org.fastnate.generator.dialect

Class GeneratorDialect

java.lang.Object

org.fastnate.generator.dialect.GeneratorDialect

Direct Known Subclasses:

H2Dialect, MsSqlDialect, MySqlDialect, OracleDialect, PostgresDialect

public abstract class GeneratorDialect
extends Object

Handles database specific conversions. The conversions are limited, for some of the known limitations, see the database specific implementations.

Author:

Tobias Liefke

See Also:

Comparison of different SQL implementations

Field Summary

Fields

Modifier and Type	Field and Description
private char[]	letter
static Date	NOW Deprecated. Use RelativeDate.NOW instead

Constructor Summary

Constructors

Constructor and Description
GeneratorDialect()

Method Summary

Modifier and Type	Method and Description
protected void	addQuotedCharacter(StringBuilder result, char c) Adds a quoted character to the result string buffer.
void	adjustNextIdentityValue(StatementsWriter writer, GeneratorTable table, GeneratorColumn column, long nextValue) Adjusts the next value of the given identity column to ensure that it is bigger than the last generated value.
void	adjustNextSequenceValue(StatementsWriter writer, String sequenceName, long currentSequenceValue, long nextSequenceValue, int incrementSize) Adjusts the given sequence to ensure that the next value is exactly the given value.
String	buildCurrentSequenceValue(String sequence, int incrementSize, boolean firstCall) Builds the SQL expression that is used for referencing the current value of the given sequence.
String	buildNextSequenceValue(String sequence, int incrementSize) Builds the SQL expression resp. statement that is used for creating the next value of the given sequence.
String	convertBooleanValue(boolean value) Converts a boolean value to an SQL expression for the current database type.
String	convertNumberValue(Number value) Converts a numeric value to an SQL expression for the current database type.
protected String	convertTemporalValue(Date sqlDate) Builds the SQL expression for a date / time / timestamp.
String	convertTemporalValue(Date value, javax.persistence.TemporalType type) Converts a date to an appropriate SQL expression.
Date	convertToDatabaseDate(Date value, javax.persistence.TemporalType type) Converts any Date value to a java.sql specific date object.
protected String	createAddDateExpression(String referenceDate, long value, String unit) Creates an SQL expression to add a value to a date.
String	createBlobExpression(byte[] blob) Converts the given byte array to an SQL expression for the current database.
protected String	createHexBlobExpression(String prefix, byte[] blob, String suffix) Creates the hex presentation of the given blob.
private static void	finishPart(StringBuilder result, String value, int start, int end, boolean isOpen, boolean close, String concatOperator)
javax.persistence.GenerationType	getAutoGenerationType() Resolves the GenerationType used, if GenerationType.AUTO is set for a GeneratedValue.
String	getConcatOperator() The operator used to concat two Strings.
Object	getEmptyValuesExpression() The SQL expression to use in an empty insert statement.
char[]	getLetter()
String	getOptionalTable() Returns the string to use when no table is required, e.g. for "SELECT 1, 2 FROM DUAL" this would return "FROM DUAL".
boolean	isEmptyStringEqualToNull() Indicates that the empty string is equal to null in this database.
boolean	isEmulatingSequences() Indicates that tables are used in place of sequences, if GenerationType.SEQUENCE is defined for a GeneratedValue.
boolean	isFastInTransaction() Indicates that the database usually faster when all statements are executed within an transaction.
boolean	isIdentitySupported() Indicates that identity columns are supported by the database.
boolean	isNextSequenceValueInInsertSupported() Indicates that a sequence may be updated in the insert statement.
boolean	isSelectFromSameTableInInsertSupported() Indicates that this dialect may select from the same table in a select.
boolean	isSequenceInWhereSupported() Indicates that references to sequences in WHERE expressions are supported.
boolean	isSequenceSupported() Indicates that sequences are supported by the database.
boolean	isSettingIdentityAllowed() Indicates if this dialect supports writing absolute values to an GenerationType.IDENTITY column.
String	quoteString(String value) Quotes the given string.
void	truncateTable(StatementsWriter writer, GeneratorTable table) Adds a "truncate table" statement to the given writer.

