Commit 046ac691 authored by Grégory Mantelet's avatar Grégory Mantelet
Browse files

[ADQL] Efficient PgSphere translation of the Preferred X-Match Syntax described 

in the ADQL-2.1 standard (in section 4.2.7).

Currently, geometries are not translated in MySQL and MS-SQL Server translators.
So, the preferred xmatch syntax has not been implemented in these translators.
parent 5cc544e4

src/adql/translator/PgSphereTranslator.java

+133 −57
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ package adql.translator; 
 * You should have received a copy of the GNU Lesser General Public License

 * along with ADQLLibrary.  If not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright 2012-2017 - UDS/Centre de Données astronomiques de Strasbourg (CDS),

 * Copyright 2012-2019 - UDS/Centre de Données astronomiques de Strasbourg (CDS),

 *                       Astronomisches Rechen Institut (ARI)

 */
@@ -32,6 +32,8 @@ import adql.parser.grammar.ParseException; 
import adql.query.TextPosition;

import adql.query.constraint.Comparison;

import adql.query.constraint.ComparisonOperator;

import adql.query.operand.ADQLOperand;

import adql.query.operand.StringConstant;

import adql.query.operand.function.geometry.AreaFunction;

import adql.query.operand.function.geometry.BoxFunction;

import adql.query.operand.function.geometry.CentroidFunction;
@@ -51,8 +53,15 @@ import adql.query.operand.function.geometry.PolygonFunction; 
 * 	class. The other functions are managed by {@link PostgreSQLTranslator}.

 * </p>

 *

 * <p><i><b>Implementation note:</b>

 * 	The preferred xmatch syntax described in the section 4.2.7 of the ADQL

 * 	standard (here ADQL-2.1) is implemented here so that such query is as

 * 	efficient as a <code>CONTAINS(POINT(...), CIRCLE(...)) = 1</code>.

 * 	See {@link #translate(adql.query.constraint.Comparison)} for more details.

 * </i></p>

 *

 * @author Gr&eacute;gory Mantelet (CDS;ARI)

 * @version 1.4 (07/2017)

 * @version 2.0 (08/2019)

 */

public class PgSphereTranslator extends PostgreSQLTranslator {
@@ -201,14 +210,80 @@ public class PgSphereTranslator extends PostgreSQLTranslator { 


	@Override

	public String translate(Comparison comp) throws TranslationException {



		// CONTAINS or INTERSECTS(...) on left:

		if ((comp.getLeftOperand() instanceof ContainsFunction || comp.getLeftOperand() instanceof IntersectsFunction) && (comp.getOperator() == ComparisonOperator.EQUAL || comp.getOperator() == ComparisonOperator.NOT_EQUAL) && comp.getRightOperand().isNumeric())

			return translate(comp.getLeftOperand()) + " " + comp.getOperator().toADQL() + " '" + translate(comp.getRightOperand()) + "'";



		// CONTAINS or INTERSECTS(...) on right:

		else if ((comp.getRightOperand() instanceof ContainsFunction || comp.getRightOperand() instanceof IntersectsFunction) && (comp.getOperator() == ComparisonOperator.EQUAL || comp.getOperator() == ComparisonOperator.NOT_EQUAL) && comp.getLeftOperand().isNumeric())

			return "'" + translate(comp.getLeftOperand()) + "' " + comp.getOperator().toADQL() + " " + translate(comp.getRightOperand());



		// Preferred xmatch syntax described in the ADQL standard:

		else if (isPreferredXmatchSyntax(comp)) {

			// extract the DISTANCE and its compared value:

			DistanceFunction distFct;

			ADQLOperand numericOperand;

			if (comp.getLeftOperand() instanceof DistanceFunction) {

				distFct = (DistanceFunction)comp.getLeftOperand();

				numericOperand = comp.getRightOperand();

			} else {

				distFct = (DistanceFunction)comp.getRightOperand();

				numericOperand = comp.getLeftOperand();

			}

			try {

				// build the CIRCLE to use in the artificial CONTAINS:

				CircleFunction circleFct = new CircleFunction(new StringConstant(""), ((PointFunction)distFct.getParameter(1)).getCoord1(), ((PointFunction)distFct.getParameter(1)).getCoord2(), numericOperand);

				// adapt the translation in function of the comp. operator:

				switch(comp.getOperator()) {

					case LESS_THAN:

						return "((" + translate(distFct.getParameter(0)) + " @ " + translate(circleFct) + ") = '1' AND " + super.translate(comp) + ")";

					case LESS_OR_EQUAL:

						return "((" + translate(distFct.getParameter(0)) + " @ " + translate(circleFct) + ") = '1'" + ")";

					case GREATER_THAN:

						return "((" + translate(distFct.getParameter(0)) + " @ " + translate(circleFct) + ") = '0' AND " + super.translate(comp) + ")";

					case GREATER_OR_EQUAL:

						return "((" + translate(distFct.getParameter(0)) + " @ " + translate(circleFct) + ") = '0'" + ")";

					default: // theoretically, this case never happens!

						return super.translate(comp);

				}

			} catch(Exception ex) {

				throw new TranslationException("Impossible to translate the following xmatch syntax: \"" + comp.toADQL() + "\"! Cause: " + ex.getMessage(), ex);

			}

		}

		// Any other comparison:

		else

			return super.translate(comp);

	}



	/**

	 * Test whether the given comparison corresponds to the preferred xmatch

	 * syntax described in the ADQL standard.

