Package org.geotools.data.informix

Class InformixDialect

Object

SQLDialect

BasicSQLDialect

InformixDialect

public class InformixDialect
extends BasicSQLDialect

Informix database dialect based on basic (non-prepared) statements.

Author:

George Dewar, Land Information New Zealand, Ines Falcao, Land Information New Zealand

Field Summary

Fields inherited from class SQLDialect

BASE_DBMS_CAPABILITIES, dataStore, forceLongitudeFirst, LOGGER, UNWRAPPER_NOT_FOUND, uwMap

Constructor Summary

Constructors

Constructor	Description
InformixDialect(JDBCDataStore dataStore)

Method Summary

Modifier and Type	Method	Description
void	applyLimitOffset(StringBuffer sql, int limit, int offset)	Alters the query provided so that limit and offset are natively dealt with.
FilterToSQL	createFilterToSQL()	Creates the filter encoder to be used by the datastore when encoding query predicates.
Envelope	decodeGeometryEnvelope(ResultSet rs, int column, Connection cx)	Decodes the result of a spatial extent function in a SELECT statement.
Geometry	decodeGeometryValue(GeometryDescriptor descriptor, ResultSet rs, String column, GeometryFactory factory, Connection cx, Hints hints)	Decodes a geometry value from the result of a query.
void	encodeGeometryColumn(GeometryDescriptor gatt, String prefix, int srid, Hints hints, StringBuffer sql)	Encodes the name of a geometry column in a SELECT statement.
void	encodeGeometryEnvelope(String tableName, String geometryColumn, StringBuffer sql)	Encodes the spatial extent function of a geometry column in a SELECT statement.
void	encodeGeometryValue(Geometry value, int dimension, int srid, StringBuffer sql)	Encodes a geometry value in an sql statement.
void	encodePostColumnCreateTable(AttributeDescriptor att, StringBuffer sql)	Encodes anything post a column in a CREATE TABLE statement.
void	encodePrimaryKey(String column, StringBuffer sql)	Encodes the primary key definition in a CREATE TABLE statement.
Integer	getGeometrySRID(String schemaName, String tableName, String columnName, Connection cx)	Returns the spatial reference system identifier (srid) for a particular geometry column.
String	getGeometryTypeName(Integer type)	Returns the name of a geometric type based on its integer constant.
Object	getLastAutoGeneratedValue(String schemaName, String tableName, String columnName, Connection cx)	Obtains the last value of an auto generated column.
String	getNameEscape()	Returns the string used to escape names.
List<ReferencedEnvelope>	getOptimizedBounds(String schema, SimpleFeatureType featureType, Connection cx)	Returns the bounds of all geometry columns in the layer using any approach that proves to be faster than the plain bounds aggregation (e.g., better than the "plain select extent(geom) from table" on PostGIS), or null if none exists or the fast method has not been enabled (e.g., if the fast method is just an estimate of the bounds you probably want the user to enable it manually)
boolean	includeTable(String schemaName, String tableName, Connection cx)	Determines if the specified table should be included in those published by the datastore.
boolean	isLimitOffsetSupported()	Returns true if this dialect can encode both Query.getStartIndex() and Query.getMaxFeatures() into native SQL.
boolean	lookupGeneratedValuesPostInsert()	Controls whether keys are looked up post or pre insert.
void	postCreateTable(String schemaName, SimpleFeatureType featureType, Connection cx)	Callback to execute any additional sql statements post a create table statement.
void	registerClassToSqlMappings(Map<Class<?>,Integer> mappings)	Registers the java type to sql type mappings that the datastore uses when reading and writing objects to and from the database. *
void	registerSqlTypeNameToClassMappings(Map<String,Class<?>> mappings)	Registers the sql type name to java type mappings that the dialect uses when reading and writing objects to and from the database.

