Scala Try, Else, Except block - scala

Question

I have code like this:
val extractInfo: (Array[Byte] => String) = (fp: Array[Byte]) => {
val parser:Parser = new AutoDetectParser()
val handler:BodyContentHandler = new BodyContentHandler(Integer.MAX_VALUE)
val config:TesseractOCRConfig = new TesseractOCRConfig()
val pdfConfig:PDFParserConfig = new PDFParserConfig()
val inputstream:InputStream = new ByteArrayInputStream(fp)
val metadata:Metadata = new Metadata()
val parseContext:ParseContext = new ParseContext()
parseContext.set(classOf[TesseractOCRConfig], config)
parseContext.set(classOf[PDFParserConfig], pdfConfig)
parseContext.set(classOf[Parser], parser)
parser.parse(inputstream, handler, metadata, parseContext)
handler.toString
}
A function literal that parses text from PDFs using Apache Tika.
What I want, though, is a Try block in here that runs on parser.parse and returns an empty string if it cannot execute. I am not sure how to construct this sort of logic in Scala.

Answer 1

I think what you are looking for is Try.
val extractInfo: (Array[Byte] => String) = (fp: Array[Byte]) => Try {
val parser:Parser = new AutoDetectParser()
...
handler.toString
} getOrElse("")
What this does is catch any error in the body and recover from this error by returning the empty string.

Answer 2

You can just write
try {
val parser:Parser = new AutoDetectParser()
val handler:BodyContentHandler = new BodyContentHandler(Integer.MAX_VALUE)
val config:TesseractOCRConfig = new TesseractOCRConfig()
val pdfConfig:PDFParserConfig = new PDFParserConfig()
val inputstream:InputStream = new ByteArrayInputStream(fp)
val metadata:Metadata = new Metadata()
val parseContext:ParseContext = new ParseContext()
parseContext.set(classOf[TesseractOCRConfig], config)
parseContext.set(classOf[PDFParserConfig], pdfConfig)
parseContext.set(classOf[Parser], parser)
parser.parse(inputstream, handler, metadata, parseContext)
handler.toString
} catch {
case e: Exception => ""
}
because try is an expression in Scala, just like if or match. However, if you intend to use "" as a sentinel value (that is, check later whether an error happened by checking if the result is empty), don't; use Option[String] or Try[String] as the return type instead.