feat: add ShapeShiftBuilder

src/main/java/dev/krud/shapeshift/ShapeShift.kt

@@ -23,35 +23,21 @@ import dev.krud.shapeshift.util.setValue
 import org.slf4j.LoggerFactory
 import java.lang.reflect.Field
 
-class ShapeShift(
-    transformers: List<TransformerRegistration<out Any, out Any>> = emptyList()
+class ShapeShift constructor(
+    transformersRegistrations: List<TransformerRegistration<out Any, out Any>> = emptyList()
 ) {
-    internal val transformers: MutableList<TransformerRegistration<out Any, out Any>> = transformers.toMutableList()
+    internal val transformers: MutableList<TransformerRegistration<out Any, out Any>> = mutableListOf()
     internal val transformersByNameCache: MutableMap<String, TransformerRegistration<out Any, out Any>> = mutableMapOf()
     internal val transformersByTypeCache: MutableMap<Class<out FieldTransformer<*, *>>, TransformerRegistration<*, *>> =
         mutableMapOf()
     internal val defaultTransformers: MutableMap<ClassPair, TransformerRegistration<out Any, out Any>> = mutableMapOf()
     private val mappingStructures: MutableMap<ClassPair, MappingStructure> = mutableMapOf()
     private val entityFieldsCache: MutableMap<Class<*>, Map<String, Field>> = mutableMapOf()
 
-    fun <From : Any, To : Any> registerTransformer(registration: TransformerRegistration<From, To>) {
-        val name = registration.name ?: registration.transformer::class.simpleName!!
-        val newRegistration = registration.copy(name = name)
-        val existingTransformer = getTransformerByName(name)
-        if (existingTransformer != TransformerRegistration.EMPTY) {
-            error("Transformer with name $name already exists with type ${existingTransformer.transformer::class}")
-        }
-        if (newRegistration.default) {
-            val existingDefaultTransformer = defaultTransformers[newRegistration.transformer.id]
-            if (existingDefaultTransformer != null) {
-                error("Default transformer with pair ${newRegistration.transformer.id} already exists")
-            }
-            defaultTransformers[newRegistration.transformer.id] = newRegistration
+    init {
+        for (registration in transformersRegistrations) {
+            registerTransformer(registration)
         }
-
-        transformers.add(newRegistration)
-        transformersByNameCache.remove(name)
-        transformersByTypeCache.remove(newRegistration.transformer::class.java)
     }
 
     fun <From : Any, To : Any> map(fromObject: From, toClazz: Class<To>): To {
@@ -290,6 +276,26 @@ class ShapeShift(
         return transformerRegistration
     }
 
+    private fun <From : Any, To : Any> registerTransformer(registration: TransformerRegistration<From, To>) {
+        val name = registration.name ?: registration.transformer::class.simpleName!!
+        val newRegistration = registration.copy(name = name)
+        val existingTransformer = getTransformerByName(name)
+        if (existingTransformer != TransformerRegistration.EMPTY) {
+            error("Transformer with name $name already exists with type ${existingTransformer.transformer::class}")
+        }
+        if (newRegistration.default) {
+            val existingDefaultTransformer = defaultTransformers[newRegistration.transformer.id]
+            if (existingDefaultTransformer != null) {
+                error("Default transformer with pair ${newRegistration.transformer.id} already exists")
+            }
+            defaultTransformers[newRegistration.transformer.id] = newRegistration
+        }
+
+        transformers.add(newRegistration)
+        transformersByNameCache.remove(name)
+        transformersByTypeCache.remove(newRegistration.transformer::class.java)
+    }
+
     companion object {
         private val log = LoggerFactory.getLogger(ShapeShift::class.java)
         const val NODE_DELIMITER = "."

