Java Code Examples for java8.util.Optional#isPresent()

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
  super.onCreateDialog(savedInstanceState);
  // TODO: Inject and use custom factory.
  Optional<Project> activeProject = Loadable.getValue(homeScreenViewModel.getActiveProject());
  if (!activeProject.isPresent()) {
    addFeatureRequestSubject.onError(new IllegalStateException("No active project"));
    return fail("Could not get active project");
  }
  Optional<Point> cameraPosition =
      Optional.ofNullable(mapContainerViewModel.getCameraPosition().getValue());
  if (!cameraPosition.isPresent()) {
    addFeatureRequestSubject.onError(new IllegalStateException("No camera position"));
    return fail("Could not get camera position");
  }
  return createDialog(activeProject.get(), cameraPosition.get());
}
 

private void elseUse() {
    Student student = new Student("lucy", 18);

    // 创建一个 为 Null 的 Optional
    Optional optional = Optional.empty();

    if (optional.isEmpty()) {
        System.out.println("optional is empty");
    }


    Optional<Student> studentOptional = Optional.ofNullable(student);
    // isPresent() 可以判断当前 Optional 是否为 Null
    if (studentOptional.isPresent()) {
        System.out.println("student is present");
    }
}
 

protected boolean loadUp(ITradeBuilding tradeBuilding) {
	Optional<EMaterialType> materialType1 = tradeBuilding.tryToTakeMaterial(1).map(MaterialTypeWithCount::getMaterialType);
	Optional<EMaterialType> materialType2 = tradeBuilding.tryToTakeMaterial(1).map(MaterialTypeWithCount::getMaterialType);

	if (!materialType1.isPresent() && !materialType2.isPresent()) {
		reset();
		return false;

	} else {
		super.setMaterial(EMaterialType.BASKET);

		this.materialType1 = materialType1.orElse(null);
		this.materialType2 = materialType2.orElse(null);

		return true;
	}
}
 

@Override
void assertValue(U value, Supplier<Stream<T>> source, boolean ordered)
        throws Exception {
    Optional<U> reduced = source.get().map(mapper).reduce(reducer);
    if (value == null)
        assertTrue(!reduced.isPresent());
    else if (!reduced.isPresent()) {
        assertEquals(value, identity);
    }
    else {
        assertEquals(value, reduced.get());
    }
}
 

@Override
public void startGame() {
	int maxPlayers = mapLoader.getMaxPlayers();

	List<PlayerSlotPresenter> playerSlotPresenters = Arrays.asList(getPlayerSlots().getValue());
	PlayerSetting[] playerSettings = new PlayerSetting[maxPlayers];
	byte humanPlayerId = playerSlotPresenters.get(0).getPlayerId();

	for (int i = 0; i < maxPlayers; i++) {
		final int position = i;

		Optional<PlayerSlotPresenter> player = stream(playerSlotPresenters)
				.filter(playerSlotPresenter -> playerSlotPresenter.getStartPosition().asByte() == position)
				.findFirst();

		if (player.isPresent()) {
			playerSettings[position] = player.get().getPlayerSettings();
		} else {
			playerSettings[position] = new PlayerSetting();
		}
	}

	JSettlersGame game = new JSettlersGame(mapLoader, 4711L, humanPlayerId, playerSettings);

	gameStarter.setStartingGame(game.start());
	showMapEvent.call();
}
 

final boolean isNavigable(int x, int y) {
	Optional<ShortPoint2D> blockingOptional = HexGridArea.stream(x, y, 0, 2)
														 .filterBounds(width, height)
														 .filter((x1, y1) -> !landscapeGrid.getLandscapeTypeAt(x1, y1).isWater || objectsGrid.getMapObjectAt(x1, y1, EMapObjectType.DOCK) != null)
														 .getFirst();
	return !blockingOptional.isPresent();
}
 

