Usage
Signature:
final class ListDataProviderView<K, D, Kin, Din> implements DataProvider<K, D>
Generic Parameters
Parameter Description K Type of output key D Type of output data Kin Type of input key Din Type of input data
Typescript Import Format
//This class is exported directly as module. To import it
import ListDataProviderView= require("ojs/ojlistdataproviderview");
For additional information visit:
Final classes in JET
Classes in JET are generally final and do not support subclassing. At the moment, final is not enforced. However, this will likely change in an upcoming JET release.
Constructor
new ListDataProviderView(dataProvider, options)
Parameters:
Name | Type | Argument | Description |
---|---|---|---|
dataProvider |
DataProvider.<Kin, Din> | the DataProvider. | |
options |
ListDataProviderView.Options.<K, D, Kin, Din> |
<optional> |
Options for the ListDataProviderView |
Fields
-
(nullable) attributes :Array.<(string|FetchAttribute)>
-
Optional fetch attributes to apply. Used to set on the ListDataProviderView instance instead of through the constructor.
- Since:
- 4.1.0
Example
dataprovider.attributes = ['!lastName', '@default']; // all attributes except lastName
-
(nullable) dataMapping :DataMapping.<K, D, Kin, Din>
-
Optional dataMapping to apply. Used to set on the ListDataProviderView instance instead of through the constructor.
- Since:
- 4.1.0
Example
dataprovider.dataMapping = function (item) { let data = item.data; let mappedItem = {}; mappedItem.data = {}; mappedItem.data.label = data.name; mappedItem.data.value = data.id; mappedItem.metadata = { key: data.id }; return mappedItem; };
-
(nullable) filterCriterion :DataFilter.Filter.<D>
-
Optional filter criterion to apply. Used to set on the ListDataProviderView instance instead of through the constructor.
- Since:
- 7.0.0
Example
let filterDef = {op: '$or', criteria: [{op: '$eq', value: {name: 'Bob'}}, {op: '$gt', value: {level: 'Low'}}]}; dataprovider.filterCriterion = FilterFactory.getFilter({filterDef}); // create a standard filter using the filterFactory.
-
(nullable) from :Kin
-
Optional key to start fetching from. Used to set on the ListDataProviderView instance instead of through the constructor.
- Since:
- 4.1.0
Example
dataprovider.from = '1234';
-
(nullable) offset :number
-
Optional offset to start fetching from. Used to set on the ListDataProviderView instance instead of through the constructor.. Should be greater than or equal to zero. If a negative offset is used then it will be treated as zero.
- Since:
- 4.1.0
Example
dataprovider.offset = 5;
-
(nullable) sortCriteria :Array.<SortCriterion.<D>>
-
Optional sortCriteria to apply. Used to set on the ListDataProviderView instance instead of through the constructor.
- Since:
- 4.1.0
Example
dataprovider.sortCriteria = [{attribute: 'DepartmentName', direction: 'ascending'}];
Methods
-
addEventListener(eventType: string, listener: EventListener): void
-
Add a callback function to listen for a specific event type.
Parameters:
Name Type Description eventType
string The event type to listen for. listener
EventListener The callback function that receives the event notification. -
containsKeys(parameters : FetchByKeysParameters<K>) : Promise<ContainsKeysResults<K>>
-
Check if there are rows containing the specified keys. The resulting key map will only contain keys which were actually found.
Parameters:
Name Type Description parameters
FetchByKeysParameters contains by key parameters - Since:
- 4.2.0
Returns:
Returns Promise which resolves to ContainsKeysResults.
- Type
- Promise.<ContainsKeysResults>
Example
let keySet = new Set(); keySet.add(1001); keySet.add(556); let value = await dataprovider.containsKeys({keys: keySet}); let results = value['results']; if (results.has(1001)) { console.log('Has key 1001'); } else if (results.has(556)) { console.log('Has key 556'); }
-
dispatchEvent(evt: Event): boolean
-
Dispatch an event and invoke any registered listeners.
