Package com.exonum.binding.core.storage.indices

Class KeySetIndexProxy<E>

java.lang.Object

com.exonum.binding.core.proxy.AbstractNativeProxy

com.exonum.binding.core.storage.indices.KeySetIndexProxy<E>

Type Parameters:

E - the type of elements in this set

All Implemented Interfaces:

StorageIndex, Iterable<E>

public final class KeySetIndexProxy<E>
extends AbstractNativeProxy
implements 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

Field Summary

Fields inherited from class com.exonum.binding.core.proxy.AbstractNativeProxy

nativeHandle

Method Summary

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.
IndexAddress	getAddress()	Returns the index address: its unique identifier in the database.
Iterator<E>	iterator()	Creates an iterator over the set elements.
static <E> KeySetIndexProxy<E>	newInGroupUnsafe(String groupName, byte[] indexId, View view, Serializer<E> serializer)	Creates a new key set in a collection group with the given name.
static <E> KeySetIndexProxy<E>	newInstance(String name, View view, Serializer<E> serializer)	Creates a new key set proxy.
static <E extends com.google.protobuf.MessageLite> KeySetIndexProxy<E>	newInstance(String name, View view, Class<E> keyType)	Creates a new key set storing protobuf messages.
void	remove(E e)	Removes the element from this set.
Stream<E>	stream()	Returns a stream of the set elements.
String	toString()

Methods inherited from class com.exonum.binding.core.proxy.AbstractNativeProxy

getNativeHandle, isValidHandle

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

Methods inherited from interface com.exonum.binding.core.storage.indices.StorageIndex

getName

Method Detail

newInstance

public static <E extends com.google.protobuf.MessageLite> KeySetIndexProxy<E> newInstance(String name,
                                                                                          View view,
                                                                                          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:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

newInstance

public static <E> KeySetIndexProxy<E> newInstance(String name,
                                                  View view,
                                                  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:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

See Also:

StandardSerializers

newInGroupUnsafe

public static <E> KeySetIndexProxy<E> newInGroupUnsafe(String groupName,
                                                       byte[] indexId,
                                                       View view,
                                                       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:

IllegalStateException - if the view is not valid

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:

IllegalStateException - if this set is not valid

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:

IllegalStateException - if this set is not valid

UnsupportedOperationException - if this set is read-only

contains

public boolean contains(E e)

Returns true if this set contains the specified element.

Throws:

IllegalStateException - if this set is not valid

iterator

public Iterator<E> iterator()

Creates an iterator over the set elements. The elements are ordered lexicographically.

Specified by:

iterator in interface Iterable<E>

Returns:

an iterator over the elements of this set

Throws:

IllegalStateException - if this set is not valid

stream

public Stream<E> stream()

Returns a stream of the set elements. The elements are ordered lexicographically.

Throws:

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:

IllegalStateException - if this set is not valid

UnsupportedOperationException - if this set is read-only

getAddress

public IndexAddress getAddress()

Description copied from interface: StorageIndex

Returns the index address: its unique identifier in the database. It consists of the name and, in case this index belongs to an index family, a family identifier.

Specified by:

getAddress in interface StorageIndex

toString

public String toString()

Overrides:

toString in class Object