/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2009, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.jdbc;
import java.io.IOException;
import java.io.StringWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import org.geotools.data.jdbc.FilterToSQL;
import org.opengis.feature.simple.SimpleFeatureType;
import org.opengis.feature.type.GeometryDescriptor;
import org.opengis.filter.expression.Literal;
import com.vividsolutions.jts.geom.Geometry;
/**
*
*
* @source $URL$
*/
public abstract class BasicSQLDialect extends SQLDialect {
protected BasicSQLDialect(JDBCDataStore dataStore) {
super(dataStore);
}
/**
* Encodes a value in an sql statement.
* <p>
* Subclasses may wish to override or extend this method to handle specific
* types. This default implementation does the following:
* <ol>
* <li>The <tt>value</tt> is encoded via its {@link #toString()} representation.
* <li>If <tt>type</tt> is a character type (extends {@link CharSequence}),
* it is wrapped in single quotes (').
* </ol>
* </p>
*
*/
public void encodeValue(Object value, Class type, StringBuffer sql) {
//turn the value into a literal and use FilterToSQL to encode it
Literal literal = dataStore.getFilterFactory().literal( value );
FilterToSQL filterToSQL = dataStore.createFilterToSQL(null);
StringWriter w = new StringWriter();
filterToSQL.setWriter(w);
filterToSQL.visit(literal,type);
sql.append( w.getBuffer().toString() );
// if (CharSequence.class.isAssignableFrom(type)) {
// sql.append("'").append(value).append("'");
// } else {
// sql.append(value);
// }
}
/**
* Encodes a geometry value in an sql statement.
* <p>
* An implementations should serialize <tt>value</tt> into some exchange
* format which will then be transported to the underlying database. For
* example, consider an implementation which converts a geometry into its
* well known text representation:
* <pre>
* <code>
* sql.append( "GeomFromText('" );
* sql.append( new WKTWriter().write( value ) );
* sql.append( ")" );
* </code>
* </pre>
* </p>
* <p>
* The <tt>srid</tt> parameter is the spatial reference system identifier
* of the geometry, or 0 if not known.
* </p>
* <p>
* Attention should be paid to emtpy geometries (<code>g.isEmtpy() == true</code>) as
* they cannot be encoded in WKB and several databases fail to handle them property.
* Common treatment is to equate them to NULL</p>
*/
public abstract void encodeGeometryValue(Geometry value, int dimension, int srid, StringBuffer sql)
throws IOException;
/**
* Creates the filter encoder to be used by the datastore when encoding
* query predicates.
* <p>
* Sublcasses can override this method to return a subclass of {@link FilterToSQL}
* if need be.
* </p>
*/
public FilterToSQL createFilterToSQL() {
FilterToSQL f2s = new FilterToSQL();
f2s.setCapabilities(BASE_DBMS_CAPABILITIES);
return f2s;
}
/**
* Callback invoked before a SELECT statement is executed against the database.
* <p>
* The callback is provided with both the statement being executed and the database connection.
* Neither should be closed. Any statements created from the connection however in this method
* should be closed.
* </p>
* @param select The select statement being executed
* @param cx The database connection
* @param featureType The feature type the select is executing against.
*
* @throws SQLException
*/
public void onSelect(Statement select, Connection cx, SimpleFeatureType featureType) throws SQLException {
}
/**
* Callback invoked before a DELETE statement is executed against the database.
* <p>
* The callback is provided with both the statement being executed and the database connection.
* Neither should be closed. Any statements created from the connection however in this method
* should be closed.
* </p>
* @param delete The delete statement being executed
* @param cx The database connection
* @param featureType The feature type the delete is executing against.
*
* @throws SQLException
*/
public void onDelete(Statement delete, Connection cx, SimpleFeatureType featureType) throws SQLException {
}
/**
* Callback invoked before an INSERT statement is executed against the database.
* <p>
* The callback is provided with both the statement being executed and the database connection.
* Neither should be closed. Any statements created from the connection however in this method
* should be closed.
* </p>
* @param insert The delete statement being executed
* @param cx The database connection
* @param featureType The feature type the insert is executing against.
*
* @throws SQLException
*/
public void onInsert(Statement insert, Connection cx, SimpleFeatureType featureType) throws SQLException {
}
/**
* Callback invoked before an UPDATE statement is executed against the database.
* <p>
* The callback is provided with both the statement being executed and the database connection.
* Neither should be closed. Any statements created from the connection however in this method
* should be closed.
* </p>
* @param update The delete statement being executed
* @param cx The database connection
* @param featureType The feature type the update is executing against.
*
* @throws SQLException
*/
public void onUpdate(Statement update, Connection cx, SimpleFeatureType featureType) throws SQLException {
}
}