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Collection of methods to fetch spatial metadata in SFS database like PostGIS or H2Spatial.
Theses functions can be commonly used either in PostGIS or in H2.
Spatial utilities publish also a DataSourceFactory wrapper that provide JDBC Wrapper for spatial functionality.
/*
* h2spatial is a library that brings spatial support to the H2 Java database.
*
* h2spatial is distributed under GPL 3 license. It is produced by the "Atelier SIG"
* team of the IRSTV Institute geometryFields = getGeometryFields(connection, location);
if(geometryFields.isEmpty()) {
throw new SQLException("The table "+location+" does not contain a Geometry field, then geometry type cannot be computed");
}
fieldName = geometryFields.get(0);
}
ResultSet geomResultSet = getGeometryColumnsView(connection,location.getCatalog(),location.getSchema(),location.getTable());
while(geomResultSet.next()) {
if(fieldName.isEmpty() || geomResultSet.getString("F_GEOMETRY_COLUMN").equalsIgnoreCase(fieldName)) {
return geomResultSet.getInt("GEOMETRY_TYPE");
}
}
throw new SQLException("Field not found "+fieldName);
}
/**
* In order to be able to use {@link ResultSet#unwrap(Class)} and
* {@link java.sql.ResultSetMetaData#unwrap(Class)} to get {@link SpatialResultSet} and
* {@link SpatialResultSetMetaData} this method wrap the provided dataSource.
* @param dataSource H2 or PostGIS DataSource
* @return Wrapped DataSource, with spatial methods
*/
public static DataSource wrapSpatialDataSource(DataSource dataSource) {
return new DataSourceWrapper(dataSource);
}
/**
* Use this only if DataSource is not available.
* In order to be able to use {@link ResultSet#unwrap(Class)} and
* {@link java.sql.ResultSetMetaData#unwrap(Class)} to get {@link SpatialResultSet} and
* {@link SpatialResultSetMetaData} this method wrap the provided connection.
* @param connection H2 or PostGIS Connection
* @return Wrapped DataSource, with spatial methods
*/
public static Connection wrapConnection(Connection connection) {
return new ConnectionWrapper(connection);
}
/**
* Convert catalog.schema.table, schema.table or table into TableLocation instance.
* Not specified schema or catalog are converted into an empty string.
* @param concatenatedTableLocation Table location
* @return Java beans for table location
*/
public static TableLocation splitCatalogSchemaTableName(String concatenatedTableLocation) {
return TableLocation.parse(concatenatedTableLocation);
}
/**
* Merge the bounding box of all geometries inside the provided table.
* @param connection Active connection (not closed by this function)
* @param location Location of the table
* @param geometryField Geometry field or empty string (take the first geometry field)
* @return Envelope of the table
* @throws SQLException If the table not exists, empty or does not contain a geometry field.
*/
public static Envelope getTableEnvelope(Connection connection, TableLocation location, String geometryField) throws SQLException {
if(geometryField==null || geometryField.isEmpty()) {
List geometryFields = getGeometryFields(connection, location);
if(geometryFields.isEmpty()) {
throw new SQLException("The table "+location+" does not contain a Geometry field, then the extent cannot be computed");
}
geometryField = geometryFields.get(0);
}
ResultSet rs = connection.createStatement().executeQuery("SELECT ST_Extent("+geometryField+") ext FROM "+location);
if(rs.next()) {
// Todo under postgis it is a BOX type
return (Envelope)rs.getObject(1);
}
throw new SQLException("Unable to get the table extent it may be empty");
}
/**
* Find geometry fields name of a table.
* @param connection Active connection
* @param location Table location
* @return A list of Geometry fields name
* @throws SQLException
*/
public static List getGeometryFields(Connection connection,TableLocation location) throws SQLException {
return getGeometryFields(connection, location.getCatalog(), location.getSchema(), location.getTable());
}
private static ResultSet getGeometryColumnsView(Connection connection,String catalog, String schema, String table) throws SQLException {
Integer catalogIndex = null;
Integer schemaIndex = null;
Integer tableIndex = 1;
StringBuilder sb = new StringBuilder("SELECT * from geometry_columns where ");
if(!catalog.isEmpty()) {
sb.append("UPPER(f_table_catalog) = ? AND ");
catalogIndex = 1;
tableIndex++;
}
if(!schema.isEmpty()) {
sb.append("UPPER(f_table_schema) = ? AND ");
schemaIndex = tableIndex;
tableIndex++;
}
sb.append("UPPER(f_table_name) = ? ");
PreparedStatement geomStatement = connection.prepareStatement(sb.toString());
if(catalogIndex!=null) {
geomStatement.setString(catalogIndex,catalog.toUpperCase());
}
if(schemaIndex!=null) {
geomStatement.setString(schemaIndex,schema.toUpperCase());
}
geomStatement.setString(tableIndex,table.toUpperCase());
return geomStatement.executeQuery();
}
/**
* Find geometry fields name of a table.
* @param connection Active connection
* @param catalog Catalog that contain schema (empty for default catalog)
* @param schema Schema that contain table (empty for default schema)
* @param table Table name (case insensitive)
* @return A list of Geometry fields name
* @throws SQLException
*/
public static List getGeometryFields(Connection connection,String catalog, String schema, String table) throws SQLException {
List fieldsName = new LinkedList();
ResultSet geomResultSet = getGeometryColumnsView(connection,catalog,schema,table);
while (geomResultSet.next()) {
fieldsName.add(geomResultSet.getString("f_geometry_column"));
}
geomResultSet.close();
return fieldsName;
}
}