org.fastnate.generator.context

Class IdGenerator

java.lang.Object

org.fastnate.generator.context.IdGenerator

Direct Known Subclasses:

IdentityValue, SequenceIdGenerator, TableIdGenerator

public abstract class IdGenerator
extends Object

Saves the current value and increments the value for a GeneratedIdProperty.

Author:

Tobias Liefke

Constructor Summary

Constructors

Constructor and Description
IdGenerator()

Method Summary

Modifier and Type	Method and Description
abstract void	addNextValue(TableStatement statement, GeneratorColumn column, Number nextValue) Adds the generated value to the given statement.
abstract void	alignNextValue(StatementsWriter writer) Creates all statements that are necessary to set the next value created from the database is currentValue + 1.
protected abstract long	createNextValue() Resolves the next value of this generator.
<N extends Number> N	createNextValue(Class<N> propertyClass) Resolves the next value of this generator.
void	createPreInsertStatements(StatementsWriter writer) Creates the statements that are needed in the output before addNextValue(TableStatement, GeneratorColumn, Number).
IdGenerator	derive(GeneratorTable entityTable) Some implementations (like the Hibernate table generator) create a different generator, depending on the table name.
abstract long	getCurrentValue() The last value returned by createNextValue(Class).
abstract ColumnExpression	getExpression(GeneratorTable table, GeneratorColumn column, Number id, boolean whereExpression) Builds the reference to another entity that has the given ID.
abstract boolean	isPostIncrement() Indicates that createNextValue(Class) should be called after the entity was written - as the value is not available before.
abstract void	setCurrentValue(long currentValue) Sets a new start value.

Methods inherited from class java.lang.Object

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

Constructor Detail

IdGenerator

public IdGenerator()

Method Detail

addNextValue

public abstract void addNextValue(TableStatement statement,
                                  GeneratorColumn column,
                                  Number nextValue)

Adds the generated value to the given statement. Depending on the generator this may add the value itself or a reference to the value.

Parameters:

statement - the current insert statement

column - the ID column of the current table

nextValue - the current value of the column, previously generated with createNextValue()

alignNextValue

public abstract void alignNextValue(StatementsWriter writer)
                             throws IOException

Creates all statements that are necessary to set the next value created from the database is currentValue + 1.

Parameters:

writer - the target of the created statements

Throws:

IOException - if the writer throws one

createNextValue

protected abstract long createNextValue()

Resolves the next value of this generator.

Returns:

the generated value

createNextValue

public <N extends Number> N createNextValue(Class<N> propertyClass)

Resolves the next value of this generator.

Parameters:

propertyClass - the type of the generated value

Returns:

the generated value

createPreInsertStatements

public void createPreInsertStatements(StatementsWriter writer)
                               throws IOException

Creates the statements that are needed in the output before addNextValue(TableStatement, GeneratorColumn, Number).

Parameters:

writer - target for the created statements

Throws:

IOException - if the writer throws one

derive

public IdGenerator derive(GeneratorTable entityTable)

Some implementations (like the Hibernate table generator) create a different generator, depending on the table name.

Parameters:

entityTable - the current entity table

Returns:

the generator

getCurrentValue

public abstract long getCurrentValue()

The last value returned by createNextValue(Class).

Returns:

the current value

getExpression

public abstract ColumnExpression getExpression(GeneratorTable table,
                                               GeneratorColumn column,
                                               Number id,
                                               boolean whereExpression)

Builds the reference to another entity that has the given ID.

Parameters:

table - the main table of the entity

column - the name of the column of the ID

id - the current value of the ID

whereExpression - indicates if this expression is needed for a "SELECT ... WHERE ..." - some dialects behave differently in this situation

Returns:

the expression for selecting the ID

isPostIncrement

public abstract boolean isPostIncrement()

Indicates that createNextValue(Class) should be called after the entity was written - as the value is not available before.

Returns:

true if the database increments the value _after_ the insert statement was executed, true if it is incremented before or during the execution

setCurrentValue

public abstract void setCurrentValue(long currentValue)

Sets a new start value.

Parameters:

currentValue - the current value - most likely as extracted from the target database