Паттерн Декоратор — специальный способ организации модулей в программе, который позволяет подставить какую-то новую функцию прямо в середину цепочки вызовов, тем самым чуть-чуть подкорректировав поведение.
Например, в реальном мире очки для чтения это декоратор. Вы ставите их между вашими глазами и текстом. Глобально взаимодействие ваших глаз и текста не меняется: отражённые световые лучи от страницы книги попадают в ваши зрачки, что с очками, что без них. Но очки располагаются посередине: они принимают лучи на вход и преломляют их, передавая дальше вам в глаза уже изменёнными.
Важной особенностью является тот факт, что очки можно снять. Они не требуют ни модификации вашего тела, ни модификации книги. Вообще никакие условия не нужны, кроме наличия самих очков. А если вы в линзах, то внешний наблюдатель может даже этого не знать.
Класс-декоратор должен быть спроектирован так, чтобы не требовать никаких изменений в объектах, с которыми он работает. Его можно отключить, чаще всего буквально закомментировав одну строку.
В примере ниже программа выведет текст "Привет, мир, в натуре.", и вот это дополнение в конце как раз дописано декоратором. Можно убрать или закомментировать подчёркнутую строчку, не трогая остальной код, для всех внешних вызовов сигнатуры останутся теми же самыми, но выводиться будет уже просто "Привет, мир".
В декораторы можно прятать логику, которую буквально навешивают поверх основной функции программы. Например, проверку прав на выполнение операции. Перевод на другой язык, логирование, поддержку обратной совместимости при обновлении и так далее.
#dev
#Germany
🦇 A €200 million railway section in Germany is stalled because of bats
In Baden-Württemberg, residents of the Calw district are waiting for train traffic to resume on a railway section and tunnel whose repair took decades and cost over €200 million. But there is one insurmountable obstacle — more than 1,000 bats living in the tunnel between Calw and Weil der Stadt stations.
These animals are under strict protection, so they cannot be removed. An unusual solution was found — to build a protective concrete wall inside the tunnel. On one side, trains will run; on the other, the bats can sleep undisturbed.
This will require 300 concrete blocks and about €80 million. Additionally, ultrasonic sensors will be installed to help the bats navigate their new shelter. However, it is still unknown how quickly they will adapt to the new structure, and this will determine when the tunnel can reopen.
⚠️ This is not an isolated case: in Kiel, 900 bats prevented the demolition of an old swimming pool because the animals refused to move to new shelters.
🦇 Sometimes even very small creatures can have a big impact on massive infrastructure projects!
☘️Read the latest environmental news on the @ekologuz page. Follow us and send your suggestions and wishes via @eklguz_bot
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🇩🇪#Germany: Men in Germany aged 17 to 45 are required to obtain approval from the Bundeswehr (German armed forces) career center before leaving the country for more than three months, whether for study, work, or travel.
The provision was included in a broader military reform package approved in December, but went largely unnoticed until it was reported by the German outlet Frankfurter Rundschau. The measure received little public attention at the time and was not widely discussed.
Despite the law being in place, it remains unclear how this requirement will be implemented in practice, particularly for individuals who were unaware of it or who have already left the country.
"We cannot remain silent. No-one can remain silent when there is an ongoing genocide and when people are denied the most basic human needs ... To stand with Palestine is to be human."
Greta Thunberg calls out Israel's genocide during a speech in Leipzig, #Germany.
https://t.me/YediotNewsChat
Heidelberg, #Germany🇩🇪
Heidelberg was not affected by the bombing of the Second World War, so it was preserved in its original medieval form - a castle, numerous churches and abbey, ancient streets.
Nuremberg, #Germany🇩🇪
Every year in Nuremberg, the largest Christmas fair is held throughout Europe.
Nuremberg is the city of inventors. It was he who gave the world things such as pocket watches, a globe, a compass, a pelting and a current machine.
🇩🇪#Germany: A knife attack took place during an anti-Iranian regime protest in Hamburg.
A man went on a stabbing spree targeting protesters, reportedly deliberately targeting anti-regime demonstrators. He managed to stab two protesters. One victim is in serious condition in hospital, while the second received medical aid at the scene after being stabbed in the leg.
(via @froopashee2)
Repost via @ben_ditto on IG
🇩🇪#Germany: Cockroach swarm agents 🪳
Swarm Biotactics, a deep tech start-up based in Kassel, Germany, specialising in “bio-robotics”: putting miniature sensor backpacks on cockroaches and then sending these as swarms into environments inaccessible for conventional robots, drones, or humans such as collapsed structures following natural disasters, GPS-denied areas, or contested warfare zones. The swarm of roaches act as real-time data agents 🪳 The company has received €13 million in funding so far from a consortium of international investors, including Vertex Ventures US, Possible Ventures, and Capnamic 🪳
Footage of cockroaches taken from 60 Minutes on CBS.