Custom implementation of InputStream

java ftp inputstream java-io
John Manak picture John Manak · Jan 26, 2011 · Viewed 14.8k times · Source

To send data to a file on my FTP server, I need to create a custom InputStream implementation that reads database data row by row, converts it to CSV and publishes it via its read() methods: from the database, I get a List<Application> object with the data. For each Application object, I want to create a line in the CSV file.

My idea is to load all the data in the constructor and then override the read method. Do I need to override all InputStream's methods? I tried googling for some examples but didn't succeed - could you eventually give me a link to one?

Answer

Joachim Sauer picture Joachim Sauer · Jan 26, 2011

You only nead to implement the read() method without parameters. All other methods are implemented as calls to that method. For performance reasons (and even ease of implementation) it might be easier to implement the three-argument read() method instead and re-implement the no-args read() method in terms of that method.

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