Encapsulate Collection

Refactoring & Technical Debt

Meaning

The practice of encapsulating a collection within a class to control access and encapsulate behavior related to the collection.

Primary Function

Provide controlled access to a collection while hiding its internal representation.

Communicative Purpose

Communicate the design principle of encapsulating collections to promote encapsulation and maintainability.

Pattern

private collection field → add/remove methods → read‑only accessor

Core Structure

Encapsulate <Collection>

Função primária

Provide controlled access to a collection while hiding its internal representation.

Propósito comunicativo

Communicate the design principle of encapsulating collections to promote encapsulation and maintainability.

Situações de gatilho

When a class needs to expose a collection of objects but wants to control how the collection is accessed or modified.

Contextos

Used in object-oriented design when a class manages a collection of objects, such as a list of items, and wants to provide methods like add, remove, get, etc., without exposing the underlying collection directly.

Padrão

private collection field → add/remove methods → read‑only accessor

Estrutura central

Encapsulate <Collection>

Slots de substituição

Colocados típicos

list
set
map
collection
add
remove
get

Substituições comuns

wrap collection
hide collection

Erros comuns

Exposing the internal collection directly, returning the internal collection reference, allowing external modification.

Similar / contraste

Expose Collection, Expose Internal Collection, Public Collection Field

Interferências

Returning a reference to the internal collection allows external modification, breaking encapsulation.

Família do chunk

Encapsulate Field
Encapsulate Collection
Information Hiding

Nuance

Encapsulation does not necessarily imply immutability; it means controlling access to the collection.

Efeito pragmático

Signals to other developers that the collection is managed internally and should not be manipulated directly.

Dica de memória

Think of a capsule that hides the pills inside.

Nota

Encapsulating a collection prevents external code from mutating internal state and allows invariants to be enforced within the class.

Upgrade path

Apply immutable collections or read-only interfaces

Frequência: HighFormulaicidade: FlexibleTipo de construção: conceptPrioridade de aquisição: Active recallPrioridade de output: BothTag de espaçamento: Medium-term

Examples

public class Order { private List<Item> items = new ArrayList<>(); public void addItem(Item item) { items.add(item); } public void removeItem(Item item) { items.remove(item); } public List<Item> getItems() { return Collections.unmodifiableList(items); } }

class Order: def __init__(self): self._items = [] def add_item(self, item): self._items.append(item) def remove_item(self, item): self._items.remove(item) @property def items(self): return tuple(self._items)

public class Order { private readonly List<Item> _items = new(); public void AddItem(Item item) => _items.Add(item); public void RemoveItem(Item item) => _items.Remove(item); public IReadOnlyList<Item> Items => _items.AsReadOnly(); }