Improve result handling and add QueryResult#stream

MineKing9534 · Oct 20, 2024 · fc6a2de · fc6a2de
1 parent ebfd06c
commit fc6a2de
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Showing 4 changed files with 30 additions and 60 deletions.
diff --git a/core/src/main/kotlin/de/mineking/database/Result.kt b/core/src/main/kotlin/de/mineking/database/Result.kt
@@ -3,15 +3,9 @@ package de.mineking.database
 import org.jdbi.v3.core.result.ResultIterable
 import java.sql.ResultSet
 import java.sql.SQLException
+import java.util.stream.Stream
 
 data class ReadContext(val instance: Any?, val table: TableStructure<*>, val set: ResultSet, val selected: List<String>?, val prefix: Array<String> = emptyArray(), val autofillPrefix: (String) -> Boolean = { true }, var shouldRead: Boolean = true) {
-    fun proceed(): Boolean {
-        if (!shouldRead) return true
-
-        shouldRead = false
-        return set.next()
-    }
-
     fun formatName(name: String) = ((prefix.takeIf { it.isNotEmpty() || !autofillPrefix(name) } ?: arrayOf(table.name)) + name).joinToString(".")
 
     fun <T> read(name: String, reader: (ResultSet, String) -> T): T = reader(set, formatName(name))
@@ -28,38 +22,21 @@ interface QueryResult<T> {
         return try { first() }
         catch (_: NoSuchElementException) { null }
     }
-}
-
-interface RowQueryResult<T: Any> : QueryResult<T> {
-    val instance: () -> T
-    fun <O> execute(handler: ((T) -> Boolean) -> O): O
-
-    override fun list(): List<T> = execute { read ->
-        val result = arrayListOf<T>()
-
-        while (true) {
-            val obj = instance()
 
-            if (!read(obj)) break
-            result.add(obj)
-        }
-
-        result
-    }
-
-    override fun first(): T = execute { read ->
-        val obj = instance()
-
-        if (!read(obj)) throw NoSuchElementException()
-        else obj
-    }
+    fun stream(): Stream<T>
+    fun <R> withStream(handler: (Stream<T>) -> R): R = stream().use(handler)
 }
 
-interface ValueQueryResult<T>: QueryResult<T> {
+interface SimpleQueryResult<T>: QueryResult<T> {
     fun <O> execute(handler: (ResultIterable<T>) -> O): O
 
     override fun list(): List<T> = execute { it.list() }
     override fun first(): T = execute { it.first() }
+
+    /**
+     * Note: The returned stream has to be closed by the user!
+     */
+    override fun stream(): Stream<T> = execute { it.stream() }
 }
 
 data class UpdateResult<T>(

diff --git a/core/src/main/kotlin/de/mineking/database/Table.kt b/core/src/main/kotlin/de/mineking/database/Table.kt
@@ -70,17 +70,14 @@ abstract class TableImplementation<T: Any>(
 ) : Table<T>, InvocationHandler {
 	override val implementation: TableImplementation<T> = this
 
-	open fun parseResult(context: ReadContext): Boolean {
-		if (!context.proceed()) return false
-
+	open fun parseResult(context: ReadContext) {
 		@Suppress("UNCHECKED_CAST")
 		val instance = context.instance as T
 
 		fun <C> setField(column: DirectColumnData<T, C>) = column.set(instance, column.mapper.read(column, column.type, context, column.name))
 		structure.columns.forEach { if (context.shouldRead(it.name)) setField(it) }
 
 		if (context.instance is DataObject<*>) context.instance.afterRead()
-		return true
 	}
 
 	override fun invoke(proxy: Any?, method: Method?, args: Array<out Any?>?): Any? {

diff --git a/postgres/src/main/kotlin/de/mineking/database/vendors/PostgresTable.kt b/postgres/src/main/kotlin/de/mineking/database/vendors/PostgresTable.kt
@@ -108,17 +108,15 @@ class PostgresTable<T: Any>(
 		)
 
 		val sql = createSelect(columnList.joinToString { "\"${ it.first }\".\"${ it.second }\" as \"${ it.first }.${ it.second }\"" }, where, order, limit, offset)
-		return object : RowQueryResult<T> {
-			override val instance: () -> T = this@PostgresTable.instance
-			override fun <O> execute(handler: ((T) -> Boolean) -> O): O = structure.manager.execute { it.createQuery(sql)
+		return object : SimpleQueryResult<T> {
+			override fun <O> execute(handler: (ResultIterable<T>) -> O): O = structure.manager.execute { handler(it.createQuery(sql)
 				.bindMap(where.values(structure))
-				.execute { stmt, _ ->
-					val statement = stmt.get()
-					val set = statement.resultSet
-
-					handler { parseResult(ReadContext(it, structure, set, columnList.map { "${ it.first }.${ it.second }" })) }
+				.map { set, _ ->
+					val instance = instance()
+					parseResult(ReadContext(instance, structure, set, columnList.map { "${ it.first }.${ it.second }" }))
+					instance
 				}
-			}
+			) }
 		}
 	}
 