Parameters:
Name Type Description event
Event The event object to dispatch. Returns:
Return false if a registered listener has cancelled the event. Return true otherwise.
- Type
- boolean
-
fetchByKeys(parameters : FetchByKeysParameters<K>) : Promise<FetchByKeysResults<K, D>>
-
Fetch rows by keys. The resulting key map will only contain keys which were actually found. Fetch can be aborted if an AbortSignal is specified when calling fetchByKeys.
Parameters:
Name Type Description parameters
FetchByKeysParameters fetch by key parameters - Since:
- 4.2.0
Returns:
Returns Promise which resolves to FetchByKeysResults.
- Type
- Promise.<FetchByKeysResults>
Examples
let keySet = new Set(); keySet.add(1001); keySet.add(556); let value = await dataprovider.fetchByKeys({keys: keySet}); // get the data for key 1001 console.log(value.results.get(1001).data);
// abort on an AbortController instance will abort all requests that are associated // with the signal from that abortController. const abortController = new AbortController(); let keySet = new Set(); keySet.add(1001); keySet.add(556); // component passes AbortSignal as part of FetchByKeysParameters to fetchByKeys // on dataProvider try { let value = await dataprovider.fetchByKeys({keys: keySet, signal: abortController.signal}); } catch (err) { // if the data fetch has been aborted, retrieving data from the fetched result // will be rejected with DOMException named AbortError if (err.severity === 'info') { // if the data fetch has been aborted from a jet component as a performance concern, an AbortReason will be provided. console.log(err.message); } } // later when abort is desired, component can invoke abort() on the cached // abort controller to abort any outstanding data retrieval it requested // on asyncIterator. if (abort_is_desired) { abortController.abort(); }
-
fetchByOffset(parameters: FetchByOffsetParameters<D>): Promise<FetchByOffsetResults<K, D>>
-
Fetch rows by offset. Fetch can be aborted if an AbortSignal is specified when calling fetchByOffset.
A generic implementation of this method is available from FetchByOffsetMixin. It is for convenience and may not provide the most efficient implementation for your data provider. Classes that implement the DataProvider interface are encouraged to provide a more efficient implementation.
Parameters:
Name Type Description parameters
FetchByOffsetParameters fetch by offset parameters. If an unsupported matchBy value is included in FetchByOffsetParameters, an error will be thrown. - Since:
- 4.2.0
Returns:
Returns Promise which resolves to FetchByOffsetResults.
- Type
- Promise.<FetchByOffsetResults>
Examples
let result = await dataprovider.fetchByOffset({size: 5, offset: 2}); let results = result['results']; let data = results.map(function(value) { return value['data']; }); let keys = results.map(function(value) { return value['metadata']['key']; });
// abort on an AbortController instance will abort all requests that are associated // with the signal from that abortController. const abortController = new AbortController(); // component passes AbortSignal as part of FetchByOffsetParameters to fetchByOffset // on dataProvider try { let value = await dataprovider.fetchByOffset({ size: 5, offset: 2, signal: abortController.signal }); } catch (err) { // if the data fetch has been aborted, retrieving data from the fetched result // will be rejected with DOMException named AbortError if (err.severity === 'info') { // if the data fetch has been aborted from a jet component as a performance concern, an AbortReason will be provided. console.log(err.message); } } // later when abort is desired, component can invoke abort() on the cached // abort controller to abort any outstanding data retrieval it requested // on asyncIterator. if (abort_is_desired) { abortController.abort(); }
-
fetchFirst(parameters?: FetchListParameters<D>): AsyncIterable<FetchListResult<K, D>>
-
Get an AsyncIterable object for iterating the data.
AsyncIterable contains a Symbol.asyncIterator method that returns an AsyncIterator. AsyncIterator contains a “next” method for fetching the next block of data.
