| java.util.TreeMap
 org.apache.commons.collections.FastTreeMap
| FastTreeMap | | public class FastTreeMap extends TreeMap (Code) | | A customized implementation of java.util.TreeMap designed
to operate in a multithreaded environment where the large majority of
method calls are read-only, instead of structural changes. When operating
in "fast" mode, read calls are non-synchronized and write calls perform the
following steps:
- Clone the existing collection
- Perform the modification on the clone
- Replace the existing collection with the (modified) clone
When first created, objects of this class default to "slow" mode, where
all accesses of any type are synchronized but no cloning takes place. This
is appropriate for initially populating the collection, followed by a switch
to "fast" mode (by calling setFast(true)) after initialization
is complete.
NOTE: If you are creating and accessing a
TreeMap only within a single thread, you should use
java.util.TreeMap directly (with no synchronization), for
maximum performance.
NOTE: This class is not cross-platform.
Using it may cause unexpected failures on some architectures.
It suffers from the same problems as the double-checked locking idiom.
In particular, the instruction that clones the internal collection and the
instruction that sets the internal reference to the clone can be executed
or perceived out-of-order. This means that any read operation might fail
unexpectedly, as it may be reading the state of the internal collection
before the internal collection is fully formed.
For more information on the double-checked locking idiom, see the
Double-Checked Locking Idiom Is Broken Declaration.
since:
Commons Collections 1.0
version:
$Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
author:
Craig R. McClanahan
author:
Stephen Colebourne |
| Field Summary | |
| protected boolean | fast
| | protected TreeMap | map
The underlying map we are managing. |
| Method Summary | |
| public void | clear()
Remove all mappings from this map. | | public Object | clone()
Return a shallow copy of this FastTreeMap instance. | | public Comparator | comparator()
Return the comparator used to order this map, or null
if this map uses its keys' natural order. | | public boolean | containsKey(Object key)
Return true if this map contains a mapping for the
specified key. | | public boolean | containsValue(Object value)
Return true if this map contains one or more keys mapping
to the specified value. | | public Set | entrySet()
Return a collection view of the mappings contained in this map. | | public boolean | equals(Object o)
Compare the specified object with this list for equality. | | public Object | firstKey()
Return the first (lowest) key currently in this sorted map. | | public Object | get(Object key)
Return the value to which this map maps the specified key. | | public boolean | getFast()
Returns true if this map is operating in fast mode. | | public int | hashCode()
Return the hash code value for this map. | | public SortedMap | headMap(Object key)
Return a view of the portion of this map whose keys are strictly
less than the specified key. | | public boolean | isEmpty()
Return true if this map contains no mappings. | | public Set | keySet()
Return a set view of the keys contained in this map. | | public Object | lastKey()
Return the last (highest) key currently in this sorted map. | | public Object | put(Object key, Object value)
Associate the specified value with the specified key in this map. | | public void | putAll(Map in)
Copy all of the mappings from the specified map to this one, replacing
any mappings with the same keys. | | public Object | remove(Object key)
Remove any mapping for this key, and return any previously
mapped value. | | public void | setFast(boolean fast)
Sets whether this map is operating in fast mode. | | public int | size()
Return the number of key-value mappings in this map. | | public SortedMap | subMap(Object fromKey, Object toKey)
Return a view of the portion of this map whose keys are in the
range fromKey (inclusive) to toKey (exclusive). | | public SortedMap | tailMap(Object key)
Return a view of the portion of this map whose keys are greater than
or equal to the specified key. | | public Collection | values()
Return a collection view of the values contained in this map. |
| fast | | protected boolean fast(Code) | | Are we operating in "fast" mode?
|
| map | | protected TreeMap map(Code) | | The underlying map we are managing.
|
| FastTreeMap | | public FastTreeMap()(Code) | | Construct a an empty map.
|
| FastTreeMap | | public FastTreeMap(Comparator comparator)(Code) | | Construct an empty map with the specified comparator.
Parameters:
comparator - the comparator to use for ordering tree elements |
| FastTreeMap | | public FastTreeMap(Map map)(Code) | | Construct a new map with the same mappings as the specified map,
sorted according to the keys's natural order
Parameters:
map - the map whose mappings are to be copied |
| FastTreeMap | | public FastTreeMap(SortedMap map)(Code) | | Construct a new map with the same mappings as the specified map,
sorted according to the same ordering
Parameters:
map - the map whose mappings are to be copied |
| clear | | public void clear()(Code) | | Remove all mappings from this map.
|
| clone | | public Object clone()(Code) | | Return a shallow copy of this FastTreeMap instance.
The keys and values themselves are not copied.
a clone of this map |
| comparator | | public Comparator comparator()(Code) | | Return the comparator used to order this map, or null
if this map uses its keys' natural order.
the comparator used to order the map, or null if natural order |
| containsKey | | public boolean containsKey(Object key)(Code) | | Return true if this map contains a mapping for the
specified key.
Parameters:
key - the key to be searched for true if the map contains the key |
| containsValue | | public boolean containsValue(Object value)(Code) | | Return true if this map contains one or more keys mapping
to the specified value.
Parameters:
value - the value to be searched for true if the map contains the value |
| entrySet | | public Set entrySet()(Code) | | Return a collection view of the mappings contained in this map. Each
element in the returned collection is a Map.Entry.
|
| equals | | public boolean equals(Object o)(Code) | | Compare the specified object with this list for equality. This
implementation uses exactly the code that is used to define the
list equals function in the documentation for the
Map.equals method.
