Doma2を使ってみる(その5)

検索3

ストリーム検索

方法は2つある。

• 関数にストリームを渡す
• ストリームを返す

関数にストリームを渡す

// 検証エラーが発生する

ストリームを返す

kotlin entity.kt

DAO
```kotlin dao.kt
@Dao
@ConfigAutowireable
interface ProductDao {
    @Select
    @Suppress(messages = [Message.DOMA4274])
    fun selectAllStream(): Stream<ProductEntity>
}

main関数

kotlin main.kt

fun main(args: Array<String>) {
    val context: ApplicationContext = AnnotationConfigApplicationContext(
        ShoppingApplication::class.java)
    val productDao: ProductDao = context.getBean(ProductDao::class.java)

    val products = productDao.selectAllStream()
    products.use {
        it.forEach { product ->
            println(product)
        }
    }
}

実行結果

> Task :bootRun
20:16:16.419 [main] INFO org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseFactory -- Starting embedded database: url='jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false', username='sa'
20:16:16.513 [main] WARN org.seasar.doma.boot.autoconfigure.DomaAutoConfiguration -- StandardDialect was selected because no explicit configuration and it is not possible to guess from 'spring.datasource.url property'
ProductEntity(id=p01, name=消しゴム, price=100, stock=10)
ProductEntity(id=p02, name=ノート, price=200, stock=20)
ProductEntity(id=p03, name=pname03, price=300, stock=30)
ProductEntity(id=p04, name=pname04, price=400, stock=40)
ProductEntity(id=p05, name=pname05, price=500, stock=50)
ProductEntity(id=p06, name=pname06, price=600, stock=60)
ProductEntity(id=p07, name=pname07, price=700, stock=70)
ProductEntity(id=p08, name=pname08, price=800, stock=80)
ProductEntity(id=p09, name=pname09, price=900, stock=90)
ProductEntity(id=p10, name=pname10, price=1000, stock=100)
ProductEntity(id=p11, name=pname11, price=1100, stock=110)
ProductEntity(id=p12, name=pname12, price=1200, stock=120)
ProductEntity(id=p13, name=pname13, price=1300, stock=130)

java.sql.ResultSet 、 java.sql.PreparedStatement 、 java.sql.Connection などのリソースを
適切に閉じるために、必ず Stream を閉じる必要がある。
Kotlinではuse関数を使って、自動的にクローズ処理を行うことができため、useを使う。

コレクター検索

DAO

kotlin dao.kt

@Dao
@ConfigAutowireable
interface ProductDao {
    @Select(strategy = SelectType.COLLECT)
    fun <RESULT> selectAllCollect(collector: Collector<ProductEntity, *, RESULT>): RESULT
}

main関数

kotlin main.kt

fun main(args: Array<String>) {
    val context: ApplicationContext = AnnotationConfigApplicationContext(
        ShoppingApplication::class.java)
    val productDao: ProductDao = context.getBean(ProductDao::class.java)

    val products = productDao.selectAllCollect(Collectors.toList())
    products.forEach { product ->
        println(product)
    }
}

実行結果

> Task :bootRun
22:23:29.619 [main] INFO org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseFactory -- Starting embedded database: url='jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=false', username='sa'
22:23:29.706 [main] WARN org.seasar.doma.boot.autoconfigure.DomaAutoConfiguration -- StandardDialect was selected because no explicit configuration and it is not possible to guess from 'spring.datasource.url property'
p12=[ProductEntity(id=p12, name=pname12, price=1200, stock=120)]
p01=[ProductEntity(id=p01, name=消しゴム, price=100, stock=10)]
p11=[ProductEntity(id=p11, name=pname11, price=1100, stock=110)]
p03=[ProductEntity(id=p03, name=pname03, price=300, stock=30)]
p13=[ProductEntity(id=p13, name=pname13, price=1300, stock=130)]
p02=[ProductEntity(id=p02, name=ノート, price=200, stock=20)]
p05=[ProductEntity(id=p05, name=pname05, price=500, stock=50)]
p04=[ProductEntity(id=p04, name=pname04, price=400, stock=40)]
p07=[ProductEntity(id=p07, name=pname07, price=700, stock=70)]
p06=[ProductEntity(id=p06, name=pname06, price=600, stock=60)]
p09=[ProductEntity(id=p09, name=pname09, price=900, stock=90)]
p08=[ProductEntity(id=p08, name=pname08, price=800, stock=80)]
p10=[ProductEntity(id=p10, name=pname10, price=1000, stock=100)]

動的に生成されたコレクターを使って、結果を任意の形式で収集することができる。