Package org.apache.commons.collections4

# Interface Unmodifiable

All Known Implementing Classes:
  `UnmodifiableBag`, `UnmodifiableBidiMap`, `UnmodifiableBoundedCollection`, `UnmodifiableCollection`, `UnmodifiableEntrySet`, `UnmodifiableIterator`, `UnmodifiableList`, `UnmodifiableListIterator`, `UnmodifiableMap`, `UnmodifiableMapEntry`, `UnmodifiableMapIterator`, `UnmodifiableMultiSet`, `UnmodifiableMultiValuedMap`, `UnmodifiableNavigableSet`, `UnmodifiableOrderedBidiMap`, `UnmodifiableOrderedMap`, `UnmodifiableOrderedMapIterator`, `UnmodifiableQueue`, `UnmodifiableSet`, `UnmodifiableSortedBag`, `UnmodifiableSortedBidiMap`, `UnmodifiableSortedMap`, `UnmodifiableSortedSet`, `UnmodifiableTrie`

public interface Unmodifiable
Marker interface for collections, maps and iterators that are unmodifiable.

This interface enables testing such as:

     if (coll instanceof Unmodifiable) {
       coll = new ArrayList(coll);
     }
     // now we know coll is modifiable

Of course all this only works if you use the Unmodifiable classes defined in this library. If you use the JDK unmodifiable class via `java.util Collections` then the interface won't be there.

Since:
  3.0