static void optionalTest() {
// 不要这样,这与!=null没什么区别
Optional<String> stringOptional = Optional.of("alibaba");
if (stringOptional.isPresent()) {
System.out.println(stringOptional.get().length());
}
Optional<String> optionalValue = Optional.of("alibaba");
// 下面是推荐的常用操作
optionalValue.ifPresent(s -> System.out.println(s + " contains red"));
// 增加到集合汇总
List<String> results = Lists.newArrayList();
optionalValue.ifPresent(results::add);
// 增加到集合中，并返回操作结果
Optional<Boolean> added = optionalValue.map(results::add);
// 无值的optional
Optional<String> optionalString = Optional.empty();
// 不存在值，返回“No word”
String result = optionalValue.orElse("No word");
// 没值，计算一个默认值
result = optionalString.orElseGet(() -> System.getProperty("user.dir"));
// 无值，抛一个异常
try {
result = optionalString.orElseThrow(NoSuchElementException::new);
} catch (Throwable t) {
t.getCause();
}
}
/**
* Returns the target types that need to have conversion. The types contain first as many
* constructor parameter types as we have and then the types of properties of object as given by
* names of result-set.
*/
@NotNull
private static Optional<List<Type>> findTargetTypes(
@NotNull Constructor<?> ctor, @NotNull List<String> resultSetColumns) {
List<Type> constructorParameterTypes = asList(ctor.getGenericParameterTypes());
int constructorParameterCount = constructorParameterTypes.size();
if (constructorParameterCount > resultSetColumns.size()) {
// We don't have enough columns in ResultSet to instantiate this constructor, discard it.
return Optional.empty();
} else if (constructorParameterCount == resultSetColumns.size()) {
// We have exactly enough column in ResultSet. Use the constructor as it is.
return Optional.of(constructorParameterTypes);
} else {
// Get the types of remaining properties
ArrayList<Type> result = new ArrayList<>(resultSetColumns.size());
result.addAll(constructorParameterTypes);
List<String> propertyNames =
resultSetColumns.subList(constructorParameterCount, resultSetColumns.size());
for (String name : propertyNames) {
Type type = PropertyAccessor.findPropertyType(ctor.getDeclaringClass(), name).orElse(null);
if (type != null) result.add(type);
else return Optional.empty();
}
return Optional.of(result);
}
}
/**
* Search the tree for the first instance of `pattern`, giving preference to the left child.
*
* <p>`pattern` is a tree, representing a pattern of nodes. `NilNode`s should be considered
* wildcards.
*
* <p>Example patterns ---------------- `Tree()` Matches any tree.
*
* <p>`Tree(3)` Matches any tree where the root node has a value of `3`.
*
* <p>`Tree(3, Tree(2), Tree())` Matches any tree where the root node has a value of `3`, and a
* left sub-tree with a root value of `2`, and any (or no) right sub-tree.
*/
static Optional<Tree> find(Tree target, Tree pattern) {
if (pattern.isEmpty()) return Optional.of(target);
if (target.isEmpty()) return Optional.empty();
if (prefixMatches(target, pattern)) return Optional.of(target);
Optional<Tree> leftMatch = find(target.left(), pattern);
if (leftMatch.isPresent()) return leftMatch;
return find(target.right(), pattern);
}
@Test
public void _07_옵션값_생성() {
assertThat(inverse(0d), is(Optional.empty()));
assertThat(inverse(10d), is(Optional.of(0.1d)));
// ofNullalbe -> null 값 처리
assertThat(Optional.ofNullable(null), is(Optional.empty()));
assertThat(Optional.ofNullable("test"), is(Optional.of("test")));
}
@Test
public void _07_옵션값_합성() {
Optional<Double> result = inverse(4.0d).flatMap(Ch02ExampleTest::squareRoot);
assertThat(result, is(Optional.of(0.5d)));
Optional<Double> result2 =
Optional.of(-4.0d).flatMap(Ch02ExampleTest::inverse).flatMap(Ch02ExampleTest::squareRoot);
assertThat(
"inverse, squareRoot중 하나라도 empty 리턴하면, 결과는 empty", result2, is(Optional.<Double>empty()));
}
public Optional<List<Response>> getBatch(Optional<List<Request>> requests) {
if (!valid) {
Logger.error("CANNOT GET! NO VALID CONNECTION");
return Optional.empty();
}
List<Response> responses = new ArrayList<>();
requests.ifPresent(
reqs ->
reqs.forEach(r -> get(Optional.of(r)).ifPresent(response -> responses.add(response))));
return Optional.of(responses);
}
public void testGetIfPresent() {
assertEquals(Optional.of(TestEnum.CHEETO), Enums.getIfPresent(TestEnum.class, "CHEETO"));
assertEquals(Optional.of(TestEnum.HONDA), Enums.getIfPresent(TestEnum.class, "HONDA"));