src/main/java/dev/krud/shapeshift/ShapeShiftBuilder.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright KRUD 2022
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package dev.krud.shapeshift
+
+class ShapeShiftBuilder {
+    private val transformers: MutableList<TransformerRegistration<*, *>> = mutableListOf()
+
+    fun withTransformer(transformerRegistration: TransformerRegistration<*, *>): ShapeShiftBuilder {
+        transformers += transformerRegistration
+        return this
+    }
+
+    fun build(): ShapeShift {
+        return ShapeShift(transformers)
+    }
+}

src/test/java/dev/krud/shapeshift/ShapeShiftTests.kt

@@ -51,11 +51,14 @@ internal class ShapeShiftTests {
 
         @Test
         internal fun `simple mapping with transformer by type`() {
-            shapeShift.registerTransformer(
-                TransformerRegistration(
-                    LongToStringTransformer()
+            shapeShift = ShapeShiftBuilder()
+                .withTransformer(
+                    TransformerRegistration(
+                        LongToStringTransformer()
+                    )
                 )
-            )
+                .build()
+
             val result = shapeShift.map(TypeTransformerFrom(), StringTo::class.java)
 
             expectThat(result.long)
@@ -64,12 +67,14 @@ internal class ShapeShiftTests {
 
         @Test
         internal fun `simple mapping with transformer by name`() {
-            shapeShift.registerTransformer(
-                TransformerRegistration(
-                    LongToStringTransformer(),
-                    name = "myTransformer"
+            shapeShift = ShapeShiftBuilder()
+                .withTransformer(
+                    TransformerRegistration(
+                        LongToStringTransformer(),
+                        name = "myTransformer"
+                    )
                 )
-            )
+                .build()
             val result = shapeShift.map(NameTransformerFrom(), StringTo::class.java)
 
             expectThat(result.long)
@@ -78,12 +83,14 @@ internal class ShapeShiftTests {
 
         @Test
         internal fun `simple mapping with default transformer`() {
-            shapeShift.registerTransformer(
-                TransformerRegistration(
-                    LongToStringTransformer(),
-                    default = true
+            shapeShift = ShapeShiftBuilder()
+                .withTransformer(
+                    TransformerRegistration(
+                        LongToStringTransformer(),
+                        default = true
+                    )
                 )
-            )
+                .build()
             val result = shapeShift.map(DefaultTransformerFrom(), StringTo::class.java)
 
             expectThat(result.long)
@@ -225,9 +232,13 @@ internal class ShapeShiftTests {
             true,
             "second"
         )
-        shapeShift.registerTransformer(firstRegistration)
+
+        val builder = ShapeShiftBuilder()
+            .withTransformer(firstRegistration)
+            .withTransformer(secondRegistration)
+
         expectThrows<IllegalStateException> {
-            shapeShift.registerTransformer(secondRegistration)
+            builder.build()
         }
     }
 
@@ -238,7 +249,9 @@ internal class ShapeShiftTests {
             false,
             null
         )
-        shapeShift.registerTransformer(registration)
+        shapeShift = ShapeShiftBuilder()
+            .withTransformer(registration)
+            .build()
         expectThat(shapeShift.transformers.first().name)
             .isEqualTo(
                 "ExampleFieldTransformer"
@@ -253,9 +266,12 @@ internal class ShapeShiftTests {
             "first"
         )
 
-        shapeShift.registerTransformer(registration)
+        val builder = ShapeShiftBuilder()
+            .withTransformer(registration)
+            .withTransformer(registration)
+
         expectThrows<IllegalStateException> {
-            shapeShift.registerTransformer(registration)
+            builder.build()
         }
     }
 
@@ -330,6 +346,7 @@ internal class ShapeShiftTests {
 
             class Grandchild {
                 val greatGrandchild: GreatGrandchild = GreatGrandchild()
+
                 class GreatGrandchild {
                     val long: Long = 1L
                 }
@@ -383,6 +400,7 @@ internal class ShapeShiftTests {
     internal class FromWithMapFromSelfQualifier {
         @MappedField(target = GenericTo::class, mapFrom = "child.long")
         val child: Child = Child()
+
         class Child {
             val long: Long = 1L
         }
@@ -391,6 +409,7 @@ internal class ShapeShiftTests {
     @MappedField(target = GenericTo::class, mapFrom = "fromWithMapFromSelfQualifierOnType.child.long")
     internal class FromWithMapFromSelfQualifierOnType {
         val child: Child = Child()
+
         class Child {
             val long: Long = 1L
         }
@@ -465,6 +484,7 @@ internal class ShapeShiftTests {
 
             class Grandchild {
                 val greatGrandchild: GreatGrandchild? = null
+
                 class GreatGrandchild {
                     val long: Long? = null
                 }