Class LazyMap
- java.lang.Object
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- org.apache.commons.collections.map.AbstractMapDecorator
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- org.apache.commons.collections.map.LazyMap
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- All Implemented Interfaces:
Serializable
,Map
- Direct Known Subclasses:
LazySortedMap
@Deprecated(since="2021-04-30") public class LazyMap extends AbstractMapDecorator implements Map, Serializable
Deprecated.Commons Collections 3 is in maintenance mode. Commons Collections 4 should be used instead.Decorates anotherMap
to create objects in the map on demand.When the
get(Object)
method is called with a key that does not exist in the map, the factory is used to create the object. The created object will be added to the map using the requested key.For instance:
Factory factory = new Factory() { public Object create() { return new Date(); } } Map lazy = Lazy.map(new HashMap(), factory); Object obj = lazy.get("NOW");
After the above code is executed,obj
will contain a newDate
instance. Furthermore, thatDate
instance is mapped to the "NOW" key in the map.Note that LazyMap 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
Collections.synchronizedMap(Map)
. This class may throw exceptions when accessed by concurrent threads without synchronization.This class is Serializable from Commons Collections 3.1.
- Since:
- Commons Collections 3.0
- See Also:
- Serialized Form
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static Map
decorate(Map map, Factory factory)
Deprecated.Factory method to create a lazily instantiated map.static Map
decorate(Map map, Transformer factory)
Deprecated.Factory method to create a lazily instantiated map.Object
get(Object key)
Deprecated.-
Methods inherited from class org.apache.commons.collections.map.AbstractMapDecorator
clear, containsKey, containsValue, entrySet, equals, hashCode, isEmpty, keySet, put, putAll, remove, size, toString, values
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Methods inherited from interface java.util.Map
clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values
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Method Detail
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decorate
public static Map decorate(Map map, Factory factory)
Deprecated.Factory method to create a lazily instantiated map.- Parameters:
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null- Throws:
IllegalArgumentException
- if map or factory is null
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decorate
public static Map decorate(Map map, Transformer factory)
Deprecated.Factory method to create a lazily instantiated map.- Parameters:
map
- the map to decorate, must not be nullfactory
- the factory to use, must not be null- Throws:
IllegalArgumentException
- if map or factory is null
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