assertEquals(Optional.of(TestEnum.POODLE), Enums.getIfPresent(TestEnum.class, "POODLE"));
assertTrue(Enums.getIfPresent(TestEnum.class, "CHEETO").isPresent());
assertTrue(Enums.getIfPresent(TestEnum.class, "HONDA").isPresent());
assertTrue(Enums.getIfPresent(TestEnum.class, "POODLE").isPresent());
assertEquals(TestEnum.CHEETO, Enums.getIfPresent(TestEnum.class, "CHEETO").get());
assertEquals(TestEnum.HONDA, Enums.getIfPresent(TestEnum.class, "HONDA").get());
assertEquals(TestEnum.POODLE, Enums.getIfPresent(TestEnum.class, "POODLE").get());
}
/** Unit tests */
public static void main(String[] args) {
final Tree targetTree =
tree(
1,
tree(
2,
tree(3, tree(4), tree(3, tree(4), tree(5))),
tree(5, tree(6, tree(7), tree(8, tree(9), tree())), tree(10, tree(11), tree()))),
tree(12));
System.out.println(" Test Pattern");
checkPattern(targetTree, tree(), Optional.of(targetTree));
checkPattern(targetTree, tree(9), Optional.of(tree(9)));
checkPattern(targetTree, tree(12), Optional.of(tree(12)));
checkPattern(targetTree, tree(13), Optional.empty());
checkPattern(targetTree, tree(1), Optional.of(targetTree));
checkPattern(targetTree, tree(2, tree(3), tree(5)), Optional.of(targetTree.left()));
checkPattern(
targetTree, tree(3, tree(4), tree(5)), Optional.of(targetTree.left().left().right()));
checkPattern(
targetTree, tree(6, tree(), tree(8)), Optional.of(targetTree.left().right().left()));
checkPattern(targetTree, tree(6, tree(), tree(7)), Optional.empty());
checkPattern(
targetTree,
tree(5, tree(6, tree(7), tree(8, tree(9), tree())), tree(10, tree(11), tree())),
Optional.of(targetTree.left().right()));
}
@Override
public Optional<Class<?>> find(String name) {
Class<?> found = cache.get(name);
if (found != null) {
return Optional.of(found);
}
try {
String className = name.indexOf('+') != -1 ? name.replace('+', '$') : name;
Class<?> manifest = Class.forName(namespace + className, true, loader);
cache.put(name, manifest);
return Optional.of(manifest);
} catch (ClassNotFoundException ignore) {
return Optional.empty();
}
}
/** PUT /users -> Updates an existing User. */
@RequestMapping(
value = "/users",
method = RequestMethod.PUT,
produces = MediaType.APPLICATION_JSON_VALUE)
@Timed
@Transactional
@Secured(AuthoritiesConstants.ADMIN)
public ResponseEntity<ManagedUserDTO> updateUser(@RequestBody ManagedUserDTO managedUserDTO)
throws URISyntaxException {
log.debug("REST request to update User : {}", managedUserDTO);
return Optional.of(userRepository.findOne(managedUserDTO.getId()))
.map(
user -> {
user.setLogin(managedUserDTO.getLogin());
user.setFirstName(managedUserDTO.getFirstName());
user.setLastName(managedUserDTO.getLastName());
user.setEmail(managedUserDTO.getEmail());
user.setActivated(managedUserDTO.isActivated());
user.setLangKey(managedUserDTO.getLangKey());
Set<Authority> authorities = user.getAuthorities();
authorities.clear();
managedUserDTO
.getAuthorities()
.stream()
.forEach(authority -> authorities.add(authorityRepository.findOne(authority)));
return ResponseEntity.ok()
.headers(HeaderUtil.createEntityUpdateAlert("user", managedUserDTO.getLogin()))
.body(new ManagedUserDTO(userRepository.findOne(managedUserDTO.getId())));
})
.orElseGet(() -> new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR));
}
private Optional<MediaType> getContentType(HttpServletRequest request) {
String contentType = request.getContentType();
if (contentType != null) {
return Optional.of(MediaType.parseMediaType(contentType));
}
return Optional.empty();
}
/** @return True if the backup location was created successfully */
private boolean handleBackupLocation() {
try {
// Locate the installation directory
File applicationDataDirectory = InstallationManager.getOrCreateApplicationDataDirectory();
log.debug("Cloud backup...");
File cloudBackupLocation = null;
if (Configurations.currentConfiguration != null) {
String cloudBackupLocationString =
Configurations.currentConfiguration.getAppearance().getCloudBackupLocation();
if (cloudBackupLocationString != null && !"".equals(cloudBackupLocationString)) {
cloudBackupLocation = new File(cloudBackupLocationString);
}
}
log.debug("Backup manager...");
// Initialise backup (must be before Bitcoin network starts and on the main thread)
BackupManager.INSTANCE.initialise(
applicationDataDirectory,
cloudBackupLocation == null ? Optional.<File>absent() : Optional.of(cloudBackupLocation));