@Override
public FerryEntrance ferryAtPosition(ShortPoint2D position, byte playerId) {
	Optional<ILogicMovable> ferryOptional = HexGridArea.stream(position.x, position.y, 0, Constants.MAX_FERRY_ENTRANCE_SEARCH_DISTANCE)
													   .filterBounds(width, height)
													   .filter((x, y) -> landscapeGrid.getLandscapeTypeAt(x, y).isWater())
													   .iterateForResult((x, y) -> {
														   ILogicMovable movable = movableGrid.getMovableAt(x, y);
														   return Optional.ofNullable(movable).filter(m -> m.getMovableType() == EMovableType.FERRY);
													   });

	if (!ferryOptional.isPresent()) {
		return null;
	}

	ILogicMovable ferry = ferryOptional.get();
	ShortPoint2D ferryPosition = ferry.getPosition();
	Optional<ShortPoint2D> entranceOptional = HexGridArea.stream(ferryPosition.x, ferryPosition.y, 0, Constants.MAX_FERRY_ENTRANCE_SEARCH_DISTANCE)
														 .filterBounds(width, height)
														 .filter((x, y) -> !isBlocked(x, y))
														 .getFirst();

	if (!entranceOptional.isPresent()) {
		return null;
	}

	return new FerryEntrance(ferry, entranceOptional.get());
}
 

private MapResourceInfo findAndDecryptFilePartSafe(EOriginalMapFilePartType partType) throws MapLoadException {
	Optional<MapResourceInfo> filePart = findAndDecryptFilePart(partType);
	if (filePart.isPresent()) {
		return filePart.get();
	} else {
		throw new MapLoadException("No " + partType + " information available in mapfile!");
	}
}
 

void readStacks() throws MapLoadException {
	Optional<MapResourceInfo> filePartOptional = findAndDecryptFilePart(EOriginalMapFilePartType.STACKS);

	if (filePartOptional.isPresent()) {
		MapResourceInfo filePart = filePartOptional.get();
		// - file position
		int pos = filePart.offset;

		// - Number of buildings
		int stackCount = readBEIntFrom(pos);
		pos += 4;

		// - safety check
		if ((stackCount * 8 > filePart.size) || (stackCount < 0)) {
			throw new MapLoadException("wrong number of stacks in map File: " + stackCount);
		}

		// - read all Stacks
		for (int i = 0; i < stackCount; i++) {

			int posX = readBEWordFrom(pos);
			pos += 2;
			int posY = readBEWordFrom(pos);
			pos += 2;

			int stackType = readByteFrom(pos++);
			int count = readByteFrom(pos++);

			pos += 2; // not used - maybe: padding to size of 8 (2 INTs)

			// -------------
			// - update data
			mapData.setStack(posX, posY, stackType, count);
		}
	}
}
 

void readSettlers() throws MapLoadException {
	Optional<MapResourceInfo> filePartOptional = findAndDecryptFilePart(EOriginalMapFilePartType.SETTLERS);

	if (filePartOptional.isPresent()) {
		MapResourceInfo filePart = filePartOptional.get();
		// - file position
		int pos = filePart.offset;

		// - Number of buildings
		int settlerCount = readBEIntFrom(pos);
		pos += 4;

		// - safety check
		if ((settlerCount * 6 > filePart.size) || (settlerCount < 0)) {
			throw new MapLoadException("wrong number of settlers in map File: " + settlerCount);
		}

		// - read all Stacks
		for (int i = 0; i < settlerCount; i++) {

			int party = readByteFrom(pos++);
			int settlerType = readByteFrom(pos++);

			int posX = readBEWordFrom(pos);
			pos += 2;
			int posY = readBEWordFrom(pos);
			pos += 2;

