Package cz.o2.proxima.direct.core.randomaccess

Interface RandomAccessReader

All Superinterfaces:

java.lang.AutoCloseable, java.io.Closeable

All Known Subinterfaces:

CachedView

All Known Implementing Classes:

JdbcOnlineAttributeReader, LocalCachedPartitionedView, RandomHBaseReader, TransactionalCachedView

@Stable
public interface RandomAccessReader
extends java.io.Closeable

Reader of data stored in random access storage. Every class that implements both AbstractAttributeWriter and RandomAccessReader can be used to access data stored at that attribute family by random access. The data can be either get by pair (key, attribute) or scanned through by a mask (key, attributePrefix) for attributes that are wildcard attributes.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	RandomAccessReader.Factory<T extends RandomAccessReader>	Serializable factory for RandomAccessReader.
static class	RandomAccessReader.GetRequest<T>	A wraper for a get request.
static class	RandomAccessReader.Listing	Type of listing (either listing entities of entity attributes).
static interface	RandomAccessReader.MultiFetch	A facade for fetching multiple KeyValues in single request.

Method Summary

Modifier and Type	Method	Description
RandomAccessReader.Factory<?>	asFactory()	Convert instance of this reader to RandomAccessReader.Factory suitable for serialization.
RandomOffset	fetchOffset(RandomAccessReader.Listing type, java.lang.String key)	Construct Offset from string (representing either key of the entity or attribute).
default <T> java.util.Optional<KeyValue<T>>	get(RandomAccessReader.GetRequest<T> request)	Get single KeyValue using RandomAccessReader.GetRequest.
default <T> java.util.Optional<KeyValue<T>>	get(java.lang.String key, AttributeDescriptor<T> desc)	Retrieve data stored under given (key, attribute) pair (if any).
default <T> java.util.Optional<KeyValue<T>>	get(java.lang.String key, AttributeDescriptor<T> desc, long stamp)	Retrieve data stored under given (key, attribute) pair (if any).
default <T> java.util.Optional<KeyValue<T>>	get(java.lang.String key, java.lang.String attribute, AttributeDescriptor<T> desc)	Retrieve data stored under given (key, attribute) pair (if any).
<T> java.util.Optional<KeyValue<T>>	get(java.lang.String key, java.lang.String attribute, AttributeDescriptor<T> desc, long stamp)	Retrieve data stored under given (key, attribute) pair (if any).
EntityDescriptor	getEntityDescriptor()	Retrieve entity associated with this reader.
default void	listEntities(Consumer<Pair<RandomOffset,java.lang.String>> consumer)	List all entity keys.
void	listEntities(RandomOffset offset, int limit, Consumer<Pair<RandomOffset,java.lang.String>> consumer)	List all entity keys with offset and limit.
default RandomAccessReader.MultiFetch	multiFetch()	Return a facade RandomAccessReader.MultiFetch object that can be used to queue multiple requests to the storage and fetch them at once using RandomAccessReader.MultiFetch.fetch(Consumer).
static MultiAccessBuilder	newBuilder(Repository repo, ContextProvider context)	Create a new builder that is able to construct RandomAccessReader from multiple readers responsible for reading from various attribute families.
default <T> void	scanWildcard(java.lang.String key, AttributeDescriptor<T> wildcard, long stamp, Consumer<KeyValue<T>> consumer)	List data stored for a particular wildcard attribute.
default <T> void	scanWildcard(java.lang.String key, AttributeDescriptor<T> wildcard, Consumer<KeyValue<T>> consumer)	List data stored for a particular wildcard attribute.
default <T> void	scanWildcard(java.lang.String key, AttributeDescriptor<T> wildcard, RandomOffset offset, int limit, Consumer<KeyValue<T>> consumer)	List data stored for a particular wildcard attribute.
<T> void	scanWildcard(java.lang.String key, AttributeDescriptor<T> wildcard, RandomOffset offset, long stamp, int limit, Consumer<KeyValue<T>> consumer)	List data stored for a particular wildcard attribute.
default void	scanWildcardAll(java.lang.String key, long stamp, Consumer<KeyValue<?>> consumer)	Scan all data stored per given key.
default void	scanWildcardAll(java.lang.String key, Consumer<KeyValue<?>> consumer)	Scan all data stored per given key.
default void	scanWildcardAll(java.lang.String key, RandomOffset offset, int limit, Consumer<KeyValue<?>> consumer)	Scan all data stored per given key.
void	scanWildcardAll(java.lang.String key, RandomOffset offset, long stamp, int limit, Consumer<KeyValue<?>> consumer)	Scan all data stored per given key.

