Importing Processing Libraries from a .Java file

Contributed Library Questions

Jesse Sco..

Importing Processing Libraries from a .Java file

in Contributed Library Questions • 4 months ago

Hi Forum, long time no see.

I have an application that is using two .java files alongside my .pde ...

I am able to import the classes that I need from the processing core library,

but when I'm trying to import 3rd party libraries - for example, GSVideo - I am getting a package not found error...

Has anyone dealt with this?

I know a workaround is to add the JARs directly to the sketch - via drag n' drop or to the code directory, but Id like to know if there's a solution that involves finding the Libraries directory...

Thanks...

~ Jesse

Replies(17)

PhiLho

Re: Importing Processing Libraries from a .Java file

4 months ago

Moved from Processing with Other Languages, since you don't mention another language (Java isn't "another" language in Processing!).

I don't understand your question, particularly what the .java files does with the problem with 3rd party libraries.
I am not sure what is your problem with the libraries either. You probably have read the How to Install a Contributed Library article a long time ago, no?

Jesse Sco..

Re: Importing Processing Libraries from a .Java file

4 months ago

Hi PhiLho...

Moved from Processing with Other Languages, since you don't mention another language (Java isn't "another" language in Processing!).

Hehe. I knew you were going to take exception to that! Sorry, categorizing-from-the-hip.

I don't understand your question, particularly what the .java files does with the problem with 3rd party libraries.
I am not sure what is your problem with the libraries either. You probably have read the How to Install a Contributed Library article a long time ago, no?

The problem is that .java files seem to have no conception of the /Libraries directory.

They can import Processing classes just fine, and of course Java classes, but not third party libraries.

See the attached screenshot:

GoToLoop

Re: Importing Processing Libraries from a .Java file

3 months ago

quarks mentioned something about a subfolder named "/code"

where he said that imported libraries can be placed.

Then, I've remembered that you wanted something about using libraries

from .java files and searched for this post!

Who knows, it might be a solution for ya!?

http://forum.processing.org/topic/importing-libusb-libraries-to-processing

Jesse Sco..

Re: Re: Importing Processing Libraries from a .Java file

3 months ago

Thanks for the reply.

As I mentioned (kind of lazily ) in my first post, I know about the /code directory trick to add a jar directly to a sketch.

I was hoping to find a solution that didn't require this, since it kind of bloats the application (not that big of a deal, just being tricky). In my case, I'm trying to use the GSVideo library, which has several dependencies itself, and the /library structure is quite big...

PhiLho

Re: Importing Processing Libraries from a .Java file

3 months ago

It should work, and it does work (just made a little test with the gifAnimation library).
Processing generates a .java file out of the .pde files, then it compiles everything together, so there is no reason the classpath changes between the two kinds of files.
Is your import working in a .pde file?

For the record, I have added this code in a Test.java file in a little sketch using gifAnimation:

import processing.core.PApplet;
import gifAnimation.Gif;
class Test
{
Gif simpleGif;
Test(PApplet pa, String animation)
{
simpleGif = new Gif(pa, animation);
}
}

It compiles and run fine.

Jesse Sco..

Re: Re: Importing Processing Libraries from a .Java file

3 months ago

Totally doesn't work for me, regardless of library... ???

PhiLho

Re: Importing Processing Libraries from a .Java file

3 months ago

It could be interesting if someone not on Windows tries this. Can be a bug. Or a problem with your Processing installation...

quarks

Re: Importing Processing Libraries from a .Java file

3 months ago

I suspect that the problem is that java files do not go through Processing's pre-processor so imports of core libraries will not be located while contributed libraries are (in the Processing/libraries folder).

One solution is to make the classes inner classes then any core library will be available to them. If either of these classes have class-attributes or methods (static) then you will have to make the inner class static as well.

Jesse Sco..

Re: Re: Importing Processing Libraries from a .Java file

3 months ago

Hi Quarks,

Yeah, your analysis makes sense.

I'm not sure what you mean by 'inner classes' though... can you post a short example ?

amnon.owed

Re: Importing Processing Libraries from a .Java file

3 months ago

I just want to confirm the behavior Jesse is describing with Processing 2.0 final on Windows XP. Of course in a pde file it works as expected. However both core and contributed library imports do not work from a java file.

Of course this is also not what the PDE what designed for in the first place, right? I think solutions are:

Rename your java files to pde and perhaps make some slight adaptations (like remove the package statement).
Use a real java-based IDE like Eclipse and import the libraries/files correctly.

Jesse Sco..

Re: Re: Importing Processing Libraries from a .Java file

3 months ago

3. add them via the /Code directory

PhiLho

Re: Importing Processing Libraries from a .Java file

3 months ago

amnon.owed, can you post the code you used to reproduce the problem? It is strange I hadn't the issue myself.

amnon.owed

Re: Importing Processing Libraries from a .Java file

3 months ago

Sure, two files:

Test.pde

void setup() {
size(300, 300);
}
void draw() {
background(frameCount%255);
}

SomeJava.java

import controlP5.*;
ControlP5 cp5;

PhiLho

Re: Importing Processing Libraries from a .Java file

3 months ago

import controlP5.*;
ControlP5 cp5;

This is not a valid Java file...
Such file must define a class (or an interface or an enum), you cannot declare a "global" variable, which is a Processing-only concept.

Try:

import controlP5.*;
class SomeJava
{
ControlP5 cp5;
}

instead.

amnon.owed

Re: Importing Processing Libraries from a .Java file

3 months ago

Ok, sorry about that. This exposes me as a programmer who grew up in Processing.

Some more tests which result in two variants not working, but also one that seems to work!

Test 1 => Doesn't work (error on yellow line)

Test.pde

void setup() {
size(300, 300);
}
void draw() {
background(frameCount%255);
}

SomeJava.java

import controlP5.*;
class SomeJava {
ControlP5 cp5;
}

Result
The package "controlP5" does not exist. You might be missing a library.
Libraries must be installed in a folder named 'libraries' inside the 'sketchbook' folder.

Test 2 => Doesn't work (error on yellow line)

Test.pde

import controlP5.*;
void setup() {
size(300, 300);
}
void draw() {
background(frameCount%255);
}

SomeJava.java

class SomeJava {
ControlP5 cp5;
}

Result
Cannot find a class or type named "ControlP5"

Test 3 => Works! (at least it runs without errors)

Test.pde

import controlP5.*;
void setup() {
size(300, 300);
}
void draw() {
background(frameCount%255);
}

SomeJava.java

import controlP5.*;
class SomeJava {
ControlP5 cp5;
}

Result
Works!

PhiLho

Re: Importing Processing Libraries from a .Java file

3 months ago

That's logical (even if I didn't thought of it): Processing only scans the .pde files, and analyzes the imports found there. It will generate the classpath only for the libraries it found then.
Good finding. Good to know.
(Of course, my little test with gifAnimation had both imports from the start, so I didn't see the problem.)

Jesse Sco..

Re: Importing Processing Libraries from a .Java file

3 months ago

Aha! Works! Good find Amnon...

Top Reply