Initial Kotlin support for Having

Author: jeffgbutler

src/main/kotlin/org/mybatis/dynamic/sql/util/kotlin/KotlinSelectBuilder.kt

@@ -15,11 +15,14 @@
  */
 package org.mybatis.dynamic.sql.util.kotlin
 
+import org.mybatis.dynamic.sql.AndOrCriteriaGroup
 import org.mybatis.dynamic.sql.BasicColumn
 import org.mybatis.dynamic.sql.SortSpecification
+import org.mybatis.dynamic.sql.SqlCriterion
 import org.mybatis.dynamic.sql.SqlTable
 import org.mybatis.dynamic.sql.select.QueryExpressionDSL
 import org.mybatis.dynamic.sql.select.SelectModel
+import org.mybatis.dynamic.sql.select.SubQuery
 import org.mybatis.dynamic.sql.util.Buildable
 import org.mybatis.dynamic.sql.util.Messages
 
@@ -29,25 +32,30 @@ typealias SelectCompleter = KotlinSelectBuilder.() -> Unit
 class KotlinSelectBuilder(private val fromGatherer: QueryExpressionDSL.FromGatherer<SelectModel>) :
     KotlinBaseJoiningBuilder<QueryExpressionDSL<SelectModel>>(), Buildable<SelectModel> {
 
-    private var dsl: QueryExpressionDSL<SelectModel>? = null
+    private var dsl: KQueryExpressionDSL? = null
 
     fun from(table: SqlTable) {
-        dsl = fromGatherer.from(table)
+        dsl = KQueryExpressionDSL(fromGatherer, table)
     }
 
     fun from(table: SqlTable, alias: String) {
-        dsl = fromGatherer.from(table, alias)
+        dsl = KQueryExpressionDSL(fromGatherer, table, alias)
     }
 
     fun from(subQuery: KotlinQualifiedSubQueryBuilder.() -> Unit) {
         val builder = KotlinQualifiedSubQueryBuilder().apply(subQuery)
-        dsl = fromGatherer.from(builder, builder.correlationName)
+        dsl = KQueryExpressionDSL(fromGatherer, builder)
     }
 
     fun groupBy(vararg columns: BasicColumn) {
         getDsl().groupBy(columns.toList())
     }
 
+    fun having(criteria: GroupingCriteriaReceiver): Unit =
+        with(GroupingCriteriaCollector().apply(criteria)) {
+            this@KotlinSelectBuilder.getDsl().applyHaving(initialCriterion, subCriteria)
+        }
+
     fun orderBy(vararg columns: SortSpecification) {
         getDsl().orderBy(columns.toList())
     }
@@ -72,7 +80,34 @@ class KotlinSelectBuilder(private val fromGatherer: QueryExpressionDSL.FromGathe
 
     override fun build(): SelectModel = getDsl().build()
 
-    override fun getDsl(): QueryExpressionDSL<SelectModel> {
+    override fun getDsl(): KQueryExpressionDSL {
         return dsl?: throw KInvalidSQLException(Messages.getString("ERROR.27")) //$NON-NLS-1$
     }
 }
+
+/**
+ * Extension of the QueryExpressionDSL class that provides access to protected methods in that class.
+ * We do this especially for having support because we don't want to publicly expose a "having" method
+ * directly in QueryExpressionDSL as it would be in an odd place for the Java DSL.
+ */
+class KQueryExpressionDSL: QueryExpressionDSL<SelectModel> {
+    constructor(fromGatherer: FromGatherer<SelectModel>, table: SqlTable) : super(fromGatherer, table)
+
+    constructor(fromGatherer: FromGatherer<SelectModel>, table: SqlTable, alias: String) :
+            super(fromGatherer, table, alias)
+
+    constructor(fromGatherer: FromGatherer<SelectModel>, subQuery: KotlinQualifiedSubQueryBuilder) :
+            super(fromGatherer, buildSubQuery(subQuery))
+
+    internal fun applyHaving(initialCriterion: SqlCriterion?, subCriteria: List<AndOrCriteriaGroup>) {
+        having(initialCriterion, subCriteria)
+    }
+
+    companion object {
+        fun buildSubQuery(subQuery: KotlinQualifiedSubQueryBuilder): SubQuery {
+            return SubQuery.Builder().withSelectModel(subQuery.build())
+                .withAlias(subQuery.correlationName)
+                .build()
+        }
+    }
+}