Merge pull request #178 from avaje/SentryMan-methods

support json property methods

Author: SentryMan

blackbox-test/src/main/java/org/example/customer/naming/WithName.java

@@ -11,4 +11,11 @@ public record WithName(
   String simplePlus,
   int myOneRed) {
 
+  /**
+   * A read-only JSON property without an underlying field.
+   */
+  @Json.Property("derived")
+  public int calculated() {
+    return myOneRed * 2;
+  }
 }

blackbox-test/src/test/java/org/example/customer/naming/WithNameTest.java

@@ -17,7 +17,7 @@ void toFrom()  {
     WithName bean = new WithName("sim", "simPlus", 42);
 
     String asJson = jsonType.toJson(bean);
-    assertThat(asJson).isEqualTo("{\"Some Thing Odd\":\"sim\",\"simple-plus\":\"simPlus\",\"my-one-red\":42}");
+    assertThat(asJson).isEqualTo("{\"Some Thing Odd\":\"sim\",\"simple-plus\":\"simPlus\",\"my-one-red\":42,\"derived\":84}");
 
     WithName fromJson = jsonType.fromJson(asJson);
     assertEquals(fromJson, bean);

jsonb-generator/src/main/java/io/avaje/jsonb/generator/ClassReader.java

@@ -424,10 +424,12 @@ private void writeFromJsonImplementation(Append writer, String varName) {
     } else {
       writer.append("    // variables to read json values into, constructor params don't need _set$ flags").eol();
       for (final FieldReader allField : allFields) {
-        if (isRecord) {
-          allField.writeFromJsonVariablesRecord(writer);
-        } else if (allField.includeFromJson()) {
-          allField.writeFromJsonVariables(writer);
+        if (allField.includeFromJson()) {
+          if (isRecord) {
+            allField.writeFromJsonVariablesRecord(writer);
+          } else {
+            allField.writeFromJsonVariables(writer);
+          }
         }
       }
     }

jsonb-generator/src/main/java/io/avaje/jsonb/generator/FieldReader.java

@@ -1,6 +1,7 @@
 package io.avaje.jsonb.generator;
 
 import javax.lang.model.element.Element;
+import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.Modifier;
 import java.util.*;
 
@@ -24,18 +25,20 @@ final class FieldReader {
     addSubType(subType);
     final PropertyIgnoreReader ignoreReader = new PropertyIgnoreReader(element);
     this.unmapped = ignoreReader.unmapped();
+    var isMethod = element instanceof ExecutableElement;
     this.raw = ignoreReader.raw();
     this.serialize = ignoreReader.serialize();
-    this.deserialize = ignoreReader.deserialize();
+    this.deserialize = !isMethod && ignoreReader.deserialize();
 
     final var fieldName = element.getSimpleName().toString();
-    final var publicField = element.getModifiers().contains(Modifier.PUBLIC);
-    this.property = new FieldProperty(element.asType(), raw, unmapped, genericTypeParams, publicField, fieldName);
-    this.propertyName =
-      PropertyPrism.getOptionalOn(element)
-        .map(PropertyPrism::value)
-        .map(Util::escapeQuotes)
-        .orElse(namingConvention.from(fieldName));
+    final var publicField = !isMethod && element.getModifiers().contains(Modifier.PUBLIC);
+    final var type = isMethod ? ((ExecutableElement) element).getReturnType() : element.asType();
+
+    this.property = new FieldProperty(type, raw, unmapped, genericTypeParams, publicField, fieldName);
+    this.propertyName = PropertyPrism.getOptionalOn(element)
+      .map(PropertyPrism::value)
+      .map(Util::escapeQuotes)
+      .orElse(namingConvention.from(fieldName));
 
