public T match(String s) {
Matcher m = pattern.matcher(s);
if (m.find()) {
return parser.apply(m.group(m.groupCount()));
}
return parser.apply(null);
}
@Test
public void test0() {
Function<Integer, Integer> f = ((Integer) 0)::compareTo;
Function<Integer, Integer> f1 = f.compose(f);
// f1 does what?!
}
@Test
public void converts() throws Exception {
Function<Double, Double> converterFunction = new Converter_1_2().apply(CONVERSION_RATE);
assertEquals(4.5, converterFunction.apply(3.0), 0.0001);
assertEquals(6.0, converterFunction.apply(4.0), 0.0001);
assertEquals(7.5, converterFunction.apply(5.0), 0.0001);
}
public List<T> collect() {
List<T> list = new ArrayList<>();
for (Pair<String, String> p : map.keySet()) {
String folder = p.first;
String pattern = p.second;
Function<String, ? extends T> func = map.get(p);
DirectoryStream<Path> dirStream;
try {
dirStream = Files.newDirectoryStream(Paths.get(folder), pattern);
logger.info(String.format("Load files from folder %s with pattern %s.", folder, pattern));
// sort the files
List<String> files = new ArrayList<>();
dirStream.forEach(s -> files.add(s.toString()));
Collections.sort(files);
for (String s : files) {
logger.info(String.format("Loading file %s.", s));
list.add(func.apply(s));
}
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException(String.format("Could not load files from patern: %s", pattern));
}
}
return list;
}
public void set(T result) {
try {
final Object use = result;
if (pipeline == null || pipeline.functions.length == 0) {
this.result.lazySet(use);
done();
return;
}
Function op = pipeline.functions[0];
if (this.pipeline.executors[0] != null) {
this.pipeline.executors[0].execute(
() -> {
set(() -> (T) op.apply(use), 1);
});
} else {
set(() -> (T) op.apply(use), 1);
}
} catch (Throwable t) {
completeExceptionally(t);
}
}
private void set(Supplier<T> result, int index) {
try {
Object current = result.get();
final Object use = current;
if (index < pipeline.functions.length) {
Function op = pipeline.functions[index];
this.pipeline.executors[index].execute(
() -> {
set(() -> (T) op.apply(use), index + 1);
});
return;
}
this.result.lazySet(current);
done();
} catch (Throwable t) {
if (t instanceof CompletedException) {
if (this.doFinally != null) doFinally.accept(this);
}
completeExceptionally(t);
}
}
public static void main(String[] args) {
// Write custom functional interfaces that can be implemented via lambda expressions.
ReverseType newText =
(testText) -> {
String tempStr = "";
for (String part : testText.split(" ")) {
tempStr = new StringBuilder(part).reverse().toString();
}
return tempStr;
};
System.out.println(newText.reverse("HELLO"));
// Use a functional interface that is contained within the java.util.function package to
// implement a lambda expression
Function<String, String> newText2 =
(testText) -> {
String tempStr = "";
for (String part : testText.split(" ")) {
tempStr = new StringBuilder(part).reverse().toString();
}
return tempStr;
};
System.out.println(newText2.apply("WORLD"));
}
@Before
public void setUp() {
consumersForMergeParams.put(OrderEventType.MERGE_OK, eventConsumerMock);
consumersForMergeParams.put(OrderEventType.MERGE_REJECTED, eventConsumerMock);
when(actionConsumerMock.apply(orderForTest)).thenReturn(actionMock);
when(mergePositionParamsMock.instrument()).thenReturn(instrumentEURUSD);
when(mergePositionParamsMock.mergeOrderLabel()).thenReturn(mergeOrderLabel);
when(mergePositionParamsMock.consumerForEvent()).thenReturn(consumersForMergeParams);
when(closePositionComposeParamsMock.composeData()).thenReturn(composeData);
closeParams =
CloseParams.withOrder(orderForTest)
.doOnStart(actionMock)
.doOnComplete(actionMock)
.doOnError(errorConsumerMock)
.retryOnReject(retryParams)
.doOnClose(eventConsumerMock)
.doOnPartialClose(eventConsumerMock)
.doOnReject(eventConsumerMock)
.build();
when(closeParamsFactoryMock.apply(orderForTest)).thenReturn(closeParams);
closePositionParams =
ClosePositionParams.newBuilder(mergePositionParamsMock, closeParamsFactoryMock)
.withCloseExecutionMode(CloseExecutionMode.CloseFilled)
.withClosePositonParams(closePositionComposeParamsMock)
.build();
}
public static <T, U> Function<T, U> ternaryOperator(
Predicate<? super T> condition,
Function<? super T, ? extends U> ifTrue,
Function<? super T, ? extends U> ifFalse) {
return (x -> condition.test(x) ? ifTrue.apply(x) : ifFalse.apply(x));
}
public static void main(String... args) {
Function<String, String> addHeader = Letter::addHeader;
Function<String, String> transformationPipeline =
addHeader.andThen(Letter::checkSpelling).andThen(Letter::addFooter);
System.out.println(transformationPipeline.apply("C++ stay away from me!"));
}
protected JsonNode loadConfiguration(Map<String, String> properties, Map<String, String> vars) {
// hopefully sharing the mapper between parsers is safe... Does it
// change the state during parse?
