|
||||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||
java.lang.Objectjava.util.AbstractMap
java.util.TreeMap
org.apache.commons.collections.FastTreeMap
public class FastTreeMap
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:
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.
| Field Summary | |
|---|---|
protected boolean |
fast
Are we operating in "fast" mode? |
protected java.util.TreeMap |
map
The underlying map we are managing. |
| Constructor Summary | |
|---|---|
FastTreeMap()
Construct a an empty map. |
|
FastTreeMap(java.util.Comparator comparator)
Construct an empty map with the specified comparator. |
|
FastTreeMap(java.util.Map map)
Construct a new map with the same mappings as the specified map, sorted according to the keys's natural order |
|
FastTreeMap(java.util.SortedMap map)
Construct a new map with the same mappings as the specified map, sorted according to the same ordering |
|
| Method Summary | |
|---|---|
void |
clear()
Remove all mappings from this map. |
java.lang.Object |
clone()
Return a shallow copy of this FastTreeMap instance. |
java.util.Comparator |
comparator()
Return the comparator used to order this map, or null
if this map uses its keys' natural order. |
boolean |
containsKey(java.lang.Object key)
Return true if this map contains a mapping for the
specified key. |
boolean |
containsValue(java.lang.Object value)
Return true if this map contains one or more keys mapping
to the specified value. |
java.util.Set |
entrySet()
Return a collection view of the mappings contained in this map. |
boolean |
equals(java.lang.Object o)
Compare the specified object with this list for equality. |
java.lang.Object |
firstKey()
Return the first (lowest) key currently in this sorted map. |
java.lang.Object |
get(java.lang.Object key)
Return the value to which this map maps the specified key. |
boolean |
getFast()
Returns true if this map is operating in fast mode. |
int |
hashCode()
Return the hash code value for this map. |
java.util.SortedMap |
headMap(java.lang.Object key)
Return a view of the portion of this map whose keys are strictly less than the specified key. |
boolean |
isEmpty()
Return true if this map contains no mappings. |
java.util.Set |
keySet()
Return a set view of the keys contained in this map. |
java.lang.Object |
lastKey()
Return the last (highest) key currently in this sorted map. |
java.lang.Object |
put(java.lang.Object key,
java.lang.Object value)
Associate the specified value with the specified key in this map. |
void |
putAll(java.util.Map in)
Copy all of the mappings from the specified map to this one, replacing any mappings with the same keys. |
java.lang.Object |
remove(java.lang.Object key)
Remove any mapping for this key, and return any previously mapped value. |
void |
setFast(boolean fast)
Sets whether this map is operating in fast mode. |
int |
size()
Return the number of key-value mappings in this map. |
java.util.SortedMap |
subMap(java.lang.Object fromKey,
java.lang.Object toKey)
Return a view of the portion of this map whose keys are in the range fromKey (inclusive) to toKey (exclusive). |
java.util.SortedMap |
tailMap(java.lang.Object key)
Return a view of the portion of this map whose keys are greater than or equal to the specified key. |
java.util.Collection |
values()
Return a collection view of the values contained in this map. |
| Methods inherited from class java.util.AbstractMap |
|---|
toString |
| Methods inherited from class java.lang.Object |
|---|
finalize, getClass, notify, notifyAll, wait, wait, wait |
| Field Detail |
|---|
protected java.util.TreeMap map
protected boolean fast
| Constructor Detail |
|---|
public FastTreeMap()
public FastTreeMap(java.util.Comparator comparator)
comparator - the comparator to use for ordering tree elementspublic FastTreeMap(java.util.Map map)
map - the map whose mappings are to be copiedpublic FastTreeMap(java.util.SortedMap map)
map - the map whose mappings are to be copied| Method Detail |
|---|
public boolean getFast()
public void setFast(boolean fast)
fast - true if this map should operate in fast modepublic java.lang.Object get(java.lang.Object key)
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.
get in interface java.util.Mapget in class java.util.TreeMapkey - the key whose value is to be returned
public int size()
size in interface java.util.Mapsize in class java.util.TreeMappublic boolean isEmpty()
true if this map contains no mappings.
isEmpty in interface java.util.MapisEmpty in class java.util.AbstractMappublic boolean containsKey(java.lang.Object key)
true if this map contains a mapping for the
specified key.
containsKey in interface java.util.MapcontainsKey in class java.util.TreeMapkey - the key to be searched for
public boolean containsValue(java.lang.Object value)
true if this map contains one or more keys mapping
to the specified value.
containsValue in interface java.util.MapcontainsValue in class java.util.TreeMapvalue - the value to be searched for
public java.util.Comparator comparator()
null
if this map uses its keys' natural order.
comparator in interface java.util.SortedMapcomparator in class java.util.TreeMappublic java.lang.Object firstKey()
firstKey in interface java.util.SortedMapfirstKey in class java.util.TreeMappublic java.lang.Object lastKey()
lastKey in interface java.util.SortedMaplastKey in class java.util.TreeMap
public java.lang.Object put(java.lang.Object key,
java.lang.Object value)
put in interface java.util.Mapput in class java.util.TreeMapkey - the key with which the value is to be associatedvalue - the value to be associated with this key
public void putAll(java.util.Map in)
putAll in interface java.util.MapputAll in class java.util.TreeMapin - the map whose mappings are to be copiedpublic java.lang.Object remove(java.lang.Object key)
remove in interface java.util.Mapremove in class java.util.TreeMapkey - the key whose mapping is to be removed
public void clear()
clear in interface java.util.Mapclear in class java.util.TreeMappublic boolean equals(java.lang.Object o)
Map.equals method.
equals in interface java.util.Mapequals in class java.util.AbstractMapo - the object to be compared to this list
public int hashCode()
Map.hashCode method.
hashCode in interface java.util.MaphashCode in class java.util.AbstractMappublic java.lang.Object clone()
FastTreeMap instance.
The keys and values themselves are not copied.
clone in class java.util.TreeMappublic java.util.SortedMap headMap(java.lang.Object key)
headMap in interface java.util.SortedMapheadMap in class java.util.TreeMapkey - Key higher than any in the returned map
public java.util.SortedMap subMap(java.lang.Object fromKey,
java.lang.Object toKey)
subMap in interface java.util.SortedMapsubMap in class java.util.TreeMapfromKey - Lower limit of keys for the returned maptoKey - Upper limit of keys for the returned map
public java.util.SortedMap tailMap(java.lang.Object key)
tailMap in interface java.util.SortedMaptailMap in class java.util.TreeMapkey - Key less than or equal to any in the returned map
public java.util.Set entrySet()
Map.Entry.
entrySet in interface java.util.MapentrySet in class java.util.TreeMappublic java.util.Set keySet()
keySet in interface java.util.MapkeySet in class java.util.TreeMappublic java.util.Collection values()
values in interface java.util.Mapvalues in class java.util.TreeMap
|
||||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||