001: /*
002: * GeoTools - OpenSource mapping toolkit
003: * http://geotools.org
004: * (C) 2003-2006, GeoTools Project Managment Committee (PMC)
005: *
006: * This library is free software; you can redistribute it and/or
007: * modify it under the terms of the GNU Lesser General Public
008: * License as published by the Free Software Foundation;
009: * version 2.1 of the License.
010: *
011: * This library is distributed in the hope that it will be useful,
012: * but WITHOUT ANY WARRANTY; without even the implied warranty of
013: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014: * Lesser General Public License for more details.
015: */
016: package org.geotools.data;
017:
018: import java.io.IOException;
019: import java.util.ArrayList;
020: import java.util.List;
021: import java.util.logging.Level;
022: import java.util.logging.Logger;
023:
024: import org.geotools.data.crs.ReprojectFeatureReader;
025: import org.geotools.data.store.DataFeatureCollection;
026: import org.geotools.feature.AttributeType;
027: import org.geotools.feature.Feature;
028: import org.geotools.feature.FeatureCollection;
029: import org.geotools.feature.FeatureCollections;
030: import org.geotools.feature.FeatureType;
031: import org.geotools.feature.IllegalAttributeException;
032: import org.geotools.feature.SchemaException;
033: import org.geotools.feature.type.GeometricAttributeType;
034: import org.geotools.geometry.jts.ReferencedEnvelope;
035: import org.geotools.referencing.CRS;
036: import org.opengis.referencing.FactoryException;
037: import org.opengis.referencing.crs.CoordinateReferenceSystem;
038: import org.opengis.referencing.operation.MathTransform;
039:
040: import com.vividsolutions.jts.geom.Envelope;
041:
042: /**
043: * Generic "results" of a query, class.
044: * <p>
045: * Please optimize this class when use with your own content.
046: * For example a "ResultSet" make a great cache for a JDBCDataStore,
047: * a temporary copy of an original file may work for shapefile etc.
048: * </p>
049: *
050: * @author Jody Garnett, Refractions Research
051: * @source $URL: http://svn.geotools.org/geotools/tags/2.4.1/modules/library/main/src/main/java/org/geotools/data/DefaultFeatureResults.java $
052: */
053: public class DefaultFeatureResults extends DataFeatureCollection {
054: /** Shared package logger */
055: private static final Logger LOGGER = org.geotools.util.logging.Logging
056: .getLogger("org.geotools.data");
057:
058: /** Query used to define this subset of features from the feature source */
059: protected Query query;
060:
061: /**
062: * Feature source used to aquire features, note we are only a
063: * "view" of this FeatureSource, its contents, transaction and events
064: * need to be forwarded through this collection api to simplier code
065: * such as renderers.
066: */
067: protected FeatureSource featureSource;
068:
069: protected FeatureType schema;
070: protected MathTransform transform;
071:
072: /**
073: * FeatureResults query against featureSource.
074: * <p>
075: * Please note that is object will not be valid
076: * after the transaction has closed.
077: * </p>
078: * <p>
079: * Really? I think it would be, it would just reflect the
080: * same query against the featuresource using AUTO_COMMIT.
