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jpl

Running all the examples and the benchmarks requires XVM (with its jni plug-in installed) or SWI-Prolog (with the JPL library installed). YAP most likely would be usable when the old JPL library bundled with it is updated. Some examples (but not the benchmarks) can also be used with JIProlog.

This folder contains GUI examples, most of them adapted from the JPL library distributed with SWI-Prolog and YAP, of calling Java from Logtalk. It uses a lightweight abstraction included in the Logtalk library for calling Java.

Adaptations of the JColorChooser and JOptionPane dialog examples and the JTable example from the JPL distribution are included.

When running the GUI examples on the macOS Terminal application, you may get a Java error saying that the AWT cannot be started. In alternative, try to run the example from within the SWI-Prolog macOS application instead of using the shell integration script. This issue is due to a macOS Java issue that's orthogonal to both SWI-Prolog/YAP and Logtalk.

Print Logtalk, Prolog backend, and kernel versions (if running as a notebook):

%versions

Start by loading the example:

logtalk_load(jpl(loader)).

Get the Java version by using the getProperty/1 static method:

java('java.lang.System', Version)::getProperty('java.version').

<!-- Version = '1.7.0_51'. -->

Get the value of the "pi" constant by accessing the 'PI' class field:

java('java.lang.Math')::get_field('PI', Pi).

<!-- Pi = 3.141592653589793. -->

Create a new instance of ArrayList and add some elements to it:

java('java.util.ArrayList')::new(ArrayList), java(ArrayList)::(add('Paulo'), add('Carlos'), add('Helena')).

<!-- true. -->

Round-trip conversion:

java::terms_to_array([x,[1,a,7,[y,z]],k,[],3.14,foo(bar)], Array), java::array_to_terms(Array, List).

<!-- Array = @'J#00000140321793636416', List = [x, [1, a, 7, [y, z]], k, [], 3.14, foo(bar)]. -->

Run some benchmarks comparing plain JPL calls with calls to Logtalk's thin abstraction layer:

benchmarks::run.

<!-- ... -->

Some GUI examples, adapted from the JPL distribution examples (skip if running as a notebook)

JColorChooser dialog example:

(current_object(jupyter) -> true; color_chooser::color(Color)).

<!-- Color = @'J#00000140727398998200'. -->

JTable example:

(current_object(jupyter) -> true; flags_table::display).

<!-- true. -->

JList dialog example:

(current_object(jupyter) -> true; jlist::display).

<!-- true. -->

JOptionPane dialog example:

(current_object(jupyter) -> true; text_entry::text(Text)).

<!-- Text = ... . -->