Parameters:
o - the object to be compared to this list true if the two maps are equal |
| firstKey | | public Object firstKey()(Code) | | Return the first (lowest) key currently in this sorted map.
the first key in the map |
| get | | public Object get(Object key)(Code) | | Return the value to which this map maps the specified key. Returns
null if the map contains no mapping for this key, or if
there is a mapping with a value of null. Use the
containsKey() method to disambiguate these cases.
Parameters:
key - the key whose value is to be returned the value mapped to that key, or null |
| getFast | | public boolean getFast()(Code) | | Returns true if this map is operating in fast mode.
true if this map is operating in fast mode |
| hashCode | | public int hashCode()(Code) | | Return the hash code value for this map. This implementation uses
exactly the code that is used to define the list hash function in the
documentation for the Map.hashCode method.
a suitable integer hash code |
| headMap | | public SortedMap headMap(Object key)(Code) | | Return a view of the portion of this map whose keys are strictly
less than the specified key.
Parameters:
key - Key higher than any in the returned map a head map |
| isEmpty | | public boolean isEmpty()(Code) | | Return true if this map contains no mappings.
is the map currently empty |
| keySet | | public Set keySet()(Code) | | Return a set view of the keys contained in this map.
|
| lastKey | | public Object lastKey()(Code) | | Return the last (highest) key currently in this sorted map.
the last key in the map |
| put | | public Object put(Object key, Object value)(Code) | | Associate the specified value with the specified key in this map.
If the map previously contained a mapping for this key, the old
value is replaced and returned.
Parameters:
key - the key with which the value is to be associated
Parameters:
value - the value to be associated with this key the value previously mapped to the key, or null |
| putAll | | public void putAll(Map in)(Code) | | Copy all of the mappings from the specified map to this one, replacing
any mappings with the same keys.
Parameters:
in - the map whose mappings are to be copied |
| remove | | public Object remove(Object key)(Code) | | Remove any mapping for this key, and return any previously
mapped value.
Parameters:
key - the key whose mapping is to be removed the value removed, or null |
| setFast | | public void setFast(boolean fast)(Code) | | Sets whether this map is operating in fast mode.
Parameters:
fast - true if this map should operate in fast mode |
| size | | public int size()(Code) | | Return the number of key-value mappings in this map.
the current size of the map |
| subMap | | public SortedMap subMap(Object fromKey, Object toKey)(Code) | | Return a view of the portion of this map whose keys are in the
range fromKey (inclusive) to toKey (exclusive).
Parameters:
fromKey - Lower limit of keys for the returned map
Parameters:
toKey - Upper limit of keys for the returned map a sub map |
| tailMap | | public SortedMap tailMap(Object key)(Code) | | Return a view of the portion of this map whose keys are greater than
or equal to the specified key.
Parameters:
key - Key less than or equal to any in the returned map a tail map |
| values | | public Collection values()(Code) | | Return a collection view of the values contained in this map.
|
| Methods inherited from java.util.TreeMap | public Map.Entry<K, V> ceilingEntry(K key)(Code)(Java Doc)
public K ceilingKey(K key)(Code)(Java Doc)
public void clear()(Code)(Java Doc)
public Object clone()(Code)(Java Doc)
public Comparator<? super K> comparator()(Code)(Java Doc)
public boolean containsKey(Object key)(Code)(Java Doc)
public boolean containsValue(Object value)(Code)(Java Doc)
public NavigableSet<K> descendingKeySet()(Code)(Java Doc)
public NavigableMap<K, V> descendingMap()(Code)(Java Doc)
public Set<Map.Entry<K, V>> entrySet()(Code)(Java Doc)
public Map.Entry<K, V> firstEntry()(Code)(Java Doc)
public K firstKey()(Code)(Java Doc)
public Map.Entry<K, V> floorEntry(K key)(Code)(Java Doc)
public K floorKey(K key)(Code)(Java Doc)
public V get(Object key)(Code)(Java Doc)
public NavigableMap<K, V> headMap(K toKey, boolean inclusive)(Code)(Java Doc)
public SortedMap<K, V> headMap(K toKey)(Code)(Java Doc)
public Map.Entry<K, V> higherEntry(K key)(Code)(Java Doc)
public K higherKey(K key)(Code)(Java Doc)
public Set<K> keySet()(Code)(Java Doc)
public Map.Entry<K, V> lastEntry()(Code)(Java Doc)
public K lastKey()(Code)(Java Doc)
public Map.Entry<K, V> lowerEntry(K key)(Code)(Java Doc)
public K lowerKey(K key)(Code)(Java Doc)
public NavigableSet<K> navigableKeySet()(Code)(Java Doc)
public Map.Entry<K, V> pollFirstEntry()(Code)(Java Doc)
public Map.Entry<K, V> pollLastEntry()(Code)(Java Doc)
public V put(K key, V value)(Code)(Java Doc)
public void putAll(Map<? extends K, ? extends V> map)(Code)(Java Doc)
public V remove(Object key)(Code)(Java Doc)
public int size()(Code)(Java Doc)
public NavigableMap<K, V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)(Code)(Java Doc)
public SortedMap<K, V> subMap(K fromKey, K toKey)(Code)(Java Doc)
public NavigableMap<K, V> tailMap(K fromKey, boolean inclusive)(Code)(Java Doc)
public SortedMap<K, V> tailMap(K fromKey)(Code)(Java Doc)
public Collection<V> values()(Code)(Java Doc)
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