Lttoolbox-java

Nic Cottrell contributed an initial version of a Java port of lttoolbox; this work needs to be completed.

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.

Prerequisites

• You don't need much knowlede of MT or NLP to do lttoolbox-java. But you need to know C++ and Java and be able to debug both.
• You only have to understand what lt-expand, lt-comp and lt-proc does with a .dix file.
• Ability to debug C++ and Java

What is lttoolbox

lttoolbox are 1) making binary files out of the .dix files (lt-comp), 2) analysing or generating text (lt-proc) and 3) expanding a .dix file (lt-expand).

Download preferably via SVN. It it fails, try [1] and [2] ("Download GNU tarball" will give a compressed archive)

Pls compile lttoolbox and apertium and a language pair of your choice. Then you have the setup needed to understand the role of lt-toolbox.

Required

• Binary compatibility with lttoolbox (input and output files should be the same)
• a test suite which runs on both lttoolbox (C++) and lttoolbox-java
• lttoolbox-java needs to at least be able to _read_ the binary files (see 2) abobe: analysing or generating text (lt-proc))

Problems

• Right now we have a line-for-line port of the C++ code of lttoolbox in apertium-tools/lttoolbox-java. It's NOT working.
• it's amost line for line identical to the C++, aside from Java/C++ differences.

But the languages are different. C++ for example has some methods where some simple type variables are changed (the reference is passed) But in Java simple type variables can only be passed by value, and thus the caller's value is not changes. That sort of things needs to be sorted out.

• The biggest problem is the XML handling: The C code's library callback calls a method in the code both when it meets a START and an END tag (for C++, we use libxml2).
  • The Java's XML library only calls the callback method at the START tag.
  • Perhaps we could find another Java XML library that could be made also call for the end tags. Or some kind of wrapper-inbetween thing could be made. Or you could use SAX and make your own callback thing.
• There might be other problems. The project just got stranded on the XML parse part.

XML Handling

As lttoolbox is parsing the same files as Apertium-dixtools it might be an idea to use dixtools to do the parsing. However, the XML handling in dixtools is in needs of improvements (see Apertium-dixtools#Wishlist_and_notes_for_Apertium-dixtools)

[21:02:23] Apertium Java-lttoolboc Nic Cottrell: I would recommend dom4j
[21:02:43] Jacob Nordfalk: Why would you that?
[21:02:55] Apertium Java-lttoolboc Nic Cottrell: which lets you load the whole xml file into a dom tree and then you can do searches and manipulations very easily
[21:04:13] Jacob Nordfalk: yes, Nic, but what is neede is either to rewrite the code competely or somehow get callback when encountering an END tag.
[21:04:30] … and as far as I understand thats possible with SAX
[21:04:32] Apertium Java-lttoolboc Nic Cottrell: Yes, exactly
[21:04:44] … Oh, ok. then that's probably the fastest way to make it work
[21:04:49] Jacob Nordfalk: dom4j != SAX :-)
[21:05:04] … OK, so we agree :-)
[21:05:07] Apertium Java-lttoolboc Nic Cottrell: but I personally believe that dom4j gives better code readability and flexibility for later on
[21:05:40] Jacob Nordfalk: yes, you might be rignt.
[21:06:20] … its a question of how much the two sets (C++ and Java) should differ.

Other notes

<Drew_> jacobEo: I can't find a main class in the source code, am I looking in the wrong place? :S
<jacobEo> Drew_: LTComp.java, LTExpand.java, LTProc.java

[21:08:21] Jacob Nordfalk: So, Nic, how much time do you probably have the next months? Would you like to be a co-mentor on this, or 
  would you like to just occasionally be informed about progress?
[21:08:58] Apertium Java-lttoolboc Nic Cottrell: Well, I would love to be a co-mentor, but I fear that I might not be able to give 
  enough time to perform that role
[21:09:12] … But I would definitely like to be in the loop and can jump in to help when I can