081: * </p>
082: *
083: * @param source
084: * @param query
085: */
086: public DefaultFeatureResults(FeatureSource source, Query query)
087: throws IOException {
088: this .featureSource = source;
089: FeatureType origionalType = source.getSchema();
090:
091: String typeName = origionalType.getTypeName();
092: if (typeName.equals(query.getTypeName())) {
093: this .query = query;
094: } else {
095: // jg: this should be an error, we are deliberatly gobbling a mistake
096: // option 1: remove Query.getTypeName
097: // option 2: throw a warning
098: // option 3: restore exception code
099: this .query = new DefaultQuery(query);
100: ((DefaultQuery) this .query).setTypeName(typeName);
101: //((DefaultQuery) this.query).setCoordinateSystem(query.getCoordinateSystem());
102: //((DefaultQuery) this.query).setCoordinateSystemReproject(query.getCoordinateSystemReproject());
103: }
104: CoordinateReferenceSystem cs = null;
105: if (query.getCoordinateSystemReproject() != null) {
106: cs = query.getCoordinateSystemReproject();
107: } else if (query.getCoordinateSystem() != null) {
108: cs = query.getCoordinateSystem();
109: }
110: try {
111: if (cs == null) {
112: if (query.retrieveAllProperties()) { // we can use the origionalType as is
113: schema = featureSource.getSchema();
114: } else {
115: schema = DataUtilities.createSubType(featureSource
116: .getSchema(), query.getPropertyNames());
117: }
118: } else {
119: // we need to change the projection of the origional type
120: schema = DataUtilities.createSubType(origionalType,
121: query.getPropertyNames(), cs, query
122: .getTypeName(), null);
123: }
124: } catch (SchemaException e) {
125: // we were unable to create the schema requested!
126: //throw new DataSourceException("Could not create schema", e);
127: LOGGER.log(Level.WARNING, "Could not change projection to "
128: + cs, e);
129: schema = null; // client will notice something is amiss when getSchema() return null
130: }
131: if (origionalType.getDefaultGeometry() == null) {
132: return; // no transform needed
133: }
134: CoordinateReferenceSystem origionalCRS = origionalType
135: .getDefaultGeometry().getCoordinateSystem();
136: if (query.getCoordinateSystem() != null) {
137: origionalCRS = query.getCoordinateSystem();
138: }
139: if (cs != null && cs != origionalCRS) {
140: try {
141: transform = CRS.findMathTransform(origionalCRS, cs,
142: true);
143: } catch (FactoryException noTransform) {
144: throw (IOException) new IOException(
145: "Could not reproject data to " + cs)
146: .initCause(noTransform);
147: }
148: }
149: }
150:
151: /**
152: * FeatureSchema for provided query.
153: *
154: * <p>
155: * If query.retrieveAllProperties() is <code>true</code> the FeatureSource
156: * getSchema() will be returned.
157: * </p>
158: *
159: * <p>
160: * If query.getPropertyNames() is used to limit the result of the Query a
161: * sub type will be returned based on FeatureSource.getSchema().
162: * </p>
163: *
164: * @return DOCUMENT ME!
165: *
166: * @throws IOException DOCUMENT ME!
167: * @throws DataSourceException DOCUMENT ME!
168: */
169: public FeatureType getSchema() {
170: return schema;
171: }
172:
173: /**
174: * Returns transaction from featureSource (if it is a FeatureStore), or
175: * Transaction.AUTO_COMMIT if it is not.
176: *
177: * @return Transacstion this FeatureResults opperates against
178: */
179: protected Transaction getTransaction() {
180: if (featureSource instanceof FeatureStore) {
181: FeatureStore featureStore = (FeatureStore) featureSource;
182:
183: return featureStore.getTransaction();
184: } else {
185: return Transaction.AUTO_COMMIT;
186: }
187: }
188:
189: /**
190: * Retrieve a FeatureReader for this Query
191: *
192: * @return FeatureReader for this Query
193: *
194: * @throws IOException If results could not be obtained
195: */
196: public FeatureReader reader() throws IOException {
197: FeatureReader reader = featureSource.getDataStore()
198: .getFeatureReader(query, getTransaction());
199:
200: int maxFeatures = query.getMaxFeatures();
201: if (maxFeatures != Integer.MAX_VALUE) {
202: reader = new MaxFeatureReader(reader, maxFeatures);
203: }
204: if (transform != null) {
205: reader = new ReprojectFeatureReader(reader, schema,
206: transform);
207: }
208: return reader;
209: }
210:
211: /**
212: * Retrieve a FeatureReader for the geometry attributes only, designed for bounds computation
213: */
214: protected FeatureReader boundsReader() throws IOException {
215: List attributes = new ArrayList();
216: FeatureType schema = featureSource.getSchema();
217: for (int i = 0; i < schema.getAttributeCount(); i++) {
218: AttributeType at = schema.getAttributeType(i);
219: if (at instanceof GeometricAttributeType)
220: attributes.add(at.getName());
221: }
222:
223: DefaultQuery q = new DefaultQuery(query);
224: q.setPropertyNames(attributes);
225: FeatureReader reader = featureSource.getDataStore()
226: .getFeatureReader(q, getTransaction());
227: int maxFeatures = query.getMaxFeatures();
228:
229: if (maxFeatures == Integer.MAX_VALUE) {
230: return reader;
231: } else {
232: return new MaxFeatureReader(reader, maxFeatures);
233: }
234: }
235:
236: /**
237: * Returns the bounding box of this FeatureResults
238: *
239: * <p>
240: * This implementation will generate the correct results from reader() if
241: * the provided FeatureSource does not provide an optimized result via
242: * FeatureSource.getBounds( Query ).
