Jlua

JLua is a scripting tool for Java. This tool allows scripts written in Lua to manipulate components developed in Java and vice versa.

JLua is a fork of "LuaJava". It offers the following improvements:

Added LuaState wrapper to ease manipulation of lua objects.
Simpler creation of Java objects from Lua.
Lua error automatically causes Java exception and vice versa.
Added "try ... catch ... finally" mechanism to Lua.
Allows simpler implementation of Java interfaces in Lua.
Simple Java array creation from lua.
Fixed some multithreading issues.
Plenty of other bug fixes.

Building JLua

First, change your current working directory to the build directory. Then, run cmake:

cmake /path/to/source/

For 64-bit build run:

cmake /path/to/source/ -DCMAKE_GENERATOR_PLATFORM=x64

On Linux/Mac the default generator is Unix Makefiles, so the build can be started by invoking the make executable:

make

On Windows the default generator is a Visual Studio project file. You can open the file and build manually or execute the following command from the VS Native Tools command prompt:

devenv Project.sln /build Debug

Before running the Java program, make sure you have the .so (UNIX) or .dll (Windows) file path in your "LD_LIBRARY_PATH" (UNIX) or "PATH" (Windows) environment variable.

Usage from Lua

This library offers 5 functions:

jlua.getClass ( class_name )

Get a Java class to lua code. Examples:

System = jlua.getClass("java.lang.System")
System.out:println("Hello world")

ArrayList = jlua.getClass("java.util.ArrayList")
a = ArrayList:new(2)
a:add("Hello")
a:add("World")
print(a:get(0))
print(a:get(1))

jlua.newArray ( class_name, num_of_elements )

Create new Java array from Lua. Examples:

a = jlua.newArray("int", 3)
a[1] = 7
a[2] = 5
a[3] = 8
print(a[1] + a[2] + a[3])

a = jlua.newArray("java.lang.String", 2)
a[1] = "aa"
a[2] = "bb"
print(a[1] .. a[2])

jlua.throw ( trowable_or_string )

Throws Java exception or string. Examples:

jlua.throw("Error!!")

Exception = jlua.getClass("java.lang.Exception")
jlua.throw(Exception:new("some exception"))

jlua.try ( try_block, catch_block ) or
jlua.try ( try_block, catch_block, finally_block ) or
jlua.try ( try_block, nil, finally_block )

Implement "try ... cache ... finally" block. Examples:

jlua.try(function()
            print("aa")
            jlua.throw(jlua.getClass("java.lang.Exception"):new("hey"))
            print("bb")
        end, function(e)
            print(e:toString())
         end)

jlua.try(function()
    jlua.try(function()
        print("aa")
        jlua.throw(jlua.getClass("java.lang.Exception"):new("hey"))
        print("bb")
    end, nil , function()
        print("ff")
    end)
end, function(e)
    print(e:toString())
    end)

jlua.createProxy ( java_interface, lua_table )

Create lua implementation of Java interface. Example:

runnable = {}
function runnable:run()
    print("hey")
end
runnableJava = jlua.createProxy("java.lang.Runnable", runnable)
thread = jlua.getClass("java.lang.Thread"):new(runnableJava)
thread:start()

Actually, in this example there is no need to use jlua.createProxy. JLua automatically convert lua table to Java interface as it passes as a parameter. Simplified example:

runnable = {}
function runnable:run()
    print("hey")
end
thread = jlua.getClass("java.lang.Thread"):new(runnable)
thread:start()

Usage from Java

The "Lua" object offer many methods to manipulate lua objects. See src/java/org/jlua/Console.java for simple usage example.

nirhal/JLua

Jlua

Building JLua

Usage from Lua

Usage from Java