Package org.apache.jackrabbit.oak.commons.collections

Class MapUtils

java.lang.Object
org.apache.jackrabbit.oak.commons.collections.MapUtils
public class MapUtils extends Object
Utility methods for Map conversions.

  • Method Details

    • newHashMap

      @NotNull public static <K, V> @NotNull Map<K,V> newHashMap(int capacity)
      Creates a new, empty HashMap with expected capacity.

      The returned map uses the default load factor of 0.75, and its capacity is large enough to add expected number of elements without resizing.

      Parameters:
      capacity - the expected number of elements
      Throws:
      IllegalArgumentException - if capacity is negative
      See Also:

    • fromProperties

      @NotNull public static @NotNull Map<String,String> fromProperties(@NotNull @NotNull Properties properties)
      Converts a Properties object to an unmodifiable Map with string keys and values.
      Parameters:
      properties - the Properties object to convert, must not be null
      Returns:
      an unmodifiable Map containing the same entries as the given Properties object
      Throws:
      NullPointerException - if the properties parameter is null

    • filterKeys

      @NotNull public static <K, V> @NotNull Map<K,V> filterKeys(@NotNull @NotNull Map<K,V> map, @NotNull @NotNull Predicate<? super K> predicate)
      Create a new Map after filtering the entries of the given map based on the specified predicate applied to the keys.
      Type Parameters:
      K - the type of keys in the map
      V - the type of values in the map
      Parameters:
      map - the map to filter, must not be null
      predicate - the predicate to apply to the keys, must not be null
      Returns:
      a new map containing only the entries whose keys match the predicate
      Throws:
      NullPointerException - if the map or predicate is null
      See Also:

    • filterValues

      @NotNull public static <K, V> @NotNull Map<K,V> filterValues(@NotNull @NotNull Map<K,V> map, @NotNull @NotNull Predicate<? super V> predicate)
      Create a new Map after filtering the entries of the given map based on the specified predicate applied to the values.
      Type Parameters:
      K - the type of keys in the map
      V - the type of values in the map
      Parameters:
      map - the map to filter, must not be null
      predicate - the predicate to apply to the values, must not be null
      Returns:
      a new map containing only the entries whose values match the predicate
      Throws:
      NullPointerException - if the map or predicate is null
      See Also:

    • filterEntries

      @NotNull public static <K, V> @NotNull Map<K,V> filterEntries(@NotNull @NotNull Map<K,V> map, @NotNull @NotNull Predicate<? super Map.Entry<K,V>> predicate)
      Create a new Map after filtering the entries of the given map based on the specified predicate applied to the Map.Entry.
      Type Parameters:
      K - the type of keys in the map
      V - the type of values in the map
      Parameters:
      map - the map to filter, must not be null
      predicate - the predicate to apply to the Map.Entry, must not be null
      Returns:
      a new map containing only the entries whose values match the predicate
      Throws:
      NullPointerException - if the map or predicate is null
      See Also: