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The Java Developers Almanac 1.4Order this book from Amazon. |
e348. Making a Collection Read-OnlyMaking a collection read-only involves wrapping the collection in another object whose mutation methods all throwUnsupportedOperationException .
List stuff = Arrays.asList(new String[]{"a", "b"}); // Make a list read-only List list = new ArrayList(stuff); list = Collections.unmodifiableList(list); try { // Try modifying the list list.set(0, "new value"); } catch (UnsupportedOperationException e) { // Can't modify } // Make a set read-only Set set = new HashSet(stuff); set = Collections.unmodifiableSet(set); // Make a map read-only Map map = new HashMap(); // Add key/value pairs ... map = Collections.unmodifiableMap(map);
e343. Implementing a Stack e344. Implementing a Least-Recently-Used (LRU) Cache e345. Listing the Elements of a Collection e346. Storing Primitive Types in a Collection e347. Creating a Copy of a Collection
© 2002 Addison-Wesley. |