org.mybatis.dynamic.sql.select

Interface CountDSLCompleter

All Superinterfaces:

Function<CountDSL<SelectModel>,Buildable<SelectModel>>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface CountDSLCompleter
extends Function<CountDSL<SelectModel>,Buildable<SelectModel>>

Represents a function that can be used to create a general count method. When using this function, you can create a method that does not require a user to call the build() and render() methods - making client code look a bit cleaner.

This function is intended to by used in conjunction with a utility method like MyBatis3Utils.countFrom(ToLongFunction, CountDSL, CountDSLCompleter)

For example, you can create mapper interface methods like this:

 @SelectProvider(type=SqlProviderAdapter.class, method="select")
 long count(SelectStatementProvider selectStatement);

 default long count(CountDSLCompleter completer) {
     return MyBatis3Utils.count(this::count, person, completer);
 }
 

And then call the simplified default method like this:

 long rows = mapper.count(c ->
         c.where(occupation, isNull()));
 

You can implement a "count all" with the following code:

 long rows = mapper.count(c -> c);
 

Or

 long rows = mapper.count(CountDSLCompleter.allRows());
 

Author:

Jeff Butler

Method Summary

Modifier and Type	Method and Description
static CountDSLCompleter	allRows() Returns a completer that can be used to count every row in a table.

Methods inherited from interface java.util.function.Function

andThen, apply, compose, identity

Method Detail

allRows

static CountDSLCompleter allRows()

Returns a completer that can be used to count every row in a table.

Returns:

the completer that will count every row in a table