Collections - Revision history

Suhridk: /* Lists */

2011-09-10T12:50:59Z

Lists

2011-09-10T12:33:00Z

Maps

2011-09-10T12:31:51Z

Sets

2011-09-10T12:24:20Z

Implementation

2011-09-08T18:25:33Z

Sets

2011-09-08T18:24:24Z

Maps

2011-09-08T18:19:18Z

Sets

2011-09-08T18:15:27Z

Sets

2011-09-06T13:04:49Z

Converting Arrays To Lists To Arrays

2011-09-06T12:50:05Z

Converting Arrays To Lists To Arrays

← Older revision		Revision as of 12:50, 10 September 2011
Line 217:		Line 217:

	* Lists maintain their elements in insertion order.		* Lists maintain their elements in insertion order.
		+	* Offer index based methods like: set(int index, Object element) , get(int index) etc.
		+	* Range view method subList(int start, int end) returns a SubList backed by the main list.
	* List offers a ListIterator<E> which is a bidirectional Iterator.		* List offers a ListIterator<E> which is a bidirectional Iterator.

@@ Line 324: / Line 324: @@
 * LinkedHashMap implements an ordered map. Is a subclass of HashMap.
 ** Ordering is key-insertion order. The first key inserted will be the first key returned.
-* TreeMap implements a sorted map.
+* TreeMap implements a sorted map. Also it is possible to construct a TreeMap using the same sort order as another SortedMap.

@@ Line 137: / Line 137: @@
 * Sorted Sets
-** Sorted sets implement the SortedSet<E> interface.
+** Sorted sets implement the SortedSet<E> interface. TreeSet is the implementing class.
 ** They have additional methods - first() and last()
 ** headSet(e) - returns all elements less than e (e is the headelement),
@@ Line 179: / Line 180: @@
 *** higher(e) and lower(e) - difference from the ceiling and floor is they return values strictly higher and lower than e. (The equals test is skipped).
-* TreeSet implements NavigableSet - so it is also a SortedSet.
+* TreeSet<E> is the implementing implements NavigableSet.
 <syntaxhighlight lang="java5">

@@ Line 109: / Line 109: @@
 * Set, List and Queue implement the interface Collection.
-* Each one of the concrete collections has a constructor which accepts another Collection - so collections can be easily interchanged.
+* Each one of the concrete collections has a constructor which accepts another Collection - so collections can be easily interchanged. This constructor will create a '''new indepedent''' collection.
 * The Collection interface implements basic methods such as:
 ** add/addAll, remove/removeAll,

@@ Line 142: / Line 142: @@
 ** tailSet(e), - e is the tail element, returns all elements greater than or equal to e.
 ** combining both is subSet(e1, e2) - includes e1, excludes e2
-** The above range view methods return a SortedSet that is backed by the main set. Changes to one set will affect the other set.
+** The above range view methods return a SortedSet that is backed by the main set '''for all elements in the range'''. Changes to one set will affect the other set.
 ** '''IMPORTANT:''' If an element is inserted which is outside the set's range an IllegalArgumentException will be thrown!
 ** Outside the range means an element more than the head value of an headset or less than the tail value of a tailset.

@@ Line 299: / Line 299: @@
 * A key,value pair is called an entry.
 * No duplicate keys.
-* A map is NOT a Collection.
+* A map is '''NOT-A''' Collection.
 * Methods: usual put(), get(), containsKey(), containsValue()
 * putAll(Map)
@@ Line 336: / Line 336: @@
 * Methods analogous to NavigableSet<E>:
 * pollFirstEntry(), pollLastEntry(), firstEntry(), lastEntry()
-* headMap(), tailMap() and subMap() add the boolean inclusive flag.
+* headMap(), tailMap() and subMap() add the boolean inclusive flag. The range-views return a SortedMap which is backed by the main map for ALL entries in range of Sorted Map.
 * then all the celing, floor, higher and lower methods. they are two variants one for entry and for key.
 * e.g. ceilingEntry(key) - returns the least entry which is >= to key. ceilingKey(k) returns only the key.
 * descendingMap() returns a reverse-order map.
 * The TreeMap<K,V> implements NavigableMap<K,V> so it is navigablemap and sortedmap.

@@ Line 452: / Line 452: @@
 * Converting Lists to Arrays - the toArray() method
 * There are two versions of toArray(). The first:
 <syntaxhighlight lang="java5">
 public Object[] toArray();
 </syntaxhighlight>
@@ Line 461: / Line 461: @@
 public <T> T[] toArray(T[] a)
 //Returns an array of the type specified in the parameter.
 //The method will allocate a new array, if the argument is too small to contain the list.
 //If it's too large, the left-over elements will be padded with null !