程序包 org.babyfish.jimmer.sql.ast.query

接口 Filterable

所有已知子接口:

FieldFilterArgs<T>, FieldFilterArgsImplementor<T>, FilterableImplementor, FilterArgs<P>, MutableDelete, MutableQuery, MutableRootQuery<T>, MutableSubQuery, MutableUpdate, Sortable

所有已知实现类:

AbstractMutableQueryImpl, AbstractMutableStatementImpl, FieldFilterArgsImpl, FilterArgsImpl, MutableDeleteImpl, MutableRootQueryImpl, MutableSubQueryImpl, MutableUpdateImpl

public interface Filterable

方法概要

修饰符和类型	方法	说明
Filterable	where(Predicate... predicates)	Add some predicates(logical and)
default Filterable	whereIf(boolean condition, Supplier<Predicate> block)	Avoid using this method whenever possible, using Dynamic Predicates are a more convenient approach.
default Filterable	whereIf(boolean condition, Predicate predicate)	已过时。

方法详细资料

where

@OldChain
Filterable where(Predicate... predicates)

Add some predicates(logical and)

参数:

predicates - Predicates, everything one can be null

返回:

Return the current object to support chain programming style

whereIf

@Deprecated
@OldChain
default Filterable whereIf(boolean condition,
 Predicate predicate)

已过时。

This method is deprecated, using Dynamic Predicates is a more convenient approach.

Please look at this example:

 whereIf(name != null, table.name().eq(name))
 

When name is null, this code works because eq(null) is automatically translated by Jimmer to isNull(), which doesn't cause an exception.

Let's look at another example:

 whereIf(minPrice != null, table.price().ge(minPrice))
 

Except RUST marco, almost all programming languages calculate all parameters first and then call the function. Therefore, before whereIf is executed, ge(null) already causes an exception.

For this reason, whereIf provides an overloaded form with a lambda parameter:

 whereIf(minPrice != null, () -> table.price().ge(minPrice))
 

Although this overloaded form can solve this problem, it ultimately adds a mental burden during development.

Therefore, Jimmer provides Dynamic Predicates

• Java: eqIf, neIf, ltIf, leIf, gtIf, geIf, likeIf, ilikeIf, betweenIf
• Kotlin: eq?, ne?, lt?, le?, gt?, ge?, like?, ilike?, betweenIf?

Taking Java's geIf as an example, this functionality is ultimately implemented like this.

 where(table.price().geIf(minPrice))
 

whereIf

@OldChain
default Filterable whereIf(boolean condition,
 Supplier<Predicate> block)

Avoid using this method whenever possible, using Dynamic Predicates are a more convenient approach.

Please look at this example:

 whereIf(name != null, table.name().eq(name))
 

When name is null, this code works because eq(null) is automatically translated by Jimmer to isNull(), which doesn't cause an exception.

Let's look at another example:

 whereIf(minPrice != null, table.price().ge(minPrice))
 

Except RUST marco, almost all programming languages calculate all parameters first and then call the function. Therefore, before whereIf is executed, ge(null) already causes an exception.

For this reason, whereIf provides an overloaded form with a lambda parameter:

 whereIf(minPrice != null, () -> table.price().ge(minPrice))
 

Although this overloaded form can solve this problem, it ultimately adds a mental burden during development.

Therefore, Jimmer provides Dynamic Predicate

• Java: eqIf, neIf, ltIf, leIf, gtIf, geIf, likeIf, ilikeIf, betweenIf
• Kotlin: eq?, ne?, lt?, le?, gt?, ge?, like?, ilike?, betweenIf?

Taking Java's geIf as an example, this functionality is ultimately implemented like this.

 where(table.price().geIf(minPrice))
 

参数:

condition - The condition

block - A lambda to create predicate when condition is true

返回:

Return the current object to support chain programming style