nl.b3p.geotools.data.arcgis

Class ArcGISDataStore

java.lang.Object

org.geotools.data.store.ContentDataStore

nl.b3p.geotools.data.arcgis.ArcGISDataStore

All Implemented Interfaces:

org.geotools.data.DataAccess<org.opengis.feature.simple.SimpleFeatureType,org.opengis.feature.simple.SimpleFeature>, org.geotools.data.DataStore

public class ArcGISDataStore
extends org.geotools.data.store.ContentDataStore

DataStore for ArcGIS Server REST API for MapServer or FeatureServer (read-only) services.

Because of the nature of the REST API, paging is not suited for stateless code such as web pages. When you request a FeatureReader with a Query with paging parameters set using Query.setStartIndex(java.lang.Integer) and Query.setMaxFeatures(int), the data store must always request all object ids matching the rest of the query and then request the features in the page using the object ids. If the feature collection is very large this can take a long time.

It is possible to request the object ids matching the Query using ArcGISFeatureReader.getObjectIds() and use this List later on to request features with ArcGISFeatureReader.getFeaturesByObjectIds(java.util.List). The list with object ids can be cached where appropriate and be used to request a sublist for paging.

Unfortunately the object ids cannot be used as a row id in a query to pass on the start index and max features. While sometimes the object ids start at 1 and increment for each subsequent feature, this is not guaranteed.

Although ArcGIS server sends ETag headers in response to requests, there is not really a performance improvement using conditional HTTP requests - with very large feature collections the performance is abysmal no matter what. Because of this the HTTP cache (using HttpCache4j) is disabled by default * so the HttpCache4j libraries are not required. To enable HTTP caching you must patch HttpCache4j to support non-conformant ETag headers sent by ESRI (see CachingHTTPClient, renamed to CachingHTTPClient.java.disabled) and uncomment the relevant lines in this class and ArcGISDataStoreFactory. Then pass a HTTPCache instance to the constructor or using the HTTP_CACHE Param for the factory.

When reading features ArcGIS server may produce invalid JSON when it apparently has an invalid coordinate and sends "*****************" instead. Like non-well formed XML we do not accept this so ArcGISFeatureReader.next() may throw an exception (consistently, the ESRI WFS server also produces invalid posLists this way).

The standard ESRI spatial querying restrictions apply: only one spatial operator with the default geometry and a literal geometry operand is supported and can only be combined with other attribute queries in a Boolean AND.

Author:

Matthijs Laan

Field Summary

Fields inherited from class org.geotools.data.store.ContentDataStore

dataStoreFactory, entries, featureFactory, filterFactory, geometryFactory, JOINED_FEATURE_TYPE, lockingManager, LOGGER, namespaceURI, typeFactory, WRITER_ADD, WRITER_COMMIT, WRITER_UPDATE

Constructor Summary

Constructors

Constructor and Description
ArcGISDataStore(URL url)
ArcGISDataStore(URL url, String user, String passwd, Integer timeout, Boolean gzip, org.opengis.referencing.crs.CoordinateReferenceSystem crs, Object httpCache, String currentVersion)

Method Summary

Methods

Modifier and Type	Method and Description
static String	appendUrlParameters(String url, Map<String,String> params)
protected org.geotools.data.store.ContentFeatureSource	createFeatureSource(org.geotools.data.store.ContentEntry ce)
protected List<org.opengis.feature.type.Name>	createTypeNames()
org.opengis.referencing.crs.CoordinateReferenceSystem	getCRS()
int	getCurrentMajorVersion()
String	getCurrentVersion()
org.json.simple.JSONObject	getLayerJSON(String id)
org.json.simple.JSONObject	getServerJSONResponse(String extraUrl)
org.json.simple.JSONObject	getServerJSONResponse(String extraUrl, Map<String,String> params)
String	toString()

Methods inherited from class org.geotools.data.store.ContentDataStore

createContentState, createSchema, dispose, ensureEntry, ensureFeatureStore, entry, getDataStoreFactory, getEntry, getFeatureFactory, getFeatureReader, getFeatureSource, getFeatureSource, getFeatureSource, getFeatureSource, getFeatureTypeFactory, getFeatureWriter, getFeatureWriter, getFeatureWriterAppend, getFilterFactory, getGeometryFactory, getInfo, getLockingManager, getLogger, getNames, getNamespaceURI, getSchema, getSchema, getTypeNames, name, removeEntry, removeSchema, removeSchema, setDataStoreFactory, setFeatureFactory, setFeatureTypeFactory, setFilterFactory, setGeometryFactory, setNamespaceURI, updateSchema, updateSchema

Methods inherited from class java.lang.Object

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

Constructor Detail

ArcGISDataStore

public ArcGISDataStore(URL url)

ArcGISDataStore

public ArcGISDataStore(URL url,
               String user,
               String passwd,
               Integer timeout,
               Boolean gzip,
               org.opengis.referencing.crs.CoordinateReferenceSystem crs,
               Object httpCache,
               String currentVersion)

Method Detail

getCurrentVersion

public String getCurrentVersion()
                         throws IOException

Throws:

IOException

getCurrentMajorVersion

public int getCurrentMajorVersion()
                           throws IOException

Throws:

IOException

getServerJSONResponse

public org.json.simple.JSONObject getServerJSONResponse(String extraUrl)
                                                 throws IOException

Throws:

IOException

appendUrlParameters

public static String appendUrlParameters(String url,
                         Map<String,String> params)

getServerJSONResponse

public org.json.simple.JSONObject getServerJSONResponse(String extraUrl,
                                               Map<String,String> params)
                                                 throws IOException

Throws:

IOException

getLayerJSON

public org.json.simple.JSONObject getLayerJSON(String id)
                                        throws IOException

Throws:

IOException

createTypeNames

protected List<org.opengis.feature.type.Name> createTypeNames()
                                                       throws IOException

Specified by:

createTypeNames in class org.geotools.data.store.ContentDataStore

Throws:

IOException

createFeatureSource

protected org.geotools.data.store.ContentFeatureSource createFeatureSource(org.geotools.data.store.ContentEntry ce)
                                                                    throws IOException

Specified by:

createFeatureSource in class org.geotools.data.store.ContentDataStore

Throws:

IOException

getCRS

public org.opengis.referencing.crs.CoordinateReferenceSystem getCRS()

toString

public String toString()

Overrides:

toString in class Object