Methods inherited from class BasicSQLDialect

encodeValue, onDelete, onInsert, onSelect, onUpdate

Methods inherited from class SQLDialect

addSupportedHints, applyHintsOnVirtualTables, canGroupOnGeometry, canSimplifyPoints, convertValue, createCRS, createIndex, decodeGeometryValue, dropIndex, encodeColumnAlias, encodeColumnName, encodeColumnType, encodeCreateTable, encodeGeometryColumnGeneralized, encodeGeometryColumnSimplified, encodeJoin, encodeNextSequenceValue, encodePostCreateTable, encodePostSelect, encodeSchemaName, encodeTableAlias, encodeTableName, escapeName, getAggregateConverter, getDefaultVarcharSize, getDesiredTablesType, getGeometryDimension, getIndexes, getLastAutoGeneratedValue, getMapping, getMapping, getNextAutoGeneratedValue, getNextSequenceValue, getPkColumnValue, getPrimaryKey, getRestrictions, getResultTypes, getSequenceForColumn, getSQLType, handleSelectHints, handleUserDefinedType, initializeConnection, isAggregatedSortSupported, isArray, isAutoCommitQuery, isGroupBySupported, ne, postCreateAttribute, postCreateFeatureType, postDropTable, preDropTable, registerAggregateFunctions, registerSqlTypeToClassMappings, registerSqlTypeToSqlTypeNameOverrides, splitFilter, supportsSchemaForIndex, unwrapConnection

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

InformixDialect

public InformixDialect(JDBCDataStore dataStore)

Method Details

includeTable

public boolean includeTable(String schemaName,
 String tableName,
 Connection cx)
                     throws SQLException

Description copied from class: SQLDialect

Determines if the specified table should be included in those published by the datastore.

This method returns true if the table should be published as a feature type, otherwise it returns false. Subclasses should override this method, this default implementation returns true.

A database connection is provided to the dialect but it should not be closed. However any statements objects or result sets that are instantiated from it must be closed.

Overrides:

includeTable in class SQLDialect

Parameters:

schemaName - The schema of the table, might be null..

tableName - The name of the table.

cx - Database connection.

Throws:

SQLException

getNameEscape

public String getNameEscape()

Description copied from class: SQLDialect

Returns the string used to escape names.

This value is used to escape any name in a query. This includes columns, tables, schemas, indexes, etc... If no escape is necessary this method should return the empty string, and never return null.

This default implementation returns a single double quote ("), subclasses must override to provide a different espcape.

Overrides:

getNameEscape in class SQLDialect

getGeometryTypeName

public String getGeometryTypeName(Integer type)

Description copied from class: SQLDialect

Returns the name of a geometric type based on its integer constant.

The constant, type, is registered in SQLDialect.registerSqlTypeNameToClassMappings(Map).

This default implementation returns null, subclasses should override.

Overrides:

getGeometryTypeName in class SQLDialect

getGeometrySRID

public Integer getGeometrySRID(String schemaName,
 String tableName,
 String columnName,
 Connection cx)
                        throws SQLException

Description copied from class: SQLDialect

Returns the spatial reference system identifier (srid) for a particular geometry column.

This method is given a direct connection to the database. The connection must not be closed. However any statements or result sets instantiated from the connection must be closed.

In the event that the srid cannot be determined, this method should return null .

Overrides:

getGeometrySRID in class SQLDialect

Parameters:

schemaName - The database schema, could be null.

tableName - The table, never null.

columnName - The column name, never null

cx - The database connection.

Throws:

SQLException

encodeGeometryColumn

public void encodeGeometryColumn(GeometryDescriptor gatt,
 String prefix,
 int srid,
 Hints hints,
 StringBuffer sql)

Description copied from class: SQLDialect

Encodes the name of a geometry column in a SELECT statement.

This method should wrap the column name in any functions that are used to retrieve its value. For instance, often it is necessary to use the function asText, or asWKB when fetching a geometry.

This method must also be sure to properly encode the name of the column with the SQLDialect.encodeColumnName(String, String, StringBuffer) function.

Example:

   
   sql.append( "asText(" );
   column( gatt.getLocalName(), sql );
   sql.append( ")" );
   
 

Overrides:

encodeGeometryColumn in class SQLDialect

encodeGeometryEnvelope

public void encodeGeometryEnvelope(String tableName,
 String geometryColumn,
 StringBuffer sql)

Description copied from class: SQLDialect

Encodes the spatial extent function of a geometry column in a SELECT statement.

This method must also be sure to properly encode the name of the column with the #encodeColumnName(String, StringBuffer) function.

