February 2014
Intermediate to advanced
160 pages
4h 59m
English
Content preview from Functional Programming in Java
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Listing Immediate Subdirectories Using flatMap
We saw how to list the members of a given directory. Let’s look at the effort to explore the immediate (one level deep) subdirectories in a given directory, first using a rudimentary operation and then, more conveniently, using the flatMap method.
Let’s use the traditional for loop first to iterate over the files in a given directory. If a subdirectory contains any files, we’ll add them to our list; otherwise, we’ll add the subdirectory itself to the list. Finally, we’ll print the total number of files found. Here’s the code—for the hard way.
| compare/fpij/ListSubDirs.java | |
| | public static void listTheHardWay() { |
| | List<File> files = new ArrayList<>(); |
| | |
| | File[] filesInCurrentDir ... |
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