return true;
} catch (Exception e) {
log.error("Failed to create backup location.", e);
}
// Must have failed to be here
return false;
}
public ProjectDto getProject(String id) {
if (cache.isCached(id)) {
return cache.tryGetCached(id);
}
ProjectInfo info = null;
try {
info = caller.waitOrCall(() -> api.projects().name(id).get());
} catch (Exception e) {
logger.error(Logging.prepare("getProject", id), e);
}
if (info != null) {
ProjectDto project = new ProjectDto(info.id, info.name);
if (info.parent != null && downloadParents) {
ProjectDto parent = getProject(info.parent);
project.parentId = Optional.of(parent.id);
}
project = repo.add(project);
// getProjectBranches(project);
// getApprovals(project);
cache.cache(project);
return project;
}
return null;
}
@Override
public Optional<Suggestion> requestPlayerSuggestion(Player player, Room room) {
char userWantsToMakeSuggestion = '\0';
while (userWantsToMakeSuggestion != 'Y' && userWantsToMakeSuggestion != 'N') {
this.out.println("Do you want to make an suggestion (Y/N)?");
this.out.println("Your cards are: " + player.cards);
userWantsToMakeSuggestion = this.scanner.next().charAt(0);
}
if (userWantsToMakeSuggestion == 'Y') {
this.out.printf("You suggest it was done in the %s, by: \n", room);
Stream<String> suspects =
Arrays.stream(CluedoCharacter.values()).map(CluedoCharacter::toString);
CluedoCharacter suspect = CluedoCharacter.values()[this.selectOptionFromList(suspects)];
this.out.println("with the ");
Stream<String> weapons = Arrays.stream(Weapon.values()).map(Weapon::toString);
Weapon weapon = Weapon.values()[this.selectOptionFromList(weapons)];
return Optional.of(new Suggestion(suspect, weapon, room));
} else {
return Optional.empty();
}
}
/**
* Perform one setter operation with the provided value.
*
* @param instance Instance of class under test to operate on.
* @param property Property being tested
* @param field Field being tested
* @param testVal Test value to use.
* @return Optional that will contain an error message if the test failed, otherwise empty.
* @throws InvocationTargetException
* @throws IllegalAccessException
*/
private Optional<String> testSetterWithVal(
T instance, PropertyDescriptor property, Field field, Object testVal)
throws InvocationTargetException, IllegalAccessException {
Objects.requireNonNull(instance, "Instance of target class required.");
boolean status = true;
property.getWriteMethod().invoke(instance, testVal);
Object expected, actual;
if (property.getPropertyType().isPrimitive()) {
expected = String.valueOf(testVal);
actual = String.valueOf(field.get(instance));
status = expected.equals(actual);
} else {
expected = testVal;
actual = field.get(instance);
if (expected == null) {
status = actual == null;
} else {
status = expected.equals(actual);
}
}
if (status == false) {
return Optional.of(
String.format(
"Failed during setter test: %s. Expected: %s Actual: %s",
property.getWriteMethod(), expected, actual));
}
return Optional.empty();
}
private static Optional<PredictionBatch> asOptional(PredictionBatch pb) {
if (pb == null || pb.predictions.isEmpty()) {
return Optional.empty();
} else {
return Optional.of(pb);
}
}
public Optional<Response> get(Optional<Request> request) {
if (!valid) {
Logger.error("CANNOT GET! NO VALID CONNECTION");
return Optional.empty();
}
Response response = new Response();
if (request.isPresent()) {
Request r = request.get();
response.key = r.key;
response.table = r.table;
try {
final Table htable = connection.getTable(TableName.valueOf(r.table));
Result result = htable.get(new Get(r.key));
if (result == null || result.isEmpty()) {
return Optional.empty();
}
r.columns.forEach(
c ->
response.columns.add(
new Request.Column(
c.family,
c.qualifier,
result.getValue(c.family.getBytes(), c.qualifier.getBytes()))));
} catch (IOException e) {
e.printStackTrace();
}
}
return Optional.of(response);
}
public static Container setup(
DataSource dataSource,
Properties properties,
Optional<File> pluginsPath,
Optional<ClassLoader> classLoader)
throws IOException {
ClassLoader loader;
if (pluginsPath.isPresent()) {
File[] jars = pluginsPath.get().listFiles(f -> f.getPath().toLowerCase().endsWith(".jar"));
List<URL> urls = new ArrayList<>(jars.length);
for (File j : jars) {
try {
urls.add(j.toURI().toURL());
} catch (MalformedURLException ex) {
