Usage
Signature:
final class TreeDataProviderView<K, D, Kin, Din> implements TreeDataProvider<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 TreeDataProviderView= require("ojs/ojtreedataproviderview");
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 TreeDataProviderView(dataProvider, options)
Parameters:
Name | Type | Argument | Description |
---|---|---|---|
dataProvider |
TreeDataProvider.<K, D> | the DataProvider. | |
options |
TreeDataProviderView.Options.<K, D, Kin, Din> |
<optional> |
Options for the TreeDataProviderView |
Fields
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. If this method is called on a DataProvider returned from
getChildDataProvider(key)
, the rows will be only those from the children of thekey
.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 containsKeys = [1001, 556]; let value = await dataprovider.containsKeys({keys: containsKeys}); 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. If this method is called on a DataProvider returned from
getChildDataProvider(key)
, the rows will be only those from the children of thekey
.Parameters:
Name Type Description parameters
FetchByKeysParameters fetch by key parameters - Since:
- 4.2.0
Returns:
Returns Promise which resolves to FetchByKeysResults.
- Type
- Promise.<FetchByKeysResults>
Example
let fetchKeys = [1001, 556]; let value = await dataprovider.fetchByKeys({keys: fetchKeys}); // get the data for key 1001 console.log(value.results.get(1001).data);
-
fetchByOffset(parameters: FetchByOffsetParameters<D>): Promise<FetchByOffsetResults<K, D>>
-
Fetch rows by offset
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 - Since:
- 4.2.0
Returns:
Returns Promise which resolves to FetchByOffsetResults.
- Type
- Promise.<FetchByOffsetResults>
Example
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']; });
-
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: "fetchByKeys", "fetchByOffset", "sort", "fetchCapability" and "filter". - Since:
- 4.2.0
Returns:
capability information or null if undefined
- If capabilityName is "fetchByKeys", returns a FetchByKeysCapability object.
- If capabilityName is "fetchByOffset", returns a FetchByOffsetCapability object.
- If capabilityName is "sort", returns a SortCapability object.
- If capabilityName is "filter", returns a FilterCapability object.
- If capabilityName is "fetchCapability", returns a FetchCapability object.
- Type
- Object
Example
let capabilityInfo = dataprovider.getCapability('fetchByKeys'); if (capabilityInfo.implementation == 'iteration') { // the DataProvider supports iteration for fetchByKeys ...
-
getChildDataProvider(key: K): TreeDataProvider<K, D> | null
-
Get the data provider for the children of the row identified by key.
Parameters:
Name Type Description key
any key of the row to get child data provider for. - Since:
- 5.1.0
Returns:
A TreeDataProvider if the row can (but doesn't have to) have children; or null if the row cannot have children. Use the
isEmpty
method on the returned TreeDataProvider to determine if it currently has children.- Type
- TreeDataProvider | null
-
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 dataMapping
DataMapping.<K, D, Kin, Din> <optional>
mapping to apply to the data.