Package org.dataloader

Class DataLoaderRegistry

java.lang.Object

org.dataloader.DataLoaderRegistry

Direct Known Subclasses:

ScheduledDataLoaderRegistry

@PublicApi
@NullMarked
public class DataLoaderRegistry
extends java.lang.Object

This allows data loaders to be registered together into a single place, so they can be dispatched as one. It also allows you to retrieve data loaders by name from a central place.

Notes on DataLoaderInstrumentation : A DataLoaderRegistry can have an instrumentation associated with it. As each DataLoader is added to the registry, the DataLoaderInstrumentation of the registry is applied to that DataLoader.

The DataLoader is changed and hence the object in the registry is not the same one as was originally registered. So you MUST get access to the DataLoader via getDataLoader(String) methods and not use the original DataLoader object.

If the DataLoader has no DataLoaderInstrumentation then the registry one is added to it. If it does have one already then a ChainedDataLoaderInstrumentation is created with the registry DataLoaderInstrumentation in it first and then any other DataLoaderInstrumentations added after that. If the registry DataLoaderInstrumentation instance and DataLoader DataLoaderInstrumentation instance are the same object, then nothing is changed, since the same instrumentation code is being run.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DataLoaderRegistry.Builder

Field Summary

Fields

Modifier and Type	Field	Description
protected java.util.Map<java.lang.String,DataLoader<?,?>>	dataLoaders
protected @Nullable DataLoaderInstrumentation	instrumentation

Constructor Summary

Constructors

Modifier	Constructor	Description
	DataLoaderRegistry()
protected	DataLoaderRegistry(java.util.Map<java.lang.String,DataLoader<?,?>> dataLoaders, @Nullable DataLoaderInstrumentation instrumentation)

Method Summary

Modifier and Type	Method	Description
DataLoaderRegistry	combine(DataLoaderRegistry registry)	This will combine all the current data loaders in this registry and all the data loaders from the specified registry and return a new combined registry
<K,V> DataLoader<K,V>	computeIfAbsent(java.lang.String key, java.util.function.Function<java.lang.String,DataLoader<?,?>> mappingFunction)	Computes a data loader if absent or return it if it was already registered at that key.
void	dispatchAll()	This will be called DataLoader.dispatch() on each of the registered DataLoaders
int	dispatchAllWithCount()	Similar to dispatchAll(), this calls DataLoader.dispatch() on each of the registered DataLoaders, but returns the number of dispatches.
int	dispatchDepth()
<K,V> DataLoader<K,V>	getDataLoader(java.lang.String key)	Returns the dataloader that was registered under the specified key
java.util.List<DataLoader<?,?>>	getDataLoaders()
java.util.Map<java.lang.String,DataLoader<?,?>>	getDataLoadersMap()
@Nullable DataLoaderInstrumentation	getInstrumentation()
java.util.Set<java.lang.String>	getKeys()
Statistics	getStatistics()
static DataLoaderRegistry.Builder	newRegistry()
DataLoaderRegistry	register(java.lang.String key, DataLoader<?,?> dataLoader)	This will register a new DataLoader
DataLoaderRegistry	register(DataLoader<?,?> dataLoader)	This will register a new named dataloader.
<K,V> DataLoader<K,V>	registerAndGet(java.lang.String key, DataLoader<?,?> dataLoader)	This will register a new DataLoader and then return it.
DataLoaderRegistry	unregister(java.lang.String key)	This will unregister a new dataloader

Methods inherited from class java.lang.Object

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

Field Detail

dataLoaders

protected final java.util.Map<java.lang.String,DataLoader<?,?>> dataLoaders

instrumentation

protected final @Nullable DataLoaderInstrumentation instrumentation

Constructor Detail

DataLoaderRegistry

public DataLoaderRegistry()

DataLoaderRegistry

protected DataLoaderRegistry(java.util.Map<java.lang.String,DataLoader<?,?>> dataLoaders,
                             @Nullable DataLoaderInstrumentation instrumentation)

Method Detail

getInstrumentation

public @Nullable DataLoaderInstrumentation getInstrumentation()

Returns:

the DataLoaderInstrumentation associated with this registry which can be null

register

public DataLoaderRegistry register(DataLoader<?,?> dataLoader)

This will register a new named dataloader. The DataLoader must be named something and cannot have a null name.