throw new IOException(ex);
}
}
loader =
classLoader.isPresent()
? new URLClassLoader(urls.toArray(new URL[urls.size()]), classLoader.get())
: new URLClassLoader(urls.toArray(new URL[urls.size()]));
} else if (classLoader.isPresent()) {
loader = classLoader.get();
} else {
loader = Thread.currentThread().getContextClassLoader();
}
ServiceLoader<SystemAspect> aspects = ServiceLoader.load(SystemAspect.class, loader);
return setup(dataSource, properties, Optional.of(loader), aspects.iterator());
}
@Test
public void _08_리덕션() {
Stream<Integer> values = Stream.of(digits);
// x 이전값, y 지금 요소 (v0 + v1 + v2.....)
Optional<Integer> sum = values.reduce((x, y) -> x + y);
assertThat(sum, is(Optional.of(366)));
}
public Optional<Put> getPut() {
if (valid()) {
Put p = new Put(key);
columns.forEach(c -> p.addColumn(c.family.getBytes(), c.qualifier.getBytes(), c.value));
return Optional.of(p);
}
return Optional.empty();
}
/**
* Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
* constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
* user input or falling back to a default enum constant. For example, {@code
* Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
*
* @since 12.0
*/
public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
checkNotNull(enumClass);
checkNotNull(value);
try {
return Optional.of(Enum.valueOf(enumClass, value));
} catch (IllegalArgumentException iae) {
return Optional.absent();
}
}
/**
* Update the items to display. If this tab is currently selected the content will be refreshed.
* Else it will be refreshed whenever this tab becomes active
*
* @param timereportContext The TaskWithWorklogs to show in this tab
*/
public void updateItems(FetchTimereportContext timereportContext) {
this.fetchTimereportContext = Optional.of(timereportContext);
resultToDisplayChangedSinceLastRender = true;
if (isSelected()) {
refreshWorklogTableViewAndResults();
}
}
@Override
public Optional<Point2D[]> findIntersection(Parabola thatParabola) {
final double temp =
Math.pow(thatParabola.getB(), 2) - 4 * thatParabola.getA() * (thatParabola.getC() - yValue);
if (temp < 0) {
return Optional.empty();
} else if (temp == 0) {
final double xRes = -1.0 * thatParabola.getB() / (2.0 * thatParabola.getA());
final Point2D[] result = {new Point2D(xRes, this.yValue)};
return Optional.of(result);
} else {
final double xRes1 =
(-1.0 * thatParabola.getB() - Math.sqrt(temp)) / (2.0 * thatParabola.getA());
final double xRes2 =
(-1.0 * thatParabola.getB() + Math.sqrt(temp)) / (2.0 * thatParabola.getA());
final Point2D[] result = {new Point2D(xRes1, this.yValue), new Point2D(xRes2, this.yValue)};
return Optional.of(result);
}
}
@Override
public Optional<InternalConstructorDefinition> findConstructor(List<ActualParam> actualParams) {
ensureIsInitialized(symbolResolver());
for (InternalConstructorDefinition constructor : constructors) {
if (constructor.match(symbolResolver(), actualParams)) {
return Optional.of(constructor);
}
}
return Optional.empty();
}
@RequestMapping(value = "/events/{id}/prices/update", method = POST)
public ValidationResult updatePrices(
@PathVariable("id") int id,
@RequestBody EventModification eventModification,
Errors errors,
Principal principal) {
Event event = eventManager.getSingleEventById(id, principal.getName());
return validateEventPrices(Optional.of(event), eventModification, errors)
.ifSuccess(
() -> eventManager.updateEventPrices(event, eventModification, principal.getName()));
}
@Override
public Optional<Symbol> findSymbol(String name, SymbolResolver resolver) {
// TODO support references to methods
for (Property property : this.getAllProperties(resolver)) {
if (property.getName().equals(name)) {
return Optional.of(property);
}
}
return super.findSymbol(name, resolver);
}
public <T> Optional<T> execSelectSqlAsPojoOpt(String sql, Object... args) {
try {
@SuppressWarnings("unchecked")
T t = (T) jdbcTemplate.queryForObject(sql, makeRowMapperInstance(), args);
if (log.isDebugEnabled()) log.debug("查找到记录：" + t);
return Optional.of(t);
} catch (EmptyResultDataAccessException e) {
if (log.isDebugEnabled()) log.debug("没有查找到数据");
return Optional.empty();
}
}
@Test
public void _07_옵션_다루기() {
final Optional<String> optional = words.stream().filter(w -> w.contains("red")).findFirst();
try {
optional.ifPresent(
v -> {
throw new RuntimeException();
});
assert false; // 이 행은 실행되면 안됨.