Specified by:

encodeGeometryEnvelope in class SQLDialect

encodeGeometryValue

public void encodeGeometryValue(Geometry value,
 int dimension,
 int srid,
 StringBuffer sql)

Description copied from class: BasicSQLDialect

Encodes a geometry value in an sql statement.

An implementations should serialize value 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:

   
   sql.append( "GeomFromText('" );
   sql.append( new WKTWriter().write( value ) );
   sql.append( ")" );
   
  

The srid parameter is the spatial reference system identifier of the geometry, or 0 if not known.

Attention should be paid to emtpy geometries (g.isEmtpy() == true) as they cannot be encoded in WKB and several databases fail to handle them property. Common treatment is to equate them to NULL

Specified by:

encodeGeometryValue in class BasicSQLDialect

decodeGeometryEnvelope

public Envelope decodeGeometryEnvelope(ResultSet rs,
 int column,
 Connection cx)
                                throws SQLException,
IOException

Description copied from class: SQLDialect

Decodes the result of a spatial extent function in a SELECT statement.

This method is given direct access to a result set. The column parameter is the index into the result set which contains the spatial extent value. The query for this value is build with the SQLDialect.encodeGeometryEnvelope(String, String, StringBuffer) method.

This method must not read any other objects from the result set other then the one referenced by column.

Specified by:

decodeGeometryEnvelope in class SQLDialect

Parameters:

rs - A result set

column - Index into the result set which points at the spatial extent value.

cx - The database connection.

Throws:

SQLException

IOException

decodeGeometryValue

public Geometry decodeGeometryValue(GeometryDescriptor descriptor,
 ResultSet rs,
 String column,
 GeometryFactory factory,
 Connection cx,
 Hints hints)
                             throws IOException,
SQLException

Description copied from class: SQLDialect

Decodes a geometry value from the result of a query.

This method is given direct access to a result set. The column parameter is the index into the result set which contains the geometric value.

An implementation should deserialize the value provided by the result set into Geometry object. For example, consider an implementation which deserializes from well known text:

   String wkt = rs.getString( column );
   if ( wkt == null ) {
     return null;
   }
   return new WKTReader(factory).read( wkt );
   

Note that implementations must handle null values.

The factory parameter should be used to instantiate any geometry objects.

Specified by:

decodeGeometryValue in class SQLDialect

Throws:

IOException

SQLException

registerClassToSqlMappings

public void registerClassToSqlMappings(Map<Class<?>,Integer> mappings)

Description copied from class: SQLDialect

Registers the java type to sql type mappings that the datastore uses when reading and writing objects to and from the database. *

Subclasses should extend (not override) this method to provide additional mappings, or to override mappings provided by this implementation. This implementation provides the following mappings:

Overrides:

registerClassToSqlMappings in class SQLDialect

registerSqlTypeNameToClassMappings

public void registerSqlTypeNameToClassMappings(Map<String,Class<?>> mappings)

Description copied from class: SQLDialect

Registers the sql type name to java type mappings that the dialect uses when reading and writing objects to and from the database.

Subclasses should extend (not override) this method to provide additional mappings, or to override mappings provided by this implementation. This implementation provides the following mappings:

Overrides:

registerSqlTypeNameToClassMappings in class SQLDialect

encodePostColumnCreateTable

public void encodePostColumnCreateTable(AttributeDescriptor att,
 StringBuffer sql)

Description copied from class: SQLDialect

Encodes anything post a column in a CREATE TABLE statement.

This is appended after the column name and type. Subclasses may choose to override this method, the default implementation does nothing.

Overrides:

encodePostColumnCreateTable in class SQLDialect

Parameters:

att - The attribute corresponding to the column.

postCreateTable

public void postCreateTable(String schemaName,
 SimpleFeatureType featureType,
 Connection cx)
                     throws SQLException,
IOException

Description copied from class: SQLDialect

Callback to execute any additional sql statements post a create table statement.

This method should be implemented by subclasses that need to do some post processing on the database after a table has been created. Examples might include:

• Creating a sequence for a primary key
• Registering geometry column metadata
• Creating a spatial index

A common case is creating an auto incrementing sequence for the primary key of a table. It should be noted that all tables created through the datastore use the column "fid" as the primary key.

