Better usage of Kotlin self type

Author: jeffgbutler

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

@@ -24,85 +24,90 @@ import org.mybatis.dynamic.sql.util.Buildable
 import org.mybatis.dynamic.sql.where.AbstractWhereDSL
 
 abstract class KotlinBaseBuilder<M, W : AbstractWhereDSL<W>, B : KotlinBaseBuilder<M, W, B>> : Buildable<M> {
-    fun <T> where(column: BindableColumn<T>, condition: VisitableCondition<T>): B {
-        getWhere().where(column, condition)
-        return getThis()
-    }
-
-    fun <T> where(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B {
-        getWhere().where(column, condition, collect)
-        return getThis()
-    }
-
-    fun applyWhere(whereApplier: WhereApplier): B {
-        getWhere().applyWhere(whereApplier)
-        return getThis()
-    }
-
-    fun <T> and(column: BindableColumn<T>, condition: VisitableCondition<T>): B {
-        getWhere().and(column, condition)
-        return getThis()
-    }
-
-    fun <T> and(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B {
-        getWhere().and(column, condition, collect)
-        return getThis()
-    }
-
-    fun <T> or(column: BindableColumn<T>, condition: VisitableCondition<T>): B {
-        getWhere().or(column, condition)
-        return getThis()
-    }
-
-    fun <T> or(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B {
-        getWhere().or(column, condition, collect)
-        return getThis()
-    }
+    fun <T> where(column: BindableColumn<T>, condition: VisitableCondition<T>): B =
+        applySelf {
+            getWhere().where(column, condition)
+        }
+
+    fun <T> where(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B =
+        applySelf {
+            getWhere().where(column, condition, collect)
+        }
+
+    fun applyWhere(whereApplier: WhereApplier): B =
+        applySelf {
+            getWhere().applyWhere(whereApplier)
+        }
+
+    fun <T> and(column: BindableColumn<T>, condition: VisitableCondition<T>): B =
+        applySelf {
+            getWhere().and(column, condition)
+        }
+
+    fun <T> and(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B =
+        applySelf {
+            getWhere().and(column, condition, collect)
+        }
+
+    fun <T> or(column: BindableColumn<T>, condition: VisitableCondition<T>): B =
+        applySelf {
+            getWhere().or(column, condition)
+        }
+
+    fun <T> or(column: BindableColumn<T>, condition: VisitableCondition<T>, collect: CriteriaReceiver): B =
+        applySelf {
+            getWhere().or(column, condition, collect)
+        }
+
+    protected fun applySelf(block: B.() -> Unit): B =
+        self().apply { block() }
+
+    protected abstract fun self(): B
 
     protected abstract fun getWhere(): W
-    protected abstract fun getThis(): B
 }
 
-abstract class KotlinBaseJoiningBuilder<T : AbstractQueryExpressionDSL<T, SelectModel>, W: AbstractWhereDSL<W>, B : KotlinBaseJoiningBuilder<T, W, B>>(private val dsl: AbstractQueryExpressionDSL<T, SelectModel>) :
-    KotlinBaseBuilder<SelectModel, W, B>() {
-
-    fun join(table: SqlTable, receiver: JoinReceiver) =
-            apply {
-                dsl.join(table, receiver)
-            }
-
-    fun join(table: SqlTable, alias: String, receiver: JoinReceiver) =
-            apply {
-                dsl.join(table, alias, receiver)
-            }
-
-    fun fullJoin(table: SqlTable, receiver: JoinReceiver) =
-            apply {
-                dsl.fullJoin(table, receiver)
-            }
-
-    fun fullJoin(table: SqlTable, alias: String, receiver: JoinReceiver) =
-            apply {
-                dsl.fullJoin(table, alias, receiver)
-            }
-
-    fun leftJoin(table: SqlTable, receiver: JoinReceiver) =
-            apply {
-                dsl.leftJoin(table, receiver)
-            }
-
-    fun leftJoin(table: SqlTable, alias: String, receiver: JoinReceiver) =
-            apply {
-                dsl.leftJoin(table, alias, receiver)
-            }
-
-    fun rightJoin(table: SqlTable, receiver: JoinReceiver) =
-            apply {
-                dsl.rightJoin(table, receiver)
-            }
-
-    fun rightJoin(table: SqlTable, alias: String, receiver: JoinReceiver) =
-            apply {
-                dsl.rightJoin(table, alias, receiver)
-            }
+abstract class KotlinBaseJoiningBuilder<T : AbstractQueryExpressionDSL<T, SelectModel>, W : AbstractWhereDSL<W>, B : KotlinBaseJoiningBuilder<T, W, B>>(
+    private val dsl: AbstractQueryExpressionDSL<T, SelectModel>
+) : KotlinBaseBuilder<SelectModel, W, B>() {
+
+    fun join(table: SqlTable, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.join(table, receiver)
+        }
+
+    fun join(table: SqlTable, alias: String, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.join(table, alias, receiver)
+        }
+
+    fun fullJoin(table: SqlTable, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.fullJoin(table, receiver)
+        }
+
+    fun fullJoin(table: SqlTable, alias: String, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.fullJoin(table, alias, receiver)
+        }
+
+    fun leftJoin(table: SqlTable, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.leftJoin(table, receiver)
+        }
+
+    fun leftJoin(table: SqlTable, alias: String, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.leftJoin(table, alias, receiver)
+        }
+
+    fun rightJoin(table: SqlTable, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.rightJoin(table, receiver)
+        }
+
+    fun rightJoin(table: SqlTable, alias: String, receiver: JoinReceiver): B =
+        applySelf {
+            dsl.rightJoin(table, alias, receiver)
+        }
 }

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

@@ -30,5 +30,5 @@ class KotlinCountBuilder(private val dsl: CountDSL<SelectModel>) :
 
     override fun getWhere(): CountDSL<SelectModel>.CountWhereBuilder = dsl.where()
 
-    override fun getThis() = this
+    override fun self() = this
 }

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

@@ -30,5 +30,5 @@ class KotlinDeleteBuilder(private val dsl: DeleteDSL<DeleteModel>) :
 
     override fun getWhere(): DeleteDSL<DeleteModel>.DeleteWhereBuilder = dsl.where()
 
-    override fun getThis(): KotlinDeleteBuilder = this
+    override fun self() = this
 }

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

@@ -54,5 +54,5 @@ class KotlinQueryBuilder(private val dsl: QueryExpressionDSL<SelectModel>) :
 
     override fun getWhere(): QueryExpressionDSL<SelectModel>.QueryExpressionWhereBuilder = dsl.where()
 
-    override fun getThis() = this
+    override fun self() = this
 }

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

@@ -38,5 +38,5 @@ class KotlinUpdateBuilder(private val dsl: UpdateDSL<UpdateModel>) :
 
     override fun getWhere(): UpdateDSL<UpdateModel>.UpdateWhereBuilder = dsl.where()
 
-    override fun getThis(): KotlinUpdateBuilder = this
+    override fun self() = this
 }