What is lttoolbox-java
lttoolbox-java is a Java port of the whole Apertium runtime system, including both lttoolbox and apertium.
lttoolbox can do the following:
- Compile: make binary files out of the .dix files (lt-comp),
- Proces: analysing or generating text (lt-proc) and
- Expand: Expand a dictionary .dix file (lt-expand).
The Java port of lttoolbox is also capable of
apertium runtime functions
The Java port implements the typical functions used by Apertium during runtime.
- Read .mode files and execute the steps included in them
- Execute the tagger
- Execute transfer stages (all 3 of them)
The Java port needs the C++ binaries for preparing/developing a language pair, i.a. to compile transfer files and train the tagger.
The Java port of lttoolbox is also capable of
- Generate bytecode for transfer and execute it. The bytecode runs typically 10 times faster than the C++ version.
A "Java port" of Apertium enables use on
- Android phones,
- Cross-platform desktop application,
- Java server applications.
The last 2 is relevant as, for example a LibreOffice plugin should be platform independent to be maintainable.
We havent seen anyone embedding Apertium in a desktop application. Currently Apertium is usable in a local subdir but installation isnt trivial to an end user.
Having a packaged easy-to-use version of Apertium ready for embedding MT in a larger program would be very cool. Ideally should a self-contained Apertium JAR file, only dependent on JRE and an additional JAR file per language pair.
Another "embedding" approach is to use a client stub to one of our Apertium services, but there can be reasons why people prefers to have things installed locally (we don't need to repeat them here).
- Binary compatibility with lttoolbox. lttoolbox-java is able read and write the binary files lttoolbox and generates exactly the same output
- There is a comprehensive test suite that tests both lttoolbox (C++) and lttoolbox-java.
- apache-ant (for compilation)
Under Arch Linux, you can install the prerequisites with
pacman -S openjdk6 apache-ant
sudo apt-get install ant ant-optional # what else??
Download, compile, install
Download the newest release or check out from github:
git clone https://github.com/apertium/lttoolbox-java/
Use Netbeans or Unix, whatever suits you best:
sh autogen.sh make sudo make install
You can also build and install using Maven 2 (http://maven.apache.org), by typing:
mvn install -DskipTests
See also the README file
$ java -jar dist/lttoolbox.jar lttoolbox: is a toolbox for lexical processing, morphological analysis and generation of words USAGE: java -jar dist/lttoolbox.jar [task] Examples: java -jar dist/lttoolbox.jar lt-expand dictionary.dix expands a dictionary java -jar dist/lttoolbox.jar lt-comp lr dic.dix dic.bin compiles a dictionary java -jar dist/lttoolbox.jar lt-proc dic.bin morphological analysis
or, using the a shell scripts:
$ lt-comp-j v3.2j: build a letter transducer from a dictionary USAGE: LTComp lr | rl dictionary_file output_file [acx_file] Modes: lr: left-to-right compilation rl: right-to-left compilation
$ lt-proc-j LTProc: process a stream with a letter transducer USAGE: LTProc [-c] [-a|-g|-n|-d|-b|-p|-s|-t] fst_file [input_file [output_file]] Options: -a: morphological analysis (default behavior) -c: use the literal case of the incoming characters -e: morphological analysis, with compound analysis on unknown words -f: match flags (experimental) -g: morphological generation -n: morph. generation without unknown word marks -d: morph. generation with all the stuff -t: morph. generation, but retaining part-of-speech -p: post-generation -s: SAO annotation system input processing -t: apply transliteration dictionary -z: flush output on the null character -v: version -D: debug; print diagnostics to stderr -h: show this help
$ lt-expand-j v3.2j: expand the contents of a dictionary fileUSAGE: LTExpand dictionary_file [output_file]
$ lt-validate-j v3.2j: validate an XML file according to a schema USAGE : LTValidate -dix dictionary.xml LTValidate -acx dictionary.acx
Use the new compounding feature:
echo "lambakjöti" | java -jar dist/lttoolbox.jar lt-proc -e /home/j/esperanto/apertium/apertium-is-en/is.bin
Try -Dfile.encoding=UTF-8, like
echo "lambakjöti" | java -Dfile.encoding=UTF-8 -jar dist/lttoolbox.jar lt-proc -e /home/j/esperanto/apertium/apertium-is-en/is.bin
You need JDK1.6. Try
/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Commands/java -jar dist/lttoolbox.jar
By default, the windows console uses UTF-16, whereas apertium's data is encoded with utf-8. This command switches the dos box to utf-8:
Note: you also need to use an unicode-capable font for the windows console, like Lucida Console (Properties -> Font).