A direct connection to the database is provided (cx). This connection must not be closed, however any statements or result sets instantiated from the connection must be closed.

Overrides:

postCreateTable in class SQLDialect

Parameters:

schemaName - The name of the schema, may be null.

featureType - The feature type that has just been created on the database.

cx - Database connection.

Throws:

SQLException

IOException

encodePrimaryKey

public void encodePrimaryKey(String column,
 StringBuffer sql)

Description copied from class: SQLDialect

Encodes the primary key definition in a CREATE TABLE statement.

Subclasses should override this method if need be, the default implementation does the following:

   
   encodeColumnName( column, sql );
   sql.append( " int PRIMARY KEY" );
   
 

Overrides:

encodePrimaryKey in class SQLDialect

lookupGeneratedValuesPostInsert

public boolean lookupGeneratedValuesPostInsert()

Description copied from class: SQLDialect

Controls whether keys are looked up post or pre insert.

When a row is inserted into a table, and a key is automatically generated it can be looked up before the insert occurs, or after the insert has been made. Returning false will cause the lookup to occur before the insert via SQLDialect.getNextAutoGeneratedValue(String, String, String, Connection). Returning true will cause the lookup to occur after the insert via SQLDialect.getLastAutoGeneratedValue(String, String, String, Connection).

Subclasses returning false should implement:

• SQLDialect.getNextAutoGeneratedValue(String, String, String, Connection)

Subclasses returning true should implement:

• SQLDialect.getLastAutoGeneratedValue(String, String, String, Connection)

Overrides:

lookupGeneratedValuesPostInsert in class SQLDialect

getLastAutoGeneratedValue

public Object getLastAutoGeneratedValue(String schemaName,
 String tableName,
 String columnName,
 Connection cx)
                                 throws SQLException

Description copied from class: SQLDialect

Obtains the last value of an auto generated column.

This method is only called when SQLDialect.lookupGeneratedValuesPostInsert() returns true. Implementations should determine the previous value of a column for which was automatically generated by the database.

This method is given a direct connection to the database, but this connection should never be closed. However any statements or result sets instantiated from the connection must be closed.

Implementations should handle the case where schemaName is null.

Overrides:

getLastAutoGeneratedValue in class SQLDialect

Parameters:

schemaName - The schema name, this might be null.

tableName - The name of the table.

columnName - The column.

cx - The database connection.

Returns:

The previous value of the column, or null.

Throws:

SQLException

isLimitOffsetSupported

public boolean isLimitOffsetSupported()

Description copied from class: SQLDialect

Returns true if this dialect can encode both Query.getStartIndex() and Query.getMaxFeatures() into native SQL.

Overrides:

isLimitOffsetSupported in class SQLDialect

applyLimitOffset

public void applyLimitOffset(StringBuffer sql,
 int limit,
 int offset)

Description copied from class: SQLDialect

Alters the query provided so that limit and offset are natively dealt with. This might mean simply appending some extra directive to the query, or wrapping it into a bigger one.

Overrides:

applyLimitOffset in class SQLDialect

createFilterToSQL

public FilterToSQL createFilterToSQL()

Description copied from class: BasicSQLDialect

Creates the filter encoder to be used by the datastore when encoding query predicates.

Sublcasses can override this method to return a subclass of FilterToSQL if need be.

Overrides:

createFilterToSQL in class BasicSQLDialect

getOptimizedBounds

public List<ReferencedEnvelope> getOptimizedBounds(String schema,
 SimpleFeatureType featureType,
 Connection cx)
                                            throws IOException

Description copied from class: SQLDialect

Returns the bounds of all geometry columns in the layer using any approach that proves to be faster than the plain bounds aggregation (e.g., better than the "plain select extent(geom) from table" on PostGIS), or null if none exists or the fast method has not been enabled (e.g., if the fast method is just an estimate of the bounds you probably want the user to enable it manually)

Overrides:

getOptimizedBounds in class SQLDialect

Parameters:

schema - The database schema, if any, or null

featureType - The feature type containing the geometry columns whose bounds need to computed. Mind, it may be retyped and thus contain less geometry columns than the table

Returns:

a list of referenced envelopes (some of which may be null or empty)

Throws:

IOException