H2Dialect (Geotools modules 28-SNAPSHOT API)

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 and Description

static String H2_SPATIAL_INDEX
- Fields inherited from class SQLDialect
  BASE_DBMS_CAPABILITIES, dataStore, forceLongitudeFirst, LOGGER

Fields
Modifier and Type	Field and Description
`static String`	`H2_SPATIAL_INDEX`

Constructor Summary

Constructors
Constructor and Description

H2Dialect(JDBCDataStore dataStore)

Constructors
Constructor and Description
`H2Dialect(JDBCDataStore dataStore)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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. * Subclasses should extend (not override) this method to provide additional mappings, or to override mappings provided by this implementation.
`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, 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

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 #registerSqlTypeNameToClassMappings(Map) 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

Class H2Dialect

Field Summary

Fields inherited from class SQLDialect

Constructor Summary

Method Summary

Methods inherited from class SQLDialect

Methods inherited from class Object

Field Detail

H2_SPATIAL_INDEX

Constructor Detail

H2Dialect

Method Detail

getNameEscape

initializeConnection

includeTable

getMapping

encodePostColumnCreateTable

registerSqlTypeToClassMappings

registerClassToSqlMappings

postCreateTable

postCreateFeatureType

preDropTable

getGeometrySRID

encodeGeometryEnvelope

decodeGeometryEnvelope

encodeGeometryValue

decodeGeometryValue

encodePrimaryKey

getSequenceForColumn

getNextSequenceValue

encodeNextSequenceValue

getNextAutoGeneratedValue

isLimitOffsetSupported

applyLimitOffset

supportsSchemaForIndex

registerSqlTypeToSqlTypeNameOverrides

canGroupOnGeometry