/*
* 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.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Set;
import org.geotools.feature.IllegalAttributeException;
import org.geotools.filter.AttributeExpression;
import org.opengis.feature.Feature;
import org.opengis.feature.type.FeatureType;
import org.opengis.filter.Filter;
import org.opengis.filter.Id;
import org.opengis.filter.identity.Identifier;
import org.opengis.filter.spatial.BBOX;
import org.opengis.filter.spatial.BinarySpatialOperator;
import org.opengis.filter.spatial.Contains;
import org.opengis.filter.spatial.Crosses;
import org.opengis.filter.spatial.Overlaps;
import org.opengis.filter.spatial.Touches;
import org.opengis.filter.spatial.Within;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
/**
* A FeatureReader that considers differences.
* <p>
* Used to implement In-Process Transaction support. This implementation will need to peek ahead in
* order to check for deletetions.
* </p>
*
* @author Jody Garnett, Refractions Research
*
* @source $URL$
*/
public class DiffFeatureReader<T extends FeatureType, F extends Feature> implements FeatureReader<T, F> {
FeatureReader<T, F> reader;
Diff diff;
/** Next value as peeked by hasNext() */
F next = null;
private Filter filter;
private Set encounteredFids;
private Iterator<F> addedIterator;
private Iterator<F> modifiedIterator;
private Iterator<Identifier> fids;
private Iterator<F> spatialIndexIterator;
private boolean indexedGeometryFilter = false;
private boolean fidFilter = false;
/**
* This constructor grabs a "copy" of the current diff.
* <p>
* This reader is not "live" to changes over the course of the Transaction. (Iterators are not
* always stable of the course of modifications)
* </p>
*
* @param reader
* @param diff2 Differences of Feature by FID
*/
public DiffFeatureReader(FeatureReader<T, F> reader, Diff diff2 ) {
this(reader, diff2, Filter.INCLUDE);
}
/**
* This constructor grabs a "copy" of the current diff.
* <p>
* This reader is not "live" to changes over the course of the Transaction. (Iterators are not
* always stable of the course of modifications)
* </p>
*
* @param reader
* @param diff2 Differences of Feature by FID
*/
public DiffFeatureReader(FeatureReader<T, F> reader, Diff diff2, Filter filter ) {
this.reader = reader;
this.diff = diff2;
this.filter = filter;
encounteredFids=new HashSet();
if( filter instanceof Id){
fidFilter=true;
}else if( isSubsetOfBboxFilter(filter) ){
indexedGeometryFilter=true;
}
synchronized (diff) {
if( indexedGeometryFilter ){
spatialIndexIterator=getIndexedFeatures().iterator();
}
addedIterator=(Iterator<F>)diff.added.values().iterator();
modifiedIterator=(Iterator<F>)diff.modified2.values().iterator();
}
}
/**
* @see org.geotools.data.FeatureReader#getFeatureType()
*/
public T getFeatureType() {
return reader.getFeatureType();
}
/**
* @see org.geotools.data.FeatureReader#next()
*/
public F next() throws IOException, IllegalAttributeException, NoSuchElementException {
if (hasNext()) {
F live = next;
next = null;
return live;
}
throw new NoSuchElementException("No more Feature exists");
}
/**
* @see org.geotools.data.FeatureReader#hasNext()
*/
public boolean hasNext() throws IOException {
if (next != null) {
// We found it already
return true;
}
F peek;
if( filter==Filter.EXCLUDE)
return false;
while( (reader != null) && reader.hasNext() ) {
try {
peek = reader.next();
} catch (NoSuchElementException e) {
throw new DataSourceException("Could not aquire the next Feature", e);
} catch (IllegalAttributeException e) {
throw new DataSourceException("Could not aquire the next Feature", e);
}
String fid = peek.getIdentifier().getID();
encounteredFids.add(fid);
if (diff.modified2.containsKey(fid)) {
F changed = (F) diff.modified2.get(fid);
if (changed == TransactionStateDiff.NULL || !filter.evaluate(changed) ) {
continue;
} else {
next = changed;
return true;
}
} else {
next = peek; // found feature
return true;
}
}
queryDiff();
return next != null;
}
/**
* @see org.geotools.data.FeatureReader#close()
*/
public void close() throws IOException {
if (reader != null) {
reader.close();
reader = null;
}
if (diff != null) {
diff = null;
addedIterator=null;
}
}
protected void queryDiff() {
if( fidFilter ){
queryFidFilter();
} else if( indexedGeometryFilter ){
querySpatialIndex();
} else {
queryAdded();
queryModified();
}
}
protected void querySpatialIndex() {
while( spatialIndexIterator.hasNext() && next == null ){
F f = (F) spatialIndexIterator.next();
if( encounteredFids.contains(f.getIdentifier().getID()) || !filter.evaluate(f)){
continue;
}
next = f;
}
}
protected void queryAdded() {
while( addedIterator.hasNext() && next == null ){
next = (F) addedIterator.next();
if( encounteredFids.contains(next.getIdentifier().getID()) || !filter.evaluate(next)){
next = null;
}
}
}
protected void queryModified() {
while( modifiedIterator.hasNext() && next == null ){
next = (F) modifiedIterator.next();
if( next==TransactionStateDiff.NULL || encounteredFids.contains(next.getIdentifier().getID()) || !filter.evaluate(next) ){
next = null;
}
}
}
protected void queryFidFilter() {
Id fidFilter = (Id) filter;
if (fids == null) {
fids = fidFilter.getIdentifiers().iterator();
}
while( fids.hasNext() && next == null ) {
String fid = fids.next().toString();
if( !encounteredFids.contains(fid) ){
next = (F) diff.modified2.get(fid);
if( next==null ){
next = (F) diff.added.get(fid);
}
}
}
}
protected List getIndexedFeatures() {
// TODO: check geom is default geom.
Envelope env = null;
env = extractBboxForSpatialIndexQuery((BinarySpatialOperator)filter);
return diff.queryIndex(env);
}
protected Envelope extractBboxForSpatialIndexQuery(BinarySpatialOperator filter){
org.opengis.filter.expression.Expression leftGeom = filter.getExpression1();
org.opengis.filter.expression.Expression rightGeom = filter.getExpression2();
Geometry g ;
if (leftGeom instanceof org.opengis.filter.expression.Literal){
g = (Geometry)((org.opengis.filter.expression.Literal)leftGeom).getValue();
}else{
g = (Geometry)((org.opengis.filter.expression.Literal)rightGeom).getValue();
}
return g.getEnvelopeInternal();
}
protected boolean isDefaultGeometry(AttributeExpression ae) {
return reader.getFeatureType().getGeometryDescriptor().getLocalName().equals(ae.getAttributePath());
}
protected boolean isSubsetOfBboxFilter(Filter f) {
return filter instanceof Contains ||
filter instanceof Crosses ||
filter instanceof Overlaps ||
filter instanceof Touches ||
filter instanceof Within ||
filter instanceof BBOX;
}
}