ObjectMapper textToJsonMapper = jacksonService.newObjectMapper();
Map<ParserType, Function<InputStream, Optional<JsonNode>>> parsers =
new EnumMap<>(ParserType.class);
parsers.put(ParserType.YAML, new JsonNodeYamlParser(textToJsonMapper));
parsers.put(ParserType.JSON, new JsonNodeJsonParser(textToJsonMapper));
Function<URL, Optional<JsonNode>> parser = new MultiFormatJsonNodeParser(parsers, bootLogger);
BinaryOperator<JsonNode> singleConfigMerger = new InPlaceLeftHandMerger(bootLogger);
Function<JsonNode, JsonNode> overrider = new InPlaceMapOverrider(properties, true, '.');
if (!vars.isEmpty()) {
overrider = overrider.andThen(new InPlaceMapOverrider(vars, false, '_'));
}
return JsonNodeConfigurationBuilder.builder()
.parser(parser)
.merger(singleConfigMerger)
.resources(configurationSource)
.overrider(overrider)
.build();
}
public GExpansion rewrite(Function<GExpansion, GExpansion> f) {
switch (kind) {
case LookAhead:
if (semanticLookahead != null || amount != -1) {
return f.apply(this);
}
case Choice:
case Sequence:
case ZeroOrOne:
case ZeroOrMore:
case OneOrMore:
List<GExpansion> rewroteChildren =
children.stream().map(e -> e.rewrite(f)).collect(Collectors.toList());
return f.apply(
new GExpansion(
kind,
rewroteChildren,
name,
symbol,
hints,
arguments,
action,
amount,
semanticLookahead,
negativeLookahead));
case NonTerminal:
case Terminal:
case Action:
return f.apply(this);
default:
}
return null;
}
@Override
public void forEachRemaining(Consumer<? super R> action) {
while (left != null) {
accept(handleLeft(), action);
}
if (cur == none()) {
if (!source.tryAdvance(this)) {
accept(pushRight(none(), none()), action);
return;
}
}
acc = mapper.apply(cur);
source.forEachRemaining(
next -> {
if (!this.mergeable.test(cur, next)) {
action.accept(acc);
acc = mapper.apply(next);
} else {
acc = accumulator.apply(acc, next);
}
cur = next;
});
if (accept(pushRight(acc, cur), action)) {
if (right != null) {
action.accept(right.acc);
right = null;
}
}
}
public static void main(String[] args) {
Function<String, Integer> f1 = String::length;
Function<String, Integer> f2 = x -> x.length();
System.out.println(f1.apply("cluck")); // 5
System.out.println(f2.apply("cluckssss")); //
}
/**
* Calculates the minimum of this elements within the co-domain of a specific function.
