Package org.geotools.data.h2

Class H2Dialect

Object

SQLDialect

H2Dialect

public class H2Dialect
extends SQLDialect

Delegate for H2DialectBasic and H2DialectPrepared which implements the common parts of the dialect api.

Author:

Justin Deoliveira, OpenGEO

Field Summary

Fields

Modifier and Type	Field	Description
static String	H2_SPATIAL_INDEX

Fields inherited from class SQLDialect

BASE_DBMS_CAPABILITIES, dataStore, forceLongitudeFirst, LOGGER, UNWRAPPER_NOT_FOUND, uwMap

Constructor Summary

Constructors

Constructor	Description
H2Dialect(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.
boolean	canGroupOnGeometry()	Returns true if this database can "group by" on a Geometry column.
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	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 srid, StringBuffer sql)
String	encodeNextSequenceValue(String schemaName, String sequenceName)	Encodes how to get the next sequence value from the DB.
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.
Class<?>	getMapping(ResultSet columnMetaData, Connection cx)	Determines the class mapping for a particular column of a table.
String	getNameEscape()	Returns the string used to escape names.
Object	getNextAutoGeneratedValue(String schemaName, String tableName, String columnName, Connection cx)	Obtains the next value of an auto generated column.
Object	getNextSequenceValue(String schemaName, String sequenceName, Connection cx)	Obtains the next value of a sequence, incrementing the sequence to the next state in the process.
String	getSequenceForColumn(String schemaName, String tableName, String columnName, Connection cx)	Determines the name of the sequence (if any) which is used to increment generate values for a table column.
boolean	includeTable(String schemaName, String tableName, Connection cx)	Determines if the specified table should be included in those published by the datastore.
void	initializeConnection(Connection cx)	Initializes a newly created database connection.
boolean	isLimitOffsetSupported()	Returns true if this dialect can encode both Query.getStartIndex() and Query.getMaxFeatures() into native SQL.
void	postCreateFeatureType(SimpleFeatureType featureType, DatabaseMetaData metadata, String schemaName, Connection cx)	Callback which executes after a feature type has been built from a database table.
void	postCreateTable(String schemaName, SimpleFeatureType featureType, Connection cx)	Callback to execute any additional sql statements post a create table statement.
void	preDropTable(String schemaName, SimpleFeatureType featureType, Connection cx)	Callback which executes before a table is about to be dropped.
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	registerSqlTypeToClassMappings(Map<Integer,Class<?>> mappings)	Registers the sql type to java type mappings that the dialect uses when reading and writing objects to and from the database.
void	registerSqlTypeToSqlTypeNameOverrides(Map<Integer,String> overrides)	Registers any overrides that should occur when mapping an integer sql type value to an underlying sql type name.
protected boolean	supportsSchemaForIndex()	Return true if the database supports individual schemas for indices.

Methods inherited from class SQLDialect

addSupportedHints, applyHintsOnVirtualTables, canSimplifyPoints, convertValue, createCRS, createIndex, decodeGeometryValue, dropIndex, encodeColumnAlias, encodeColumnName, encodeColumnType, encodeCreateTable, encodeGeometryColumn, encodeGeometryColumnGeneralized, encodeGeometryColumnSimplified, encodeJoin, encodePostCreateTable, encodePostSelect, encodeSchemaName, encodeTableAlias, encodeTableName, escapeName, getAggregateConverter, getDefaultVarcharSize, getDesiredTablesType, getGeometryDimension, getGeometryTypeName, getIndexes, getLastAutoGeneratedValue, getLastAutoGeneratedValue, getMapping, getOptimizedBounds, getPkColumnValue, getPrimaryKey, getRestrictions, getResultTypes, getSQLType, handleSelectHints, handleUserDefinedType, isAggregatedSortSupported, isArray, isAutoCommitQuery, isGroupBySupported, lookupGeneratedValuesPostInsert, ne, postCreateAttribute, postDropTable, registerAggregateFunctions, registerSqlTypeNameToClassMappings, splitFilter, unwrapConnection

Methods inherited from class Object

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

Field Detail

H2_SPATIAL_INDEX

public static String H2_SPATIAL_INDEX

Constructor Detail

H2Dialect

public H2Dialect(JDBCDataStore dataStore)

Method Detail

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

initializeConnection

public void initializeConnection(Connection cx)
                          throws SQLException

Description copied from class: SQLDialect

Initializes a newly created database connection.

Subclasses should override this method if there is some additional action that needs to be taken when a new connection to the database is created. The default implementation does nothing.

Overrides:

initializeConnection in class SQLDialect

Parameters:

cx - The new database connection.

