Unhandled Exception type ImageProcessingException...what is this error about?

nikpalmer

Unhandled Exception type ImageProcessingException...what is this error about?

in Contributed Library Questions • 2 years ago

I'm quickly trying to get the exif/xmp data out of some jpeg's (i have checked that the data does exist within the file using a hex editor, although it's not even getting to the run stage). On pressing run on the processing IDE i get the above error. The code doesn't run so i guess it's some precompile or more likely preprocessor. The code is super simple testpiece to prove it works (haha) before i moved it into my main application.

import com.drew.imaging.*;
import com.drew.imaging.jpeg.*;
import com.drew.metadata.*;
import com.drew.metadata.exif.*;
import com.drew.metadata.iptc.*;
import com.drew.metadata.jpeg.*;
void setup() {
size(200, 200);
background(50);
fill(200);
}
void draw() {
File jpegFile = new File("09000d5d822c7ed2.jpg");
try
{
Metadata metadata = ImageMetadataReader.readMetadata(jpegFile);
}
catch (JpegProcessingException ex)
{
println("Ouch! " + jpegFile.getName());
}
}

I've seen this used elsewhere in processing forums. I dragged the com.drew jar files onto the IDE.

What does it all mean????

thanks in advance if you can help.

nik

Replies(4)

PhiLho

Re: Unhandled Exception type ImageProcessingException...what is this error about?

2 years ago

As you guessed, it is a compile-time error.
It just means you have to catch the said exception, like you caught the JpegProcessingException. That's the problem with checked exceptions (ie. exceptions you cannot ignore).

nikpalmer

Re: Unhandled Exception type ImageProcessingException...what is this error about?

2 years ago

Thanks for the info...maybe i am being obtuse but if this exception means that the jpeg file data is incorrect (which it isn't anyhow) then how is this known at compile time? The code is in the draw function so that wouldn't be run until after compile and setup was run.

Sorry to re ask.

nikpalmer

Re: Unhandled Exception type ImageProcessingException...what is this error about?

2 years ago

Ah i see now... I guess the Exceptions are "registered" somewhere and the compiler checks to see that i can handle (have code in place to handle) the possibility of a "registered" exception taking place during run time.

I think i understand.

thanks

nik

PhiLho

Re: Unhandled Exception type ImageProcessingException...what is this error about?

2 years ago

Yes, exactly. Unlike any other programming languages, Java designer thought it was a good idea to classify exceptions in two categories: those you can ignore, like null pointer exception, array index out of bounds exception, etc. because they can happen everywhere; and those you must catch (checked exceptions), because they are very likely to happen (IO exceptions are a good example). Even if you are sure of your environment, these exceptions must be caught, just in case.

I moved this question to the Contributed Libraries section because you use one, and because Processing tends to insulate from these exceptions, catching them itself.

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