org.geotools.data.DefaultFeatureResults Maven / Gradle / Ivy
/*
* 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.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.geotools.data.crs.ReprojectFeatureReader;
import org.geotools.data.simple.SimpleFeatureCollection;
import org.geotools.data.simple.SimpleFeatureSource;
import org.geotools.data.simple.SimpleFeatureStore;
import org.geotools.data.store.DataFeatureCollection;
import org.geotools.feature.DefaultFeatureCollection;
import org.geotools.feature.SchemaException;
import org.geotools.feature.type.GeometryDescriptorImpl;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.referencing.CRS;
import org.opengis.feature.IllegalAttributeException;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.MathTransform;
/**
* Generic "results" of a query, class.
*
* Please optimize this class when use with your own content. For example a "ResultSet" make a
* great cache for a JDBCDataStore, a temporary copy of an original file may work for shapefile etc.
*
* @author Jody Garnett, Refractions Research
*/
public class DefaultFeatureResults extends DataFeatureCollection {
/** Shared package logger */
private static final Logger LOGGER =
org.geotools.util.logging.Logging.getLogger(DefaultFeatureResults.class);
/** Query used to define this subset of features from the feature source */
protected Query query;
/**
* Feature source used to aquire features, note we are only a "view" of this FeatureSource, its
* contents, transaction and events need to be forwarded through this collection api to simplier
* code such as renderers.
*/
protected SimpleFeatureSource featureSource;
protected MathTransform transform;
/**
* FeatureResults query against featureSource.
*
*
Please note that is object will not be valid after the transaction has closed.
*
*
Really? I think it would be, it would just reflect the same query against the
* SimpleFeatureSource using AUTO_COMMIT.
*/
public DefaultFeatureResults(SimpleFeatureSource source, Query query) throws IOException {
super(null, getSchemaInternal(source, query));
this.featureSource = source;
SimpleFeatureType originalType = source.getSchema();
String typeName = originalType.getTypeName();
if (typeName.equals(query.getTypeName())) {
this.query = query;
} else {
// jg: this should be an error, we are deliberatly gobbling a mistake
// option 1: remove Query.getTypeName
// option 2: throw a warning
// option 3: restore exception code
this.query = new Query(query);
this.query.setTypeName(typeName);
}
if (originalType.getGeometryDescriptor() == null) {
return; // no transform needed
}
CoordinateReferenceSystem cs = null;
if (query.getCoordinateSystemReproject() != null) {
cs = query.getCoordinateSystemReproject();
} else if (query.getCoordinateSystem() != null) {
cs = query.getCoordinateSystem();
}
CoordinateReferenceSystem originalCRS =
originalType.getGeometryDescriptor().getCoordinateReferenceSystem();
if (query.getCoordinateSystem() != null) {
originalCRS = query.getCoordinateSystem();
}
if (cs != null && cs != originalCRS) {
try {
transform = CRS.findMathTransform(originalCRS, cs, true);
} catch (FactoryException noTransform) {
throw (IOException)
new IOException("Could not reproject data to " + cs).initCause(noTransform);
}
}
}
static SimpleFeatureType getSchemaInternal(SimpleFeatureSource featureSource, Query query) {
SimpleFeatureType originalType = featureSource.getSchema();
SimpleFeatureType schema = null;
CoordinateReferenceSystem cs = null;
if (query.getCoordinateSystemReproject() != null) {
cs = query.getCoordinateSystemReproject();
} else if (query.getCoordinateSystem() != null) {
cs = query.getCoordinateSystem();
}
try {
if (cs == null) {
if (query.retrieveAllProperties()) { // we can use the originalType as is
schema = featureSource.getSchema();
} else {
schema =
DataUtilities.createSubType(
featureSource.getSchema(), query.getPropertyNames());
}
} else {
// we need to change the projection of the original type
schema =
DataUtilities.createSubType(
originalType,
query.getPropertyNames(),
cs,
query.getTypeName(),
null);
}
} catch (SchemaException e) {
// we were unable to create the schema requested!
// throw new DataSourceException("Could not create schema", e);
LOGGER.log(Level.WARNING, "Could not change projection to " + cs, e);
schema = null; // client will notice something is amiss when getSchema() return null
}
return schema;
}
/**
* FeatureSchema for provided query.
*
*
If query.retrieveAllProperties() is true the FeatureSource getSchema() will
* be returned.
*
*
If query.getPropertyNames() is used to limit the result of the Query a sub type will be
* returned based on FeatureSource.getSchema().
