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I'm not skilled at Java at all so I could really use your help. I'm trying to read the duration and bit rate from an mp3 file. I'm using a java library called "mp3spi" from http://www.javazoom.net/mp3spi/documents.html.

So var I've been able to determine that these objects exist:

<cfset AudioFormat = createObject("java", "org.tritonus.share.sampled.TAudioFormat")>
<cfset AudioFileFormat = createObject("java", "org.tritonus.share.sampled.file.TAudioFileFormat")>
<cfset AudioFileReader = createObject("java", "javax.sound.sampled.spi.AudioFileReader")>

I'm having trouble with the following code and converting it to ColdFusion:

File file = new File("filename.mp3");
AudioFileFormat baseFileFormat = new MpegAudioFileReader().getAudioFileFormat(file);
Map properties = baseFileFormat.properties();
Long duration = (Long) properties.get("duration");

I've tried several ways of setting the above variables, but I keep getting an error that either MpegAudioFileReader or getAudioFileFormat doesn't exist. However when I dump the variables I used to create the Java objects, they do exist.

Here is what I have:

<cfscript>
    mp3file = FileOpen(ExpandPath("./") & originalfile, "readBinary");
    baseFileFormat = AudioFileReader.getAudioFileFormat(mp3file);
    properties = baseFileFormat.properties();
    duration = properties.get("duration");
</cfscript>
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  • 7
    Welcome to SO. Please read the FAQ and How to Ask for tips on writing good questions. In general, you are expected to do some research, attempt to solve the problem yourself, and then show what you have tried, what didn't work, and what specifically you have a problem with. Just saying "please help me port this code" with no indication you've actually done anything is not considered appropriate. Commented Oct 3, 2013 at 16:59
  • getAudioFileFormat doesn't exist Actually the error says a bit more than that: ie "Either there are no methods with the specified method name and argument types or the xxxx method is overloaded with argument types that ColdFusion cannot decipher reliably.". So it often means the method you are calling DOES exist, you are just passing in the wrong argument type. The code above is passing binary to getAudioFileFormat(), when it requires a java.io.File object instead. Hence the error. See @Adam's example for how to create a File object (but use an absolute path, not just the file name) Commented Oct 3, 2013 at 18:22

2 Answers 2

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I'm not going to write your code for you, Simone, but there's a coupla general tips.

File file = new File("filename.mp3");

Well as you probably know, CFML is loosely-type, so you can dispense with the typing on the LHS, and then you need to use the createObject() function to create Java objects, which you already have a handle on. CF can't import Java libraries, so you'll need to give a fully-qualified path to the File class. You also need to explicitly call the constructor:

mp3File = createObject("java", "java.io.File").init("filename.mp3");

(as @Leigh points out below, file is a kinda reserved word in CFML, so best not to use it as a variable name! So I'm using mp3File here)

From there... you should be able to do the work for the other three statements easy enough. Basic method calls and assignments can pretty much be ported straight from the Java source, just lose the static-typing bits as per above, and the type-casting (long) etc.

If you cannot sort everything out from here, update your question with your experimentation, and we can improve this answer (or someone can post a different one). But you need to give us your specific problems, not just a general "write my code please". People won't do that, and you shouldn't be asking people to here (it's against the rules, and people are very big on rules on StackOverflow).

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Though probably best to avoid using file as a CF variable name as it is also the name of a scope a.k.a. CFFILE.
5

Adam's answer is solid. Since you'll need to invoke the constructor of a Java class in order to create an instance rather than being limited to using static methods, the "init()" method must be called. As follows...

mp3file = createObject("java", "java.io.File").init("filename.mp3");
baseFileFormat = createObject("java", "path.to.MpegAudioFileReader").init().getAudioFileFormat(mp3file);
properties = baseFileFormat.properties();
duration = properties.get("duration");

Adam's guidance is right on in that typing your variables when you initialize them won't fly. I don't have a ColdFusion environment set up to try this, but in the past we've used approaches like the one above to expand on ColdFusion's Hibernate integration by creating instances of the Java classes and invoking their methods. So long as the external libs that you're dependent on are in ColdFusion server's class path, you shouldn't have any trouble with this.

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2 Comments

FYI, The init method is not a method of the object, but a ColdFusion identifier that calls the new function on the class constructor." So createObject("java", "path.to.SomeClass").init(...) is equivalent to the java code new SomeClass(..).
Correct, which is critical in Simone's case since he needs to invoke the constructor on both the File and MpegAudioFileReader classes.

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