Recipients and setters and container objects (ArrayList, HashMap, etc.)

Question

Say you have a domain class that has an ArrayList attribute. What is the best practice when writing getters and setters for this type of instance (to avoid changing it)?

Answer 1

public List getList() {
  return Collections.unmodifiableList(list);
}

Answer 2

Returns a list that is not modified using the method Collection.unmodifiableList():

Collections - Collection.unmodifiableList ()

Answer 3

Collections.unmodifiableList(). .

Answer 4

lweller - , , UnsupportOperationException, , , . , UnmodifiableList, List , , , . , couse, Collection.

Answer 5

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, :

return Collections.unmodifiableList(new ArrayList<Thing>(things));
    // Bit big - shame there isn't a single method and class to do this.

return new ArrayList<Thing>(things);
    // Do you really want to see client code modifying the list?

return Collections.unmodifiableList(things);
    // Client may expecting a snapshot, modifications to the original will mess up.

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Answer 6

.

public List getList() {
    ArrayList copy = new ArrayList(this.list);
    return Collections.unmodifiableList(copy);
}

Answer 7

,

listXXX(); 

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Answer 8

guava ImmutableList. :

public ImmutableList<T> getMyList() {
  ImmutableList.copyOf(myList);
}

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