Package org.anchoranalysis.core.identifier.provider

Class NamedProviderCombine<T>

Object

NamedProviderCombine<T>

Type Parameters:

T - element-type

All Implemented Interfaces:

NamedProvider<T>

public class NamedProviderCombine<T>
extends Object
implements NamedProvider<T>

Combines one more NamedProviders into a unitary NamedProvider.

Queries are applied sequentially to each NamedProvider until successful.

All keys from all underlying NamedProviders are valid, but maximally one entry will be returned for a corresponding key, as first encountered during iteration.

Author:

Owen Feehan

Constructor Summary

Constructors

Constructor	Description
NamedProviderCombine(Stream<NamedProvider<T>> stream)	Create from a stream of NamedProviders.

Method Summary

Modifier and Type	Method	Description
Optional<T>	getOptional(String key)	Retrieves the item if it exists, or returns Optional.empty() if it doesn't exist.
Set<String>	keys()	Returns a set of keys associated with the provider.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.anchoranalysis.core.identifier.provider.NamedProvider

getArbitraryElement, getException, isEmpty

Constructor Details

NamedProviderCombine

public NamedProviderCombine(Stream<NamedProvider<T>> stream)

Create from a stream of NamedProviders.

Note that the order of this stream, determines the order in which queries occur.

Parameters:

stream - the stream

Method Details

getOptional

public Optional<T> getOptional(String key)
                        throws NamedProviderGetException

Description copied from interface: NamedProvider

Retrieves the item if it exists, or returns Optional.empty() if it doesn't exist.

Note that a 'key' might still throw an exception for another reason (but never because a particular key is absent).

Specified by:

getOptional in interface NamedProvider<T>

Parameters:

key - a unique name for the item.

Returns:

the item, if it exists, otherwise Optional.empty().

Throws:

NamedProviderGetException - if no item exists for identifier.

keys

public Set<String> keys()

Description copied from interface: NamedProvider

Returns a set of keys associated with the provider.

There's no guarantee that it refers to all valid keys.

Specified by:

keys in interface NamedProvider<T>

Returns:

a set of all keys associated with the provider.