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Maps API for Javascript
China specific
Maps API for JavaScript Developer's Guide

H.map.provider.LocalObjectProvider

Class Summary

Extends: H.map.provider.ObjectProvider

A LocalObjectProvider acts as a database for map objects. It provides functionality to fetch visible objects for specific geographical bounds and zoom levels. All objects are organized in a hierarchical group structure. An object can be added to the provider by adding it to a group within this structure. The root group of the provider can be fetched via the method H.map.provider.LocalObjectProvider#getRootGroup. A H.Map has its own LocalObjectProvider and offer a means to add and remove objects. Only in advanced use cases, is there a need to create an additional LocalObjectProvider.

[ For full details, see the Class Details ]

Property Summary

Table 1. Properties
Properties

uri : {string}

This property holds the provider's unique resource identifier. If it is not provided at construction time, it defaults to provider's uid.

min : {number}

This property holds a value indicating the minimum zoom level at which the given provider can serve data. The value is set at construction time.

max : {number}

This property holds a value indicating the maximum zoom level at which the given provider can server data. The value is set at construction time.

uid : {string}

This property holds the unique identifier for the provider instance. The value is generated at construction time.

Method Summary

Table 2. Methods
Methods

getRootGroup () : {H.map.Group}

This method retrieves the root group for the given provider.

removeObject (object)

This method removes an object from the given provider's database. It must not called directly. It is invoked by H.map.Group which checks beforehand that it is an H.map.Object instance and its provider is the given provider.

getInvalidations (opt_type) : {H.map.provider.Invalidations}

This method retrieves the accumulated invalidations of the given provider's objects.

invalidateObject (mapObject, changes)

This method signals to the provider that a map object has changed. The method updates the Invalidations of the given provider and the specified map object and triggers dispatchUpdate().

requestOverlays (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Overlay>}

This method retrieves all overlay objects which intersect with the specified area.

requestSpatials (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Spatial>}

This method retrieves all polyline, polygon, circle and rectangle objects which intersect with the provided area.

requestSpatialsByTile (tile, visiblesOnly, cacheOnly) : {Array<H.map.Spatial>}

This method retrieves the spatial objects which intersect the given tile.

requestMarkers (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Marker>}

This method retrieves all Marker map objects which intersect with the provided rectangular area.

requestDomMarkers (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.DomMarker>}

This method retrieves all DomMarker map objects which intersect with the provided rectangular area.

getCopyrights (bounds, level) : {?Array<H.map.ICopyright>}

This method retrieves the copyrights for the provided content for a certain geographical area and zoom level.

providesSpatials () : {boolean}

This method checks whether this provider currently provides spatial map objects. A concrete implementation of Provider must override it if it currently provides Spatials.

providesOverlays () : {boolean}

This method checks whether this provider currently provides overlay map objects. A concrete implementation of Provider must override it if it currently provides overlays.

providesMarkers () : {boolean}

This method checks whether this provider currently provides Marker map objects. A concrete implementation of Provider must override it if it currently provides Markers.

providesDomMarkers () : {boolean}

This method checks whether this provider currentky provides DomMarker map objects. A concrete implementation of Provider must override it if it currently provides Markers.

addEventListener (type, handler, opt_capture, opt_scope)

This method adds a listener for a specific event.

removeEventListener (type, handler, opt_capture, opt_scope)

This method removes a previously added listener from the EventTarget instance.

dispatchEvent (evt)

This method dispatches an event on the EventTarget object.

dispose ()

This method removes listeners from the given object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.

addOnDisposeCallback (callback, opt_scope)

This method adds a callback which is triggered when the EventTarget object is being disposed.

Events Summary

Table 3. Events
Events

update : {H.util.Event}

Event fired when this provider's data updates.

Class Description

A LocalObjectProvider acts as a database for map objects. It provides functionality to fetch visible objects for specific geographical bounds and zoom levels. All objects are organized in a hierarchical group structure. An object can be added to the provider by adding it to a group within this structure. The root group of the provider can be fetched via the method H.map.provider.LocalObjectProvider#getRootGroup. A H.Map has its own LocalObjectProvider and offer a means to add and remove objects. Only in advanced use cases, is there a need to create an additional LocalObjectProvider.

