de.otto.synapse.state

Class ConcurrentMapStateRepository<V>

java.lang.Object

de.otto.synapse.state.ConcurrentMapStateRepository<V>

All Implemented Interfaces:

StateRepository<V>, java.lang.AutoCloseable

Direct Known Subclasses:

ChronicleMapStateRepository

public class ConcurrentMapStateRepository<V>
extends java.lang.Object
implements StateRepository<V>

Constructor Summary

Constructors

Constructor and Description
ConcurrentMapStateRepository(java.lang.String name) Creates a StateRepository with the given name, that is using a ConcurrentHashMap to store event-sourced entities.
ConcurrentMapStateRepository(java.lang.String name, java.util.concurrent.ConcurrentMap<java.lang.String,V> map) Creates a StateRepository with the given name, that is using the given ConcurrentMap to store event-sourced entities.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all of the mappings from this repository (optional operation).
void	close() Closes the StateRepository.
java.util.Optional<V>	compute(java.lang.String key, java.util.function.BiFunction<? super java.lang.String,? super java.util.Optional<V>,? extends V> remappingFunction) Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).
void	consumeAll(java.util.function.BiConsumer<? super java.lang.String,? super V> consumer) Computes each entry within the repository.
java.util.Optional<V>	get(java.lang.String key) Returns the optional value to which the specified key is mapped, or Optional.empty() if this repository contains no mapping for the key.
java.lang.String	getName() The unique name of the StateRepository.
java.util.Set<java.lang.String>	keySet() Returns an immutable set of the keys in this repository.
java.util.Optional<V>	put(java.lang.String key, V value) Associates the specified value with the specified key in this repository.
java.util.Optional<V>	remove(java.lang.String key) Removes the mapping for a key from this repository if it is present.
long	size() Returns the number of key-value mappings in this repository.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConcurrentMapStateRepository

public ConcurrentMapStateRepository(java.lang.String name)

Creates a StateRepository with the given name, that is using a ConcurrentHashMap to store event-sourced entities.

Parameters:

name - the name of the repository.

ConcurrentMapStateRepository

public ConcurrentMapStateRepository(java.lang.String name,
                                    java.util.concurrent.ConcurrentMap<java.lang.String,V> map)

Creates a StateRepository with the given name, that is using the given ConcurrentMap to store event-sourced entities.

Usable to create StateRepository instances from ConcurrentMap implementations like, for example, ChronicleMap

Parameters:

name - the name of the repository.

map - the delegate map used to store the entity state

Method Detail

getName

public java.lang.String getName()

Description copied from interface: StateRepository

The unique name of the StateRepository.

Using the same name for multiple repositories will lead to

Specified by:

getName in interface StateRepository<V>

Returns:

name

compute

public java.util.Optional<V> compute(java.lang.String key,
                                     java.util.function.BiFunction<? super java.lang.String,? super java.util.Optional<V>,? extends V> remappingFunction)

Description copied from interface: StateRepository

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). For example, to either create or append a String msg to a value mapping:

 
 repository.compute(key, (k, v) -> (v == null) ? msg : v.concat(msg))

If the function returns null, the mapping is removed (or remains absent if initially absent). If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

The default implementation is equivalent to performing the following steps for this repository, then returning the current value or null if absent:

 
 OptionalV> oldValue = repository.get(key);
 V newValue = remappingFunction.apply(key, oldValue);
 if (!oldValue.isEmpty()) {
    if (newValue != null)
       repository.put(key, newValue);
    else
       repository.remove(key);
 } else {
    if (newValue != null)
       repository.put(key, newValue);
    else
       return Optional.empty();
 }
 

Specified by:

compute in interface StateRepository<V>

Parameters:

key - key with which the specified value is to be associated

remappingFunction - the function to compute a value

Returns:

the Optional containing the new value associated with the specified key, or Optional.empty() if none

consumeAll

public void consumeAll(java.util.function.BiConsumer<? super java.lang.String,? super V> consumer)

Description copied from interface: StateRepository

Computes each entry within the repository.

Specified by:

consumeAll in interface StateRepository<V>

Parameters:

consumer - the consumer that will be applied on each repository entry

put

public java.util.Optional<V> put(java.lang.String key,
                                 V value)

Description copied from interface: StateRepository

Associates the specified value with the specified key in this repository. If the repository previously contained a mapping for the key, the old value is replaced by the specified value. (A repository m is said to contain a mapping for a key k if and only if m.get(k) would return a non-empty value.)

Specified by:

put in interface StateRepository<V>

Parameters:

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

the previous value associated with key, or Optional.empty() if there was no mapping for key.

remove

public java.util.Optional<V> remove(java.lang.String key)

Description copied from interface: StateRepository

Removes the mapping for a key from this repository if it is present. More formally, if this repository contains a mapping from key k to value v such that (key==null ? k==null : key.equals(k)), that mapping is removed. (The repository can contain at most one such mapping.)

Returns the optional value to which this repository previously associated the key, or Optional.empty() if the repository contained no mapping for the key.

The repository will not contain a mapping for the specified key once the call returns.

Specified by:

remove in interface StateRepository<V>

Parameters:

key - key whose mapping is to be removed from the repository

Returns:

the optional previous value associated with key, or Optional.empty() if there was no mapping for key.

clear

public void clear()

Description copied from interface: StateRepository

Removes all of the mappings from this repository (optional operation). The repository will be empty after this call returns.

Specified by:

clear in interface StateRepository<V>

get

public java.util.Optional<V> get(java.lang.String key)

Description copied from interface: StateRepository

Returns the optional value to which the specified key is mapped, or Optional.empty() if this repository contains no mapping for the key.

More formally, if this repository contains a mapping from a key k to a value v such that (key==null ? k==null : key.equals(k)), then this method returns Optional.of(v); otherwise it returns Optional.empty(). (There can be at most one such mapping.)

Specified by:

get in interface StateRepository<V>

Parameters:

key - the key whose associated value is to be returned

Returns:

the Optional containing the value to which the specified key is mapped, or Optional.empty() if this repository contains no mapping for the key

keySet

public java.util.Set<java.lang.String> keySet()

Description copied from interface: StateRepository

Returns an immutable set of the keys in this repository.

Specified by:

keySet in interface StateRepository<V>

Returns:

a set view of the keys contained in this repository

size

public long size()

Description copied from interface: StateRepository

Returns the number of key-value mappings in this repository. If the repository contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface StateRepository<V>

Returns:

the number of key-value mappings in this repository

close

public void close()
           throws java.lang.Exception

Description copied from interface: StateRepository

Closes the StateRepository.

Depending on the implementation of the interface, it might be required to close() the repository on shutdown in order to prevent data loss.

Specified by:

close in interface StateRepository<V>

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.lang.Exception - if closing the repository fails for some reason.