Package com.exonum.binding.storage.indices

Class KeySetIndexProxy<E>

  • Type Parameters:
    E - the type of elements in this set
    All Implemented Interfaces:
    java.lang.Iterable<E>
    public final class KeySetIndexProxy<E>
extends AbstractNativeProxy
implements java.lang.Iterable<E>
    A key set is an index that contains no duplicate elements (keys). This implementation does not permit null elements.

    The elements are stored as keys in the underlying database in the lexicographical order. As each operation accepting an element needs to pass the entire element to the underlying database as a key, it's better, in terms of performance, to use this index with small elements. If you need to store large elements and can perform operations by hashes of the elements, consider using a ValueSetIndexProxy.

    The "destructive" methods of the set, i.e., the ones that change its contents, are specified to throw UnsupportedOperationException if the set has been created with a read-only database view.

    All method arguments are non-null by default.

    This class is not thread-safe and and its instances shall not be shared between threads.

    When the view goes out of scope, this set is destroyed. Subsequent use of the closed set is prohibited and will result in IllegalStateException.

    See Also:
    ValueSetIndexProxy, View

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(E e)
      Adds a new element to the set.
      void clear()
      Removes all of the elements from this set.
      boolean contains​(E e)
      Returns true if this set contains the specified element.
      java.lang.String getName()
      Returns the name of this index.
      java.util.Iterator<E> iterator()
      Creates an iterator over the set elements.
      static <E> KeySetIndexProxy<E> newInGroupUnsafe​(java.lang.String groupName, byte[] indexId, View view, com.exonum.binding.common.serialization.Serializer<E> serializer)
      Creates a new key set in a collection group with the given name.
      static <E> KeySetIndexProxy<E> newInstance​(java.lang.String name, View view, com.exonum.binding.common.serialization.Serializer<E> serializer)
      Creates a new key set proxy.
      static <E extends com.google.protobuf.MessageLite>
      KeySetIndexProxy<E>      		 newInstance​(java.lang.String name, View view, java.lang.Class<E> keyType)
      Creates a new key set storing protobuf messages.
      void remove​(E e)
      Removes the element from this set.
      java.lang.String toString()  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

      • Methods inherited from interface java.lang.Iterable

        forEach, spliterator

    • Method Detail

      • newInstance

        public static <E extends com.google.protobuf.MessageLite> KeySetIndexProxy<E> newInstance​(java.lang.String name,
                                                                                          View view,
                                                                                          java.lang.Class<E> keyType)
        Creates a new key set storing protobuf messages.
        Type Parameters:
        E - the type of keys in this set; must be a protobuf message that has a public static #parseFrom(byte[]) method
        Parameters:
        name - a unique alphanumeric non-empty identifier of this set in the underlying storage: [a-zA-Z0-9_]
        view - a database view. Must be valid. If a view is read-only, "destructive" operations are not permitted.
        keyType - the class of a key-protobuf message
        Throws:
        java.lang.IllegalStateException - if the view is not valid
        java.lang.IllegalArgumentException - if the name is empty

      • newInstance

        public static <E> KeySetIndexProxy<E> newInstance​(java.lang.String name,
                                                  View view,
                                                  com.exonum.binding.common.serialization.Serializer<E> serializer)
        Creates a new key set proxy.
        Type Parameters:
        E - the type of keys in this set
        Parameters:
        name - a unique alphanumeric non-empty identifier of this set in the underlying storage: [a-zA-Z0-9_]
        view - a database view. Must be valid. If a view is read-only, "destructive" operations are not permitted.
        serializer - a serializer of set keys
        Throws:
        java.lang.IllegalStateException - if the view is not valid
        java.lang.IllegalArgumentException - if the name is empty
        See Also:
        StandardSerializers

      • newInGroupUnsafe

        public static <E> KeySetIndexProxy<E> newInGroupUnsafe​(java.lang.String groupName,
                                                       byte[] indexId,
                                                       View view,
                                                       com.exonum.binding.common.serialization.Serializer<E> serializer)
        Creates a new key set in a collection group with the given name.

        See a caveat on index identifiers.

        Type Parameters:
        E - the type of keys in this set
        Parameters:
        groupName - a name of the collection group
        indexId - an identifier of this collection in the group, see the caveats
        view - a database view
        serializer - a serializer of set keys
        Returns:
        a new key set
        Throws:
        java.lang.IllegalStateException - if the view is not valid
        java.lang.IllegalArgumentException - if the name or index id is empty
        See Also:
        StandardSerializers

      • add

        public void add​(E e)
        Adds a new element to the set. The method has no effect if the set already contains such element.
        Parameters:
        e - an element to add
        Throws:
        java.lang.IllegalStateException - if this set is not valid
        java.lang.UnsupportedOperationException - if this set is read-only

      • clear

        public void clear()
        Removes all of the elements from this set. The set will be empty after this method returns.
        Throws:
        java.lang.IllegalStateException - if this set is not valid
        java.lang.UnsupportedOperationException - if this set is read-only

      • contains

        public boolean contains​(E e)
        Returns true if this set contains the specified element.
        Throws:
        java.lang.IllegalStateException - if this set is not valid

      • iterator

        public java.util.Iterator<E> iterator()
        Creates an iterator over the set elements. The elements are ordered lexicographically.

        Any destructive operation on the same Fork this set uses (but not necessarily on this set) will invalidate the iterator.

        Specified by:
        iterator in interface java.lang.Iterable<E>
        Returns:
        an iterator over the elements of this set
        Throws:
        java.lang.IllegalStateException - if this set is not valid

      • remove

        public void remove​(E e)
        Removes the element from this set. If it's not in the set, does nothing.
        Parameters:
        e - an element to remove.
        Throws:
        java.lang.IllegalStateException - if this set is not valid
        java.lang.UnsupportedOperationException - if this set is read-only

      • getName

        public final java.lang.String getName()
        Returns the name of this index.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object