Iteration.java

package com.insightfullogic.java8.examples.chapter3;

import com.insightfullogic.java8.examples.chapter1.Artist;

import java.util.Iterator;
import java.util.List;

public class Iteration {

    public int externalCountArtistsFromLondon(List<Artist> allArtists) {
        // BEGIN external_count_londoners
int count = 0;
for (Artist artist : allArtists) {
    if (artist.isFrom("London")) {
        count++;
    }
}
        // END external_count_londoners
        return count;
    }

    public int externalCountArtistsFromLondonExpanded(List<Artist> allArtists) {
        // BEGIN external_count_londoners_expanded
int count = 0;
Iterator<Artist> iterator = allArtists.iterator();
while(iterator.hasNext()) {
    Artist artist = iterator.next();
    if (artist.isFrom("London")) {
        count++;
    }
}
        // END external_count_londoners_expanded
        return count;
    }


    public long internalCountArtistsFromLondon(List<Artist> allArtists) {
        // BEGIN internal_count_londoners
long count = allArtists.stream()
                       .filter(artist -> artist.isFrom("London"))
                       .count();
        // END internal_count_londoners
        return count;
    }

    public void filterArtistsFromLondon(List<Artist> allArtists) {
        // BEGIN filter_londoners
allArtists.stream()
          .filter(artist -> artist.isFrom("London"));
        // END filter_londoners
    }

    public void filterArtistsFromLondonPrinted(List<Artist> allArtists) {
        // BEGIN filter_londoners_printed
allArtists.stream()
          .filter(artist -> {
              System.out.println(artist.getName());
              return artist.isFrom("London");
          });
        // END filter_londoners_printed
    }

    public long internalCountArtistsFromLondonPrinted(List<Artist> allArtists) {
        // BEGIN internal_count_londoners_printed
long count = allArtists.stream()
                       .filter(artist -> {
                           System.out.println(artist.getName());
                           return artist.isFrom("London");
                       })
                       .count();
        // END internal_count_londoners_printed
        return count;
    }

}