Also, don't forget to set these Runtime flags: -Xms64m -Xmx800 -Dfile.encoding=UTF-8
Reasons for a Java port
- There are several devices (mobile phones, for example) which can run quite complicated software, but only if written in Java. lttoolbox is the first step to having Apertium run on these devices.
- Windows port. It won't be as powerfull as Unix based system, but it will be there
- Apertium will be the first MT system *ever* that can be demonstrated within a Java applets
- Transfer in bytecode has a promise of speedup factor 4 - compared to what we use now (interpreted XML). And transfer CPU usage is dominating when processing large amounts of text
Performance of Java port
Compatibility and performance can be checked by invoking test_java_and_c.sh in testdata/regression.
Single-core processor (Jimmy O'Regan)
java version "1.6.0_18" OpenJDK Runtime Environment (IcedTea6 1.8) (6b18~pre4-1ubuntu1) OpenJDK Client VM (build 16.0-b13, mixed mode, sharing) C analysis is... 0.59sec OK Java analysis is... 1.15sec OK C generator -g is ... 0.54sec OK Java generator -g is ... 1.13sec OK C generator -d is ... 0.56sec OK Java generator -d is ... 1.12sec OK C generator -n is ... 0.52sec OK Java generator -n is ... 1.12sec OK C postgenerator -p is ... 0.07sec OK Java postgenerator -p is ... 0.33sec OK All tests passed
Dual-core processor (Jacob)
Java HotSpot(TM) Client VM (build 1.6.0-beta2-b86, mixed mode, sharing) C analysis is... 0.39sec OK Java analysis is... 0.66sec OK C generator -g is ... 0.32sec OK Java generator -g is ... 0.62sec OK C generator -d is ... 0.33sec OK Java generator -d is ... 0.58sec OK C generator -n is ... 0.32sec OK Java generator -n is ... 0.64sec OK C postgenerator -p is ... 0.03sec OK Java postgenerator -p is ... 0.20sec OK All tests passed
As you see Java version is currently (april 2010) a factor 2 slower than the C version. There are ways to remedy this (using simple types collection classes), but it hasnt been implemented, as no-one has requested it.
It still gives great performance, however, and Apertium running on Java is very fast, compared to other MT systems. The overhead of using the Java version instead of the C version is negligible, as transfer is the big ressource hog anyway.
The above test compares the basic lttoolbox functions. As Java transfer is much faster the result of performance test of a pure-Java and pure-C++ chain are comparable (and mostly in Java's favor). A hybrid can be made which beats performance of both systems.
Oct 2019: lttoolbox-java kan read files compiled with lttoolbox version 3.5.0
- note* lttoolbox-java currently lacks support for functionality added the last 5 years - and it doesent work in Java JDK 9+, as it uses BCEL classes that was embedded Java 8 but changed package name in Java 9.
Instead we should include BCEL as a library.
- Nic Cottrell contributed an initial version of a Java port of lttoolbox.
- During GSOC2009 Raphaël and Sergio worked on it, but processing still didnt work (compilation and expansion worked)
- November 2009 Jacob Nordfalk finished it up and optimized some parts of it
- During GSOC 2010 Jacob mentored a full Java Runtime Port of Apertium (i.e. not just lttoolbox) made by Stephen Tigner.