com.exonum.binding.core.storage.indices

Class ProofMapIndexProxy<K,V>

java.lang.Object

com.exonum.binding.core.proxy.AbstractNativeProxy

com.exonum.binding.core.storage.indices.ProofMapIndexProxy<K,V>

Type Parameters:

K - the type of keys in this map

V - the type of values in this map

All Implemented Interfaces:

MapIndex<K,V>, StorageIndex

public final class ProofMapIndexProxy<K,V>
extends AbstractNativeProxy
implements MapIndex<K,V>

A ProofMapIndexProxy is an index that maps keys to values. A map cannot contain duplicate keys; each key corresponds to at most one value. This map is capable of providing cryptographic proofs that a certain key is mapped to a particular value or that there are no mapping for the key in the map.

This map is implemented as a Merkle-Patricia tree. It does not permit null keys and values.

The Merkle-Patricia tree backing the proof map uses internal 32-byte keys. The tree balance relies on the internal keys being uniformly distributed.

Key hashing in proof maps

By default, when creating the proof map using methods #newInstance and #newInGroupUnsafe, the user keys are converted into internal keys through hashing. This allows to use keys of an arbitrary size and ensures the balance of the internal tree. It is also possible to create a proof map that will not hash keys with methods #newInstanceNoKeyHashing and #newInGroupUnsafeNoKeyHashing. In this mode the map will use the user keys as internal tree keys. Such mode of operation is appropriate iff all of the following conditions hold:

• All keys are 32-byte long
• The keys are uniformly distributed
• The keys come from a trusted source that cannot influence their distribution and affect the tree balance.

The "destructive" methods of the map, i.e., the one that change the map contents, are specified to throw UnsupportedOperationException if the map 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 map is destroyed. Subsequent use of the closed map is prohibited and will result in IllegalStateException.

See Also:

View

Field Summary

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

nativeHandle

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all of the key-value pairs from the map.
boolean	containsKey(K key) Returns true if this map contains a mapping for the specified key.
Iterator<com.exonum.binding.common.collect.MapEntry<K,V>>	entries() Returns an iterator over the map entries.
V	get(K key) Returns the value associated with the specified key, or null if there is no mapping for the key.
IndexAddress	getAddress() Returns the index address: its unique identifier in the database.
com.exonum.binding.common.hash.HashCode	getIndexHash() Returns the index hash which represents the complete state of this map.
com.exonum.binding.common.proofs.map.UncheckedMapProof	getProof(Collection<? extends K> keys) Deprecated. Proofs are temporarily disabled since 0.9.0-rc1, and will be re-enabled in a later release
com.exonum.binding.common.proofs.map.UncheckedMapProof	getProof(K key, K... otherKeys) Deprecated. Proofs are temporarily disabled since 0.9.0-rc1, and will be re-enabled in a later release
Iterator<K>	keys() Returns an iterator over the map keys.
static <K,V> ProofMapIndexProxy<K,V>	newInGroupUnsafe(String groupName, byte[] mapId, View view, com.exonum.binding.common.serialization.Serializer<K> keySerializer, com.exonum.binding.common.serialization.Serializer<V> valueSerializer) Creates a new proof map in a collection group with the given name.
static <K,V> ProofMapIndexProxy<K,V>	newInGroupUnsafeNoKeyHashing(String groupName, byte[] mapId, View view, com.exonum.binding.common.serialization.Serializer<K> keySerializer, com.exonum.binding.common.serialization.Serializer<V> valueSerializer) Creates a new proof map that uses non-hashed keys in a collection group with the given name.
static <K,V> ProofMapIndexProxy<K,V>	newInstance(String name, View view, com.exonum.binding.common.serialization.Serializer<K> keySerializer, com.exonum.binding.common.serialization.Serializer<V> valueSerializer) Creates a ProofMapIndexProxy.
static <K,V> ProofMapIndexProxy<K,V>	newInstanceNoKeyHashing(String name, View view, com.exonum.binding.common.serialization.Serializer<K> keySerializer, com.exonum.binding.common.serialization.Serializer<V> valueSerializer) Creates a ProofMapIndexProxy that uses non-hashed keys.
void	put(K key, V value) Puts a new key-value pair into the map.
void	putAll(Map<? extends K,? extends V> sourceMap) Puts all key-value pairs from the given map into this map.
void	remove(K key) Removes the value mapped to the specified key from the map.
String	toString()
Iterator<V>	values() Returns an iterator over the map values.

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 com.exonum.binding.core.storage.indices.MapIndex

isEmpty

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

getAddress, getName

Method Detail

newInstance

public static <K,V> ProofMapIndexProxy<K,V> newInstance(String name,
                                                        View view,
                                                        com.exonum.binding.common.serialization.Serializer<K> keySerializer,
                                                        com.exonum.binding.common.serialization.Serializer<V> valueSerializer)

Creates a ProofMapIndexProxy.

Type Parameters:

K - the type of keys in the map

V - the type of values in the map

Parameters:

name - a unique alphanumeric non-empty identifier of this map 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.

keySerializer - a serializer of keys

valueSerializer - a serializer of values

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

See Also:

StandardSerializers

newInstanceNoKeyHashing

public static <K,V> ProofMapIndexProxy<K,V> newInstanceNoKeyHashing(String name,
                                                                    View view,
                                                                    com.exonum.binding.common.serialization.Serializer<K> keySerializer,
                                                                    com.exonum.binding.common.serialization.Serializer<V> valueSerializer)

Creates a ProofMapIndexProxy that uses non-hashed keys. Requires that keys are 32-byte long.

