@Override
public TypeSpec buildTypeSpec() {
TypeSpec.Builder classBuilder = TypeSpec.classBuilder(schema.getSchemaClassName().simpleName());
classBuilder.addModifiers(Modifier.PUBLIC);
classBuilder.addSuperinterface(Types.getSchema(schema.getModelClassName()));
classBuilder.addFields(buildFieldSpecs());
classBuilder.addMethods(buildMethodSpecs());
return classBuilder.build();
}
public static DeriveResult<DerivedCodeSpec> derive(
AlgebraicDataType adt, DeriveContext deriveContext, DeriveUtils deriveUtils) {
// skip constructors for enums
if (adt.typeConstructor().declaredType().asElement().getKind() == ElementKind.ENUM) {
return result(none());
}
TypeConstructor typeConstructor = adt.typeConstructor();
TypeElement lazyTypeElement =
FlavourImpl.findF0(deriveContext.flavour(), deriveUtils.elements());
TypeName lazyArgTypeName =
TypeName.get(
deriveUtils.types().getDeclaredType(lazyTypeElement, typeConstructor.declaredType()));
String lazyArgName = Utils.uncapitalize(typeConstructor.typeElement().getSimpleName());
TypeName typeName = TypeName.get(typeConstructor.declaredType());
List<TypeVariableName> typeVariableNames =
adt.typeConstructor()
.typeVariables()
.stream()
.map(TypeVariableName::get)
.collect(Collectors.toList());
String className = "Lazy";
TypeSpec.Builder typeSpecBuilder =
TypeSpec.classBuilder(className)
.addModifiers(Modifier.PRIVATE, Modifier.STATIC, Modifier.FINAL)
.addTypeVariables(typeVariableNames)
.addField(
FieldSpec.builder(
TypeName.get(Object.class), "lock", Modifier.PRIVATE, Modifier.FINAL)
.initializer("new Object()")
.build())
.addField(FieldSpec.builder(lazyArgTypeName, "expression", Modifier.PRIVATE).build())
.addField(
FieldSpec.builder(typeName, "evaluation", Modifier.PRIVATE, Modifier.VOLATILE)
.build())
.addMethod(
MethodSpec.constructorBuilder()
.addParameter(ParameterSpec.builder(lazyArgTypeName, lazyArgName).build())
.addStatement("this.expression = $N", lazyArgName)
.build())
.addMethod(
MethodSpec.methodBuilder("eval")
.addModifiers(Modifier.PRIVATE)
.returns(typeName)
.addCode(
CodeBlock.builder()
.addStatement("$T _evaluation = this.evaluation", typeName)
.beginControlFlow("if (_evaluation == null)")
.beginControlFlow("synchronized (this.lock)")
.addStatement("_evaluation = this.evaluation")
.beginControlFlow("if (_evaluation == null)")
.addStatement(
"this.evaluation = _evaluation = expression.$L()",
Utils.getAbstractMethods(lazyTypeElement.getEnclosedElements())
.get(0)
.getSimpleName())
.addStatement("this.expression = null")
.endControlFlow()
.endControlFlow()
.endControlFlow()
.addStatement("return _evaluation")
.build())
.build())
.addMethod(
Utils.overrideMethodBuilder(adt.matchMethod().element())
.addStatement(
"return this.eval().$L($L)",
adt.matchMethod().element().getSimpleName(),
Utils.asArgumentsStringOld(adt.matchMethod().element().getParameters()))
.build());
if (adt.typeConstructor().declaredType().asElement().getKind() == ElementKind.INTERFACE) {
typeSpecBuilder.addSuperinterface(typeName);
} else {
typeSpecBuilder.superclass(typeName);
}
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractEquals(typeConstructor.typeElement(), deriveUtils.elements())
.map(
equals ->
deriveUtils
.overrideMethodBuilder(equals)
.addStatement(
"return this.eval().equals($L)",
equals.getParameters().get(0).getSimpleName())
.build()))
.collect(Collectors.toList()));
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractHashCode(typeConstructor.typeElement(), deriveUtils.elements())
.map(
hashCode ->
deriveUtils
.overrideMethodBuilder(hashCode)
.addStatement("return this.eval().hashCode()")
.build()))
.collect(Collectors.toList()));
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractToString(typeConstructor.typeElement(), deriveUtils.elements())
.map(
toString ->
deriveUtils
.overrideMethodBuilder(toString)
.addStatement("return this.eval().toString()")
.build()))
.collect(Collectors.toList()));
return result(
codeSpec(
typeSpecBuilder.build(),
MethodSpec.methodBuilder("lazy")
.addModifiers(Modifier.PUBLIC, Modifier.STATIC)
.addTypeVariables(
typeConstructor
.typeVariables()
.stream()
.map(TypeVariableName::get)
.collect(Collectors.toList()))
.addParameter(lazyArgTypeName, lazyArgName)
.returns(typeName)
.addStatement(
"return new $L$L($L)",
className,
typeVariableNames.isEmpty() ? "" : "<>",
lazyArgName)
.build()));
}