*
* @param f A function that maps this elements to comparable elements
* @param <U> The type where elements are compared
* @return The element of type T which is the minimum within U
*/
default <U extends Comparable<? super U>> Option<T> minBy(Function<? super T, ? extends U> f) {
Objects.requireNonNull(f, "f is null");
if (isEmpty()) {
return None.instance();
} else {
return minBy((t1, t2) -> f.apply(t1).compareTo(f.apply(t2)));
}
}
@Test
public void test2() {
Function<Integer, Integer> f =
((Function<Integer, Integer>) ((Integer) 0)::compareTo).compose(((Integer) 0)::compareTo);
Assert.assertEquals(Integer.valueOf(0), f.apply(0));
Assert.assertEquals(Integer.valueOf(1), f.apply(100));
Assert.assertEquals(Integer.valueOf(-1), f.apply(-100));
}
@Override
public <U> Array<T> sortBy(
Comparator<? super U> comparator, Function<? super T, ? extends U> mapper) {
final Function<? super T, ? extends U> domain = Function1.of(mapper::apply).memoized();
return toJavaStream()
.sorted((e1, e2) -> comparator.compare(domain.apply(e1), domain.apply(e2)))
.collect(collector());
}
private void calibration_market_quote_sensitivity_check(
Function<MarketData, ImmutableRatesProvider> calibrator, double shift) {
double notional = 100_000_000.0;
double fx = 1.1111;
double fxPts = 0.0012;
FxSwapTrade trade =
EUR_USD.toTrade(
VAL_DATE, Period.ofWeeks(6), Period.ofMonths(5), BuySell.BUY, notional, fx, fxPts);
ImmutableRatesProvider result =
CALIBRATOR.calibrate(CURVE_GROUP_CONFIG, VAL_DATE, ALL_QUOTES, TS);
PointSensitivities pts = FX_PRICER.presentValueSensitivity(trade.getProduct(), result);
CurveCurrencyParameterSensitivities ps = result.curveParameterSensitivity(pts);
CurveCurrencyParameterSensitivities mqs = MQC.sensitivity(ps, result);
double pvUsd = FX_PRICER.presentValue(trade.getProduct(), result).getAmount(USD).getAmount();
double pvEur = FX_PRICER.presentValue(trade.getProduct(), result).getAmount(EUR).getAmount();
double[] mqsUsd1Computed =
mqs.getSensitivity(USD_DSCON_CURVE_NAME, USD).getSensitivity().toArray();
for (int i = 0; i < USD_DSC_NB_NODES; i++) {
Map<MarketDataKey<?>, Object> map = new HashMap<>(ALL_QUOTES.getValues());
map.put(
QuoteKey.of(StandardId.of(SCHEME, USD_DSC_ID_VALUE[i])),
USD_DSC_MARKET_QUOTES[i] + shift);
ImmutableMarketData marketData = ImmutableMarketData.of(map);
ImmutableRatesProvider rpShifted = calibrator.apply(marketData);
double pvS = FX_PRICER.presentValue(trade.getProduct(), rpShifted).getAmount(USD).getAmount();
assertEquals(mqsUsd1Computed[i], (pvS - pvUsd) / shift, TOLERANCE_PV_DELTA);
}
double[] mqsUsd2Computed =
mqs.getSensitivity(USD_DSCON_CURVE_NAME, EUR).getSensitivity().toArray();
for (int i = 0; i < USD_DSC_NB_NODES; i++) {
Map<MarketDataKey<?>, Object> map = new HashMap<>(ALL_QUOTES.getValues());
map.put(
QuoteKey.of(StandardId.of(SCHEME, USD_DSC_ID_VALUE[i])),
USD_DSC_MARKET_QUOTES[i] + shift);
ImmutableMarketData ov = ImmutableMarketData.of(map);
ImmutableRatesProvider rpShifted = calibrator.apply(ov);
double pvS = FX_PRICER.presentValue(trade.getProduct(), rpShifted).getAmount(EUR).getAmount();
assertEquals(mqsUsd2Computed[i], (pvS - pvEur) / shift, TOLERANCE_PV_DELTA);
}
double[] mqsEur1Computed =
mqs.getSensitivity(EUR_DSC_CURVE_NAME, USD).getSensitivity().toArray();
for (int i = 0; i < EUR_DSC_NB_NODES; i++) {
assertEquals(mqsEur1Computed[i], 0.0, TOLERANCE_PV_DELTA);
}
double[] mqsEur2Computed =
mqs.getSensitivity(EUR_DSC_CURVE_NAME, EUR).getSensitivity().toArray();
for (int i = 0; i < EUR_DSC_NB_NODES; i++) {
Map<MarketDataKey<?>, Object> map = new HashMap<>(ALL_QUOTES.getValues());
map.put(
QuoteKey.of(StandardId.of(SCHEME, EUR_DSC_ID_VALUE[i])),
EUR_DSC_MARKET_QUOTES[i] + shift);
ImmutableMarketData marketData = ImmutableMarketData.of(map);
ImmutableRatesProvider rpShifted = calibrator.apply(marketData);
double pvS = FX_PRICER.presentValue(trade.getProduct(), rpShifted).getAmount(EUR).getAmount();
assertEquals(mqsEur2Computed[i], (pvS - pvEur) / shift, TOLERANCE_PV_DELTA, "Node " + i);
}
}
/**
* Tests the performance of an event listener on the map for Update events of 2 MB strings. Expect
* it to handle at least 50 2 MB updates per second.