Type Parameters:

K - the type of keys in the map

V - the type of values in the map

Parameters:

name - a unique alphanumeric non-empty identifier of this map 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.

keySerializer - a serializer of keys, must always produce 32-byte long values

valueSerializer - a serializer of values

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name is empty

See Also:

StandardSerializers

newInGroupUnsafe

public static <K,V> ProofMapIndexProxy<K,V> newInGroupUnsafe(String groupName,
                                                             byte[] mapId,
                                                             View view,
                                                             com.exonum.binding.common.serialization.Serializer<K> keySerializer,
                                                             com.exonum.binding.common.serialization.Serializer<V> valueSerializer)

Creates a new proof map in a collection group with the given name.

See a caveat on index identifiers.

Type Parameters:

K - the type of keys in the map

V - the type of values in the map

Parameters:

groupName - a name of the collection group

mapId - an identifier of this collection in the group, see the caveats

view - a database view

keySerializer - a serializer of keys

valueSerializer - a serializer of values

Returns:

a new map proxy

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name or index id is empty

See Also:

StandardSerializers

newInGroupUnsafeNoKeyHashing

public static <K,V> ProofMapIndexProxy<K,V> newInGroupUnsafeNoKeyHashing(String groupName,
                                                                         byte[] mapId,
                                                                         View view,
                                                                         com.exonum.binding.common.serialization.Serializer<K> keySerializer,
                                                                         com.exonum.binding.common.serialization.Serializer<V> valueSerializer)

Creates a new proof map that uses non-hashed keys in a collection group with the given name. Requires that keys are 32-byte long.

See a caveat on index identifiers.

Type Parameters:

K - the type of keys in the map

V - the type of values in the map

Parameters:

groupName - a name of the collection group

mapId - an identifier of this collection in the group, see the caveats

view - a database view

keySerializer - a serializer of keys, must always produce 32-byte long values

valueSerializer - a serializer of values

Returns:

a new map proxy

Throws:

IllegalStateException - if the view is not valid

IllegalArgumentException - if the name or index id is empty

See Also:

StandardSerializers

containsKey

public boolean containsKey(K key)

Description copied from interface: MapIndex

Returns true if this map contains a mapping for the specified key.

Specified by:

containsKey in interface MapIndex<K,V>

put

public void put(K key,
                V value)

Puts a new key-value pair into the map. If this map already contains a mapping for the specified key, overwrites the old value with the specified value.

Specified by:

put in interface MapIndex<K,V>

Parameters:

key - a proof map key

value - a storage value to associate with the key

Throws:

IllegalStateException - if this map is not valid

IllegalArgumentException - if the size of the key is not 32 bytes (in case of a proof map that uses non-hashed keys)

UnsupportedOperationException - if this map is read-only

putAll

public void putAll(Map<? extends K,? extends V> sourceMap)

Description copied from interface: MapIndex

Puts all key-value pairs from the given map into this map. Equivalent to a sequence of individual MapIndex.put(K, V) operations.

Specified by:

putAll in interface MapIndex<K,V>

Parameters:

sourceMap - a map to put into this one

get

public V get(K key)

Description copied from interface: MapIndex

Returns the value associated with the specified key, or null if there is no mapping for the key.

Specified by:

get in interface MapIndex<K,V>

Parameters:

key - a storage key

Returns:

the value mapped to the specified key, or null if this map contains no mapping for the key.

getProof

@Deprecated
public com.exonum.binding.common.proofs.map.UncheckedMapProof getProof(K key,
                                                                                   K... otherKeys)

Deprecated. Proofs are temporarily disabled since 0.9.0-rc1, and will be re-enabled in a later release

Returns a proof that there are values mapped to the specified keys or that there are no such mappings.

Parameters:

key - a proof map key which might be mapped to some value

otherKeys - other proof map keys which might be mapped to some values

Throws:

IllegalStateException - if this map is not valid

IllegalArgumentException - if the size of any of the keys is not 32 bytes (in case of a proof map that uses non-hashed keys)

getProof

@Deprecated
public com.exonum.binding.common.proofs.map.UncheckedMapProof getProof(Collection<? extends K> keys)

Deprecated. Proofs are temporarily disabled since 0.9.0-rc1, and will be re-enabled in a later release

Returns a proof that there are values mapped to the specified keys or that there are no such mappings.

Parameters:

keys - proof map keys which might be mapped to some values

Throws:

IllegalStateException - if this map is not valid

IllegalArgumentException - if the size of any of the keys is not 32 bytes (in case of a proof map that uses non-hashed keys) or keys collection is empty

getIndexHash

public com.exonum.binding.common.hash.HashCode getIndexHash()

Returns the index hash which represents the complete state of this map. Any modifications to the stored entries affect the index hash.

Throws:

IllegalStateException - if this map is not valid

remove

public void remove(K key)

Description copied from interface: MapIndex

Removes the value mapped to the specified key from the map. If there is no such mapping, has no effect.

Specified by:

remove in interface MapIndex<K,V>

Parameters:

key - a storage key

keys

public Iterator<K> keys()

Description copied from interface: MapIndex

Returns an iterator over the map keys. The keys are ordered in lexicographical order.

Specified by:

keys in interface MapIndex<K,V>

values

public Iterator<V> values()

Description copied from interface: MapIndex

Returns an iterator over the map values. The values are ordered in lexicographical order of keys.

Specified by:

values in interface MapIndex<K,V>

entries

public Iterator<com.exonum.binding.common.collect.MapEntry<K,V>> entries()

Description copied from interface: MapIndex

Returns an iterator over the map entries. The entries are ordered by keys in lexicographical order.

Specified by:

entries in interface MapIndex<K,V>

clear

public void clear()

Description copied from interface: MapIndex

Removes all of the key-value pairs from the map. The map will be empty after this method returns.

Specified by:

clear in interface MapIndex<K,V>

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