| java.util.concurrent.ConcurrentMap
| ConcurrentMap | | public interface ConcurrentMap extends Map<K, V>(Code) | | A
java.util.Map providing additional atomic
putIfAbsent, remove, and replace methods.
This interface is a member of the
Java Collections Framework.
since:
1.5
author:
Doug Lea<
Parameters:
K - > the type of keys maintained by this map<
Parameters:
V - > the type of mapped values |
| Method Summary | |
| V | putIfAbsent(K key, V value)
If the specified key is not already associated
with a value, associate it with the given value.
This is equivalent to
if (!map.containsKey(key))
return map.put(key, value);
else
return map.get(key);
Except that the action is performed atomically.
Parameters:
key - key with which the specified value is to be associated.
Parameters:
value - value to be associated with the specified key. | | boolean | remove(Object key, Object value)
Remove entry for key only if currently mapped to given value.
Acts as
if ((map.containsKey(key) && map.get(key).equals(value)) {
map.remove(key);
return true;
} else return false;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
value - value associated with the specified key. | | boolean | replace(K key, V oldValue, V newValue)
Replace entry for key only if currently mapped to given value.
Acts as
if ((map.containsKey(key) && map.get(key).equals(oldValue)) {
map.put(key, newValue);
return true;
} else return false;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
oldValue - value expected to be associated with the specified key.
Parameters:
newValue - value to be associated with the specified key. | | V | replace(K key, V value)
Replace entry for key only if currently mapped to some value.
Acts as
if ((map.containsKey(key)) {
return map.put(key, value);
} else return null;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
value - value to be associated with the specified key. |
| putIfAbsent | | V putIfAbsent(K key, V value)(Code) | | If the specified key is not already associated
with a value, associate it with the given value.
This is equivalent to
if (!map.containsKey(key))
return map.put(key, value);
else
return map.get(key);
Except that the action is performed atomically.
Parameters:
key - key with which the specified value is to be associated.
Parameters:
value - value to be associated with the specified key. previous value associated with specified key, or nullif there was no mapping for key. A null return canalso indicate that the map previously associated nullwith the specified key, if the implementation supportsnull values.
throws:
UnsupportedOperationException - if the put operation isnot supported by this map.
throws:
ClassCastException - if the class of the specified key or valueprevents it from being stored in this map.
throws:
IllegalArgumentException - if some aspect of this key or valueprevents it from being stored in this map.
throws:
NullPointerException - if this map does not permit nullkeys or values, and the specified key or value isnull. |
| remove | | boolean remove(Object key, Object value)(Code) | | Remove entry for key only if currently mapped to given value.
Acts as
if ((map.containsKey(key) && map.get(key).equals(value)) {
map.remove(key);
return true;
} else return false;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
value - value associated with the specified key. true if the value was removed, false otherwise
throws:
NullPointerException - if this map does not permit nullkeys or values, and the specified key or value isnull. |
| replace | | boolean replace(K key, V oldValue, V newValue)(Code) | | Replace entry for key only if currently mapped to given value.
Acts as
if ((map.containsKey(key) && map.get(key).equals(oldValue)) {
map.put(key, newValue);
return true;
} else return false;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
oldValue - value expected to be associated with the specified key.
Parameters:
newValue - value to be associated with the specified key. true if the value was replaced
throws:
NullPointerException - if this map does not permit nullkeys or values, and the specified key or value isnull. |
| replace | | V replace(K key, V value)(Code) | | Replace entry for key only if currently mapped to some value.
Acts as
if ((map.containsKey(key)) {
return map.put(key, value);
} else return null;
except that the action is performed atomically.
Parameters:
key - key with which the specified value is associated.
Parameters:
value - value to be associated with the specified key. previous value associated with specified key, or nullif there was no mapping for key. A null return canalso indicate that the map previously associated nullwith the specified key, if the implementation supportsnull values.
throws:
NullPointerException - if this map does not permit nullkeys or values, and the specified key or value isnull. |
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