Example 

  // Create your own LocalObjectProvider and add some hierarchical objects:

  myProvider = new H.map.provider.LocalObjectProvider();
  myMap.addLayer(new H.map.layer.ObjectLayer(myProvider));
  position = {lat: 52.5308, lng: 13.3852};
  myGroup = new H.map.Group();
  myGroup.addObject(new H.map.Circle(position, 35));
  myProvider.getRootGroup().addObjects([
  myGroup,
  new H.map.Marker(position)
  ]);
  myMap.setCenter(position).setZoom(18);

Constructor Details

H.map.provider.LocalObjectProvider(opt_options)

Parameters:
 
opt_options:
{H.map.provider.Provider.Options=} [optional]
 
An object containing configuration options

Property Details

uri: {string}

This property holds the provider's unique resource identifier. If it is not provided at construction time, it defaults to provider's uid.

min: {number}

This property holds a value indicating the minimum zoom level at which the given provider can serve data. The value is set at construction time.

max: {number}

This property holds a value indicating the maximum zoom level at which the given provider can server data. The value is set at construction time.

uid: {string}

This property holds the unique identifier for the provider instance. The value is generated at construction time.

Method Details

getRootGroup () : {H.map.Group}

This method retrieves the root group for the given provider.

Returns:
 
{H.map.Group}
An object representing the root group for the given provider

removeObject (object)

This method removes an object from the given provider's database. It must not called directly. It is invoked by H.map.Group which checks beforehand that it is an H.map.Object instance and its provider is the given provider.

Parameters:
 
object:
{!H.map.Object}
 
The object to remove

getInvalidations (opt_type) : {H.map.provider.Invalidations}

This method retrieves the accumulated invalidations of the given provider's objects.

Parameters:
 
opt_type:
{H.map.Object.Type=} [optional]
 
The type of objects to consider for the invalidations. If undefined, all types are taken into account.
Returns:
 
{H.map.provider.Invalidations}
An object specifying invalidations

invalidateObject (mapObject, changes)

This method signals to the provider that a map object has changed. The method updates the Invalidations of the given provider and the specified map object and triggers dispatchUpdate().

Parameters:
 
mapObject:
{!H.map.Object}
 
The map object to be invalidated
changes:
{H.math.BitMask}
 
The flags indicating the types of changes that have occurred

requestOverlays (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Overlay>}

This method retrieves all overlay objects which intersect with the specified area.

Parameters:
 
geoRect:
{H.geo.Rect}
 
A rectangular area defined in terms of the geographic coordinates of its top-left and bottom-right corners
zoomLevel:
{number}
 
The zoom level for which the objects are requested
visiblesOnly:
{boolean}
 
A value indicating whether only invisible objects are to be considered (true) or not (false)
cacheOnly:
{boolean}
 
A value indicating whether only cached objects are to be considered (true) or not (false)
Returns:
 
{Array<H.map.Overlay>}
A list of intersecting objects

requestSpatials (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Spatial>}

This method retrieves all polyline, polygon, circle and rectangle objects which intersect with the provided area.

Parameters:
 
geoRect:
{H.geo.Rect}
 
A rectangular area defined in terms of the geographic coordinates of its top-left and bottom-right corners
zoomLevel:
{number}
 
The zoom level for which the objects are requested
visiblesOnly:
{boolean}
 
A value indicating whether only invisible objects are to be considered (true) or not (false)
cacheOnly:
{boolean}
 
A value indicating whether only cached objects are to be considered (true) or not (false)
Returns:
 
{Array<H.map.Spatial>}
A list of intersecting objects

requestSpatialsByTile (tile, visiblesOnly, cacheOnly) : {Array<H.map.Spatial>}

This method retrieves the spatial objects which intersect the given tile.

Parameters:
 
tile:
{H.map.provider.SpatialTile}
 
The tile for which the objects are requested
visiblesOnly:
{boolean}
 
A value indicating whether only invisible objects are to be considered (true) or not (false)
cacheOnly:
{boolean}
 
A value indicating whether only cached objects are to be considered (true) or not (false)
Returns:
 
{Array<H.map.Spatial>}
A list of intersecting objects

requestMarkers (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.Marker>}

This method retrieves all Marker map objects which intersect with the provided rectangular area.

