Implement GPrefer

README.md

@@ -16,14 +16,15 @@ The goal of this AP is to
 - Nested serializable types
 - Arrays
 - Collections (Sets, Lists, Queues, Deques)
+- GPrefer to resolve multiple factories/constructors
 
 ## TODO
+- Setters/field access in read()
 - Maps with string, primitive or enum keys
 - Date via ISO8601Utils
 - Enums
 - Support for nested types from libraries
 - Static classes (for configs)
-- GPrefer to bypass builder/constructor recovery
 
 ## Credit
 The Gson-Compile processor is based on [gsonvalue](https://github.com/evant/gsonvalue) and [value-processor](https://github.com/evant/value-processor) by Eva Tatarka.

gson-compile-annotations/src/main/java/io/gitlab/jfronny/gson/compile/annotations/GSerializable.java

@@ -5,6 +5,13 @@ import java.lang.annotation.*;
 @Target({ElementType.TYPE})
 @Retention(RetentionPolicy.SOURCE)
 public @interface GSerializable {
+    /**
+     * @return The class implementing this types serialization/deserialization. Must have static read/write methods
+     */
     Class<?> with() default void.class;
+
+    /**
+     * @return Whether to generate an adapter class to use with normal gson adapter resolution
+     */
     boolean generateAdapter() default false;
 }

gson-compile-example/src/main/java/io/gitlab/jfronny/gson/Main.java

@@ -1,8 +1,7 @@
 package io.gitlab.jfronny.gson;
 
 import io.gitlab.jfronny.gson.annotations.SerializedName;
-import io.gitlab.jfronny.gson.compile.annotations.GComment;
-import io.gitlab.jfronny.gson.compile.annotations.GSerializable;
+import io.gitlab.jfronny.gson.compile.annotations.*;
 
 import java.util.*;
 
@@ -49,5 +48,9 @@ public class Main {
 
     @GSerializable
     public record ExampleRecord(String hello, @GComment("Sheesh") ExamplePojo2 pojo) {
+        @GPrefer
+        public ExampleRecord(String yes) {
+            this(yes, null);
+        }
     }
 }

gson-compile-processor/src/main/java/io/gitlab/jfronny/gson/compile/processor/GsonCompileProcessor.java

@@ -72,7 +72,6 @@ public class GsonCompileProcessor extends AbstractProcessor2 {
                         if (bld.with == null) throw new IllegalArgumentException("Missing annotation parameter: with");
                         if (bld.generateAdapter == null) throw new IllegalArgumentException("Missing annotation parameter: generateAdapter");
                         if (bld.with.toString().equals("void")) bld.with = null;
-                        if (bld.with != null && bld.generateAdapter) throw new IllegalArgumentException("Adapter for " + element + " already exists, not generating another!");
 
                         toGenerate.add(SerializableClass.of((TypeElement) element, bld.with, bld.generateAdapter));
                     }
@@ -154,19 +153,13 @@ public class GsonCompileProcessor extends AbstractProcessor2 {
     }
 
     private static void generateDelegateToAdapter(TypeSpec.Builder spec, TypeName classType, TypeMirror adapter) {
-        TypeName adapterType = TypeName.get(adapter);
-        spec.addField(
-                FieldSpec.builder(adapterType, "ADAPTER", Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)
-                        .initializer("new $T()", adapterType)
-                        .build()
-        );
         spec.addMethod(
                 MethodSpec.methodBuilder("read")
                         .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                         .addParameter(Cl.GSON_READER, "reader")
                         .addException(IOException.class)
                         .returns(classType)
-                        .addCode("return ADAPTER.read(reader);")
+                        .addCode("return $T.read(reader);", adapter)
                         .build()
         );
         spec.addMethod(
@@ -176,7 +169,7 @@ public class GsonCompileProcessor extends AbstractProcessor2 {
                         .addParameter(classType, "value")
                         .addException(IOException.class)
                         .returns(classType)
-                        .addCode("ADAPTER.write(reader, value);")
+                        .addCode("$T.write(reader, value);", adapter)
                         .build()
         );
     }
@@ -264,7 +257,7 @@ public class GsonCompileProcessor extends AbstractProcessor2 {
     }
 
     private void generateSerialisation(TypeSpec.Builder spec, TypeName classType, TypeElement classElement, List<TypeVariableName> typeVariables, Set<SerializableClass> otherAdapters) throws ElementException {
-        Value value = valueCreator.from(classElement);
+        Value value = valueCreator.from(classElement, false);
         ConstructionSource constructionSource = value.getConstructionSource();
         Properties properties = value.getProperties();
 

gson-compile-processor/src/main/java/io/gitlab/jfronny/gson/compile/processor/util/valueprocessor/ValueCreator.java

@@ -1,5 +1,7 @@
 package io.gitlab.jfronny.gson.compile.processor.util.valueprocessor;
 
+import io.gitlab.jfronny.gson.compile.annotations.GPrefer;
+
 import javax.annotation.processing.ProcessingEnvironment;
 import javax.lang.model.element.*;
 import javax.lang.model.util.ElementFilter;
@@ -12,10 +14,6 @@ public class ValueCreator {
         this.env = env;
     }
 
-    public Value from(Element element) throws ElementException {
-        return from(element, false);
-    }
-
     /**
      * Creates a [Value] from the given element. This element can be the [TypeElement] of the target class, or a
      * specific constructor or factory method. If [isBuilder] is true, then the element represents the builder class,
@@ -133,17 +131,23 @@ public class ValueCreator {
                 constructors.add(method);
             }
         }
-        if (constructors.isEmpty() && noArgConstructor != null) {
-            constructors.add(noArgConstructor);
+        if (constructors.isEmpty()) {
+            if (noArgConstructor != null) return noArgConstructor;
+            else throw new ElementException("Lacking constructor or factory method", klazz);
         }
-        if (constructors.size() == 1) {
-            return constructors.get(0);
-        } else {
-            List<ElementException.Message> messages = new ArrayList<>();
-            messages.add(new ElementException.Message("More than one constructor or factory method found.", klazz));
-            constructors.stream().map(s -> new ElementException.Message("  " + s, s)).forEach(messages::add);
-            throw new ElementException(messages);
+        if (constructors.size() == 1) return constructors.get(0);
+        if (noArgConstructor != null) constructors.add(noArgConstructor);
+        List<ExecutableElement> preferred = new ArrayList<>();
+        for (ExecutableElement constructor : constructors) {
+            if (constructor.getAnnotationsByType(GPrefer.class).length != 0) {
+                preferred.add(constructor);
+            }
         }
+        if (preferred.size() == 1) return preferred.get(0);
+        List<ElementException.Message> messages = new ArrayList<>();
+        messages.add(new ElementException.Message("More than one constructor or factory method found.", klazz));
+        constructors.stream().map(s -> new ElementException.Message("  " + s, s)).forEach(messages::add);
+        throw new ElementException(messages);
     }
 
     private static void checkKind(Element element, ElementKind kind) {