Package org.apache.commons.collections.map

Class LazyMap

java.lang.Object
org.apache.commons.collections.map.AbstractMapDecorator
org.apache.commons.collections.map.LazyMap
All Implemented Interfaces:
Serializable, Map
Direct Known Subclasses:
LazySortedMap
@Deprecated(since="2021-04-30") public class LazyMap extends AbstractMapDecorator implements Map, Serializable
Deprecated.
Apache Commons Collections version 3.x is being deprecated from AEMaaCS. The upgraded version 4.4 of Commons Collections is already included as replacement. Customers are advised to upgrade to this version of the library. Please note: the package name was changed to org.apache.commons.collections4. Further note that there are AEM APIs currently exposing the old collections classes; these will be updated in upcoming releases.
Decorates another Map 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 new Date instance. Furthermore, that Date 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:

  • Method Details

    • 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 null
      factory - the factory to use, must not be null
      Throws:
      IllegalArgumentException - if map or factory is null

    • 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 null
      factory - the factory to use, must not be null
      Throws:
      IllegalArgumentException - if map or factory is null

    • get

      public Object get(Object key)
      Deprecated.
      Specified by:
      get in interface Map
      Overrides:
      get in class AbstractMapDecorator