/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2003-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.data;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.logging.Logger;
import org.geotools.data.crs.ForceCoordinateSystemFeatureResults;
import org.geotools.data.crs.ReprojectFeatureResults;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.data.store.EmptyFeatureCollection;
import org.geotools.feature.SchemaException;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.Name;
import org.opengis.filter.Filter;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import com.vividsolutions.jts.geom.Envelope;
/**
* This is a starting point for providing your own SimpleFeatureSource implementation.
*
* <p>
* Subclasses must implement:
* </p>
*
* <ul>
* <li>
* getDataStore()
* </li>
* <li>
* getSchema()
* </li>
* <li>
* addFeatureListener()
* </li>
* <li>
* removeFeatureListener()
* </li>
* </ul>
*
* <p>
* You may find a SimpleFeatureSource implementations that is more specific to your needs - such as
* JDBCFeatureSource.
* </p>
*
* <p>
* For an example of this class customized for use please see MemoryDataStore.
* </p>
*
* @author Jody Garnett, Refractions Research Inc
*
* @source $URL$
*/
public abstract class AbstractFeatureSource implements SimpleFeatureSource {
/** The logger for the filter module. */
private static final Logger LOGGER = org.geotools.util.logging.Logging.getLogger("org.geotools.data");
protected Set hints = Collections.EMPTY_SET;
protected QueryCapabilities queryCapabilities = new QueryCapabilities();
public AbstractFeatureSource() {
// just to keep the default constructor around
}
/**
* Overrides to explicitly type narrow the return type to {@link DataStore}
*/
public abstract DataStore getDataStore();
/**
* Returns the same name than the feature type (ie,
* {@code getSchema().getName()} to honor the simple feature land common
* practice of calling the same both the Features produces and their types
*
* @since 2.5
* @see FeatureSource#getName()
*/
public Name getName() {
return getSchema().getName();
}
/**
* This constructors allows to set the supported hints
* @param hints
*/
public AbstractFeatureSource(Set hints) {
this.hints = Collections.unmodifiableSet(new HashSet(hints));
}
public ResourceInfo getInfo() {
return new ResourceInfo(){
final Set<String> words = new HashSet<String>();
{
words.add("features");
words.add( AbstractFeatureSource.this.getSchema().getTypeName() );
}
public ReferencedEnvelope getBounds() {
try {
return AbstractFeatureSource.this.getBounds();
} catch (IOException e) {
return null;
}
}
public CoordinateReferenceSystem getCRS() {
return AbstractFeatureSource.this.getSchema().getCoordinateReferenceSystem();
}
public String getDescription() {
return null;
}
public Set<String> getKeywords() {
return words;
}
public String getName() {
return AbstractFeatureSource.this.getSchema().getTypeName();
}
public URI getSchema() {
Name name = AbstractFeatureSource.this.getSchema().getName();
URI namespace;
try {
namespace = new URI( name.getNamespaceURI() );
return namespace;
} catch (URISyntaxException e) {
return null;
}
}
public String getTitle() {
Name name = AbstractFeatureSource.this.getSchema().getName();
return name.getLocalPart();
}
};
}
public QueryCapabilities getQueryCapabilities(){
return queryCapabilities;
}
/**
* Retrieve the Transaction this SimpleFeatureSource is operating against.
*
* <p>
* For a plain SimpleFeatureSource that cannot modify this will always be Transaction.AUTO_COMMIT.
* </p>
*
* @return Transacstion SimpleFeatureSource is operating against
*/
public Transaction getTransaction() {
return Transaction.AUTO_COMMIT;
}
/**
* Provides an interface to for the Results of a Query.
*
* <p>
* Various queries can be made against the results, the most basic being to retrieve Features.
* </p>
*
* @param query
*
*
* @see org.geotools.data.FeatureSource#getFeatures(org.geotools.data.Query)
*/
public SimpleFeatureCollection getFeatures(Query query) throws IOException {
SimpleFeatureType schema = getSchema();
String typeName = schema.getTypeName();
if( query.getTypeName() == null ){ // typeName unspecified we will "any" use a default
DefaultQuery defaultQuery = new DefaultQuery(query);
defaultQuery.setTypeName( typeName );
}
else if ( !typeName.equals( query.getTypeName() ) ){
return new EmptyFeatureCollection( schema );
}
final QueryCapabilities queryCapabilities = getQueryCapabilities();
if(!queryCapabilities.supportsSorting(query.getSortBy())){
throw new DataSourceException("DataStore cannot provide the requested sort order");
}
SimpleFeatureCollection collection = new DefaultFeatureResults(this, query);
if( collection.getSchema().getGeometryDescriptor() == null ){
return collection; // no geometry no reprojection needed
}
// if( false ){ // we need to have our CRS forced
// if ( query.getCoordinateSystem() != null ){
// try {
// collection = new ForceCoordinateSystemFeatureResults(collection, query.getCoordinateSystem() );
// } catch (SchemaException e) {
// throw new IOException( "Could not force CRS "+query.getCoordinateSystem() );
// }
// }
// }
// if( false ){ // we need our data reprojected
// if ( query.getCoordinateSystemReproject() != null){
// try {
// collection = new ReprojectFeatureResults(collection, query.getCoordinateSystemReproject() );
// } catch (Exception e) {
// throw new IOException( "Could not reproject to "+query.getCoordinateSystemReproject() );
// }
// }
// }
return collection;
}
/**
* Retrieve all Feature matching the Filter.