Throws:

SQLException

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

getMapping

public Class<?> getMapping(ResultSet columnMetaData,
                           Connection cx)
                    throws SQLException

Description copied from class: SQLDialect

Determines the class mapping for a particular column of a table.

Implementing this method is optional. It is used to allow database to perform custom type mappings based on various column metadata. It is called before the mappings registered in SQLDialect.registerSqlTypeToClassMappings(Map) and are used to determine the mapping. Subclasses should implement as needed, this default implementation returns null.

The columnMetaData argument is provided from {@link DatabaseMetaData#getColumns(String, String, String, String)}.

Overrides:

getMapping in class SQLDialect

Parameters:

columnMetaData - The column metadata

cx - The connection used to retrieve the metadata

Returns:

The class mapped to the to column, or null.

Throws:

SQLException

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.

registerSqlTypeToClassMappings

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

Description copied from class: SQLDialect

Registers the sql type 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:

registerSqlTypeToClassMappings in class SQLDialect

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

postCreateTable

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

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

postCreateFeatureType

public void postCreateFeatureType(SimpleFeatureType featureType,
                                  DatabaseMetaData metadata,
                                  String schemaName,
                                  Connection cx)
                           throws SQLException

Description copied from class: SQLDialect

Callback which executes after a feature type has been built from a database table.

This base implementation does nothing, subclasses should override as need be.

Overrides:

postCreateFeatureType in class SQLDialect

Parameters:

featureType - The build feature type.

metadata - The database metadata.

schemaName - The name of the database scheam containing the table containing the column

cx - The database connection.

Throws:

SQLException

preDropTable

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

Description copied from class: SQLDialect

Callback which executes before a table is about to be dropped.

This base implementation does nothing, subclasses should override as need be.

Overrides:

preDropTable in class SQLDialect

Parameters:

schemaName - The database schema containing the table.

featureType - The featureType/table being dropped.

cx - The database connection.

Throws:

SQLException

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

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

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

encodeGeometryValue

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

Throws:

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

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

getSequenceForColumn

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

Description copied from class: SQLDialect

Determines the name of the sequence (if any) which is used to increment generate values for a table column.

This method should return null if no such sequence exists.

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.

Overrides:

getSequenceForColumn in class SQLDialect

Parameters:

schemaName - The schema name, this might be null.

tableName - The table name.

columnName - The column name.

cx - The database connection.

Throws:

SQLException

getNextSequenceValue

public Object getNextSequenceValue(String schemaName,
                                   String sequenceName,
                                   Connection cx)
                            throws SQLException

Description copied from class: SQLDialect

Obtains the next value of a sequence, incrementing the sequence to the next state in the process.

Implementations should determine the next value of a column for which values are 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:

getNextSequenceValue in class SQLDialect

Parameters:

schemaName - The schema name, this might be null.

sequenceName - The name of the sequence.

cx - The database connection.

Returns:

The next value of the sequence, or null.

Throws:

SQLException

encodeNextSequenceValue

public String encodeNextSequenceValue(String schemaName,
                                      String sequenceName)

Description copied from class: SQLDialect

Encodes how to get the next sequence value from the DB.

Implementations should handle the case where schemaName is null.

Overrides:

encodeNextSequenceValue in class SQLDialect

getNextAutoGeneratedValue

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

Description copied from class: SQLDialect

Obtains the next value of an auto generated column.

Implementations should determine the next value of a column for which values are 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:

getNextAutoGeneratedValue 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 next 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

supportsSchemaForIndex

protected boolean supportsSchemaForIndex()

Description copied from class: SQLDialect

Return true if the database supports individual schemas for indices.

The SQL encoding would be CREATE INDEX SCHEMANAME.INDEXNAME ON ....

The default is false and the encoding is CREATE INDEX INDEXNAME ON ....

Overrides:

supportsSchemaForIndex in class SQLDialect

Returns:

true or false

registerSqlTypeToSqlTypeNameOverrides

public void registerSqlTypeToSqlTypeNameOverrides(Map<Integer,String> overrides)

Description copied from class: SQLDialect

Registers any overrides that should occur when mapping an integer sql type value to an underlying sql type name.

The default implementation of this method does nothing. Subclasses should override in cases where:

• database type metadata does not provide enough information to properly map
• to support custom types (those not in Types)

Overrides:

registerSqlTypeToSqlTypeNameOverrides in class SQLDialect

canGroupOnGeometry

public boolean canGroupOnGeometry()

Description copied from class: SQLDialect

Returns true if this database can "group by" on a Geometry column. Defaults to false, specific implementations with this capability should override

Overrides:

canGroupOnGeometry in class SQLDialect