GeoWaveFeatureWriter.java

package mil.nga.giat.geowave.adapter.vector.plugin;

import java.io.IOException;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.UUID;

import mil.nga.giat.geowave.adapter.vector.plugin.transaction.GeoWaveTransaction;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.geotools.data.FeatureWriter;
import org.geotools.feature.simple.SimpleFeatureBuilder;
import org.geotools.util.Utilities;
import org.opengis.feature.simple.SimpleFeature;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.AttributeDescriptor;

/**
 * This class wraps a geotools data store as well as one for statistics (for
 * example to display Heatmaps) into a GeoTools FeatureReader for simple feature
 * data. It acts as a helper for GeoWave's GeoTools data store.
 * 
 */
public class GeoWaveFeatureWriter implements
		FeatureWriter<SimpleFeatureType, SimpleFeature>
{

	private SimpleFeature original = null;
	private SimpleFeature live = null;
	private final GeoWaveTransaction transaction;
	private final GeoWaveFeatureReader myReader;
	private final SimpleFeatureType featureType;

	public GeoWaveFeatureWriter(
			final GeoWaveDataStoreComponents components,
			final GeoWaveTransaction transaction,
			final GeoWaveFeatureReader reader ) {
		this.transaction = transaction;
		myReader = reader;
		featureType = components.getAdapter().getFeatureType();
	}

	@Override
	public void close()
			throws IOException {

	}

	@Override
	public SimpleFeatureType getFeatureType() {
		return featureType;
	}

	@Override
	public boolean hasNext()
			throws IOException {
		return ((myReader != null) && myReader.hasNext());
	}

	@Override
	public SimpleFeature next()
			throws IOException,
			IllegalArgumentException,
			NoSuchElementException {
		if (hasNext()) {
			original = myReader.next();
			final List<AttributeDescriptor> descriptors = featureType.getAttributeDescriptors();
			final Object[] defaults = new Object[descriptors.size()];
			int p = 0;
			for (final AttributeDescriptor descriptor : descriptors) {
				defaults[p++] = original.getAttribute(descriptor.getName());
			}
			live = SimpleFeatureBuilder.build(
					featureType,
					defaults,
					original.getID());
		}
		else {
			original = null;
			final List<AttributeDescriptor> descriptors = featureType.getAttributeDescriptors();
			final Object[] defaults = new Object[descriptors.size()];
			int p = 0;
			for (final AttributeDescriptor descriptor : descriptors) {
				defaults[p++] = descriptor.getDefaultValue();
			}

			live = SimpleFeatureBuilder.build(
					featureType,
					defaults,
					UUID.randomUUID().toString());
		}
		return live;
	}

	@Override
	public void remove()
			throws IOException {
		transaction.remove(
				live.getID(),
				live);
	}

	private final static Logger LOGGER = LoggerFactory.getLogger(GeoWaveFeatureWriter.class);

	@Override
	public void write()
			throws IOException {
		if (live == null) {
			LOGGER.error("Unable to process transaction " + transaction.toString());
			throw new IOException(
					"No current feature to write");
		}

		if (original == null) {
			transaction.add(
					live.getID(),
					live);
		}
		else if (!Utilities.deepEquals(
				live,
				original)) {
			transaction.modify(
					live.getID(),
					original,
					live);
		}
		original = null;
		live = null;
	}

}