Methods inherited from class java.lang.Object

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

Field Detail

NOW

@Deprecated
public static final Date NOW

Deprecated. Use RelativeDate.NOW instead

letter

private final char[] letter

Constructor Detail

GeneratorDialect

public GeneratorDialect()

Method Detail

finishPart

private static void finishPart(StringBuilder result,
                               String value,
                               int start,
                               int end,
                               boolean isOpen,
                               boolean close,
                               String concatOperator)

addQuotedCharacter

protected void addQuotedCharacter(StringBuilder result,
                                  char c)

Adds a quoted character to the result string buffer.

Parameters:

result - the current result buffer

c - the character to quote

adjustNextIdentityValue

public void adjustNextIdentityValue(StatementsWriter writer,
                                    GeneratorTable table,
                                    GeneratorColumn column,
                                    long nextValue)
                             throws IOException

Adjusts the next value of the given identity column to ensure that it is bigger than the last generated value.

Parameters:

writer - the target of any generated statement

table - the table of the column

column - the (auto increment) identity column

nextValue - the next value of the identity column

Throws:

IOException - if the writer throws one

adjustNextSequenceValue

public void adjustNextSequenceValue(StatementsWriter writer,
                                    String sequenceName,
                                    long currentSequenceValue,
                                    long nextSequenceValue,
                                    int incrementSize)
                             throws IOException

Adjusts the given sequence to ensure that the next value is exactly the given value.

Parameters:

writer - the target of the generated statements

sequenceName - the fully qualified name of the sequence

currentSequenceValue - the current value of the sequence

nextSequenceValue - the next value of the sequence

incrementSize - the increment size of the sequence

Throws:

IOException - if the writer throws one

buildCurrentSequenceValue

public String buildCurrentSequenceValue(String sequence,
                                        int incrementSize,
                                        boolean firstCall)

Builds the SQL expression that is used for referencing the current value of the given sequence.

Parameters:

sequence - the fully qualified name of the sequence

incrementSize - the expected incrementSize, as given in the schema - used by some dialects to ensure that exactly that inrement is used

firstCall - indicates that the sequence was not updated before in this session - we may need to use a different approach to get the current value

Returns:

the SQL expression to use in statement

buildNextSequenceValue

public String buildNextSequenceValue(String sequence,
                                     int incrementSize)

Builds the SQL expression resp. statement that is used for creating the next value of the given sequence. Depending on isNextSequenceValueInInsertSupported() this will return an expression or a statement.

Parameters:

sequence - the fully qualified name of the sequence

incrementSize - the expected incrementSize, as given in the schema - used by some dialects to ensure that exactly that inrement is used

Returns:

the SQL to use in resp. before the insert / update statement

convertBooleanValue

public String convertBooleanValue(boolean value)

Converts a boolean value to an SQL expression for the current database type.

Parameters:

value - the value to convert

Returns:

the SQL representation of the value

convertNumberValue

public String convertNumberValue(Number value)

Converts a numeric value to an SQL expression for the current database type.

Parameters:

value - the numeric value

Returns:

the SQL expression of that value

convertTemporalValue

protected String convertTemporalValue(Date sqlDate)

Builds the SQL expression for a date / time / timestamp.

Parameters:

sqlDate - the date, already converted to one from javax.sql.*

Returns:

the SQL expression representing the value.

convertTemporalValue

public String convertTemporalValue(Date value,
                                   javax.persistence.TemporalType type)

Converts a date to an appropriate SQL expression.

Parameters:

value - the timestamp value

type - the type

Returns:

SQL expression representing the value.

convertToDatabaseDate

public Date convertToDatabaseDate(Date value,
                                  javax.persistence.TemporalType type)

Converts any Date value to a java.sql specific date object.

Parameters:

value - the Java-Date object

type - the type of the conversion

Returns:

the corresponding java.sql specific date object

createAddDateExpression

protected String createAddDateExpression(String referenceDate,
                                         long value,
                                         String unit)

Creates an SQL expression to add a value to a date.

