org.apache.commons.collections.map
public class CompositeMap extends Object implements Map
Changes made to this map will actually be made on the decorated map. Add and remove operations require the use of a pluggable strategy. If no strategy is provided then add and remove are unsupported.
Note that CompositeMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using java.util.Collections#synchronizedMap(Map). This class may throw exceptions when accessed by concurrent threads without synchronization.
Since: Commons Collections 3.0
Version: $Revision: 348007 $ $Date: 2005-11-21 22:52:57 +0000 (Mon, 21 Nov 2005) $
Nested Class Summary | |
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static interface | CompositeMap.MapMutator
This interface allows definition for all of the indeterminate
mutators in a CompositeMap, as well as providing a hook for
callbacks on key collisions. |
Constructor Summary | |
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CompositeMap()
Create a new, empty, CompositeMap. | |
CompositeMap(Map one, Map two)
Create a new CompositeMap with two composited Map instances.
| |
CompositeMap(Map one, Map two, CompositeMap.MapMutator mutator)
Create a new CompositeMap with two composited Map instances.
| |
CompositeMap(Map[] composite)
Create a new CompositeMap which composites all of the Map instances in the
argument. | |
CompositeMap(Map[] composite, CompositeMap.MapMutator mutator)
Create a new CompositeMap which composites all of the Map instances in the
argument. |
Method Summary | |
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void | addComposited(Map map)
Add an additional Map to the composite.
|
void | clear()
Calls clear() on all composited Maps.
|
boolean | containsKey(Object key)
Returns true if this map contains a mapping for the specified
key. |
boolean | containsValue(Object value)
Returns true if this map maps one or more keys to the
specified value. |
Set | entrySet()
Returns a set view of the mappings contained in this map. |
boolean | equals(Object obj)
Checks if this Map equals another as per the Map specification.
|
Object | get(Object key)
Returns the value to which this map maps the specified key. |
int | hashCode()
Gets a hash code for the Map as per the Map specification. |
boolean | isEmpty()
Returns true if this map contains no key-value mappings.
|
Set | keySet()
Returns a set view of the keys contained in this map. |
Object | put(Object key, Object value)
Associates the specified value with the specified key in this map
(optional operation). |
void | putAll(Map map)
Copies all of the mappings from the specified map to this map
(optional operation). |
Object | remove(Object key)
Removes the mapping for this key from this map if it is present
(optional operation). |
Map | removeComposited(Map map)
Remove a Map from the composite.
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void | setMutator(CompositeMap.MapMutator mutator)
Specify the MapMutator to be used by mutation operations.
|
int | size()
Returns the number of key-value mappings in this map. |
Collection | values()
Returns a collection view of the values contained in this map. |
Parameters: one the first Map to be composited two the second Map to be composited
Throws: IllegalArgumentException if there is a key collision
Parameters: one the first Map to be composited two the second Map to be composited mutator MapMutator to be used for mutation operations
Parameters: composite the Maps to be composited
Throws: IllegalArgumentException if there is a key collision
Parameters: composite Maps to be composited mutator MapMutator to be used for mutation operations
Parameters: map the Map to be added to the composite
Throws: IllegalArgumentException if there is a key collision and there is no MapMutator set to handle it.
clear()
on all composited Maps.
Throws: UnsupportedOperationException if any of the composited Maps do not support clear()
Parameters: key key whose presence in this map is to be tested.
Returns: true if this map contains a mapping for the specified key.
Throws: ClassCastException if the key is of an inappropriate type for this map (optional). NullPointerException if the key is null and this map does not not permit null keys (optional).
Parameters: value value whose presence in this map is to be tested.
Returns: true if this map maps one or more keys to the specified value.
Throws: ClassCastException if the value is of an inappropriate type for this map (optional). NullPointerException if the value is null and this map does not not permit null values (optional).
Map.Entry
. The set is backed by the
map, so changes to the map are reflected in the set, and vice-versa.
If the map is modified while an iteration over the set is in progress,
the results of the iteration are undefined. The set supports element
removal, which removes the corresponding mapping from the map, via the
Iterator.remove, Set.remove, removeAll,
retainAll and clear operations. It does not support
the add or addAll operations.
This implementation returns a CompositeSet
which
composites the entry sets from all of the composited maps.
Returns: a set view of the mappings contained in this map.
See Also: CompositeSet
Parameters: obj the object to compare to
Returns: true if the maps are equal
More formally, if this map contains a mapping from a key k to a value v such that (key==null ? k==null : key.equals(k)), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)
Parameters: key key whose associated value is to be returned.
Returns: the value to which this map maps the specified key, or null if the map contains no mapping for this key.
Throws: ClassCastException if the key is of an inappropriate type for this map (optional). NullPointerException key is null and this map does not not permit null keys (optional).
See Also: containsKey
Returns: true if this map contains no key-value mappings.
This implementation returns a CompositeSet
which
composites the key sets from all of the composited maps.
Returns: a set view of the keys contained in this map.
m.containsKey(k)
would return
true.))
Parameters: key key with which the specified value is to be associated. value value to be associated with the specified key.
Returns: previous value associated with specified key, or null if there was no mapping for key. A null return can also indicate that the map previously associated null with the specified key, if the implementation supports null values.
Throws: UnsupportedOperationException if no MapMutator has been specified ClassCastException if the class of the specified key or value prevents it from being stored in this map. IllegalArgumentException if some aspect of this key or value prevents it from being stored in this map. NullPointerException this map does not permit null keys or values, and the specified key or value is null.
put(k, v)
on this map once
for each mapping from key k to value v in the
specified map. The behavior of this operation is unspecified if the
specified map is modified while the operation is in progress.
Parameters: map Mappings to be stored in this map.
Throws: UnsupportedOperationException if the putAll method is not supported by this map. ClassCastException if the class of a key or value in the specified map prevents it from being stored in this map. IllegalArgumentException some aspect of a key or value in the specified map prevents it from being stored in this map. NullPointerException the specified map is null, or if this map does not permit null keys or values, and the specified map contains null keys or values.
(key==null ? k==null : key.equals(k))
, that mapping
is removed. (The map can contain at most one such mapping.)
Returns the value to which the map previously associated the key, or null if the map contained no mapping for this key. (A null return can also indicate that the map previously associated null with the specified key if the implementation supports null values.) The map will not contain a mapping for the specified key once the call returns.
Parameters: key key whose mapping is to be removed from the map.
Returns: previous value associated with specified key, or null if there was no mapping for key.
Throws: ClassCastException if the key is of an inappropriate type for the composited map (optional). NullPointerException if the key is null and the composited map does not not permit null keys (optional). UnsupportedOperationException if the remove method is not supported by the composited map containing the key
Parameters: map the Map to be removed from the composite
Returns: The removed Map or null
if map is not in the composite
Parameters: mutator the MapMutator to be used for mutation delegation
Returns: the number of key-value mappings in this map.
Returns: a collection view of the values contained in this map.