Support multiple child types #1

Author: Bethibande

processor/src/main/java/de/bethibande/serial/processor/generator/FieldInfo.java

@@ -13,9 +13,7 @@
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.TypeMirror;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 
 @Builder(toBuilder = true)
 @AllArgsConstructor(access = AccessLevel.PRIVATE)
@@ -33,8 +31,7 @@ public class FieldInfo implements HasAttributes {
     private AttributeMap attributes;
 
     @Getter
-    @Setter
-    private FieldInfo child;
+    private List<FieldInfo> children;
     @Getter
     @Setter
     private FieldInfo parent;
@@ -67,6 +64,15 @@ public FieldInfo(final TypeElement clazz, final VariableElement field, final Str
         this.attributes = new AttributeMap();
         this.nullable = false;
         this.generatedMethods = new HashMap<>();
+        this.children = new ArrayList<>();
+    }
+
+    public FieldInfo getFirstChild() {
+        return children.getFirst();
+    }
+
+    public void addChild(final FieldInfo child) {
+        children.add(child);
     }
 
     public TypeElement getTypeElement() {

processor/src/main/java/de/bethibande/serial/processor/serializer/EmbeddedTypeTransformer.java

@@ -2,6 +2,7 @@
 
 import de.bethibande.serial.processor.generator.FieldInfo;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 
 public abstract class EmbeddedTypeTransformer implements FieldBasedObjectTransformer {
@@ -17,16 +18,17 @@ public boolean isApplicable(final FieldInfo field, final ElementSerializer seria
         final FieldInfo child = createChildType(field, serializer)
                 .toBuilder()
                 .generatedMethods(new HashMap<>()) // Avoid sharing the same map instance with the parent
+                .children(new ArrayList<>()) // Avoid sharing the same list instance with the parent
                 .build();
         child.setTransformer(serializer.getFieldTransformer(child).orElseThrow());
         child.setParent(field);
-        field.setChild(child);
+        field.addChild(child);
 
         return true;
     }
 
     public String embeddedMethodName(final FieldInfo field) {
-        return methodName(field.getChild());
+        return methodName(field.getChildren().getFirst());
     }
 
 }

processor/src/main/java/de/bethibande/serial/processor/serializer/FieldBasedObjectTransformer.java

@@ -12,9 +12,7 @@
 import javax.lang.model.AnnotatedConstruct;
 import javax.lang.model.element.*;
 import javax.lang.model.type.TypeMirror;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Optional;
+import java.util.*;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -45,29 +43,43 @@ default Optional<String> wrappedMethodNameSuffix() {
         return Optional.empty();
     }
 
+    default void forEachSingleChild(final FieldInfo root,
+                                    final Function<FieldInfo, FieldInfo> childFunction,
+                                    final Consumer<FieldInfo> consumer) {
+        forEach(root, field -> {
+            final FieldInfo child = childFunction.apply(field);
+            if (child == null) return Collections.emptyList();
+            return Collections.singletonList(child);
+        }, consumer);
+    }
+
     default void forEach(final FieldInfo root,
-                         final Function<FieldInfo, FieldInfo> nextFunction,
+                         final Function<FieldInfo, Collection<FieldInfo>> childFunction,
                          final Consumer<FieldInfo> consumer) {
-        FieldInfo current = root;
-        while (current != null) {
+        final Stack<FieldInfo> stack = new Stack<>();
+        stack.push(root);
+        while (!stack.isEmpty()) {
+            final FieldInfo current = stack.pop();
+            if (current == null) continue;
+
             consumer.accept(current);
-            current = nextFunction.apply(current);
+            childFunction.apply(current).forEach(stack::push);
         }
     }
 
     default <T> List<T> mapEach(final FieldInfo root,
-                         final Function<FieldInfo, FieldInfo> nextFunction,
-                         final Function<FieldInfo, T> consumer) {
+                                final Function<FieldInfo, Collection<FieldInfo>> childFunction,
+                                final Function<FieldInfo, T> consumer) {
         final List<T> values = new ArrayList<>();
-        forEach(root, nextFunction, (current) -> values.add(consumer.apply(current)));
+        forEach(root, childFunction, (current) -> values.add(consumer.apply(current)));
 
         return values;
     }
 
     default String methodName(final FieldInfo field) {
         final StringBuilder builder = new StringBuilder(field.getFieldName());
         if (field.getParent() != null) {
-            forEach(
+            forEachSingleChild(
                     field.getParent(),
                     FieldInfo::getParent,
                     parent -> parent.getTransformer()
@@ -112,7 +124,7 @@ default void transformType(final TypeSpec.Builder builder,
                                final SerializationContext ctx) {
         final List<MethodSpec> methods = mapEach(
                 field,
-                FieldInfo::getChild,
+                FieldInfo::getChildren,
                 child -> {
                     final FieldBasedObjectTransformer transformer = child.getTransformer();
                     final MethodSpec method = switch (methodType) {

processor/src/main/java/de/bethibande/serial/processor/serializer/types/ArrayTypes.java

@@ -45,7 +45,7 @@ public Optional<String> wrappedMethodNameSuffix() {
     public CodeBlock createSerializationCode(final FieldInfo field, final SerializationContext ctx) {
         return CodeBlock.builder()
                 .addStatement("$L.writeInt($L.length)", "writer", "value")
-                .beginControlFlow("for ($T item : $L)", field.getChild().getType(), "value")
+                .beginControlFlow("for ($T item : $L)", field.getFirstChild().getType(), "value")
                 .addStatement("$L(item)", embeddedMethodName(field))
                 .endControlFlow()
                 .addStatement("return this")
@@ -55,7 +55,7 @@ public CodeBlock createSerializationCode(final FieldInfo field, final Serializat
     @Override
     public CodeBlock createDeserializationCode(final FieldInfo field, final SerializationContext ctx) {
         return CodeBlock.builder()
-                .addStatement("final $T $L = new $T[$L.readInt()]", field.getType(), "value", field.getChild().getType(), "reader")
+                .addStatement("final $T $L = new $T[$L.readInt()]", field.getType(), "value", field.getFirstChild().getType(), "reader")
                 .beginControlFlow("for (int i = 0; i < $L.length; i++)", "value")
                 .addStatement("$L[i] = $L()", "value", embeddedMethodName(field))
                 .endControlFlow()