org.apache.commons.collections.map
public class MultiKeyMap extends Object implements IterableMap, Serializable
Map
implementation that uses multiple keys to map the value.
This class is the most efficient way to uses multiple keys to map to a value.
The best way to use this class is via the additional map-style methods.
These provide get
, containsKey
, put
and
remove
for individual keys which operate without extra object creation.
The additional methods are the main interface of this map.
As such, you will not normally hold this map in a variable of type Map
.
The normal map methods take in and return a MultiKey.
If you try to use put()
with any other object type a
ClassCastException
is thrown. If you try to use null
as
the key in put()
a NullPointerException
is thrown.
This map is implemented as a decorator of a AbstractHashedMap
which
enables extra behaviour to be added easily.
MultiKeyMap.decorate(new LinkedMap())
creates an ordered map.
MultiKeyMap.decorate(new LRUMap())
creates an least recently used map.
MultiKeyMap.decorate(new ReferenceMap())
creates a garbage collector sensitive map.
IdentityMap
and ReferenceIdentityMap
are unsuitable
for use as the key comparison would work on the whole MultiKey, not the elements within.
As an example, consider a least recently used cache that uses a String airline code and a Locale to lookup the airline's name:
private MultiKeyMap cache = MultiKeyMap.decorate(new LRUMap(50)); public String getAirlineName(String code, String locale) { String name = (String) cache.get(code, locale); if (name == null) { name = getAirlineNameFromDB(code, locale); cache.put(code, locale, name); } return name; }
Note that MultiKeyMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. This class may throw exceptions when accessed by concurrent threads without synchronization.
Since: Commons Collections 3.1
Version: $Revision: 348007 $ $Date: 2005-11-21 22:52:57 +0000 (Mon, 21 Nov 2005) $
Field Summary | |
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protected AbstractHashedMap | map The decorated map |
Constructor Summary | |
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MultiKeyMap()
Constructs a new MultiKeyMap that decorates a HashedMap . | |
protected | MultiKeyMap(AbstractHashedMap map)
Constructor that decorates the specified map and is called from
decorate.
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Method Summary | |
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protected void | checkKey(Object key)
Check to ensure that input keys are valid MultiKey objects.
|
void | clear() |
Object | clone()
Clones the map without cloning the keys or values.
|
boolean | containsKey(Object key1, Object key2)
Checks whether the map contains the specified multi-key.
|
boolean | containsKey(Object key1, Object key2, Object key3)
Checks whether the map contains the specified multi-key.
|
boolean | containsKey(Object key1, Object key2, Object key3, Object key4)
Checks whether the map contains the specified multi-key.
|
boolean | containsKey(Object key1, Object key2, Object key3, Object key4, Object key5)
Checks whether the map contains the specified multi-key.
|
boolean | containsKey(Object key) |
boolean | containsValue(Object value) |
static MultiKeyMap | decorate(AbstractHashedMap map)
Decorates the specified map to add the MultiKeyMap API and fast query.
|
Set | entrySet() |
boolean | equals(Object obj) |
Object | get(Object key1, Object key2)
Gets the value mapped to the specified multi-key.
|
Object | get(Object key1, Object key2, Object key3)
Gets the value mapped to the specified multi-key.
|
Object | get(Object key1, Object key2, Object key3, Object key4)
Gets the value mapped to the specified multi-key.
|
Object | get(Object key1, Object key2, Object key3, Object key4, Object key5)
Gets the value mapped to the specified multi-key.
|
Object | get(Object key) |
protected int | hash(Object key1, Object key2)
Gets the hash code for the specified multi-key.
|
protected int | hash(Object key1, Object key2, Object key3)
Gets the hash code for the specified multi-key.
|
protected int | hash(Object key1, Object key2, Object key3, Object key4)
Gets the hash code for the specified multi-key.
|
protected int | hash(Object key1, Object key2, Object key3, Object key4, Object key5)
Gets the hash code for the specified multi-key.
|
int | hashCode() |
boolean | isEmpty() |
protected boolean | isEqualKey(AbstractHashedMap.HashEntry entry, Object key1, Object key2)
Is the key equal to the combined key.
|
protected boolean | isEqualKey(AbstractHashedMap.HashEntry entry, Object key1, Object key2, Object key3)
Is the key equal to the combined key.
|
protected boolean | isEqualKey(AbstractHashedMap.HashEntry entry, Object key1, Object key2, Object key3, Object key4)
Is the key equal to the combined key.
|
protected boolean | isEqualKey(AbstractHashedMap.HashEntry entry, Object key1, Object key2, Object key3, Object key4, Object key5)
Is the key equal to the combined key.