*/
@Test
public void testSubscriptionMapEventListenerUpdatePerformance() {
_testMap.clear();
// Put values before testing as we want to ignore the insert events
Function<Integer, Object> putFunction =
a -> _testMap.put(TestUtils.getKey(_mapName, a), _twoMbTestString);
IntStream.range(0, _noOfPuts)
.forEach(
i -> {
putFunction.apply(i);
});
Jvm.pause(100);
// Create subscriber and register
TestChronicleMapEventListener mapEventListener =
new TestChronicleMapEventListener(_mapName, _twoMbTestStringLength);
Subscriber<MapEvent> mapEventSubscriber = e -> e.apply(mapEventListener);
clientAssetTree.registerSubscriber(
_mapName + "?bootstrap=false", MapEvent.class, mapEventSubscriber);
KVSSubscription subscription =
(KVSSubscription) serverAssetTree.getAsset(_mapName).subscription(false);
waitFor(() -> subscription.entrySubscriberCount() == 1);
Assert.assertEquals(1, subscription.entrySubscriberCount());
// Perform test a number of times to allow the JVM to warm up, but verify runtime against
// average
TestUtils.runMultipleTimesAndVerifyAvgRuntime(
i -> {
if (i > 0) {
waitFor(() -> mapEventListener.getNoOfUpdateEvents().get() >= _noOfPuts);
// Test that the correct number of events were triggered on event listener
Assert.assertEquals(_noOfPuts, mapEventListener.getNoOfUpdateEvents().get());
}
Assert.assertEquals(0, mapEventListener.getNoOfInsertEvents().get());
Assert.assertEquals(0, mapEventListener.getNoOfRemoveEvents().get());
mapEventListener.resetCounters();
},
() -> {
IntStream.range(0, _noOfPuts)
.forEach(
i -> {
putFunction.apply(i);
});
},
_noOfRunsToAverage,
3 * _secondInNanos);
clientAssetTree.unregisterSubscriber(_mapName, mapEventSubscriber);
waitFor(() -> subscription.entrySubscriberCount() == 0);
Assert.assertEquals(0, subscription.entrySubscriberCount());
}
@Test
public void chunkFromString() {
Function<Node, ContentChunk> chunkGenerator = FileContentReplace.chunkFromString("Test chunk.");
Node ourNode = new NodeImpl(new RevisionImpl(2));
ourNode.getHeaders().put(NodeHeader.ACTION, "add");
ourNode.getHeaders().put(NodeHeader.PATH, "/somepath/is/here.txt");
assertThat(new String(chunkGenerator.apply(ourNode).getContent()), is(equalTo("Test chunk.")));
}
@Override
public TestProperty replaceValue(
TestProperty value, Function<String, String> replacementFunction) {
return new TestProperty(
value
.getConfiguration()
.clone(
replacementFunction.apply(value.getConfiguration().getName()), replacementFunction),
replacementFunction.apply(value.getValue()));
}
public static void main(String[] args) {
Predicate<Object> condition = Objects::isNull;
Function<Object, Integer> ifTrue = obj -> 0;
Function<CharSequence, Integer> ifFalse = CharSequence::length;
Function<String, Integer> safeStringLength = ternaryOperator(condition, ifTrue, ifFalse);
System.out.println(safeStringLength.apply("1234"));
System.out.println(safeStringLength.apply(""));
System.out.println(safeStringLength.apply(null));
}
private void traceDone(final T value) {
_shallowTraceBuilder.setResultType(ResultType.SUCCESS);
final Function<T, String> traceValueProvider = _traceValueProvider;
if (traceValueProvider != null) {
try {
_shallowTraceBuilder.setValue(traceValueProvider.apply(value));
} catch (Exception e) {
_shallowTraceBuilder.setValue(Exceptions.failureToString(e));
}
}
}
/**
* Uso da interface funcional java.util.consumer.Function<T, R> método principal: R apply(T t);
*/
public static void exampleOfFunction() {
BigDecimal notFormatted = BigDecimal.valueOf(3.141592653);
