Java SE 8 Lambdas and Streams - Java: How to Program Early Objects - page 735

Intermediate Stream operations

filter Results in a stream containing only the elements that satisfy a condition.

distinct

Results in a stream containing only the unique elements.

limit

Results in a stream with the specified number of elements from the beginning
of the original stream.

map

Results in a stream in which each element of the original stream is mapped to
a new value (possibly of a different type)—e.g., mapping numeric values to
the squares of the numeric values. The new stream has the same number of
elements as the original stream.

sorted

Results in a stream in which the elements are in sorted order. The new stream
has the same number of elements as the original stream.

Fig. 17.3 | Common intermediate Stream operations.

Ter minal Stream operations

forEach Performs processing on every element in a stream (e.g., display each element).
Reduction operations —Take all values in the stream and return a single value
average Calculates the average of the elements in a numeric stream.
count Returns the number of elements in the stream.
max Locates the largest value in a numeric stream.
min Locates the smallest value in a numeric stream.
reduce Reduces the elements of a collection to a single value using an associative accumu-
lation function (e.g., a lambda that adds two elements).
Mutable reduction operations —Create a container (such as a collection or StringBuilder )
collect Creates a new collection of elements containing the results of the stream's prior
operations.
toArray Creates an array containing the results of the stream's prior operations.
Search operations
findFirst

Finds the first stream element based on the prior intermediate operations; immedi-
ately terminates processing of the stream pipeline once such an element is found.

findAny

Finds any stream element based on the prior intermediate operations; immediately
terminates processing of the stream pipeline once such an element is found.

anyMatch

Determines whether any stream elements match a specified condition; immedi-
ately terminates processing of the stream pipeline if an element matches.

allMatch

Determines whether all of the elements in the stream match a specified condition.

Fig. 17.4 | Common terminal Stream operations.

Stream in File Processing vs. Stream in Functional Programming
Throughout this chapter, we use the term stream in the context of functional program-
ming—this is not the same concept as the I/O streams we discussed in Chapter 15, Files,