*/
public SimpleFeatureType getSchema() {
return super.getSchema();
}
/**
* Returns transaction from SimpleFeatureSource (if it is a FeatureStore), or
* Transaction.AUTO_COMMIT if it is not.
*
* @return Transacstion this FeatureResults opperates against
*/
protected Transaction getTransaction() {
if (featureSource instanceof FeatureStore) {
SimpleFeatureStore featureStore;
featureStore = (SimpleFeatureStore) featureSource;
return featureStore.getTransaction();
} else {
return Transaction.AUTO_COMMIT;
}
}
/**
* Retrieve a FeatureReader for this Query
*
* @return FeatureReader for this Query
* @throws IOException If results could not be obtained
*/
public FeatureReader reader() throws IOException {
FeatureReader reader;
reader =
((DataStore) featureSource.getDataStore())
.getFeatureReader(query, getTransaction());
int maxFeatures = query.getMaxFeatures();
if (maxFeatures != Integer.MAX_VALUE) {
reader = new MaxFeatureReader(reader, maxFeatures);
}
if (transform != null) {
reader = new ReprojectFeatureReader(reader, getSchema(), transform);
}
return reader;
}
/**
* Retrieve a FeatureReader for the geometry attributes only,
* designed for bounds computation
*/
protected FeatureReader boundsReader() throws IOException {
List attributes = new ArrayList();
SimpleFeatureType schema = featureSource.getSchema();
for (int i = 0; i < schema.getAttributeCount(); i++) {
AttributeDescriptor at = schema.getDescriptor(i);
if (at instanceof GeometryDescriptorImpl) attributes.add(at.getLocalName());
}
Query q = new Query(query);
q.setPropertyNames(attributes);
FeatureReader reader =
((DataStore) featureSource.getDataStore()).getFeatureReader(q, getTransaction());
int maxFeatures = query.getMaxFeatures();
if (maxFeatures == Integer.MAX_VALUE) {
return reader;
} else {
return new MaxFeatureReader(reader, maxFeatures);
}
}
/**
* Returns the bounding box of this FeatureResults
*
* This implementation will generate the correct results from reader() if the provided
* SimpleFeatureSource does not provide an optimized result via FeatureSource.getBounds( Query
* ). If the feature has no geometry, then an empty envelope is returned.
*
* @throws DataSourceException See IOException
* @see org.geotools.data.FeatureResults#getBounds()
*/
public ReferencedEnvelope getBounds() {
ReferencedEnvelope bounds;
try {
bounds = featureSource.getBounds(query);
} catch (IOException e1) {
bounds = new ReferencedEnvelope((CoordinateReferenceSystem) null);
}
if (bounds == null) {
try {
SimpleFeature feature;
bounds = new ReferencedEnvelope();
FeatureReader reader = boundsReader();
try {
while (reader.hasNext()) {
feature = reader.next();
bounds.include(feature.getBounds());
}
} finally {
reader.close();
}
} catch (IllegalAttributeException e) {
// throw new DataSourceException("Could not read feature ", e);
bounds = new ReferencedEnvelope();
} catch (IOException e) {
bounds = new ReferencedEnvelope();
}
}
return bounds;
}
/**
* Number of Features in this query.
*
* This implementation will generate the correct results from reader() if the provided
* SimpleFeatureSource does not provide an optimized result via FeatureSource.getCount( Query ).
*
* @throws IOException If feature could not be read
* @throws DataSourceException See IOException
* @see org.geotools.data.FeatureResults#getCount()
*/
public int getCount() throws IOException {
int count;
count = featureSource.getCount(query);
if (count != -1) {
// optimization worked, return maxFeatures if count is
// greater.
int maxFeatures = query.getMaxFeatures();
return (count < maxFeatures) ? count : maxFeatures;
}
// Okay lets count the FeatureReader
try {
count = 0;
FeatureReader reader = reader();
try {
for (; reader.hasNext(); count++) {
reader.next();
}
} finally {
reader.close();
}
return count;
} catch (IllegalAttributeException e) {
throw new DataSourceException("Could not read feature ", e);
}
}
public SimpleFeatureCollection collection() throws IOException {
try {
DefaultFeatureCollection collection = new DefaultFeatureCollection(null, null);
FeatureReader reader = reader();
try {
while (reader.hasNext()) {
collection.add(reader.next());
}
} finally {
reader.close();
}
return collection;
} catch (org.opengis.feature.IllegalAttributeException e) {
throw new DataSourceException("Could not read feature ", e);
}
}
}