Streams in Java8

API-Definition: http://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html,

Kommentar: Dave Hartveld http://blog.hartveld.com/2013/03/jdk-8-33-stream-api.html

List<Block> blocks = ...;

int sumOfWeights = 0;
for (Block block : blocks) {
  if (block.getColor() == Color.RED) {
    sumOfWeights += block.getWeight();  }  }

int sumOfWeights = blocks.stream()
     .filter(b -> b.getColor() == Color.RED)
     .map(b -> b.getWeight()).sum();