EPSGResolveCache.java

/*
 * Copyright (c) 2015 Data Harmonisation Panel
 * 
 * All rights reserved. This program and the accompanying materials are made
 * available under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     Data Harmonisation Panel <http://www.dhpanel.eu>
 */

package eu.esdihumboldt.hale.common.instance.geometry.impl;

import java.util.HashMap;
import java.util.Map;

import org.geotools.gml2.SrsSyntax;
import org.geotools.referencing.CRS;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;

import eu.esdihumboldt.hale.common.instance.geometry.CRSResolveCache;
import eu.esdihumboldt.hale.common.schema.geometry.CRSDefinition;

/**
 * Tries to resolve a CRS against the EPSG database.
 * 
 * @author Simon Templer
 */
public class EPSGResolveCache implements CRSResolveCache {

	private final Map<CoordinateReferenceSystem, CRSDefinition> cached = new HashMap<>();

	@Override
	public CRSDefinition resolveCRS(final CoordinateReferenceSystem crs) {
		CRSDefinition result = cached.get(crs);
		if (result == null) {
			try {
				Integer epsgCode = CRS.lookupEpsgCode(crs, true);
				if (epsgCode != null) {
					String code = SrsSyntax.OGC_URN + String.valueOf(epsgCode);
					CoordinateReferenceSystem resolved = CRS.decode(code);
					result = new CodeDefinition(code, resolved);
				}
			} catch (FactoryException e) {
				// ignore
			}

			if (result == null) {
				// prevent further lookups of this CRS
				result = new WKTDefinition(crs.toWKT(), crs);
			}

			cached.put(crs, result);
		}

		return result;
	}

}