Add prettier

- At least one of the following input data shall be provided:

  - a. selector of Entity Types;

  - b. list of Attribute names, including at least one non-system Attribute;

  - c. NGSI-LD Query, including at least one non-system Attribute;

  - d. NGSI-LD GeoQuery;

  - e. local scope (see clause 8.6).

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  a. selector of Entity Types;

  b. list of Attribute names, including at least one non-system Attribute;

  c. NGSI-LD Query, including at least one non-system Attribute;

  d. NGSI-LD GeoQuery;

  e. local scope (see clause 8.6).

<!-- prettier-ignore-end -->

- If none of the above is provided, then an error of type

  [BadRequestData]{.HTML-Error}

- At least one of the following input data shall be provided:

  - a. selector of Entity Types;

  - b. list of Attribute names, including at least one non-system Attribute;

  - c. NGSI-LD Query, including at least one non-system Attribute;

  - d. NGSI-LD GeoQuery;

  - e. local scope (see clause 8.6).

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  a. selector of Entity Types;

  b. list of Attribute names, including at least one non-system Attribute;

  c. NGSI-LD Query, including at least one non-system Attribute;

  d. NGSI-LD GeoQuery;

  e. local scope (see clause 8.6).

<!-- prettier-ignore-end -->

- If none of the above is provided, then an error of type

  [BadRequestData]{.HTML-Error}

  validation.

- At least one of the following input data shall be provided:

  - a. selector of Entity Types;

  - b. list of Attribute names;

  - c. NGSI-LD Query;

  - d. NGSI-LD GeoQuery.

<!-- prettier-ignore-start -->

  a. selector of Entity Types;

  b. list of Attribute names;

  c. NGSI-LD Query;

  d. NGSI-LD GeoQuery.

<!-- prettier-ignore-edn -->

- If none of them is provided, then an error of type

  [BadRequestData]{.HTML-Error} with a _list of Attribute names_

### 14.5.4 Behaviour

- At least one of the following input data shall be provided:

  - a. selector of Entity Types;

  - b. list of Attribute names, including at least one non-system Attribute;

  - c. NGSI-LD Query, including at least one non-system Attribute;

  - d. NGSI-LD GeoQuery;

  - e. local scope (see Clause+++clause-8+++root.6). If none of the above is

    provided, then an error of type [BadRequestData]{.HTML-Error}

<!-- prettier-ignore-start -->

  a. selector of Entity Types;

  b. list of Attribute names, including at least one non-system Attribute;

  c. NGSI-LD Query, including at least one non-system Attribute;

  d. NGSI-LD GeoQuery;

  e. local scope (see Clause+++clause-8+++root.6).

  If none of the above is provided, then an error of type [BadRequestData]{.HTML-Error}

<!-- prettier-ignore-start -->

- If the list of Entity identifiers includes a URI which it is not valid, or the

  query, geoquery or context source filter are not syntactically valid (as per

  the referred Clause+++clause-7+++root.2.3 and Clause+++clause-7+++root.2.4) an

- If a temporal query is not provided then an error of type

  [BadRequestData]{.HTML-Error} shall be raised.

- At least one of the following input data shall be provided:

  - a. selector of Entity Types;

  - b. list of Attribute names, including at least one non-system Attribute;

  - c. NGSI-LD Query, including at least one non-system Attribute;

  - d. NGSI-LD GeoQuery;

  - e. local scope (see Clause+++clause-8+++root.6). If none of the above is

<!-- prettier-ignore-start -->

  a. selector of Entity Types;

  b. list of Attribute names, including at least one non-system Attribute;

  c. NGSI-LD Query, including at least one non-system Attribute;

  d. NGSI-LD GeoQuery;

  e. local scope (see Clause+++clause-8+++root.6). If none of the above is

     provided, then an error of type [BadRequestData]{.HTML-Error}.

<!-- prettier-ignore-end -->

- If projection attributes or filter conditions indicate the use of [Linked

  Entity]{.HTML-Keyboard} retrieval, an error of type

  [BadRequestData]{.HTML-Error} shall be raised.