Parameters:
 
geoRect:
{H.geo.Rect}
 
A rectangular area defined in terms of the geographic coordinates of its top-left and bottom-right corners
zoomLevel:
{number}
 
The zoom level for which the objects are requested
visiblesOnly:
{boolean}
 
A value indicating whether only invisible objects are to be considered (true) or not (false)
cacheOnly:
{boolean}
 
A value indicating whether only cached objects are to be considered (true) or not (false)
Returns:
 
{Array<H.map.Marker>}
A list of intersecting objects

requestDomMarkers (geoRect, zoomLevel, visiblesOnly, cacheOnly) : {Array<H.map.DomMarker>}

This method retrieves all DomMarker map objects which intersect with the provided rectangular area.

Parameters:
 
geoRect:
{H.geo.Rect}
 
A rectangular area defined in terms of the geographic coordinates of its top-left and bottom-right corners
zoomLevel:
{number}
 
The zoom level for which the objects are requested
visiblesOnly:
{boolean}
 
A value indicating whether only invisible objects are to be considered (true) or not (false)
cacheOnly:
{boolean}
 
A value indicating whether only cached objects are to be considered (true) or not (false)
Returns:
 
{Array<H.map.DomMarker>}
A list of intersecting objects

getCopyrights (bounds, level) : {?Array<H.map.ICopyright>}

This method retrieves the copyrights for the provided content for a certain geographical area and zoom level.

Note: This function may be overridden by H.map.provider.Provider.Options.getCopyrights property. The default implementation returns null.

Parameters:
 
bounds:
{H.geo.Rect}
 
The bounding area for which to retrieve the copyright information
level:
{number}
 
The zoom level for which to retrieve the copyright information
Returns:
 
{?Array<H.map.ICopyright>}
A list of copyright information objects for the provided area and zoom level

providesSpatials () : {boolean}

This method checks whether this provider currently provides spatial map objects. A concrete implementation of Provider must override it if it currently provides Spatials.

Returns:
 
{boolean}
A value indicating whether the provider provides map objects (true) or not (false)

providesOverlays () : {boolean}

This method checks whether this provider currently provides overlay map objects. A concrete implementation of Provider must override it if it currently provides overlays.

Returns:
 
{boolean}
true if the provider provides overlays, otherwse false

providesMarkers () : {boolean}

This method checks whether this provider currently provides Marker map objects. A concrete implementation of Provider must override it if it currently provides Markers.

Returns:
 
{boolean}
A value indicating if the given provider provides Markers (true) or not (false)

providesDomMarkers () : {boolean}

This method checks whether this provider currentky provides DomMarker map objects. A concrete implementation of Provider must override it if it currently provides Markers.

Returns:
 
{boolean}
A value indicating if the given provider provides Markers (true) or not (false)

addEventListener (type, handler, opt_capture, opt_scope)

This method adds a listener for a specific event.

Note that to prevent potential memory leaks, you must either call removeEventListener or dispose on the given object when you no longer need it.

Parameters:
 
type:
{string}
 
The name of the event
handler:
{!Function}
 
An event handler function
opt_capture:
{boolean=} [optional]
 
true indicates that the method should listen in the capture phase (bubble otherwise)
opt_scope:
{Object=} [optional]
 
An object defining the scope for the handler function

removeEventListener (type, handler, opt_capture, opt_scope)

This method removes a previously added listener from the EventTarget instance.

Parameters:
 
type:
{string}
 
The name of the event
handler:
{!Function}
 
A previously added event handler
opt_capture:
{boolean=} [optional]
 
true indicates that the method should listen in the capture phase (bubble otherwise)
opt_scope:
{Object=} [optional]
 
An oject defining the scope for the handler function

dispatchEvent (evt)

This method dispatches an event on the EventTarget object.

Parameters:
 
evt:
{(H.util.Event | string)}
 
An object representing the event or a string with the event name

dispose ()

This method removes listeners from the given object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.

addOnDisposeCallback (callback, opt_scope)

This method adds a callback which is triggered when the EventTarget object is being disposed.

Parameters:
 
callback:
{!Function}
 
The callback function.
opt_scope:
{Object=} [optional]
 
An optional scope for the callback function

Event Details

update: {H.util.Event}

Event fired when this provider's data updates.

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