Module litebridge.orm

Package org.litebridge.orm.engine

Class FromClauseEngine

java.lang.Object

org.litebridge.orm.engine.FromClauseEngine

public final class FromClauseEngine
extends Object

The FromClauseEngine class represents the generation of SQL "FROM" clauses with support for both DTO-based and raw expression-based queries.

It acts as a builder for specifying the table and columns to be used in a query, while also managing aliasing, context, and relationships between entities.

This class depends on various components such as a database provider, table registry, change tracker, DTO constructor, and context supplier to construct SQL queries effectively.

This class is immutable and thread-safe. Instances of this class should not be modified after construction.

Field Summary

Fields

Modifier and Type	Field	Description
static final Aliased[]	ALL_COLUMNS	Used to indicate that all fields or expressions should be selected.

Constructor Summary

Constructors

Constructor	Description
FromClauseEngine(TransactionalDatabaseProvider databaseProvider, TableRegistry tableRegistry, ChangeTracker changeTracker, DtoConstructor dtoConstructor, Supplier<LitebridgeContext> contextSupplier)	Constructs a new FromClauseEngine.

Method Summary

Modifier and Type	Method	Description
<DTO> DtoFromClauseTerminal<DTO>	from(Class<DTO> dtoClass, Class<?> contextDtoClass)	Constructs a DTO-based FROM clause using a context DTO class.
<TypeOverride> DtoFromClauseTerminal<TypeOverride>	from(ExpressionSpec[] expressionSpecs, Class<?> dtoClass, Class<TypeOverride> typeOverrideClass, @Nullable RelatedDtoStrategy relatedDtoStrategy)	Constructs a DTO-based FROM clause with a type override.
<DTO> DtoFromClauseTerminal<DTO>	from(ExpressionSpec[] expressionSpecs, Class<DTO> dtoClass, @Nullable RelatedDtoStrategy relatedDtoStrategy)	Constructs a DTO-based FROM clause.
SqlFromClauseTerminal	from(ExpressionSpec[] expressionSpecs, String table)	Constructs an SQL-based FROM clause.

Methods inherited from class java.lang.Object

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

Field Details

ALL_COLUMNS

public static final Aliased[] ALL_COLUMNS

Used to indicate that all fields or expressions should be selected.

Constructor Details

FromClauseEngine

public FromClauseEngine(TransactionalDatabaseProvider databaseProvider,
 TableRegistry tableRegistry,
 ChangeTracker changeTracker,
 DtoConstructor dtoConstructor,
 Supplier<LitebridgeContext> contextSupplier)

Constructs a new FromClauseEngine.

Parameters:

databaseProvider - the database provider.

tableRegistry - the table registry.

changeTracker - the change tracker.

dtoConstructor - the DTO constructor.

contextSupplier - the context supplier.

Method Details

from

public <DTO> DtoFromClauseTerminal<DTO> from(ExpressionSpec[] expressionSpecs,
 Class<DTO> dtoClass,
 @Nullable RelatedDtoStrategy relatedDtoStrategy)

Constructs a DTO-based FROM clause.

Type Parameters:

DTO - the DTO type.

Parameters:

expressionSpecs - the expression specifications.

dtoClass - the DTO class.

relatedDtoStrategy - the related DTO strategy.

Returns:

the DTO from clause terminal.

from

public <TypeOverride>
DtoFromClauseTerminal<TypeOverride> from(ExpressionSpec[] expressionSpecs,
 Class<?> dtoClass,
 Class<TypeOverride> typeOverrideClass,
 @Nullable RelatedDtoStrategy relatedDtoStrategy)

Constructs a DTO-based FROM clause with a type override.

Type Parameters:

TypeOverride - the type override.

Parameters:

expressionSpecs - the expression specifications.

dtoClass - the DTO class.

typeOverrideClass - the type override class.

relatedDtoStrategy - the related DTO strategy.

Returns:

the DTO from clause terminal.

from

public <DTO> DtoFromClauseTerminal<DTO> from(Class<DTO> dtoClass,
 Class<?> contextDtoClass)

Constructs a DTO-based FROM clause using a context DTO class.

Type Parameters:

DTO - the DTO type.

Parameters:

dtoClass - the DTO class.

contextDtoClass - the context DTO class.

Returns:

the DTO from clause terminal.

from

public SqlFromClauseTerminal from(ExpressionSpec[] expressionSpecs,
 String table)

Constructs an SQL-based FROM clause.

Parameters:

expressionSpecs - the expression specifications.

table - the table name.

Returns:

the SQL from clause terminal.