Parameters:

referenceDate - the expression for the reference date

value - the value to add to the date

unit - the unit of the value

Returns:

the SQL expression that adds the value

createBlobExpression

public String createBlobExpression(byte[] blob)

Converts the given byte array to an SQL expression for the current database.

Parameters:

blob - the bytes to convert

Returns:

the expression for the bytes

createHexBlobExpression

protected String createHexBlobExpression(String prefix,
                                         byte[] blob,
                                         String suffix)

Creates the hex presentation of the given blob.

Parameters:

prefix - the prefix to add to the hex

blob - the binary blob to convert

suffix - the suffix to add to the hex

Returns:

prefix + hex(blob) + suffix

getAutoGenerationType

public javax.persistence.GenerationType getAutoGenerationType()

Resolves the GenerationType used, if GenerationType.AUTO is set for a GeneratedValue.

Returns:

the replacement for GenerationType.AUTO for the current dialect in Hibernate.

getConcatOperator

public String getConcatOperator()

The operator used to concat two Strings.

Returns:

the operator to use for "string1 OPERATOR string2" (including any necessary whitespace) or null if this dialect does not have such an operator

getEmptyValuesExpression

public Object getEmptyValuesExpression()

The SQL expression to use in an empty insert statement.

Returns:

the SQL expression if an insert statement contains no values

getOptionalTable

public String getOptionalTable()

Returns the string to use when no table is required, e.g. for "SELECT 1, 2 FROM DUAL" this would return "FROM DUAL".

Returns:

the SQL to use in "SELECT x [OPTIONALTABLE] WHERE ..."

isEmptyStringEqualToNull

public boolean isEmptyStringEqualToNull()

Indicates that the empty string is equal to null in this database. Important for NotNull constraints, where an empty string would result in the same constraint violation.

Returns:

true if this database assumes that an empty string is the same as null

isEmulatingSequences

public boolean isEmulatingSequences()

Indicates that tables are used in place of sequences, if GenerationType.SEQUENCE is defined for a GeneratedValue.

Returns:

true if sequences are emulated with tables, false if sequences are supported

isFastInTransaction

public boolean isFastInTransaction()

Indicates that the database usually faster when all statements are executed within an transaction. For example Oracle is approx. 25% faster but H2 is 200% slower compared to auto commit. Only relevant if executed against a running database.

Returns:

true if an transaction is faster than auto commit

isIdentitySupported

public boolean isIdentitySupported()

Indicates that identity columns are supported by the database.

Returns:

true if the database supports identities

isNextSequenceValueInInsertSupported

public boolean isNextSequenceValueInInsertSupported()

Indicates that a sequence may be updated in the insert statement.

Returns:

true to indicate that buildNextSequenceValue(String,int) will return an expression that may be used in an INSERT statement, false to indicate that buildNextSequenceValue(String,int) returns a full statement

isSelectFromSameTableInInsertSupported

public boolean isSelectFromSameTableInInsertSupported()

Indicates that this dialect may select from the same table in a select.

Returns:

true if "INSERT INTO XXX (a) VALUES (SELECT max(a) FROM XXX)" is supported

isSequenceInWhereSupported

public boolean isSequenceInWhereSupported()

Indicates that references to sequences in WHERE expressions are supported.

Returns:

true if this database supports sequences in WHERE expressions

isSequenceSupported

public boolean isSequenceSupported()

Indicates that sequences are supported by the database.

Returns:

true if the database supports sequences

isSettingIdentityAllowed

public boolean isSettingIdentityAllowed()

Indicates if this dialect supports writing absolute values to an GenerationType.IDENTITY column.

Returns:

true if we can write fix values for identity columns

quoteString

public String quoteString(String value)

Quotes the given string.

Parameters:

value - the value to quote

Returns:

the quoted string

truncateTable

public void truncateTable(StatementsWriter writer,
                          GeneratorTable table)
                   throws IOException

Adds a "truncate table" statement to the given writer.

Parameters:

writer - the target of the statement

table - the table to truncate

Throws:

IOException - if the writer throws one

getLetter

@Generated(value="lombok")
public char[] getLetter()