Libraries - Java 8 Lambdas - page 47

System . out . printf ( "Max: %d, Min: %d, Ave: %f, Sum: %d" ,
trackLengthStats . getMax (),
trackLengthStats . getMin (),
trackLengthStats . getAverage (),
trackLengthStats . getSum ());

}

Example 4-4 prints out a summary of track length information to the console. Instead of cal-
culating that information ourselves, we map each track to its length, using the primitive spe-
cialized mapToInt method. Because this method returns an IntStream , we can call sum-
maryStatistics , which calculates statistics such as the minimum, maximum, average, and
sum values on the IntStream .

These values are available on all the specialized streams, such as DoubleStream and
LongStream . It's also possible to calculate the individual summary statistics if you don't
need all of them through the min , max , average , and sum methods, which are all also avail-
able on all three primitive specialized Stream variants.

Overload Resolution

It's possible in Java to overload methods, so you have multiple methods with the same name
but different signatures. This approach poses a problem for parameter-type inference because
it means that there are several types that could be inferred. In these situations javac will pick
the most specific type for you. For example, the method call in Example 4-5 , when choosing
between the two methods in Example 4-6 , prints out String , not Object .

Example 4-5. A method that could be dispatched to one of two methods
overloadedMethod ( "abc" );

Example 4-6. Two methods that are overloaded
private

private void void overloadedMethod ( Object o ) {

System . out . print ( "Object" );

}

private private void void overloadedMethod ( String s ) {

System . out . print ( "String" );

}