All Known Implementing Classes:: AbstractAccess, Fork, Prefixed, RoErasedAccess, Snapshot

public interface Access

Provides access to Exonum MerkleDB indexes. An access object corresponds to a certain database state.

An access can be read-only or read-write. Read-only accesses produce indexes that forbid modifying operations.

The changes made to read-write accesses are not usually applied immediately to the database state, but are performed separately. For example, Exonum will apply the changes made by all transactions when a block is confirmed.

Accesses may perform index address resolution: they may modify the passed index address before fetching it from the database. That implies that addresses passed to index factory methods are relative to an access object. The address resolution rules must be documented in interface implementations.

As each Access object requires some MerkleDB resources to function, they work in a scope that is usually managed by the framework. When an Access is closed, all indexes created with it are destroyed and become inaccessible; and no new indexes can be created.

All method arguments are non-null by default.

This Java interface is similar to a combination of Rust Access and AccessExt traits.

See Also:: com.exonum.binding.core.storage.indices, StandardSerializers

Method Summary

Modifier and Type	Method	Description
`boolean`	`canModify()`	Returns true if this access allows modifications to the database state; false if it is immutable.
`long`	`getAccessNativeHandle()`	Returns a native handle of this access.
`<E> EntryIndex<E>`	`getEntry(IndexAddress address, Serializer<E> serializer)`	Creates a new Entry.
`<E> KeySetIndexProxy<E>`	`getKeySet(IndexAddress address, Serializer<E> serializer)`	Creates a new KeySet.
`<E> ListIndexProxy<E>`	`getList(IndexAddress address, Serializer<E> serializer)`	Creates a new ListIndex.
`<K, V> MapIndexProxy<K,V>`	`getMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)`	Creates a new MapIndex.
`<E> ProofEntryIndex<E>`	`getProofEntry(IndexAddress address, Serializer<E> serializer)`	Creates a new ProofEntry.
`<E> ProofListIndexProxy<E>`	`getProofList(IndexAddress address, Serializer<E> serializer)`	Creates a new ProofListIndex.
`<K, V> ProofMapIndexProxy<K,V>`	`getProofMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)`	Creates a new ProofMapIndex.
`<K, V> ProofMapIndexProxy<K,V>`	`getRawProofMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)`	Creates a new "raw" ProofMapIndex.
`<E> ValueSetIndexProxy<E>`	`getValueSet(IndexAddress address, Serializer<E> serializer)`	Creates a new ValueSet.

Method Details
- getProofList
  
  <E> ProofListIndexProxy<E> getProofList(IndexAddress address, Serializer<E> serializer)
  
  Creates a new ProofListIndex.
  
  Type Parameters:
  
  E - the type of elements in this list
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - a serializer of list elements
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  StandardSerializers
- getList
  
  <E> ListIndexProxy<E> getList(IndexAddress address, Serializer<E> serializer)
  
  Creates a new ListIndex.
  
  Type Parameters:
  
  E - the type of elements in this list
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - a serializer of list elements
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  getProofList(IndexAddress, Serializer), StandardSerializers
- getProofMap
  
  <K, V> ProofMapIndexProxy<K,V> getProofMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)
  
  Creates a new ProofMapIndex.
  
  Type Parameters:
  
  K - the type of keys in the map
  
  V - the type of values in the map
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  keySerializer - a serializer of keys
  
  valueSerializer - a serializer of values
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  StandardSerializers
- getRawProofMap
  
  <K, V> ProofMapIndexProxy<K,V> getRawProofMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)
  
  Creates a new "raw" ProofMapIndex. A raw ProofMapIndex does not hash keys, hence imposes some requirements on them.
  
  Type Parameters:
  
  K - the type of keys in the map
  
  V - the type of values in the map
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  keySerializer - a serializer of keys, must always produce 32-byte long values that suit the requirements
  
  valueSerializer - a serializer of values
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  getProofMap(IndexAddress, Serializer, Serializer), StandardSerializers
- getMap
  
  <K, V> MapIndexProxy<K,V> getMap(IndexAddress address, Serializer<K> keySerializer, Serializer<V> valueSerializer)
  
  Creates a new MapIndex.
  
  Type Parameters:
  
  K - the type of keys in the map
  
  V - the type of values in the map
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  keySerializer - a serializer of keys
  
  valueSerializer - a serializer of values
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  getProofMap(IndexAddress, Serializer, Serializer), StandardSerializers
- getKeySet
  
  <E> KeySetIndexProxy<E> getKeySet(IndexAddress address, Serializer<E> serializer)
  
  Creates a new KeySet.
  
  Type Parameters:
  
  E - the type of keys in this set
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - a serializer of set keys
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  getValueSet(IndexAddress, Serializer), StandardSerializers
- getValueSet
  
  <E> ValueSetIndexProxy<E> getValueSet(IndexAddress address, Serializer<E> serializer)
  
  Creates a new ValueSet.
  
  Type Parameters:
  
  E - the type of values in this set
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - a serializer of set values
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  getKeySet(IndexAddress, Serializer), StandardSerializers
- getProofEntry
  
  <E> ProofEntryIndex<E> getProofEntry(IndexAddress address, Serializer<E> serializer)
  
  Creates a new ProofEntry.
  
  Type Parameters:
  
  E - the type of the entry
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - an entry serializer
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  StandardSerializers
- getEntry
  
  <E> EntryIndex<E> getEntry(IndexAddress address, Serializer<E> serializer)
  
  Creates a new Entry.
  
  Type Parameters:
  
  E - the type of the entry
  
  Parameters:
  
  address - an index address in the MerkleDB
  
  serializer - an entry serializer
  
  Throws:
  
  java.lang.IllegalStateException - if this access is not valid
  
  See Also:
  
  StandardSerializers
- canModify
  
  boolean canModify()
  
  Returns true if this access allows modifications to the database state; false if it is immutable.
- getAccessNativeHandle
  
  long getAccessNativeHandle()
  
  Returns a native handle of this access.
  
  Throws:
  
  java.lang.IllegalStateException - if the access is invalid (closed or nullptr)

Interface Access

Method Summary

Method Details