The "next" method returns a promise that resolves to an object, which contains a "value" property for the data and a "done" property that is set to true when there is no more data to be fetched. The "done" property should be set to true only if there is no "value" in the result. Note that "done" only reflects whether the iterator is done at the time "next" is called. Future calls to "next" may or may not return more rows for a mutable data source.
Please see the DataProvider documentation for more information on custom implementations.
Parameters:
Name Type Argument Description params
FetchListParameters <optional>
fetch parameters - See:
-
- https://github.com/tc39/proposal-async-iteration for further information on AsyncIterable.
Returns:
AsyncIterable with FetchListResult
- Type
- AsyncIterable.<FetchListResult>
Example
let asyncIterator = dataprovider.fetchFirst(options)[Symbol.asyncIterator](); let result = await asyncIterator.next(); let value = result.value; let data = value.data; let keys = value.metadata.map(function(val) { return val.key; }); // true or false for done let done = result.done;
-
getCapability(capabilityName: string): any
-
Determines whether this DataProvider defines a certain feature.
Parameters:
Name Type Description capabilityName
string capability name. Defined capability names are: "dedup", "eventFiltering", "fetchByKeys", "fetchByOffset", "fetchCapability", "fetchFirst", "filter", and "sort". - Since:
- 4.2.0
Returns:
capability information or null if undefined
- If capabilityName is "dedup", returns a DedupCapability object.
- If capabilityName is "eventFiltering", returns a EventFilteringCapability object.
- If capabilityName is "fetchByKeys", returns a FetchByKeysCapability object.
- If capabilityName is "fetchByOffset", returns a FetchByOffsetCapability object.
- If capabilityName is "fetchCapability", returns a FetchCapability object. (Deprecated since 10.0.0. Use specific fetch capabilityName (fetchByKeys/fetchByOffset/fetchFirst) instead.)
- If capabilityName is "fetchFirst", returns a FetchFirstCapability object.
- If capabilityName is "filter", returns a FilterCapability object.
- If capabilityName is "sort", returns a SortCapability object.
- Type
- Object
Example
let capabilityInfo = dataprovider.getCapability('fetchByKeys'); if (capabilityInfo.implementation == 'iteration') { // the DataProvider supports iteration for fetchByKeys ...
-
getTotalSize : {Promise.<number>}
-
Return the total number of rows in this dataprovider
Returns:
Returns a Promise which resolves to the total number of rows. -1 is unknown row count.
- Type
- Promise.<number>
Example
let value = await dataprovider.getTotalSize(); if (value === -1) { // we don't know the total row count } else { // the total count console.log(value); }
-
isEmpty(): 'yes' | 'no' | 'unknown'
-
Returns a string that indicates if this data provider is empty. Valid values are:
- "yes": this data provider is empty.
- "no": this data provider is not empty.
- "unknown": it is not known if this data provider is empty until a fetch is made.
- Since:
- 4.2.0
Returns:
string that indicates if this data provider is empty
- Type
- "yes" | "no" | "unknown"
Example
let isEmpty = dataprovider.isEmpty(); console.log('DataProvider is empty: ' + isEmpty);
-
removeEventListener(eventType: string, listener: EventListener): void
-
Remove a listener previously registered with addEventListener.
Parameters:
Name Type Description eventType
string The event type that the listener was registered for. listener
EventListener The callback function that was registered.
Type Definitions
-
Options<K, D, Kin, Din>
-
Properties:
Name Type Argument Description attributes
Array<string | FetchAttribute> <optional>
fetch attributes to apply dataMapping
DataMapping.<K, D, Kin, Din> <optional>
mapping to apply to the data. filterCriterion
DataFilter.Filter<D>= <optional>
filter criterion to apply. If the DataProvider does not support filtering then ListDataProviderView will do local filtering of the data. from
Kin= <optional>
key to start fetching from. This will be applied first before offset is applied. offset
number= <optional>
offset to start fetching from. sortCriteria
Array.<SortCriterion.<D>> <optional>
SortCriterion to apply to the data.