			// -------------
			// - update data
			mapData.setSettler(posX, posY, settlerType, party);
		}
	}
}
 

public static _MatrixEvent get(JsonObject obj) {
    String type = obj.get("type").getAsString();

    if ("m.room.member".contentEquals(type)) {
        return new MatrixJsonRoomMembershipEvent(obj);
    } else if ("m.room.power_levels".contentEquals(type)) {
        return new MatrixJsonRoomPowerLevelsEvent(obj);
    } else if ("m.room.avatar".contentEquals(type)) {
        return new MatrixJsonRoomAvatarEvent(obj);
    } else if ("m.room.name".contentEquals(type)) {
        return new MatrixJsonRoomNameEvent(obj);
    } else if ("m.room.topic".contentEquals(type)) {
        return new MatrixJsonRoomTopicEvent(obj);
    } else if ("m.room.aliases".contentEquals(type)) {
        return new MatrixJsonRoomAliasesEvent(obj);
    } else if (_RoomCanonicalAliasEvent.Type.contentEquals(type)) {
        return new MatrixJsonRoomCanonicalAliasEvent(obj);
    } else if ("m.room.message".contentEquals(type)) {
        return new MatrixJsonRoomMessageEvent(obj);
    } else if ("m.receipt".contentEquals(type)) {
        return new MatrixJsonReadReceiptEvent(obj);
    } else if ("m.room.history_visibility".contentEquals(type)) {
        return new MatrixJsonRoomHistoryVisibilityEvent(obj);
    } else if (_TagsEvent.Type.contentEquals(type)) {
        return new MatrixJsonRoomTagsEvent(obj);
    } else if (_DirectEvent.Type.contentEquals(type)) {
        return new MatrixJsonDirectEvent(obj);
    } else {
        Optional<String> timestamp = EventKey.Timestamp.findString(obj);
        Optional<String> sender = EventKey.Sender.findString(obj);

        if (!timestamp.isPresent() || !sender.isPresent()) {
            return new MatrixJsonEphemeralEvent(obj);
        } else {
            Optional<String> rId = EventKey.RoomId.findString(obj);
            if (rId.isPresent()) {
                return new MatrixJsonRoomEvent(obj);
            }

            return new MatrixJsonPersistentEvent(obj);
        }
    }
}
 

void readBuildings() throws MapLoadException {
	hasBuildings = false;

	Optional<MapResourceInfo> filePartOptional = findAndDecryptFilePart(EOriginalMapFilePartType.BUILDINGS);

	if (filePartOptional.isPresent()) {
		MapResourceInfo filePart = filePartOptional.get();
		// - file position
		int pos = filePart.offset;

		// - Number of buildings
		int buildingsCount = readBEIntFrom(pos);
		pos += 4;

		// - safety check
		if ((buildingsCount * 12 > filePart.size) || (buildingsCount < 0)) {
			throw new MapLoadException("wrong number of buildings in map File: " + buildingsCount);
		}

		hasBuildings = true;

		// - read all Buildings
		for (int i = 0; i < buildingsCount; i++) {

			int party = readByteFrom(pos++); // - Party starts with 0
			int buildingType = readByteFrom(pos++);
			int posX = readBEWordFrom(pos);
			pos += 2;
			int posY = readBEWordFrom(pos);
			pos += 2;

			pos++; // not used - maybe a filling byte to make the record 12 Byte (= 3 INTs) long or unknown?!

			// -----------
			// - number of soldier in building is saved as 4-Bit (=Nibble):
			int countSword1 = readHighNibbleFrom(pos);
			int countSword2 = readLowNibbleFrom(pos);
			pos++;

			int countArcher2 = readHighNibbleFrom(pos);
			int countArcher3 = readLowNibbleFrom(pos);
			pos++;

			int countSword3 = readHighNibbleFrom(pos);
			int countArcher1 = readLowNibbleFrom(pos);
			pos++;

			int countSpear3 = readHighNibbleFrom(pos);
			// low nibble is a not used count
			pos++;

			int countSpear1 = readHighNibbleFrom(pos);
			int countSpear2 = readLowNibbleFrom(pos);
			pos++;

			// -------------
			// - update data
			mapData.setBuilding(posX, posY, buildingType, party, countSword1, countSword2, countSword3, countArcher1, countArcher2, countArcher3, countSpear1, countSpear2, countSpear3);
		}
	}
}