Module litebridge.db.spi.impl

Package org.litebridge.db.spi.impl.function

Class FunctionExpression

java.lang.Object

org.litebridge.db.spi.expression.ColumnExpressionImpl

org.litebridge.db.spi.expression.DelegateColumnExpression

org.litebridge.db.spi.impl.function.DelegateColumnExpressionImpl

org.litebridge.db.spi.impl.function.FunctionExpression

All Implemented Interfaces:

ColumnExpression, DelegateExpression, SelectExpression

Direct Known Subclasses:

Abs, Avg, Lower, Max, Min, Substring, Upper

public abstract class FunctionExpression
extends DelegateColumnExpressionImpl

Base class for function expressions operating on a column.

Field Summary

Fields inherited from class org.litebridge.db.spi.impl.function.DelegateColumnExpressionImpl

columnIdentifierGenerator

Fields inherited from class org.litebridge.db.spi.expression.DelegateColumnExpression

target

Fields inherited from class org.litebridge.db.spi.expression.ColumnExpressionImpl

column

Constructor Summary

Constructors

Constructor	Description
FunctionExpression(ColumnExpression target, ColumnIdentifierGenerator columnIdentifierGenerator)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected abstract String	template()	Gets the template for the SQL representation of the function.
String	toSql(Operation operation, ClauseType clause, @Nullable DelegateExpression parent)	Creates a SQL representation of the expression.

Methods inherited from class org.litebridge.db.spi.expression.DelegateColumnExpression

column, target

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.litebridge.db.spi.expression.SelectExpression

toSql

Constructor Details

FunctionExpression

public FunctionExpression(ColumnExpression target,
 ColumnIdentifierGenerator columnIdentifierGenerator)

Constructor.

Parameters:

target - Target column expression to encapsulate.

columnIdentifierGenerator - Database provider-specific column identifier generator.

Method Details

toSql

public String toSql(Operation operation,
 ClauseType clause,
 @Nullable DelegateExpression parent)

Creates a SQL representation of the expression.

This is usually used for expressions that do not require any aliases.

Specified by:

toSql in interface SelectExpression

Overrides:

toSql in class DelegateColumnExpressionImpl

Parameters:

operation - the operation that is being executed

clause - The current clause type being evaluated

parent - The parent expression/nesting expression, or null if this is a top-level expression

Returns:

the SQL representation of the expression

template

protected abstract String template()

Gets the template for the SQL representation of the function.

The template should contain a single "%s" placeholder for the column identifier.

Returns:

SQL representation template