Scope /Madrid/Gardens and the whole scope tree below:

``` json

```text

/Madrid/Gardens/#,

/Madrid/Gardens, /Madrid/Gardens/ParqueNorte, /Madrid/Gardens/ParqueNorte/Parterre1, /Madrid/Gardens/ParqueSur

```

For the endpoints served, all registered [Context Sources]{.HTML-Keyboard} shall

support the normalized representation of Entities as default. Support of

additional representation formats is optional and will depend on the

implementation. System generated attributes such as _`modifiedAt`_

and _`createdAt`_ (see Clause+++clause-5+++5.2.4) should be

supported by registered [Context Sources]{.HTML-Keyboard}, at a minimum no error

shall be returned if they are not available when requested.

implementation. System generated attributes such as _`modifiedAt`_ and

_`createdAt`_ (see Clause+++clause-5+++5.2.4) should be supported by registered

[Context Sources]{.HTML-Keyboard}, at a minimum no error shall be returned if

they are not available when requested.

## 9.2 Distributed operation names

An **auxiliary** [Context Source Registration]{.HTML-Keyboard} never overrides

data held directly within a [Context Broker]{.HTML-Keyboard}. Auxiliary

distributed operations are limited to context information consumption operations

(see Clause+++clause-10+++10.4). Context data from auxiliary [Context Sources]{.HTML-Keyboard} is

only included if it is supplementary to the context data otherwise available to

the [Context Broker]{.HTML-Keyboard}. Auxiliary [Context Source

Registrations]{.HTML-Keyboard} are always accepted as there can never be a

conflict.

(see Clause+++clause-10+++10.4). Context data from auxiliary [Context

Sources]{.HTML-Keyboard} is only included if it is supplementary to the context

data otherwise available to the [Context Broker]{.HTML-Keyboard}. Auxiliary

[Context Source Registrations]{.HTML-Keyboard} are always accepted as there can

never be a conflict.

### 9.3.3 Proxied registrations

the list of Entity identifiers (if present), the id pattern (if present) and the

list of Attribute names (if present). In the case of subscriptions to [Context

Source Registrations]{.HTML-Keyboard}, it is the Entities as specified in the

array of type _EntitySelector_ in the Subscription, the

_`watchedAttributes`_ element of the Subscription and the attributes specified

as part of the _NotificationParams_ element of the Subscription.

If the attributes in the _NotificationParams_ element are empty

or not present, the matching is done as if no attribute identifiers have been

specified, otherwise the combination of the _`watchedAttributes`_ and the

attributes in the _NotificationParams_ element are used as the

specified attribute identifiers for the matching.

array of type _EntitySelector_ in the Subscription, the _`watchedAttributes`_

element of the Subscription and the attributes specified as part of the

_NotificationParams_ element of the Subscription. If the attributes in the

_NotificationParams_ element are empty or not present, the matching is done as

if no attribute identifiers have been specified, otherwise the combination of

the _`watchedAttributes`_ and the attributes in the _NotificationParams_ element

are used as the specified attribute identifiers for the matching.

Even though the way relevant Entities are specified differs in queries and

subscriptions, they consist of the same information, so for the purpose of this

Attribute names. A specification of Entity Types or Attributes shall contain at

least one of:

- a. selector of Entity Types

- b. list of Attribute names.

<!-- prettier-ignore-start -->

a. selector of Entity Types

b. list of Attribute names.

<!-- prettier-ignore-end -->

A specification of Entity Types or Attributes matches a [Context Source

Registration]{.HTML-Keyboard} if at least one of the _RegistrationInfo_ elements

previously encountered [Context Sources]{.HTML-Keyboard}.

Note that distributed queries (see Clause+++clause-9+++9.6), can be supplied

with an _EntityMap_ (see Clause+++clause-5+++5.2.6.5.5) which lists all Entity ids

successfully matched during a previous request. If the location of an [Entity Map]{.HTML-Keyboard}

is passed into a subsequent request, the retrieved [Entity Map]{.HTML-Keyboard} shall be used in

preference to the matching algorithm described above, provided that the

[Entity Map]{.HTML-Keyboard} is valid and has not expired.

with an _EntityMap_ (see Clause+++clause-5+++5.2.6.5.5) which lists all Entity

ids successfully matched during a previous request. If the location of an

[Entity Map]{.HTML-Keyboard} is passed into a subsequent request, the retrieved

[Entity Map]{.HTML-Keyboard} shall be used in preference to the matching

algorithm described above, provided that the [Entity Map]{.HTML-Keyboard} is

valid and has not expired.

## 9.5 Contacting Context Sources

In the case that a client wishes to indicate to a [Context

Broker]{.HTML-Keyboard} that a request is part of a unitary sequence of

requests, the [Context Broker]{.HTML-Keyboard} shall create and cache an

[Entity Map]{.HTML-Keyboard} for future use and should return the location of said [Entity Map]{.HTML-Keyboard} in a

specific field. The caching strategy and expiry time shall take into account a

