Functional Programming Techniques: Functional Interfaces, Streams, Parallel Collections - Java - page 351

import import java.util.Arrays java.util.Arrays ;

import import java.util.Comparator java.util.Comparator ;

public public class class ReferencesDemo4 ReferencesDemo4 {

static static final final String [] unsortedNames = {

"Gosling" , "de Raadt" , "Torvalds" , "Ritchie" , "Hopper"

};

public public static void main ( String [] args ) {

String [] names ;

static void

// Sort using
// "an Instance Method of an Arbitrary Object of a Particular Type"
names = unsortedNames . clone ();
Arrays . sort ( names , String: : compareToIgnoreCase );
dump ( names );

// Equivalent Lambda:
names = unsortedNames . clone ();
Arrays . sort ( names , ( str1 , str2 ) -> str1 . compareToIgnoreCase ( str2 ));
dump ( names );

// Equivalent old way:
names = unsortedNames . clone ();
Arrays . sort ( names , new new Comparator < String >() {

@Override
public

public int int compare ( String str1 , String str2 ) {

return return str1 . compareToIgnoreCase ( str2 );

}

});
dump ( names );

// Simpest way, using existing comparator
names = unsortedNames . clone ();
Arrays . sort ( names , String . CASE_INSENSITIVE_ORDER );
dump ( names );

}

Using “an Instance Method of an Arbitrary Object of a Particular Type,” declares a refer-
ence to the compareToIgnoreCase method of any String used in the invocation.

Shows the equivalent lambda expression.