Merge pull request #335 from jeffgbutler/master

Add composition functions for WhereApplier

Author: jeffgbutler

CHANGELOG.md

@@ -94,6 +94,7 @@ Kotlin DSL.
 - Added subquery support for "join" clauses in a select statement ([#293](https://github.com/mybatis/mybatis-dynamic-sql/pull/293))
 - Added support for the "exists" and "not exists" operator in where clauses ([#296](https://github.com/mybatis/mybatis-dynamic-sql/pull/296))
 - Refactored the built-in conditions ([#331](https://github.com/mybatis/mybatis-dynamic-sql/pull/331))
+- Added composition functions for WhereApplier ([#335](https://github.com/mybatis/mybatis-dynamic-sql/pull/335))
 
 ## Release 1.2.1 - September 29, 2020
 

src/main/java/org/mybatis/dynamic/sql/where/WhereApplier.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -18,4 +18,19 @@
 import java.util.function.Consumer;
 
 @FunctionalInterface
-public interface WhereApplier extends Consumer<AbstractWhereDSL<?>> {}
+public interface WhereApplier extends Consumer<AbstractWhereDSL<?>> {
+    /**
+     * Return a composed where applier that performs this operation followed
+     * by the after operation.
+     *
+     * @param after the operation to perform after this operation
+     * @return a composed where applier that performs this operation followed
+     *     by the after operation.
+     */
+    default WhereApplier andThen(WhereApplier after) {
+        return t -> {
+            accept(t);
+            after.accept(t);
+        };
+    }
+}

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -30,6 +30,11 @@ annotation class MyBatisDslMarker
 
 typealias WhereApplier = AbstractWhereDSL<*>.() -> Unit
 
+fun WhereApplier.andThen(after: WhereApplier): WhereApplier = {
+    invoke(this)
+    after(this)
+}
+
 @MyBatisDslMarker
 @Suppress("TooManyFunctions")
 abstract class KotlinBaseBuilder<D : AbstractWhereSupport<*>, B : KotlinBaseBuilder<D, B>> {

src/test/java/examples/spring/ReusableWhereTest.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -24,7 +24,9 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mybatis.dynamic.sql.delete.DeleteModel;
+import org.mybatis.dynamic.sql.render.RenderingStrategies;
 import org.mybatis.dynamic.sql.select.SelectModel;
+import org.mybatis.dynamic.sql.select.render.SelectStatementProvider;
 import org.mybatis.dynamic.sql.update.UpdateModel;
 import org.mybatis.dynamic.sql.util.Buildable;
 import org.mybatis.dynamic.sql.util.spring.NamedParameterJdbcTemplateExtensions;
@@ -39,7 +41,7 @@ class ReusableWhereTest {
     private NamedParameterJdbcTemplateExtensions template;
 
     @BeforeEach
-    void setup() throws Exception {
+    void setup() {
         EmbeddedDatabase db = new EmbeddedDatabaseBuilder()
                 .setType(EmbeddedDatabaseType.HSQL)
                 .generateUniqueName(true)
@@ -89,5 +91,22 @@ void testUpdate() {
         assertThat(rows).isEqualTo(3);
     }
 
-    private WhereApplier commonWhere =  d -> d.where(id, isEqualTo(1)).or(occupation, isNull());
+    @Test
+    void testComposition() {
+        WhereApplier whereApplier = commonWhere.andThen(wa -> wa.and(birthDate, isNotNull()));
+        whereApplier = whereApplier.andThen(wa -> wa.or(addressId, isLessThan(3)));
+
+        SelectStatementProvider selectStatement = select(person.allColumns())
+                .from(person)
+                .applyWhere(whereApplier)
+                .build()
+                .render(RenderingStrategies.SPRING_NAMED_PARAMETER);
+
+        assertThat(selectStatement.getSelectStatement()).isEqualTo(
+                "select * from Person " +
+                    "where id = :p1 or occupation is null and birth_date is not null or address_id < :p2");
+
+    }
+
+    private final WhereApplier commonWhere =  d -> d.where(id, isEqualTo(1)).or(occupation, isNull());
 }

src/test/kotlin/examples/kotlin/mybatis3/canonical/ReusableWhereTest.kt

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,8 +15,11 @@
  */
 package examples.kotlin.mybatis3.canonical
 
+import examples.kotlin.mybatis3.canonical.PersonDynamicSqlSupport.Person.addressId
+import examples.kotlin.mybatis3.canonical.PersonDynamicSqlSupport.Person.birthDate
 import examples.kotlin.mybatis3.canonical.PersonDynamicSqlSupport.Person.id
 import examples.kotlin.mybatis3.canonical.PersonDynamicSqlSupport.Person.occupation
+import examples.kotlin.mybatis3.canonical.PersonDynamicSqlSupport.Person
 import org.apache.ibatis.datasource.unpooled.UnpooledDataSource
 import org.apache.ibatis.jdbc.ScriptRunner
 import org.apache.ibatis.mapping.Environment
@@ -26,9 +29,13 @@ import org.apache.ibatis.session.SqlSessionFactoryBuilder
 import org.apache.ibatis.transaction.jdbc.JdbcTransactionFactory
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.jupiter.api.Test
+import org.mybatis.dynamic.sql.SqlBuilder.isLessThan
 import org.mybatis.dynamic.sql.SqlBuilder.isEqualTo
+import org.mybatis.dynamic.sql.SqlBuilder.isNotNull
 import org.mybatis.dynamic.sql.SqlBuilder.isNull
 import org.mybatis.dynamic.sql.util.kotlin.WhereApplier
+import org.mybatis.dynamic.sql.util.kotlin.andThen
+import org.mybatis.dynamic.sql.util.kotlin.mybatis3.select
 import java.io.InputStreamReader
 import java.sql.DriverManager
 
@@ -105,8 +112,31 @@ class ReusableWhereTest {
         }
     }
 
+    @Test
+    fun testComposition() {
+        var whereApplier = commonWhere.andThen {
+            and(birthDate, isNotNull())
+        }
+
+        whereApplier = whereApplier.andThen {
+            or(addressId, isLessThan(3))
+        }
+
+        val selectStatement = select(Person.allColumns()) {
+            from(Person)
+            applyWhere(whereApplier)
+        }
+
+        assertThat(selectStatement.selectStatement).isEqualTo(
+            "select * from Person " +
+                "where id = #{parameters.p1,jdbcType=INTEGER} or occupation is null " +
+                "and birth_date is not null " +
+                "or address_id < #{parameters.p2,jdbcType=INTEGER}"
+        )
+    }
+
     private val commonWhere: WhereApplier = {
-        where(id, isEqualTo(1)).or(occupation, isNull<String>())
+        where(id, isEqualTo(1)).or(occupation, isNull())
     }
 
     companion object {