*
* @param filter Indicates features to retrieve
*
* @return FeatureResults indicating features matching filter
*
* @throws IOException If results could not be obtained
*/
public SimpleFeatureCollection getFeatures(Filter filter) throws IOException {
return getFeatures(new DefaultQuery(getSchema().getTypeName(), filter));
}
/**
* Retrieve all Features.
*
* @return FeatureResults of all Features in FeatureSource
*
* @throws IOException If features could not be obtained
*/
public SimpleFeatureCollection getFeatures() throws IOException {
return getFeatures(Filter.INCLUDE);
}
/**
* Retrieve Bounds of all Features.
*
* <p>
* Currently returns null, consider getFeatures().getBounds() instead.
* </p>
*
* <p>
* Subclasses may override this method to perform the appropriate optimization for this result.
* </p>
*
* @return null representing the lack of an optimization
*
* @throws IOException DOCUMENT ME!
*/
public ReferencedEnvelope getBounds() throws IOException {
// return getBounds(Query.ALL); // DZ should this not return just the bounds for this type?
return getBounds(getSchema()==null?Query.ALL:new DefaultQuery(getSchema().getTypeName()));
}
/**
* Retrieve Bounds of Query results.
*
* <p>
* Currently returns null, consider getFeatures( query ).getBounds() instead.
* </p>
*
* <p>
* Subclasses may override this method to perform the appropriate optimization for this result.
* </p>
*
* @param query Query we are requesting the bounds of
*
* @return null representing the lack of an optimization
*
* @throws IOException
*/
public ReferencedEnvelope getBounds(Query query) throws IOException {
if (query.getFilter() == Filter.EXCLUDE) {
return new ReferencedEnvelope(new Envelope(), getSchema().getCoordinateReferenceSystem());
}
DataStore dataStore = getDataStore();
if ((dataStore == null) || !(dataStore instanceof AbstractDataStore)) {
// too expensive
return null;
} else {
// ask the abstract data store
return ((AbstractDataStore) dataStore).getBounds( namedQuery( query ) );
}
}
/**
* Ensure query modified with typeName.
* <p>
* This method will make copy of the provided query, using
* DefaultQuery, if query.getTypeName is not equal to
* getSchema().getTypeName().
* </p>
* @param query Original query
* @return Query with getTypeName() equal to getSchema().getTypeName()
*/
protected Query namedQuery( Query query ){
String typeName = getSchema().getTypeName();
if( query.getTypeName() == null ||
!query.getTypeName().equals( typeName )){
return new DefaultQuery(
typeName,
query.getFilter(),
query.getMaxFeatures(),
query.getPropertyNames(),
query.getHandle()
);
}
return query;
}
/**
* Retrieve total number of Query results.
*
* <p>
* Currently returns -1, consider getFeatures( query ).getCount() instead.
* </p>
*
* <p>
* Subclasses may override this method to perform the appropriate optimization for this result.
* </p>
*
* @param query Query we are requesting the count of
*
* @return -1 representing the lack of an optimization
*/
public int getCount(Query query) throws IOException {
if (query.getFilter() == Filter.EXCLUDE) {
return 0;
}
DataStore dataStore = (DataStore) getDataStore();
if ((dataStore == null) || !(dataStore instanceof AbstractDataStore)) {
// too expensive
return -1;
}
// ask the abstract data store
Transaction t = getTransaction();
int nativeCount = ((AbstractDataStore) dataStore).getCount( namedQuery(query));
if(nativeCount == -1)
return -1;
//State state = t.getState(dataStore);
int delta = 0;
if(t != Transaction.AUTO_COMMIT) {
if(t.getState(dataStore) == null)
return nativeCount;
if (!(t.getState(dataStore) instanceof TransactionStateDiff)) {
//we cannot proceed; abort!
return -1;
}
Diff diff = ((AbstractDataStore)dataStore).state(t).diff(namedQuery(query).getTypeName());
synchronized (diff) {
Iterator it = diff.added.values().iterator();
while(it.hasNext()){
Object feature = it.next();
if( query.getFilter().evaluate(feature) )
delta++;
}
it = diff.modified2.values().iterator();
while(it.hasNext()){
Object feature = it.next();
if(feature == TransactionStateDiff.NULL && query.getFilter().evaluate(feature)) {
delta--;
}
}
}
}
return nativeCount + delta;
}
/**
* By default, no Hints are supported
*/
public Set getSupportedHints() {
return hints;
}
}