Methods inherited from interface java.io.Closeable

close

Method Detail

newBuilder

static MultiAccessBuilder newBuilder(Repository repo,
                                     ContextProvider context)

Create a new builder that is able to construct RandomAccessReader from multiple readers responsible for reading from various attribute families.

Parameters:

repo - the Repository

context - direct translation context provider (e.g. DirectDataOperator)

Returns:

new builder for multi random access reader

fetchOffset

RandomOffset fetchOffset(RandomAccessReader.Listing type,
                         java.lang.String key)

Construct Offset from string (representing either key of the entity or attribute). The returned offset represents the first element that is following the given key, in case of equality.

Parameters:

type - the type of the key

key - the key of entity or attribute

Returns:

offset representation of the key

get

default <T> java.util.Optional<KeyValue<T>> get(java.lang.String key,
                                                AttributeDescriptor<T> desc)

Retrieve data stored under given (key, attribute) pair (if any).

Type Parameters:

T - value type

Parameters:

key - key of the entity

desc - the attribute to search for (not wildcard)

Returns:

optional KeyValue if present

get

default <T> java.util.Optional<KeyValue<T>> get(java.lang.String key,
                                                AttributeDescriptor<T> desc,
                                                long stamp)

Retrieve data stored under given (key, attribute) pair (if any).

Type Parameters:

T - value type

Parameters:

key - key of the entity

desc - the attribute to search for (not wildcard)

stamp - timestamp to relatively to which retrieve the data

Returns:

optional KeyValue if present

get

default <T> java.util.Optional<KeyValue<T>> get(java.lang.String key,
                                                java.lang.String attribute,
                                                AttributeDescriptor<T> desc)

Retrieve data stored under given (key, attribute) pair (if any).

Type Parameters:

T - value type

Parameters:

key - key of the entity

attribute - name of the attribute

desc - the attribute to search for

Returns:

optional KeyValue if present

get

default <T> java.util.Optional<KeyValue<T>> get(RandomAccessReader.GetRequest<T> request)

Get single KeyValue using RandomAccessReader.GetRequest.

Type Parameters:

T - value type

Parameters:

request - the request

Returns:

optional KeyValue if present

get

<T> java.util.Optional<KeyValue<T>> get(java.lang.String key,
                                        java.lang.String attribute,
                                        AttributeDescriptor<T> desc,
                                        long stamp)

Retrieve data stored under given (key, attribute) pair (if any).

Type Parameters:

T - value type

Parameters:

key - key of the entity

attribute - name of the attribute

desc - the attribute to search for

stamp - timestamp to relatively to which retrieve the data

Returns:

optional KeyValue if present

multiFetch

default RandomAccessReader.MultiFetch multiFetch()

Return a facade RandomAccessReader.MultiFetch object that can be used to queue multiple requests to the storage and fetch them at once using RandomAccessReader.MultiFetch.fetch(Consumer).

Returns:

the RandomAccessReader.MultiFetch

scanWildcardAll

default void scanWildcardAll(java.lang.String key,
                             Consumer<KeyValue<?>> consumer)

Scan all data stored per given key.

