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Demo app of using Java 8 features withRetrolambda andLightweight-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