/**
* Clean up resources associated with this writer.
*
* <p>Diff is not clear()ed as it is assumed that it belongs to a Transaction.State object and may
* yet be written out.
*
* @see org.geotools.data.FeatureWriter#close()
*/
public void close() throws IOException {
if (reader != null) {
reader.close();
reader = null;
}
current = null;
live = null;
next = null;
diff = null;
}
/**
* Query for more content.
*
* @see org.geotools.data.FeatureWriter#hasNext()
*/
public boolean hasNext() throws IOException {
if (next != null) {
// we found next already
return true;
}
live = null;
current = null;
if (reader.hasNext()) {
try {
next = reader.next();
} catch (NoSuchElementException e) {
throw new DataSourceException("No more content", e);
} catch (IllegalAttributeException e) {
throw new DataSourceException("No more content", e);
}
return true;
}
return false;
}
/**
* Supplys FeatureTypeFrom reader
*
* @see org.geotools.data.FeatureWriter#getFeatureType()
*/
public SimpleFeatureType getFeatureType() {
return reader.getFeatureType();
}
// Jody - Recomend moving to the following
// When we are ready for CoordinateSystem support
public FeatureReader<SimpleFeatureType, SimpleFeature> getFeatureReader(
Query query, Transaction transaction) throws IOException {
Filter filter = query.getFilter();
String typeName = query.getTypeName();
String propertyNames[] = query.getPropertyNames();
if (filter == null) {
throw new NullPointerException(
"getFeatureReader requires Filter: " + "did you mean Filter.INCLUDE?");
}
if (typeName == null) {
throw new NullPointerException(
"getFeatureReader requires typeName: "
+ "use getTypeNames() for a list of available types");
}
if (transaction == null) {
throw new NullPointerException(
"getFeatureReader requires Transaction: "
+ "did you mean to use Transaction.AUTO_COMMIT?");
}
SimpleFeatureType featureType = getSchema(query.getTypeName());
if (propertyNames != null || query.getCoordinateSystem() != null) {
try {
featureType =
DataUtilities.createSubType(featureType, propertyNames, query.getCoordinateSystem());
} catch (SchemaException e) {
LOGGER.log(Level.FINEST, e.getMessage(), e);
throw new DataSourceException("Could not create Feature Type for query", e);
}
}
if (filter == Filter.EXCLUDE || filter.equals(Filter.EXCLUDE)) {
return new EmptyFeatureReader<SimpleFeatureType, SimpleFeature>(featureType);
}
// GR: allow subclases to implement as much filtering as they can,
// by returning just it's unsupperted filter
filter = getUnsupportedFilter(typeName, filter);
if (filter == null) {
throw new NullPointerException(
"getUnsupportedFilter shouldn't return null. Do you mean Filter.INCLUDE?");
}
// There are cases where the readers have to lock. Take shapefile for example. Getting a
// Reader causes
// the file to be locked. However on a commit TransactionStateDiff locks before a writer is
// obtained. In order to
// prevent deadlocks either the diff has to obtained first or the reader has to be obtained
// first.
// Because shapefile writes to a buffer first the actual write lock is not flipped until the
// transaction has most of the work
// done. As a result I suggest getting the diff first then getting the reader.
// JE
Diff diff = null;
if (transaction != Transaction.AUTO_COMMIT) {
TransactionStateDiff state = state(transaction);
if (state != null) {
diff = state.diff(typeName);
}
}
// This calls our subclass "simple" implementation
// All other functionality will be built as a reader around
// this class
//
FeatureReader<SimpleFeatureType, SimpleFeature> reader = getFeatureReader(typeName, query);
if (diff != null)
reader =
new DiffFeatureReader<SimpleFeatureType, SimpleFeature>(reader, diff, query.getFilter());
if (!filter.equals(Filter.INCLUDE)) {
reader = new FilteringFeatureReader<SimpleFeatureType, SimpleFeature>(reader, filter);
}
if (!featureType.equals(reader.getFeatureType())) {
LOGGER.fine("Recasting feature type to subtype by using a ReTypeFeatureReader");
reader = new ReTypeFeatureReader(reader, featureType, false);
}
if (query.getMaxFeatures() != Query.DEFAULT_MAX) {
reader =
new MaxFeatureReader<SimpleFeatureType, SimpleFeature>(reader, query.getMaxFeatures());
}
return reader;
}
