Effective Java

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CHAPTER 7
LAMBDAS AND STREAMS
206
Even if you have little previous exposure to streams, this program is not hard
to understand. It opens the dictionary file in a 
try
-with-resources block, obtaining
a stream consisting of all the lines in the file. The 
stream
variable is named 
words
to suggest that each element in the stream is a word. The pipeline on this stream
has no intermediate operations; its terminal operation collects all the words into a
map that groups the words by their alphabetized form (Item 46). This is exactly
the same map that was constructed in both previous versions of the program. Then
a new 
Stream>
is opened on the 
values()
view of the map. The
elements in this stream are, of course, the anagram groups. The stream is filtered
so that all of the groups whose size is less than 
minGroupSize
are ignored, and
finally, the remaining groups are printed by the terminal operation 
forEach
. 
Note that the lambda parameter names were chosen carefully. The parameter
g
should really be named 
group
, but the resulting line of code would be too wide
for the book.