Demo app of using Java 8 features with Retrolambda and Lightweight-Stream-API.

Features:

• () -> lambda expression

  findViewById(R.id.go).setOnClickListener(v ->{finalintindex = mActionSpinner.getSelectedItemPosition(); if (index != Spinner.INVALID_POSITION){action(actions[index])} });

• Method::references

  intcmp = Objects.compare(word, other.word, String::compareToIgnoreCase);

• Stream.API()

  returnStream.of(lines) .map(str -> str.split("\t")) .filter(arr -> arr.length == 2) .map(arr -> newWord(arr[0], arr[1])) .collect(Collectors.toList());

• switch for "string"

  switch (action){case"filter 1": // Filter one wordstream = stream.filter(p -> p.getWord().split(" ").length == 1); break; case"filter 2+": // Filter two and more wordsstream = stream.filter(p -> p.getWord().split(" ").length >= 2); break; // ... }

• try(with-resources){}

  finalList<String> lines = newArrayList<>(); try (finalInputStreamis = context.getAssets().open("words.txt"); finalInputStreamReaderisr = newInputStreamReader(is, "UTF-8"); finalBufferedReaderreader = newBufferedReader(isr)){Stringline; while ( (line = reader.readLine()) != null ){lines.add(line)} }

• Objects (from Java 7)

  @Overridepublicbooleanequals(Objecto){// ...finalWordother = (Word) o; returnObjects.equals(translate, other.translate) && Objects.equals(word, other.word)} @OverridepublicinthashCode(){returnObjects.hash(word, translate)}

• try{Exceptional} catch (functional try/catch)

  returnExceptional.of(() ->{finalInputStreamis = context.getAssets().open("words.txt"); // ... operations which throws Exception ...returnlines}).ifException(e -> Log.e("Java 8 Example", "Utils.readWords", e)) .getOrElse(newArrayList<>());

Demo app: Java8StreamExample.apk

Blog (Russian): Java 8 в Android со Stream API и лямбдами

Retrolambda: https://github.com/orfjackal/retrolambda

Lightweight-Stream-API: https://github.com/aNNiMON/Lightweight-Stream-API