@@ -139,7 +137,7 @@ class PostgresTable<T: Any>(
 		val columnList = createColumnList(column?.column?.let { listOf(it) } ?: emptyList())
 
 		val sql = createSelect((columnList.map { "\"${ it.first }\".\"${ it.second }\" as \"${ it.first }.${ it.second }\"" } + "(${ target.format(structure) }) as \"value\"").joinToString(), where, order, limit, offset)
-		return object : ValueQueryResult<C> {
+		return object : SimpleQueryResult<C> {
 			override fun <O> execute(handler: (ResultIterable<C>) -> O): O = structure.manager.execute { handler(it.createQuery(sql)
 				.bindMap(target.values(structure, column?.column))
 				.bindMap(where.values(structure))
@@ -156,11 +154,11 @@ class PostgresTable<T: Any>(
 			update.bind(it.name, createArgument(it))
 		}
 
-		return update.execute { stmt, ctx -> ctx.use {
+		update.execute { stmt, ctx -> ctx.use {
 			val statement = stmt.get()
 			val set = statement.resultSet
 
-			parseResult(ReadContext(obj, structure, set, columns.filter { it.getRootColumn().reference == null }.map { it.name }, autofillPrefix = { false }))
+			if (set.next()) parseResult(ReadContext(obj, structure, set, columns.filter { it.getRootColumn().reference == null }.map { it.name }, autofillPrefix = { false }))
 		} }
 	}
 

diff --git a/sqlite/src/main/kotlin/de/mineking/database/vendors/SQLiteTable.kt b/sqlite/src/main/kotlin/de/mineking/database/vendors/SQLiteTable.kt
@@ -108,17 +108,15 @@ class SQLiteTable<T: Any>(
 		)
 
 		val sql = createSelect(columnList.joinToString { "\"${ it.first }\".\"${ it.second }\" as \"${ it.first }.${ it.second }\"" }, where, order, limit, offset)
-		return object : RowQueryResult<T> {
-			override val instance: () -> T = this@SQLiteTable.instance
-			override fun <O> execute(handler: ((T) -> Boolean) -> O): O = structure.manager.execute { it.createQuery(sql)
+		return object : SimpleQueryResult<T> {
+			override fun <O> execute(handler: (ResultIterable<T>) -> O): O = structure.manager.execute { handler(it.createQuery(sql)
 				.bindMap(where.values(structure))
-				.execute { stmt, _ ->
-					val statement = stmt.get()
-					val set = statement.resultSet
-
-					handler { parseResult(ReadContext(it, structure, set, columnList.map { "${ it.first }.${ it.second }" })) }
+				.map { set, _ ->
+					val instance = instance()
+					parseResult(ReadContext(instance, structure, set, columnList.map { "${ it.first }.${ it.second }" }))
+					instance
 				}
-			}
+			) }
 		}
 	}
 
@@ -139,7 +137,7 @@ class SQLiteTable<T: Any>(
 		val columnList = createColumnList(column?.column?.let { listOf(it) } ?: emptyList())
 
 		val sql = createSelect((columnList.map { "\"${ it.first }\".\"${ it.second }\" as \"${ it.first }.${ it.second }\"" } + "(${ target.format(structure) }) as \"value\"").joinToString(), where, order, limit, offset)
-		return object : ValueQueryResult<C> {
+		return object : SimpleQueryResult<C> {
 			override fun <O> execute(handler: (ResultIterable<C>) -> O): O = structure.manager.execute { handler(it.createQuery(sql)
 				.bindMap(target.values(structure, column?.column))
 				.bindMap(where.values(structure))
@@ -156,11 +154,11 @@ class SQLiteTable<T: Any>(
 			update.bind(it.name, createArgument(it))
 		}
 
-		return update.execute { stmt, ctx -> ctx.use {
+		update.execute { stmt, ctx -> ctx.use {
 			val statement = stmt.get()
 			val set = statement.resultSet
 
-			parseResult(ReadContext(obj, structure, set, columns.filter { it.getRootColumn().reference == null }.map { it.name }, autofillPrefix = { false }))
+			if (set.next()) parseResult(ReadContext(obj, structure, set, columns.filter { it.getRootColumn().reference == null }.map { it.name }, autofillPrefix = { false }))
 		} }
 	}