under development, so check occasionally to see whether there are any new demos or other updates. Have fun.

Example: FakeFril.java

illustrates a simple tty-based java frontend to Fril, using high-level interface functions. It almost simulates a standard ttyFril.

Instructions

ensure libJFrilLib.so or libJFrilLib.jnilib or JFrilLib.dll is on the java load library search path (e.g. LD_LIBRARY_PATH)
ensure JFril.class is in the java class path
compile FakeFril.java
run java FakeFril which behaves almost as normal Fril - note that if (for example) the trace package is used, typing carriage return on its own will not pass any input to Fril. NB ** Depending on the java implementation, input may not be echoed until "enter" is pressed

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Example: JTestEmbFril.java

simple window frontend with limited set of queries, using low-level interface functions. Based on test_emb.c in the Fril Foreign Language Interface manual.

Instructions

ensure libJFrilLib.so or libJFrilLib.jnilib or JFrilLib.dll is on the java load library search path (e.g. LD_LIBRARY_PATH)
ensure JFril.class is in the java class path
ensure lists.frl is in the working directory, so that it can be loaded by the embedded Fril
compile JTestEmbFril.java and JTestEmbWindow.java
run java JTestEmbFril The queries are
(append X Y (apples bananas cherries)) which is resatsifiable
(reverse (1 3.14159 Pi) X)
(<pred> <arg>) where <pred> and <arg> are user-supplied constants. NB - the "show" button displays the query, before or after execution. The "run" button executes the query. To run anything other than append or reverse, type a constant into each of the boxes, then click "Other query", then "Run".

Example: FrilJavaDemo.java

noughts and crosses (tic-tac-toe) with display and user interaction handled by java, calculation of moves and game outcome handled by Fril. This example uses the high-level "jFrilFind??? function and low-level interface functions to obtain the variable binding.

Instructions

ensure libJFrilLib.so or libJFrilLib.jnilib or JFrilLib.dll is on the java load library search path (e.g. LD_LIBRARY_PATH)
ensure JFril.class is in the java class path
ensure noughts5.frl is in the working directory, so that it can be loaded by the embedded Fril
compile FrilJavaDemo.java, PlayingWindow.java and JButtonSquare.java
run java FrilJavaDemo