Function<BigDecimal, String> f =
(BigDecimal param) -> {
param = param.setScale(2, BigDecimal.ROUND_HALF_EVEN);
return param.toString();
};
print(f.apply(notFormatted));
}
@SuppressWarnings("unchecked")
@Override
public Function<Object[], ?> visit(UnaryExpression e) {
final Function<Object[], ?> first = e.getFirst().accept(this);
switch (e.getExpressionType()) {
case ExpressionType.ArrayLength:
return t -> Array.getLength(first.apply(t));
case ExpressionType.BitwiseNot:
return (Function<Object[], ?>) bitwiseNot((Function<Object[], Number>) first);
case ExpressionType.Convert:
final Class<?> to = e.getResultType();
if (to.isPrimitive() || Number.class.isAssignableFrom(to))
return t -> {
Object source = first.apply(t);
if (source instanceof Number) {
Number result = (Number) source;
if (to.isPrimitive()) {
if (to == Integer.TYPE) return result.intValue();
if (to == Long.TYPE) return result.longValue();
if (to == Float.TYPE) return result.floatValue();
if (to == Double.TYPE) return result.doubleValue();
if (to == Byte.TYPE) return result.byteValue();
if (to == Character.TYPE) return (char) result.intValue();
if (to == Short.TYPE) return result.shortValue();
} else if (result != null) {
if (to == BigInteger.class) return BigInteger.valueOf(result.longValue());
if (to == BigDecimal.class) return BigDecimal.valueOf(result.doubleValue());
}
}
if (source instanceof Character) {
if (to == Integer.TYPE) return (int) (char) source;
if (to == Long.TYPE) return (long) (char) source;
if (to == Float.TYPE) return (float) (char) source;
if (to == Double.TYPE) return (double) (char) source;
}
return to.cast(source);
};
return first;
case ExpressionType.IsNull:
return first.andThen(r -> r == null);
case ExpressionType.LogicalNot:
return normalize(not((Function<Object[], Boolean>) first));
case ExpressionType.Negate:
return (Function<Object[], ?>) negate((Function<Object[], Number>) first);
case ExpressionType.Quote:
return constant(first);
// case ExpressionType.UnaryPlus:
// return abs((Function<? extends Number, Object[]>) first);
default:
throw new IllegalArgumentException(ExpressionType.toString(e.getExpressionType()));
}
}
public static <T, R> R callMemoized(
final BiFunction<Function<T, R>, T, R> function, final T input) {
Function<T, R> memoized =
new Function<T, R>() {
private final Map<T, R> store = new HashMap<>();
public R apply(final T input) {
return store.computeIfAbsent(input, key -> function.apply(this, key));
}
};
return memoized.apply(input);
}
static {
// helper functions
Function<Bet, String> teamCodeOrDefault =
t -> t.getTeam() != null ? t.getTeam().getCode() : "???";
// bi-predicates to use for the checks
BiPredicate<Bet, Bet> compatibleSameTeam =
(a, b) -> teamCodeOrDefault.apply(a).equals(teamCodeOrDefault.apply(b));
BiPredicate<Bet, Bet> compatibleSameTeamAndTime =
compatibleSameTeam.and((a, b) -> a.getTime().equals(b.getTime()));
// basic checks for bets of same type only depending on the team
MapBuilder<BetType, Map<BetType, BiPredicate<Bet, Bet>>> checks =
MapBuilder.first(
BetType.TEAM_KICKS_OFF,
MapBuilder.single(BetType.TEAM_KICKS_OFF, compatibleSameTeam))
.add(
BetType.TEAM_SCORES_FIRST_GOAL,
MapBuilder.single(BetType.TEAM_SCORES_FIRST_GOAL, compatibleSameTeam))
.add(
BetType.TEAM_AWARDED_FIRST_THROW_IN,
MapBuilder.single(BetType.TEAM_AWARDED_FIRST_THROW_IN, compatibleSameTeam));
checks // checks for bets of different types representing end states only depending on the team
