Final Class: FlattenedTreeDataProviderView

Oracle® JavaScript Extension Toolkit (JET)
15.1.0
F83698-01

Since:
  • 7.0.0
Module:
  • ojflattenedtreedataproviderview

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Methods

Type Definitions

Description

Provides row expander optimizations for TreeDataProvider by flattening the tree.

Events

Consumers can add event listeners to listen for the following event types and respond to data change.

mutate

This event is fired when items have been added or removed from the data.

Event payload is found under event.detail, which implements the DataProviderMutationEventDetail interface.

refresh

This event is fired when the data has been refreshed and components need to re-fetch the data.

This event contains no additional event payload.

Example of consumer listening for the "mutate" event type: 
var listener = function(event) {
  if (event.detail.remove) {
    var removeDetail = event.detail.remove;
    // Handle removed items
  }
};
dataProvider.addEventListener("mutate", listener);

Performance

Fetch Performance

FlattenedTreeDataProviderView will fetch depth first on expanded items.

If items are expanded and a fetch size requested is satisfied by the fetching of child nodes, the leftover unreturned higher level items will be discarded and may be re-fetched. Applications can implement their own caching data provider layer to avoid multiple fetches of the same data.


Usage

Signature:

final class FlattenedTreeDataProviderView<K, D> implements DataProvider<K, D>

Generic Parameters
ParameterDescription
KType of output key
DType of output data
Typescript Import Format
//This class is exported directly as module. To import it
import FlattenedTreeDataProviderView= require("ojs/ojflattenedtreedataproviderview");

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 FlattenedTreeDataProviderView(dataProvider, options)

Parameters:
Name Type Argument Description
dataProvider TreeDataProvider.<K, D> the wrapped TreeDataProvider to flatten.
options FlattenedTreeDataProviderView.Options.<K> <optional>
 Options for FlattenedTreeDataProviderView

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

Check if keys 1001 and 556 are contained

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');
}

createOptimizedKeyMap(initialMap?: Map<K, D>): Map<K, D>

Return an empty Map which is optimized to store key value pairs

Optionally provided by certain DataProvider implementations for storing key/value pairs from the DataProvider in a performant fashion. Sometimes components will need to temporarily store a Map of keys provided by the DataProvider, for example, in the case of maintaining a Map of selected keys. Only the DataProvider is aware of the internal structure of keys such as whether they are primitives, Strings, or objects and how to do identity comparisons. Therefore, the DataProvider can optionally provide a Map implementation which can performantly store key/value pairs surfaced by the DataProvider.

Parameters:
Name Type Argument Description
initialMap Map.<any> <optional>
 Optionally specify an initial map of key/values for the Map. If not specified, then return an empty Map.
Since:
  • 6.2.0
Returns:

Returns a Map optimized for handling keys from the DataProvider.

Type
Map.<any>
Example

create empty key Map

// create optional parameter
let initMap = new Map();
initMap.set('a', 'apple');
let keyMap = dataprovider.createOptimizedKeyMap(initMap);

createOptimizedKeySet(initialSet?: Set<K>): Set<K>

Return an empty Set which is optimized to store keys

Optionally provided by certain DataProvider implementations for storing keys from the DataProvider in a performant fashion. Sometimes components will need to temporarily store a Set of keys provided by the DataProvider, for example, in the case of maintaining a Set of selected keys. Only the DataProvider is aware of the internal structure of keys such as whether they are primitives, Strings, or objects and how to do identity comparisons. Therefore, the DataProvider can optionally provide a Set implementation which can performantly store keys surfaced by the DataProvider.

Parameters:
Name Type Argument Description
initialSet Set.<any> <optional>
 Optionally specify an initial set of keys for the Set. If not specified, then return an empty Set.
Since:
  • 6.2.0
Returns:

Returns a Set optimized for handling keys from the DataProvider.

Type
Set.<any>
Example

create empty key Set

// create optional initial parameter
let initSet = new Set();
initSet.add('a');
let keySet = dataprovider.createOptimizedKeySet(initSet);

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

Fetch for keys 1001 and 556

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);

How to abort fetchByKeys

// 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
}
// 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

Fetch by offset 5 rows starting at index 2

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'];
});

How to abort fetchByOffset

// 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
}
// 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:
Returns:

AsyncIterable with FetchListResult

Type
AsyncIterable.<FetchListResult>
Example

Get an asyncIterator and then fetch first block of data by executing next() on the iterator. Subsequent blocks can be fetched by executing next() again.

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

Type
Object
Example

Check what kind of fetchByKeys is defined.

let capabilityInfo = dataprovider.getCapability('fetchByKeys');
if (capabilityInfo.implementation == 'iteration') {
  // the DataProvider supports iteration for fetchByKeys
  ...

getExpandedObservable():{ subscribe( subscriber : ((expanded: {value: KeySet<K>, completionPromise: Promise<any>}) => void) ): {unsubscribe(): void, closed(): boolean}}

Get the observable with information about the expanded state to subscribe to. Consumers can call subscribe and unsubscribe to receive changes to the expanded property.

On the first subscribe call, the initial value will be passed to the subscriber.

The observed value is an object with the following properties: value: KeySet - new expanded key set completionPromise?: Promise - resolved after all mutations have fired relevant to the expand/collapse. Example of consumer listening for the "mutate" event type: 

expandedObserexpandedObservable = dataprovider.getExpandedObservable();
subscriber = expandedObservable.subscribe(function(detail){
 expanded = detail.value;
 promise = detail.completionPromise;
 // handle changes
});
// unsubscribe later
subscriber.unsubscribe();

See:
Returns:

an object to call subscribe on to receive changes to the expanded property. The subscribe function returns an object to call unsubscribe on.

Type
Object

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

Get the total rows

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

Check if empty

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.

setExpanded(keySet: KeySet<K>): void

Set a new expanded property on the FlattenedTreeDataProviderView.
Parameters:
Name Type Description
keySet KeySet the new key set representing expanded

Type Definitions

Options<K>

Properties:
Name Type Argument Description
expanded KeySetImpl<K> | AllKeySetImpl.<K> <optional>
 Optional key set to track the expansion state. To monitor the expansion state use the getExpandedObvservable method. To update the expansion state use the setExpanded method.