} catch (RuntimeException e) {
}
// 비어있는 경우는 실행되지 않음.
Optional.empty()
.ifPresent(
v -> {
throw new RuntimeException();
});
Set<String> results = new HashSet<>();
optional.ifPresent(results::add);
assertThat(results.contains("tired"), is(true));
// 실행 결과를 받고 싶은 경우에는 map 사용.
results = new HashSet<>();
Optional<Boolean> added = optional.map(results::add);
assertThat(added, is(Optional.of(Boolean.TRUE)));
// 대상이 빈경우에는 empty Optional 반환
Optional<Boolean> a = Optional.empty().map(v -> true);
assertThat(a.isPresent(), is(false));
Optional<String> emptyOptional = Optional.empty();
// orElse로 기본값 지정 가능
String result = emptyOptional.orElse("기본값");
assertThat(result, is("기본값"));
// 기본값 생성하는 코드 호출 가능
result = emptyOptional.orElseGet(() -> System.getProperty("user.dir"));
assertThat(result, is(System.getProperty("user.dir")));
// 값이 없는 경우 예외 던지기
try {
emptyOptional.orElseThrow(NoSuchElementException::new);
assert false;
} catch (NoSuchElementException e) {
}
}
@Override
public Optional<Point2D[]> findIntersection(Parabola thatParabola) {
final double aDiff = this.getParabola().getA() - thatParabola.getA();
final double bDiff = this.getParabola().getB() - thatParabola.getB();
final double cDiff = this.getParabola().getC() - thatParabola.getC();
final double d = bDiff / (2.0 * aDiff);
final double temp = Math.pow(d, 2) - cDiff / aDiff;
if (temp < 0) {
return Optional.empty();
} else if (temp == 0) {
final Point2D[] result = {new Point2D(d, this.getParabola().apply(d))};
return Optional.of(result);
} else {
final double e = Math.sqrt(temp);
final double deSum = -d + e;
final double deDif = -d - e;
final Point2D[] result = {
new Point2D(deDif, this.getParabola().apply(deDif)),
new Point2D(deSum, this.getParabola().apply(deSum))
};
return Optional.of(result);
}
}
/**
* Tests that replaceIssueMilestone finds issue with the right id and successfully modify the
* issue's milestone
*/
@Test
public void replaceIssueMilestone_successful() {
Optional<Integer> milestoneIdReplacement = Optional.of(1);
String repoId = "testowner/testrepo";
TurboIssue issue1 = LogicTests.createIssueWithMilestone(1, Optional.of(0));
TurboIssue issue2 = LogicTests.createIssueWithMilestone(2, Optional.of(1));
TurboIssue issue3 = LogicTests.createIssueWithMilestone(3, Optional.of(1));
List<TurboIssue> issues = Arrays.asList(issue3, issue2, issue1);
Model model =
new Model(
repoId,
issues,
new ArrayList<TurboLabel>(),
new ArrayList<TurboMilestone>(),
new ArrayList<TurboUser>());
Optional<TurboIssue> result =
model.replaceIssueMilestone(issue1.getId(), milestoneIdReplacement);
assertEquals(1, result.get().getId());
assertTrue(result.get().getMilestone().isPresent());
assertEquals(milestoneIdReplacement, result.get().getMilestone());
}
