Package com.massifmaps.datasources

Class CombinedTileDataSource

java.lang.Object

com.massifmaps.datasources.TileDataSource

com.massifmaps.datasources.CombinedTileDataSource

public class CombinedTileDataSource
extends TileDataSource

A tile data source that combines two data sources (usually offline and online) and selects tiles
based on zoom level. All requests below specified zoom level are directed to the first data source
and all requests at or above specified zoom level are directed to the second data source.

Constructor Summary

Constructors

Constructor	Description
CombinedTileDataSource(TileDataSource dataSource1, TileDataSource dataSource2, int zoomLevel)	Constructs a combined tile data source object.

Method Summary

Modifier and Type	Method	Description
String	getContainerMetaData(String key)	Reads one entry of the source's own metadata, when it has any - the MBTiles or PMTiles metadata table, for instance.
MapBounds	getDataExtent()	Returns the extent of the tiles in this data source. The bounds are in coordinate system of the projection of the data source.
int	getMaxZoom()	Returns the maximum zoom level supported by this data source.
int	getMinZoom()	Returns the minimum zoom level supported by this data source.
TileData	loadTile(MapTile tile)	Loads the specified tile. Note: the tile coordinate system used here is vertically flipped relative to layer tile coordinate system.

Methods inherited from class com.massifmaps.datasources.TileDataSource

buildTagValues, containsMetaDataKey, getMaxOverzoomLevel, getMaxZoomWithOverzoom, getMetaData, getMetaDataElement, getProjection, isMaxOverzoomLevelSet, notifyTilesChanged, setMaxOverzoomLevel, setMetaData, setMetaDataElement

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

CombinedTileDataSource

public CombinedTileDataSource(TileDataSource dataSource1,
 TileDataSource dataSource2,
 int zoomLevel)

Constructs a combined tile data source object.

Parameters:

dataSource1 - First data source that is used if requested tile is below given zoomLevel.

dataSource2 - Second data source that is used if requested tile is at or above given zoomLevel.

zoomLevel - Threshold zoom level value.

Method Details

getMinZoom

public int getMinZoom()

Description copied from class: TileDataSource

Returns the minimum zoom level supported by this data source.

Overrides:

getMinZoom in class TileDataSource

Returns:

The minimum zoom level supported (inclusive).

getMaxZoom

public int getMaxZoom()

Description copied from class: TileDataSource

Returns the maximum zoom level supported by this data source.

Overrides:

getMaxZoom in class TileDataSource

Returns:

The maximum zoom level supported (exclusive).

getDataExtent

public MapBounds getDataExtent()

Description copied from class: TileDataSource

Returns the extent of the tiles in this data source.
The bounds are in coordinate system of the projection of the data source.

Overrides:

getDataExtent in class TileDataSource

Returns:

The extent of the data source.

getContainerMetaData

public String getContainerMetaData(String key)

Description copied from class: TileDataSource

Reads one entry of the source's own metadata, when it has any - the MBTiles or PMTiles
metadata table, for instance. Sources that carry none return an empty string, as do keys
they do not define. Unlike the meta data map above this is read-only and is NOT attached
to the loaded tiles: a container's metadata can be tens of kilobytes.

Overrides:

getContainerMetaData in class TileDataSource

Parameters:

key - The metadata key, as named by the container's specification.

Returns:

The value, or empty string if the source does not provide it.

loadTile

public TileData loadTile(MapTile tile)

Description copied from class: TileDataSource

Loads the specified tile.
Note: the tile coordinate system used here is vertically flipped relative to layer tile coordinate system.

Overrides:

loadTile in class TileDataSource

Parameters:

tile - The tile to load.

Returns:

The tile data. If the tile is not available, null may be returned.