     this.aliases = initAliases(element);
   }

jsonb-generator/src/main/java/io/avaje/jsonb/generator/TypeReader.java

@@ -58,10 +58,9 @@ final class TypeReader {
     if (mixInType == null) {
       this.mixInFields = new HashMap<>();
     } else {
-      this.mixInFields =
-        mixInType.getEnclosedElements().stream()
-          .filter(e -> e.getKind() == ElementKind.FIELD)
-          .collect(Collectors.toMap(e -> e.getSimpleName().toString(), e -> e));
+      this.mixInFields = mixInType.getEnclosedElements().stream()
+        .filter(e -> e.getKind() == ElementKind.FIELD)
+        .collect(Collectors.toMap(e -> e.getSimpleName().toString(), e -> e));
     }
     this.namingConvention = namingConvention;
     this.hasJsonAnnotation = JsonPrism.isPresent(baseType) || importedJson(baseType).isPresent();
@@ -94,7 +93,7 @@ void read(TypeElement type) {
           readField(element, localFields);
           break;
         case METHOD:
-          readMethod(element, type);
+          readMethod(element, type, localFields);
           break;
       }
     }
@@ -129,11 +128,18 @@ private void readField(Element element, List<FieldReader> localFields) {
       optional = true;
     }
     if (includeField(element)) {
-      final var frequency = frequencyMap.compute(element.getSimpleName().toString(), (k, v) -> v == null ? 0 : v + 1);
+      final var frequency = frequency(element.getSimpleName().toString());
       localFields.add(new FieldReader(element, namingConvention, currentSubType, genericTypeParams, frequency));
     }
   }
 
+  /**
+   * Compute and return the frequency of the key / json property name.
+   */
+  private Integer frequency(String key) {
+    return frequencyMap.compute(key, (k, v) -> v == null ? 0 : v + 1);
+  }
+
   private boolean includeField(Element element) {
     if (extendsThrowable) {
       return !element.getModifiers().contains(Modifier.TRANSIENT)
@@ -169,7 +175,7 @@ private void readConstructor(Element element, TypeElement type) {
     }
   }
 
-  private void readMethod(Element element, TypeElement type) {
+  private void readMethod(Element element, TypeElement type, List<FieldReader> localFields) {
     ExecutableElement methodElement = (ExecutableElement) element;
     if (checkMethod2(methodElement)) {
       List<? extends VariableElement> parameters = methodElement.getParameters();
@@ -186,6 +192,19 @@ private void readMethod(Element element, TypeElement type) {
         }
       }
     }
+    // for getter/accessor methods only, not setters
+    PropertyPrism.getOptionalOn(methodElement).ifPresent(propertyPrism -> {
+      if (!methodElement.getParameters().isEmpty()) {
+        logError("Json.Property can only be placed on Getter Methods, but on %s", methodElement);
+        return;
+      }
+
+      // getter property as simulated read-only field with getter method
+      final var frequency = frequency(propertyPrism.value());
+      final var reader = new FieldReader(element, namingConvention, currentSubType, genericTypeParams, frequency);
+      reader.getterMethod(new MethodReader(methodElement, type));
+      localFields.add(reader);
+    });
   }
 
   private boolean checkMethod2(ExecutableElement methodElement) {

jsonb-generator/src/test/java/io/avaje/jsonb/generator/models/valid/TestClass.java

@@ -25,6 +25,11 @@ public class TestClass {
 
   private Optional<String> op;
 
+  @Json.Property("what_a_save!")
+  public String what_a_save() {
+    return "Chat Disabled";
+  }
+
   public String getAlias() {
     return alias;
   }

jsonb/src/main/java/io/avaje/jsonb/Json.java

@@ -110,7 +110,7 @@
    * }</pre>
    */
   @Retention(CLASS)
-  @Target(FIELD)
+  @Target({FIELD, METHOD})
   @interface Property {
 
     /**
@@ -138,7 +138,7 @@
   }
 
   /**
-   * Deprecate - migrate to {@link Json.Alias}.
+   * Deprecated - migrate to {@link Json.Alias}.
    */
   @Deprecated
   @Retention(CLASS)
@@ -188,7 +188,7 @@
    * }</pre>
    */
   @Retention(CLASS)
-  @Target(FIELD)
+  @Target({FIELD, METHOD})
   @interface Unmapped {
 
   }
@@ -278,7 +278,7 @@
    * Marks a String field as containing raw JSON content.
    */
   @Retention(CLASS)
-  @Target(FIELD)
+  @Target({FIELD, METHOD})
   @interface Raw {
 
   }