Parameters:

key - the key whose KeyValues to scan

consumer - consumer to use for scanning

scanWildcardAll

default void scanWildcardAll(java.lang.String key,
                             long stamp,
                             Consumer<KeyValue<?>> consumer)

Scan all data stored per given key.

Parameters:

key - the key whose KeyValues to scan

stamp - timestamp to relatively to which retrieve the data

consumer - consumer to use for scanning

scanWildcardAll

default void scanWildcardAll(java.lang.String key,
                             @Nullable
                             RandomOffset offset,
                             int limit,
                             Consumer<KeyValue<?>> consumer)

Scan all data stored per given key.

Parameters:

key - the key whose KeyValues to scan

offset - offset to start from (next key value will be returned)

limit - how many elements to process at most

consumer - consumer to use for scanning

scanWildcardAll

void scanWildcardAll(java.lang.String key,
                     @Nullable
                     RandomOffset offset,
                     long stamp,
                     int limit,
                     Consumer<KeyValue<?>> consumer)

Scan all data stored per given key.

Parameters:

key - the key whose KeyValues to scan

offset - offset to start from (next key value will be returned)

stamp - timestamp to relatively to which retrieve the data

limit - how many elements to process at most

consumer - consumer to use for scanning

scanWildcard

default <T> void scanWildcard(java.lang.String key,
                              AttributeDescriptor<T> wildcard,
                              Consumer<KeyValue<T>> consumer)

List data stored for a particular wildcard attribute.

Type Parameters:

T - value type

Parameters:

key - key of the entity

wildcard - wildcard attribute to scan

consumer - the consumer to stream data to

scanWildcard

default <T> void scanWildcard(java.lang.String key,
                              AttributeDescriptor<T> wildcard,
                              long stamp,
                              Consumer<KeyValue<T>> consumer)

List data stored for a particular wildcard attribute.

Type Parameters:

T - value type

Parameters:

key - key of the entity

wildcard - wildcard attribute to scan

stamp - timestamp to relatively to which retrieve the data

consumer - the consumer to stream data to

scanWildcard

default <T> void scanWildcard(java.lang.String key,
                              AttributeDescriptor<T> wildcard,
                              @Nullable
                              RandomOffset offset,
                              int limit,
                              Consumer<KeyValue<T>> consumer)

List data stored for a particular wildcard attribute.

Type Parameters:

T - value type

Parameters:

key - key of the entity

wildcard - wildcard attribute to scan

offset - name of attribute (including the prefix) to start from

limit - maximal number of items to consume

consumer - the consumer to stream data to

scanWildcard

<T> void scanWildcard(java.lang.String key,
                      AttributeDescriptor<T> wildcard,
                      @Nullable
                      RandomOffset offset,
                      long stamp,
                      int limit,
                      Consumer<KeyValue<T>> consumer)

List data stored for a particular wildcard attribute.

Type Parameters:

T - value type

Parameters:

key - key of the entity

wildcard - wildcard attribute to scan

offset - name of attribute (including the prefix) to start from

stamp - timestamp to relatively to which retrieve the data

limit - maximal number of items to consume *

consumer - the consumer to stream data to

listEntities

default void listEntities(Consumer<Pair<RandomOffset,java.lang.String>> consumer)

List all entity keys.

Parameters:

consumer - consumer that will receive keys of entities in the random access storage

listEntities

void listEntities(@Nullable
                  RandomOffset offset,
                  int limit,
                  Consumer<Pair<RandomOffset,java.lang.String>> consumer)

List all entity keys with offset and limit.

Parameters:

offset - offset of the entities

limit - limit for number of results

consumer - consumer of results

getEntityDescriptor

EntityDescriptor getEntityDescriptor()

Retrieve entity associated with this reader.

Returns:

entity associated with this reader

asFactory

RandomAccessReader.Factory<?> asFactory()

Convert instance of this reader to RandomAccessReader.Factory suitable for serialization.

Returns:

the RandomAccessReader.Factory representing this reader