Package alluxio.collections

Interface FieldIndex<T,​V>

  • Type Parameters:
    T - type of objects in this index
    V - type of the field used for indexing
    All Superinterfaces:
    java.lang.Iterable<T>
    All Known Implementing Classes:
    NonUniqueFieldIndex, UniqueFieldIndex
    public interface FieldIndex<T,​V>
extends java.lang.Iterable<T>
    An interface representing an index for IndexedSet, each index for this set must implement the interface to define how to get the value of the field chosen as the index. Users must use the same instance of the implementation of this interface as the parameter in all methods of IndexedSet to represent the same index.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      boolean add​(T o)
      Adds an object o to the index.
      void clear()
      Removes all the entries in this index.
      boolean containsField​(V fieldValue)
      Returns whether there is an object with the specified index field value in the set.
      boolean containsObject​(T o)
      Returns whether there is an object in the set.
      java.util.Set<T> getByField​(V value)
      Gets a subset of objects with the specified field value.
      T getFirst​(V value)
      Gets an object from the set of objects with the specified field value.
      java.util.Iterator<T> iterator()
      Returns an iterator over the elements in this index.
      boolean remove​(T o)
      Removes the object o from the index.
      int size()  

      • Methods inherited from interface java.lang.Iterable

        forEach, spliterator

    • Method Detail

      • add

        boolean add​(T o)
        Adds an object o to the index.
        Parameters:
        o - the object to add to the index
        Returns:
        true if object is added successfully, false otherwise

      • remove

        boolean remove​(T o)
        Removes the object o from the index.
        Parameters:
        o - the object to remove from index
        Returns:
        whether the specified element was in the index

      • clear

        void clear()
        Removes all the entries in this index.

      • containsField

        boolean containsField​(V fieldValue)
        Returns whether there is an object with the specified index field value in the set.
        Parameters:
        fieldValue - the field value to be satisfied
        Returns:
        true if there is one such object, otherwise false

      • containsObject

        boolean containsObject​(T o)
        Returns whether there is an object in the set.
        Parameters:
        o - the object to be checked
        Returns:
        true if there is one such object, otherwise false

      • getByField

        java.util.Set<T> getByField​(V value)
        Gets a subset of objects with the specified field value. If there is no object with the specified field value, an empty set is returned.
        Parameters:
        value - the field value to be satisfied
        Returns:
        the set of objects or an empty set if no such object exists

      • getFirst

        T getFirst​(V value)
        Gets an object from the set of objects with the specified field value.
        Parameters:
        value - the field value to be satisfied
        Returns:
        the object or null if there is no such object

      • iterator

        java.util.Iterator<T> iterator()
        Returns an iterator over the elements in this index. The elements are returned in no particular order. Note that the behavior of the iterator is unspecified if the underlying collection is modified while a thread is going through the iterator.
        Specified by:
        iterator in interface java.lang.Iterable<T>
        Returns:
        an iterator over the elements in this FieldIndex

      • size

        int size()
        Returns:
        the number of objects in this index set