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up vote 1 down vote favorite

I would like to test if a file does not exist before generate it.

Is it possible to use something like isFileExist ?

[template public generate(conf : Configuration) ? (isFileExist('/path/to/file.txt'))]
[file ('/path/to/file.txt', false, 'UTF-8')]
file content
[/file]
[/template]

Thanks in advance.

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1 Answer 1

up vote 1 down vote accepted

I just had the same problem as you have, and I finally got it working by "externalizing" this function in an external Java class. That way, you can just define a method such as: 

public boolean existsFile(String filepath) {
    Path p = Paths.get(filepath);
    p.normalize();
    File f = new File(filepath);
    return f.exists();
}

and then call it from Acceleo by defining a query like: 

[query public existsFile(filePath : String): 
    Boolean = invoke('utils.AcceleoUtils', 'existsFile(java.lang.String)', Sequence{filePath})
/]

This way, in your example, you could do 

[template public generate(conf : Configuration)]
    [if existsFile('/path/to/file.txt')/]
        [file ('/path/to/file.txt', false, 'UTF-8')]
            file content
        [/file]
    [/if]

[/template]

p.d: Be carefull with the paths, because the ´file´ tag outputs your files in your target path by default, so in case you´re not providing an absolute Path you will need to include it either when calling or inside the existsFile function.

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So we do not use pre guard. I did not know [file /] tag could be enclosed by an [if /] tag. thank you. –  Mickaël Gauvin Sep 15 '14 at 19:01

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