suggested expiry time, if present, and depend on implementation specific

configurations. [Context Sources]{.HTML-Keyboard} should indicate that they do

not support [Entity Maps]{.HTML-Keyboard}, through declining to return the location of an [Entity Map]{.HTML-Keyboard}

when requested to do so.

requests, the [Context Broker]{.HTML-Keyboard} shall create and cache an [Entity

Map]{.HTML-Keyboard} for future use and should return the location of said

[Entity Map]{.HTML-Keyboard} in a specific field. The caching strategy and

expiry time shall take into account a suggested expiry time, if present, and

depend on implementation specific configurations. [Context

Sources]{.HTML-Keyboard} should indicate that they do not support [Entity

Maps]{.HTML-Keyboard}, through declining to return the location of an [Entity

Map]{.HTML-Keyboard} when requested to do so.

This Entity mapping is an internal operation, not usually exposed to the end

user, however it is necessary to explicitly define a consistent mechanism for

Entity map creation, caching and retrieval.

A specific field pointing to the location of a cached [Entity Map]{.HTML-Keyboard} (e.g. a custom

header in the response in case of HTTP binding, see [i.24] ~table 7.2.3.1-2)

shall be returned within the response of a query, whenever this is requested by

the client. Similarly, the reuse of a previously created [Entity Map]{.HTML-Keyboard} can be

requested by passing the same specific field into a request.

If a subsequent request references an existent [Entity Map]{.HTML-Keyboard}, it shall be used for

the purposes of Entity registration matching, and queries shall be filtered to

only consider the Entities listed. Subsequent requests referencing an [Entity Map]{.HTML-Keyboard}

shall use the same parameters as in the original request that created the

[Entity Map]{.HTML-Keyboard}, except for the specification of Entity identifiers or parameters

related to pagination, or, in the case of temporal requests, the temporal query.

If an [Entity Map]{.HTML-Keyboard} has expired, or cannot be accessed, no inference can be made as

to which entities are held within the [Context Sources]{.HTML-Keyboard} and a

new one shall be created. An [Entity Map]{.HTML-Keyboard} fixes the Entities to be considered for

subsequent requests based on it. The creating [Context Source]{.HTML-Keyboard}

shall remove Entities from the [Entity Map]{.HTML-Keyboard} that do not match the filters of the

query at the time of processing. Other components shall only be allowed to

update the expiry timestamp of the [Entity Map]{.HTML-Keyboard}, which can optionally be extended

A specific field pointing to the location of a cached [Entity

Map]{.HTML-Keyboard} (e.g. a custom header in the response in case of HTTP

binding, see [i.24] ~table 7.2.3.1-2) shall be returned within the response of a

query, whenever this is requested by the client. Similarly, the reuse of a

previously created [Entity Map]{.HTML-Keyboard} can be requested by passing the

same specific field into a request.

If a subsequent request references an existent [Entity Map]{.HTML-Keyboard}, it

shall be used for the purposes of Entity registration matching, and queries

shall be filtered to only consider the Entities listed. Subsequent requests

referencing an [Entity Map]{.HTML-Keyboard} shall use the same parameters as in

the original request that created the [Entity Map]{.HTML-Keyboard}, except for

the specification of Entity identifiers or parameters related to pagination, or,

in the case of temporal requests, the temporal query. If an [Entity

Map]{.HTML-Keyboard} has expired, or cannot be accessed, no inference can be

made as to which entities are held within the [Context Sources]{.HTML-Keyboard}

and a new one shall be created. An [Entity Map]{.HTML-Keyboard} fixes the

Entities to be considered for subsequent requests based on it. The creating

[Context Source]{.HTML-Keyboard} shall remove Entities from the [Entity

Map]{.HTML-Keyboard} that do not match the filters of the query at the time of

processing. Other components shall only be allowed to update the expiry

timestamp of the [Entity Map]{.HTML-Keyboard}, which can optionally be extended

if the [Context Sources]{.HTML-Keyboard} implementation allows for it.

Since an **exclusive** [Context Source Registration]{.HTML-Keyboard} already

this parameter, so deployments where no split Entities are to be expected can

filter locally and thus be more efficient.

In the case of split Entities, [Entity Maps]{.HTML-Keyboard} initially only store "candidate

Entities" as no filters could be applied, because only a part of the Entity was

available. In the process of pagination, the filters will be (re-)checked. Any

Entity not (or no longer) fulfilling the filter shall be removed from the

[Entity Map]{.HTML-Keyboard}.

In the case of split Entities, [Entity Maps]{.HTML-Keyboard} initially only

store "candidate Entities" as no filters could be applied, because only a part

of the Entity was available. In the process of pagination, the filters will be

(re-)checked. Any Entity not (or no longer) fulfilling the filter shall be

removed from the [Entity Map]{.HTML-Keyboard}.

## 9.7 Limiting cascading distributed operations