Note: Registration can change the data loader instance since it might get an DataLoaderInstrumentation applied to it. So the DataLoader instance your read via getDataLoader(String) might not be the same object that was registered.

Parameters:

dataLoader - the named data loader to register

Returns:

this registry

register

public DataLoaderRegistry register(java.lang.String key,
                                   DataLoader<?,?> dataLoader)

This will register a new DataLoader

Note: Registration can change the data loader instance since it might get an DataLoaderInstrumentation applied to it. So the DataLoader instance your read via getDataLoader(String) might not be the same object that was registered.

Parameters:

key - the key to put the data loader under

dataLoader - the data loader to register

Returns:

this registry

registerAndGet

public <K,V> DataLoader<K,V> registerAndGet(java.lang.String key,
                                                        DataLoader<?,?> dataLoader)

This will register a new DataLoader and then return it.

Note: Registration can change the data loader instance since it might get an DataLoaderInstrumentation applied to it. So the DataLoader instance your read via getDataLoader(String) might not be the same object that was registered.

Parameters:

key - the key to put the data loader under

dataLoader - the data loader to register

Returns:

the data loader instance that was registered

computeIfAbsent

public <K,V> DataLoader<K,V> computeIfAbsent(java.lang.String key,
                                                         java.util.function.Function<java.lang.String,DataLoader<?,?>> mappingFunction)

Computes a data loader if absent or return it if it was already registered at that key.

Note: The entire method invocation is performed atomically, so the function is applied at most once per key.

Note: Registration can change the data loader instance since it might get an DataLoaderInstrumentation applied to it. So the DataLoader instance your read via getDataLoader(String) might not be the same object that was registered.

Type Parameters:

K - the type of keys

V - the type of values

Parameters:

key - the key of the data loader

mappingFunction - the function to compute a data loader

Returns:

a data loader

combine

public DataLoaderRegistry combine(DataLoaderRegistry registry)

This will combine all the current data loaders in this registry and all the data loaders from the specified registry and return a new combined registry

Parameters:

registry - the registry to combine into this registry

Returns:

a new combined registry

getDataLoaders

public java.util.List<DataLoader<?,?>> getDataLoaders()

Returns:

the currently registered data loaders

getDataLoadersMap

public java.util.Map<java.lang.String,DataLoader<?,?>> getDataLoadersMap()

Returns:

the currently registered data loaders as a map

unregister

public DataLoaderRegistry unregister(java.lang.String key)

This will unregister a new dataloader

Parameters:

key - the key of the data loader to unregister

Returns:

this registry

getDataLoader

public <K,V> DataLoader<K,V> getDataLoader(java.lang.String key)

Returns the dataloader that was registered under the specified key

Type Parameters:

K - the type of keys

V - the type of values

Parameters:

key - the key of the data loader

Returns:

a data loader or null if its not present

getKeys

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

Returns:

the keys of the data loaders in this registry

dispatchAll

public void dispatchAll()

This will be called DataLoader.dispatch() on each of the registered DataLoaders

dispatchAllWithCount

public int dispatchAllWithCount()

Similar to dispatchAll(), this calls DataLoader.dispatch() on each of the registered DataLoaders, but returns the number of dispatches.

Returns:

total number of entries that were dispatched from registered DataLoaders.

dispatchDepth

public int dispatchDepth()

Returns:

The sum of all batched key loads that need to be dispatched from all registered DataLoaders

getStatistics

public Statistics getStatistics()

Returns:

a combined set of statistics for all data loaders in this registry presented as the sum of all their statistics

newRegistry

public static DataLoaderRegistry.Builder newRegistry()

Returns:

A builder of DataLoaderRegistrys