com.exonum.binding.core.storage.indices

Class ValueSetIndexProxy<E>

java.lang.Object

com.exonum.binding.core.proxy.AbstractNativeProxy

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

Type Parameters:

E - the type of elements in this set

All Implemented Interfaces:

Iterable<ValueSetIndexProxy.Entry<E>>

public final class ValueSetIndexProxy<E>
extends AbstractNativeProxy
implements Iterable<ValueSetIndexProxy.Entry<E>>

A value set is an index that contains no duplicate elements (values). This implementation does not permit null elements.

The elements are stored in the underlying database as values, whereas their cryptographic hashes are used as keys, making this set implementation more suitable for storing large elements. If your application has small elements and does not need to perform set operations by hashes of the elements, consider using a KeySetIndexProxy.

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:

KeySetIndexProxy, View

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ValueSetIndexProxy.Entry<E> An entry of a value set index: a hash-value pair.

Field Summary

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

nativeHandle

Method Summary

Modifier and Type	Method and 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.
boolean	containsByHash(com.exonum.binding.common.hash.HashCode elementHash) Returns true if this set contains an element with the specified hash.
String	getName() Returns the name of this index.
Iterator<com.exonum.binding.common.hash.HashCode>	hashes() Creates an iterator over the hashes of the elements in this set.
Iterator<ValueSetIndexProxy.Entry<E>>	iterator() Returns an iterator over the entries of this set.
static <E> ValueSetIndexProxy<E>	newInGroupUnsafe(String groupName, byte[] indexId, View view, com.exonum.binding.common.serialization.Serializer<E> serializer) Creates a new value set in a collection group with the given name.
static <E extends com.google.protobuf.MessageLite> ValueSetIndexProxy<E>	newInstance(String name, View view, Class<E> valueType) Creates a new value set storing protobuf messages.
static <E> ValueSetIndexProxy<E>	newInstance(String name, View view, com.exonum.binding.common.serialization.Serializer<E> serializer) Creates a new value set.
void	remove(E e) Removes the element from this set.
void	removeByHash(com.exonum.binding.common.hash.HashCode elementHash) Removes an element from this set by its hash.
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

Method Detail

newInstance

public static <E extends com.google.protobuf.MessageLite> ValueSetIndexProxy<E> newInstance(String name,
                                                                                            View view,
                                                                                            Class<E> valueType)

Creates a new value set storing protobuf messages.

Type Parameters:

E - the type of values 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.

valueType - the class of values-protobuf messages

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

newInstance

public static <E> ValueSetIndexProxy<E> newInstance(String name,
                                                    View view,
                                                    com.exonum.binding.common.serialization.Serializer<E> serializer)

Creates a new value set.

Type Parameters:

E - the type of values 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 values

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

See Also:

StandardSerializers

newInGroupUnsafe

public static <E> ValueSetIndexProxy<E> newInGroupUnsafe(String groupName,
                                                         byte[] indexId,
                                                         View view,
                                                         com.exonum.binding.common.serialization.Serializer<E> serializer)

Creates a new value set in a collection group with the given name.

See a caveat on index identifiers.

Type Parameters:

E - the type of values 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 values

Returns:

a new value 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

See Also:

containsByHash(HashCode)

containsByHash

public boolean containsByHash(com.exonum.binding.common.hash.HashCode elementHash)

Returns true if this set contains an element with the specified hash.

Parameters:

elementHash - a hash of an element

Throws:

IllegalStateException - if this set is not valid

hashes

public Iterator<com.exonum.binding.common.hash.HashCode> hashes()

Creates an iterator over the hashes of the elements in this set. The hashes are ordered lexicographically.

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

Returns:

an iterator over the hashes of the elements in this set

Throws:

IllegalStateException - if this set is not valid

iterator

public Iterator<ValueSetIndexProxy.Entry<E>> iterator()

Returns an iterator over the entries of this set. An entry is a hash-value pair. The entries are ordered by keys 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 Iterable<ValueSetIndexProxy.Entry<E>>

Returns:

an iterator over the entries of this set

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

removeByHash

public void removeByHash(com.exonum.binding.common.hash.HashCode elementHash)

Removes an element from this set by its hash. If there is no such element in the set, does nothing.

Parameters:

elementHash - the hash of an element to remove.

Throws:

IllegalStateException - if this set is not valid

UnsupportedOperationException - if this set is read-only

getName

public final String getName()

Returns the name of this index.

toString

public String toString()

Overrides:

toString in class Object