|
Set | keySet() |
MapIterator | mapIterator() |
Object | put(Object key1, Object key2, Object value)
Stores the value against the specified multi-key.
|
Object | put(Object key1, Object key2, Object key3, Object value)
Stores the value against the specified multi-key.
|
Object | put(Object key1, Object key2, Object key3, Object key4, Object value)
Stores the value against the specified multi-key.
|
Object | put(Object key1, Object key2, Object key3, Object key4, Object key5, Object value)
Stores the value against the specified multi-key.
|
Object | put(Object key, Object value)
Puts the key and value into the map, where the key must be a non-null
MultiKey object.
|
void | putAll(Map mapToCopy)
Copies all of the keys and values from the specified map to this map.
|
Object | remove(Object key1, Object key2)
Removes the specified multi-key from this map.
|
Object | remove(Object key1, Object key2, Object key3)
Removes the specified multi-key from this map.
|
Object | remove(Object key1, Object key2, Object key3, Object key4)
Removes the specified multi-key from this map.
|
Object | remove(Object key1, Object key2, Object key3, Object key4, Object key5)
Removes the specified multi-key from this map.
|
Object | remove(Object key) |
boolean | removeAll(Object key1)
Removes all mappings where the first key is that specified.
|
boolean | removeAll(Object key1, Object key2)
Removes all mappings where the first two keys are those specified.
|
boolean | removeAll(Object key1, Object key2, Object key3)
Removes all mappings where the first three keys are those specified.
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boolean | removeAll(Object key1, Object key2, Object key3, Object key4)
Removes all mappings where the first four keys are those specified.
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int | size() |
String | toString() |
Collection | values() |
HashedMap
.Parameters: map the map to decorate
Parameters: key the key to check
Returns: a shallow clone
Parameters: key1 the first key key2 the second key
Returns: true if the map contains the key
Parameters: key1 the first key key2 the second key key3 the third key
Returns: true if the map contains the key
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: true if the map contains the key
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key
Returns: true if the map contains the key
Parameters: map the map to decorate, not null
Throws: IllegalArgumentException if the map is null or not empty
Parameters: key1 the first key key2 the second key
Returns: the mapped value, null if no match
Parameters: key1 the first key key2 the second key key3 the third key
Returns: the mapped value, null if no match
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: the mapped value, null if no match
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key
Returns: the mapped value, null if no match
Parameters: key1 the first key key2 the second key
Returns: the hash code
Parameters: key1 the first key key2 the second key key3 the third key
Returns: the hash code
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: the hash code
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key
Returns: the hash code
Parameters: entry the entry to compare to key1 the first key key2 the second key
Returns: true if the key matches
Parameters: entry the entry to compare to key1 the first key key2 the second key key3 the third key
Returns: true if the key matches
Parameters: entry the entry to compare to key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: true if the key matches
Parameters: entry the entry to compare to key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key
Returns: true if the key matches
Parameters: key1 the first key key2 the second key value the value to store
Returns: the value previously mapped to this combined key, null if none
Parameters: key1 the first key key2 the second key key3 the third key value the value to store
Returns: the value previously mapped to this combined key, null if none
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key value the value to store
Returns: the value previously mapped to this combined key, null if none
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key value the value to store
Returns: the value previously mapped to this combined key, null if none
Parameters: key the non-null MultiKey object value the value to store
Returns: the previous value for the key
Throws: NullPointerException if the key is null ClassCastException if the key is not a MultiKey
Parameters: mapToCopy to this map
Throws: NullPointerException if the mapToCopy or any key within is null ClassCastException if any key in mapToCopy is not a MultiKey
Parameters: key1 the first key key2 the second key
Returns: the value mapped to the removed key, null if key not in map
Parameters: key1 the first key key2 the second key key3 the third key
Returns: the value mapped to the removed key, null if key not in map
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: the value mapped to the removed key, null if key not in map
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key key5 the fifth key
Returns: the value mapped to the removed key, null if key not in map
This method removes all the mappings where the MultiKey
has one or more keys, and the first matches that specified.
Parameters: key1 the first key
Returns: true if any elements were removed
This method removes all the mappings where the MultiKey
has two or more keys, and the first two match those specified.
Parameters: key1 the first key key2 the second key
Returns: true if any elements were removed
This method removes all the mappings where the MultiKey
has three or more keys, and the first three match those specified.
Parameters: key1 the first key key2 the second key key3 the third key
Returns: true if any elements were removed
This method removes all the mappings where the MultiKey
has four or more keys, and the first four match those specified.
Parameters: key1 the first key key2 the second key key3 the third key key4 the fourth key
Returns: true if any elements were removed