243: * </p>
244: * If the feature has no geometry, then an empty envelope is returned.
245: *
246: *
247: * @throws DataSourceException See IOException
248: *
249: * @see org.geotools.data.FeatureResults#getBounds()
250: */
251: public ReferencedEnvelope getBounds() {
252: Envelope bounds;
253:
254: try {
255: bounds = featureSource.getBounds(query);
256: } catch (IOException e1) {
257: bounds = new Envelope();
258: }
259:
260: if (bounds == null) {
261: try {
262: Feature feature;
263: bounds = new Envelope();
264:
265: FeatureReader reader = boundsReader();
266:
267: while (reader.hasNext()) {
268: feature = reader.next();
269: bounds.expandToInclude(feature.getBounds());
270: }
271:
272: reader.close();
273: } catch (IllegalAttributeException e) {
274: //throw new DataSourceException("Could not read feature ", e);
275: bounds = new Envelope();
276: } catch (IOException e) {
277: bounds = new Envelope();
278: }
279: }
280:
281: return ReferencedEnvelope.reference(bounds);
282: }
283:
284: /**
285: * Number of Features in this query.
286: *
287: * <p>
288: * This implementation will generate the correct results from reader() if
289: * the provided FeatureSource does not provide an optimized result via
290: * FeatureSource.getCount( Query ).
291: * </p>
292: *
293: *
294: * @throws IOException If feature could not be read
295: * @throws DataSourceException See IOException
296: *
297: * @see org.geotools.data.FeatureResults#getCount()
298: */
299: public int getCount() throws IOException {
300: int count;
301: count = featureSource.getCount(query);
302:
303: if (count != -1) {
304: // optimization worked, return maxFeatures if count is
305: // greater.
306: int maxFeatures = query.getMaxFeatures();
307: return (count < maxFeatures) ? count : maxFeatures;
308: }
309:
310: // Okay lets count the FeatureReader
311: try {
312: count = 0;
313:
314: FeatureReader reader = reader();
315:
316: for (; reader.hasNext(); count++) {
317: reader.next();
318: }
319:
320: reader.close();
321:
322: return count;
323: } catch (IllegalAttributeException e) {
324: throw new DataSourceException("Could not read feature ", e);
325: }
326: }
327:
328: public FeatureCollection collection() throws IOException {
329: try {
330: FeatureCollection collection = FeatureCollections
331: .newCollection();
332: //Feature feature;
333: FeatureReader reader = reader();
334: //FeatureType type = reader.getFeatureType();
335: while (reader.hasNext()) {
336: collection.add(reader.next());
337: }
338: reader.close();
339:
340: return collection;
341: } catch (IllegalAttributeException e) {
342: throw new DataSourceException("Could not read feature ", e);
343: }
344: }
345:
346: }
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