Module litebridge.db.spi.impl

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

Class Substring

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

org.litebridge.db.spi.impl.function.scalar.Substring

All Implemented Interfaces:

ColumnExpression, DelegateExpression, SelectExpression

public class Substring
extends FunctionExpression

SUBSTRING(column, start, length) scalar function.

Field Summary

Fields

Modifier and Type	Field	Description
protected final @Nullable Integer	length	The number of characters to return.
protected final int	start	Database index, 1-based.

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
Substring(ColumnExpression target, int start, @Nullable Integer length, ColumnIdentifierGenerator columnIdentifierGenerator)	Construct a SUBSTRING function.

Method Summary

Modifier and Type	Method	Description
protected String	template()	Gets the template for the SQL representation of the function.

Methods inherited from class org.litebridge.db.spi.impl.function.FunctionExpression

toSql

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

Field Details

start

protected final int start

Database index, 1-based.

length

protected final @Nullable Integer length

The number of characters to return.

Constructor Details

Substring

public Substring(ColumnExpression target,
 int start,
 @Nullable Integer length,
 ColumnIdentifierGenerator columnIdentifierGenerator)

Construct a SUBSTRING function.

Parameters:

target - Target expression to extract characters from.

start - The starting position. The first character of a database string is always 1.

length - The number of characters to return. If null, the function extracts everything from the start position to the end of the text.

columnIdentifierGenerator - Database provider-specific column identifier generator.

Method Details

template

protected String template()

Description copied from class: FunctionExpression

Gets the template for the SQL representation of the function.

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

Specified by:

template in class FunctionExpression

Returns:

SQL representation template