.add(
BetType.TEAM_WINS,
MapBuilder.first(BetType.TEAM_WINS, compatibleSameTeam)
.add(BetType.TEAM_WINS_LEADING_WITH_NOF_GOALS, compatibleSameTeam)
.last(BetType.ENDS_TIED, compatibleSameTeam))
.add(
BetType.TEAM_WINS_LEADING_WITH_NOF_GOALS,
MapBuilder.first(BetType.TEAM_WINS_LEADING_WITH_NOF_GOALS, compatibleSameTeam)
.last(BetType.ENDS_TIED, compatibleSameTeam))
.add(BetType.ENDS_TIED, MapBuilder.single(BetType.ENDS_TIED, compatibleSameTeam));
COMPATIBLE_CHECKS =
checks // advanced checks for bets of different types representing intermediary states
// depending on the team and time
.add(
BetType.TEAM_LEADS_AFTER_TIME,
MapBuilder.first(BetType.TEAM_LEADS_AFTER_TIME, compatibleSameTeamAndTime)
.add(BetType.TEAM_LEADS_AFTER_TIME_WITH_NOF_GOALS, compatibleSameTeamAndTime)
.last(BetType.TIED_AFTER_TIME, compatibleSameTeamAndTime))
.add(
BetType.TEAM_LEADS_AFTER_TIME_WITH_NOF_GOALS,
MapBuilder.first(
BetType.TEAM_LEADS_AFTER_TIME_WITH_NOF_GOALS, compatibleSameTeamAndTime)
.last(BetType.TIED_AFTER_TIME, compatibleSameTeamAndTime))
.last(
BetType.TIED_AFTER_TIME,
MapBuilder.single(BetType.TIED_AFTER_TIME, compatibleSameTeamAndTime));
}
private static BiFunction<String[], Function<Context, Player>, Placeholder> ofIntFunction(
Function<Player, Integer> function) {
return (tokens, playerFunction) -> {
if (tokens.length == 0) {
return new PlayerBoundPlaceholder(
playerFunction, player -> function.apply(player).toString());
} else {
String format = "%0" + tokens[0] + "d";
return new PlayerBoundPlaceholder(
playerFunction, player -> String.format(format, function.apply(player)));
}
};
}
@Override
public <K2, V2> TreeMap<K2, V2> bimap(
Comparator<? super K2> keyComparator,
Function<? super K, ? extends K2> keyMapper,
Function<? super V, ? extends V2> valueMapper) {
Objects.requireNonNull(keyMapper, "keyMapper is null");
Objects.requireNonNull(valueMapper, "valueMapper is null");
return createTreeMap(
new EntryComparator<>(keyComparator),
entries
.iterator()
.map(entry -> Tuple.of(keyMapper.apply(entry._1), valueMapper.apply(entry._2))));
}
@Override
public OutputStream pipe(String command, PrintStream out, PrintStream err) {
CommandInvocation invocation = javaArgs.parse(command, JAVA_OPTIONS.separatorCode(' '));
Matcher identifierMatcher = lambdaIdentifierRegex.matcher(invocation.getUnprocessedInput());
if (identifierMatcher.matches()) {
String lambdaArgIdentifier = identifierMatcher.group("id");
String lambdaBody = identifierMatcher.group("body").trim();
if (lambdaBody.endsWith(";")) {
lambdaBody = lambdaBody.substring(0, lambdaBody.length() - 1);
}
String lineConsumerCode =
"return (java.util.function.Function<String, ?>)"
+ "(("
+ lambdaArgIdentifier.trim()
+ ") -> "
+ lambdaBody
+ ")";
JavaCode functionCode = new JavaCode(code);
functionCode.addLine(lineConsumerCode);
Optional<Callable<?>> callable =
javacService.compileJavaSnippet(functionCode, classLoaderContext, err);
if (callable.isPresent()) {
try {
Function<String, ?> callback = (Function<String, ?>) callable.get().call();
return new LineOutputStream(
line -> {
@Nullable Object output = callback.apply(line);
if (output != null) {
out.println(output);
}
},
out);
} catch (Exception e) {
err.println(e);
}
}
}
throw new RuntimeException(
"When used in a pipeline, the Java snippet must be in the form of a "
+ "lambda of type Function<String, ?> that takes one text line of the input at a time.\n"
+ "Example: ... | java line -> line.contains(\"text\") ? line : null");
}