Package org.apache.commons.collections.map

Class LazySortedMap

  • All Implemented Interfaces:
    java.io.Serializable, java.util.Map, java.util.SortedMap
    public class LazySortedMap
extends LazyMap
implements java.util.SortedMap
    Decorates another SortedMap to create objects in the map on demand.

    When the LazyMap.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();
     }
 }
 SortedMap lazy = Lazy.sortedMap(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 LazySortedMap 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.synchronizedSortedMap(java.util.SortedMap<K, V>). 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

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface java.util.Map

        java.util.Map.Entry<K extends java.lang.Object,​V extends java.lang.Object>

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      java.util.Comparator comparator()  
      static java.util.SortedMap decorate​(java.util.SortedMap map, Factory factory)
      Factory method to create a lazily instantiated sorted map.
      static java.util.SortedMap decorate​(java.util.SortedMap map, Transformer factory)
      Factory method to create a lazily instantiated sorted map.
      java.lang.Object firstKey()  
      java.util.SortedMap headMap​(java.lang.Object toKey)  
      java.lang.Object lastKey()  
      java.util.SortedMap subMap​(java.lang.Object fromKey, java.lang.Object toKey)  
      java.util.SortedMap tailMap​(java.lang.Object fromKey)  

      • Methods inherited from class java.lang.Object

        getClass, notify, notifyAll, wait, wait, wait

      • Methods inherited from interface java.util.Map

        clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, equals, forEach, get, getOrDefault, hashCode, isEmpty, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size

      • Methods inherited from interface java.util.SortedMap

        entrySet, keySet, values

    • Method Detail

      • decorate

        public static java.util.SortedMap decorate​(java.util.SortedMap map,
                                           Factory factory)
        Factory method to create a lazily instantiated sorted map.
        Parameters:
        map - the map to decorate, must not be null
        factory - the factory to use, must not be null
        Throws:
        java.lang.IllegalArgumentException - if map or factory is null

      • decorate

        public static java.util.SortedMap decorate​(java.util.SortedMap map,
                                           Transformer factory)
        Factory method to create a lazily instantiated sorted map.
        Parameters:
        map - the map to decorate, must not be null
        factory - the factory to use, must not be null
        Throws:
        java.lang.IllegalArgumentException - if map or factory is null

      • firstKey

        public java.lang.Object firstKey()
        Specified by:
        firstKey in interface java.util.SortedMap

      • lastKey

        public java.lang.Object lastKey()
        Specified by:
        lastKey in interface java.util.SortedMap

      • comparator

        public java.util.Comparator comparator()
        Specified by:
        comparator in interface java.util.SortedMap

      • subMap

        public java.util.SortedMap subMap​(java.lang.Object fromKey,
                                  java.lang.Object toKey)
        Specified by:
        subMap in interface java.util.SortedMap

      • headMap

        public java.util.SortedMap headMap​(java.lang.Object toKey)
        Specified by:
        headMap in interface java.util.SortedMap

      • tailMap

        public java.util.SortedMap tailMap​(java.lang.Object fromKey)
        Specified by:
        tailMap in interface java.util.SortedMap