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

Class ProofEntryIndexProxy<T>

java.lang.Object

com.exonum.binding.core.proxy.AbstractNativeProxy

com.exonum.binding.core.storage.indices.ProofEntryIndexProxy<T>

Type Parameters:

T - the type of an element in this entry

All Implemented Interfaces:

EntryIndex<T>, HashableIndex, ProofEntryIndex<T>, StorageIndex

public final class ProofEntryIndexProxy<T>
extends AbstractNativeProxy
implements ProofEntryIndex<T>

A proxy of a native MerkleDB ProofEntry.

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

Field Summary

Fields

Modifier and Type	Field	Description
protected com.exonum.binding.common.serialization.CheckingSerializerDecorator<T>	serializer

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

nativeHandle

Method Summary

Modifier and Type	Method	Description
T	get()	If value is present in the entry, returns it, otherwise, throws NoSuchElementException.
IndexAddress	getAddress()	Returns the index address: its identifier in the database.
com.exonum.binding.common.hash.HashCode	getIndexHash()	Returns the index hash which represents the complete state of this entry.
boolean	isPresent()	Returns true if this entry exists in the database.
protected byte[]	nativeGet(long nativeHandle)
protected byte[]	nativeGetIndexHash(long nativeHandle)
protected boolean	nativeIsPresent(long nativeHandle)
protected void	nativeRemove(long nativeHandle)
protected void	nativeSet(long nativeHandle, byte[] value)
static <E> ProofEntryIndexProxy<E>	newInstance(IndexAddress address, AbstractAccess access, com.exonum.binding.common.serialization.Serializer<E> serializer)	Creates a new Entry.
T	orElse(T valueIfAbsent)	Returns the value of this entry, if it is present; otherwise, the given value.
void	remove()	Removes a value from this entry.
void	set(T value)	Sets a new value of the entry, overwriting the previous value.
Optional<T>	toOptional()	Converts the entry to Optional.
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 com.exonum.binding.core.storage.indices.EntryIndex

get, isPresent, orElse, remove, set, toOptional

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

getAddress, getName

Field Detail

serializer

protected final com.exonum.binding.common.serialization.CheckingSerializerDecorator<T> serializer

Method Detail

newInstance

public static <E> ProofEntryIndexProxy<E> newInstance(IndexAddress address,
                                                      AbstractAccess access,
                                                      com.exonum.binding.common.serialization.Serializer<E> serializer)

Creates a new Entry.

Warning: do not invoke this method from service code, use Access.getProofEntry(IndexAddress, Serializer).

Parameters:

address - an index address. Must correspond to a regular index, not a group. Use ProofMapIndexProxy instead of groups of entries.

access - a database access. Must be valid. If an access is read-only, "destructive" operations are not permitted.

serializer - an entry serializer

Throws:

IllegalArgumentException - if the name is empty

IllegalStateException - if the access proxy is invalid

See Also:

StandardSerializers

getIndexHash

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

Description copied from interface: ProofEntryIndex

Returns the index hash which represents the complete state of this entry. Any modifications to this entry affect the index hash.

The entry index hash is computed as SHA-256 of the entry binary representation, or a hash of zeroes if the entry is not set.

Specified by:

getIndexHash in interface HashableIndex

Specified by:

getIndexHash in interface ProofEntryIndex<T>

nativeSet

protected void nativeSet(long nativeHandle,
                         byte[] value)

nativeIsPresent

protected boolean nativeIsPresent(long nativeHandle)

nativeGet

protected byte[] nativeGet(long nativeHandle)

nativeGetIndexHash

protected byte[] nativeGetIndexHash(long nativeHandle)

nativeRemove

protected void nativeRemove(long nativeHandle)

set

public void set(T value)

Description copied from interface: EntryIndex

Sets a new value of the entry, overwriting the previous value.

Specified by:

set in interface EntryIndex<T>

Parameters:

value - a value to set. Must not be null.

isPresent

public boolean isPresent()

Description copied from interface: EntryIndex

Returns true if this entry exists in the database.

Specified by:

isPresent in interface EntryIndex<T>

get

public T get()

Description copied from interface: EntryIndex

If value is present in the entry, returns it, otherwise, throws NoSuchElementException.

Specified by:

get in interface EntryIndex<T>

orElse

public T orElse(T valueIfAbsent)

Description copied from interface: EntryIndex

Returns the value of this entry, if it is present; otherwise, the given value.

Specified by:

orElse in interface EntryIndex<T>

Parameters:

valueIfAbsent - a value to return if there is none in this entry

remove

public void remove()

Description copied from interface: EntryIndex

Removes a value from this entry.

Specified by:

remove in interface EntryIndex<T>

toOptional

public Optional<T> toOptional()

Description copied from interface: EntryIndex

Converts the entry to Optional.

Be aware that this method represents a state of the entry at the time of calling. And the returned value won't reflect the entry changes:

  
    entry.set("foo");
    Optional<String> optionalEntry = entry.toOptional();
    entry.remove();
    optionalEntry.get(); // -> returns "foo"
  
 

Specified by:

toOptional in interface EntryIndex<T>

Returns:

Optional.of(value) if value is present in the entry, otherwise returns Optional.empty()

getAddress

public IndexAddress getAddress()

Description copied from interface: StorageIndex

Returns the index address: its identifier in the database.

Please note that the implementations may return either relative or absolute address. The address is not required to be equal to the one passed to the index constructor.

Specified by:

getAddress in interface StorageIndex

toString

public String toString()

Overrides:

toString in class Object