	 *

	 * <p>

	 * 	In other words, this function returns <code>true</code> if the following

	 * 	conditions are met:

	 * </p>

	 * <ul>

	 * 	<li>the left operand is DISTANCE and the right one is a numeric,

	 * 		or vice-versa,</li>

	 * 	<li>and the comparison operator is &lt;, &le;, &gt; or &ge;.</li>

	 * </ul>

	 *

	 * @param comp	The comparison to test.

	 *

	 * @return	<code>true</code> if it corresponds to a valid xmatch syntax,

	 *        	<code>false</code> otherwise.

	 *

	 * @since 2.0

	 */

	protected boolean isPreferredXmatchSyntax(final Comparison comp) {

		if ((comp.getLeftOperand() instanceof DistanceFunction && comp.getRightOperand().isNumeric()) || (comp.getLeftOperand().isNumeric() && comp.getRightOperand() instanceof DistanceFunction))

			return (comp.getOperator() == ComparisonOperator.LESS_THAN || comp.getOperator() == ComparisonOperator.LESS_OR_EQUAL || comp.getOperator() == ComparisonOperator.GREATER_THAN || comp.getOperator() == ComparisonOperator.GREATER_OR_EQUAL);

		else

			return false;

	}



	@Override

	public DBType convertTypeFromDB(final int dbmsType, final String rawDbmsTypeName, String dbmsTypeName, final String[] params) {

		// If no type is provided return VARCHAR:
@@ -427,7 +502,8 @@ public class PgSphereTranslator extends PostgreSQLTranslator { 
		/**

		 * Build the PgSphere parser.

		 */

		public PgSphereGeometryParser(){}

		public PgSphereGeometryParser() {

		}



		/**

		 * Prepare the parser in order to read the given PgSphere expression.

test/adql/translator/TestPgSphereTranslator.java

+72 −34
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ import org.postgresql.util.PGobject; 
import adql.db.DBType;

import adql.db.DBType.DBDatatype;

import adql.db.STCS.Region;

import adql.parser.ADQLParser;

import adql.parser.grammar.ParseException;

import adql.query.operand.NumericConstant;

import adql.query.operand.StringConstant;
@@ -30,16 +31,20 @@ import adql.query.operand.function.geometry.GeometryFunction.GeometryValue; 
public class TestPgSphereTranslator {



	@BeforeClass

	public static void setUpBeforeClass() throws Exception{}

	public static void setUpBeforeClass() throws Exception {

	}



	@AfterClass

	public static void tearDownAfterClass() throws Exception{}

	public static void tearDownAfterClass() throws Exception {

	}



	@Before

	public void setUp() throws Exception{}

	public void setUp() throws Exception {

	}



	@After

	public void tearDown() throws Exception{}

	public void tearDown() throws Exception {

	}



	@Test

	public void testTranslateCentroidFunction() {
@@ -349,4 +354,37 @@ public class TestPgSphereTranslator { 
		}

	}



	@Test

	public void testTranslateXMatch() {

		PgSphereTranslator translator = new PgSphereTranslator();

		ADQLParser parser = new ADQLParser();



		try {

			// CASE: CONTAINS(POINT, CIRCLE) = 1

			assertEquals("(spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.))) = '1'", translator.translate(parser.parseWhere("WHERE CONTAINS(POINT('', ra, dec), CIRCLE('', 0, 0, 1.)) = 1").get(0)));



			// CASE: 1 = CONTAINS(POINT, CIRCLE)

			assertEquals("'1' = (spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.)))", translator.translate(parser.parseWhere("WHERE 1=CONTAINS(POINT('', ra, dec), CIRCLE('', 0, 0, 1.))").get(0)));



			// CASE: DISTANCE(...) <= 1

			assertEquals("((spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.))) = '1')", translator.translate(parser.parseWhere("WHERE DISTANCE(POINT('', ra, dec), POINT('', 0, 0)) <= 1.").get(0)));



			// CASE: DISTANCE(...) >= 1

			assertEquals("((spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.))) = '0')", translator.translate(parser.parseWhere("WHERE DISTANCE(POINT('', ra, dec), POINT('', 0, 0)) >= 1.").get(0)));



			// CASE: DISTANCE(...) < 1

			assertEquals("((spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.))) = '1' AND degrees(spoint(radians(ra),radians(dec)) <-> spoint(radians(0),radians(0))) < 1.)", translator.translate(parser.parseWhere("WHERE DISTANCE(POINT('', ra, dec), POINT('', 0, 0)) < 1.").get(0)));



			// CASE: DISTANCE(...) > 1

			assertEquals("((spoint(radians(ra),radians(dec)) @ scircle(spoint(radians(0),radians(0)),radians(1.))) = '0' AND degrees(spoint(radians(ra),radians(dec)) <-> spoint(radians(0),radians(0))) > 1.)", translator.translate(parser.parseWhere("WHERE DISTANCE(POINT('', ra, dec), POINT('', 0, 0)) > 1.").get(0)));



		} catch(ParseException pe) {

			pe.printStackTrace();

			fail("Failed parsing before translation!");

		} catch(Exception ex) {

			ex.printStackTrace();

			fail("Unexpected failure of xmatch translation! (see console for more details)");

		}

	}



}