I am looking to bind from my select box in my form to a particular enum.
Consider this enum:
public enum OperatorDTO {
LESS_THAN ("<"),
GREATER_THAN (">"),
EQUALS ("="),
NOT_EQUALS("!=");
private String operator;
public String getOperator() {
return operator;
}
private OperatorDTO(String operator)
{
this.operator = operator;
}
and this snippet from my form:
<form:select path="rules[${counter.index}].operator">
<form:options itemLabel="operator" itemValue="operator" />
</form:select>
The page renders fine and displays the various ">", "<" symbols in the drop-down box
However, when I submit my form I get errors when it attempts to bind the values back to the enums
e.g. "No enum const class com.fmrco.insight.adminconsole.dto.enums.OperatorDTO.<"
Is there an easy way to perform this binding?
Thanks
Try to omit itemValue="operator".
Item value should be the name of enum constant, and as far as I remember it's a default behavior.
Form tags snippet is correct and enum is correct also. What is missing here is converter which Spring will use to convert String from form:options element to OperatorDTO enum.
1) Add two more methods to OperatorDTO enum
// Enum level method to get enum instance by operator field.
public static OperatorDTO getByOperator( final String p_operator ) {
for ( OperatorDTO operatorDTO : OperatorDTO.values() ) {
if ( operatorDTO.isOperatorEqual( p_operator ) ) {
return operatorDTO;
}
}
return null;
}
// Instance level method to compare operator field.
public boolean isOperatorEqual( final String p_operator ) {
return getOperator().equals( p_operator ) ? true : false;
}
2) Create custom converter such this
import org.springframework.core.convert.converter.Converter;
public class OperatorDTOConverter implements Converter<String, OperatorDTO> {
public OperatorDTO convert( String source ) {
return OperatorDTO.getByOperator( source.trim() );
}
}
3) Registeg converter in app configuration (java config in this case)
#Configuration
#EnableWebMvc
#ComponentScan( basePackages = { "your.base.package"} )
public class AppWebConfig extends WebMvcConfigurerAdapter {
#Override
public void addFormatters( FormatterRegistry registry ) {
registry.addConverter( String.class, OperatorDTO.class, new OperatorDTOConverter() );
}
...
}
Related
I have the following code to implement interface input parameter validation and now want to use hibernate-validator to do this
public class Order
{
private String orderNo;
private String orderId;
private String status;
private String startTime;
private String endTime;
//getter and setter...
}
public class OrderService
{
public Object search(Order order) throws Exception
{
String message = "";
if (order.getOrderId().isEmpty() && order.getOrderNo().isEmpty() && order.getStatus().isEmpty())
{
if (order.getStartTime().isEmpty() && order.getEndTime().isEmpty())
message = "xxx";
}
if (!message.isEmpty())
throw new Exception(message);
Object result = null;
// splice sql according to the attribute of order and get the result
// result = sql query result
return result;
}
}
I tried to use Hibernate-validator's group to achieve this, but if there are more parameters, I need to write a lot of groups, which seems stupid. I have more than 100 interfaces, and will be added later, using Class-level constraints would be a good idea choice?
Below is the code trying to use Hibernate-validator's group implementation:
public class Order
{
#Empty(groups = One.class)
#NotEmpty(groups = Two.class)
private String orderNo;
#Empty(groups = One.class)
#NotEmpty(groups = Three.class)
private String orderId;
#Empty(groups = One.class)
#NotEmpty(groups = Four.class)
private String status;
#NotEmpty(groups = One.class)
private String startTime;
#NotEmpty(groups = One.class)
private String endTime;
}
public class BeanValidatorUtils
{
static Validator validator;
static
{
HibernateValidatorConfiguration configuration = Validation.byProvider(HibernateValidator.class).configure();
ValidatorFactory factory = configuration.failFast(true).buildValidatorFactory();
validator = factory.getValidator();
}
public static <T> void validation(T beanParam) throws AppException
{
if (!containsGroup(beanParam, One.class))
return;
Set<ConstraintViolation<T>> validate = validator.validate(beanParam, One.class);
ConstraintViolation<T> constraintViolation = validate.iterator().next();
String firstViolationMessage = constraintViolation.getMessage();
if (!validate.isEmpty() && containsGroup(beanParam, Two.class))
{
validate = validator.validate(beanParam, Two.class);
}
if (!validate.isEmpty() && containsGroup(beanParam, Three.class))
{
validate = validator.validate(beanParam, Three.class);
}
if (!validate.isEmpty())
throw new AppException(firstViolationMessage);
}
private static boolean containsGroup(Object bean, Class<?> groupClazz)
{
// ...
}
}
Is there any other way to use Hibernate-validator to verify the Order in the search method?
As you are trying to make a validation decision based on the state of multiple properties of the Order you might want to explore these 3 options:
Class level constraint
This would mean that you have to create your own constraint annotation (let's say #ValidOrder) and a corresponding ValidOrderValidator
#Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE })
#Retention(RUNTIME)
#Documented
#Constraint(validatedBy = { ValidOrderValidator.class })
#interface ValidOrder {
String message() default "{message.key}";
Class<?>[] groups() default { };
Class<? extends Payload>[] payload() default { };
}
public class ValidOrderValidator implements ConstraintValidator<ValidOrder, Order> {
#Override
public boolean isValid(Order order, ConstraintValidatorContext constraintValidatorContext) {
//null values are valid
if ( order == null ) {
return true;
}
if (order.getOrderId().isEmpty() && order.getOrderNo().isEmpty() && order.getStatus().isEmpty()) {
if ( order.getStartTime().isEmpty() && order.getEndTime().isEmpty() ) { return false; }
}
return true;
}
}
You can also check this post for more detailed info on how to add new constraints using ServiceLoader.
#ScriptAssert constraint
If your validation logic is relatively simple and you either already have a dependency or are willing to add one for a scripting engine, you can consider using the #ScriptAssert constraint. This is similar to the previous option but you don't need to create annotations and validator implementations you just have to put script logic into this constraint:
#ScriptAssert(lang = "groovy", script = "your validation script logic")
class Order {
//...
}
#AssertTrue constraint
Last but not least, one of the easiest ways to address such validation is to use #AssertTrue constraint on a getter with validation logic inside the Order class:
class Order {
//...
#AssertTrue
public boolean isValidOrder() {
// your validation logic
}
}
Using any of these 3 approaches, you'd be able to make a validation decision based on multiple properties of the Order class.
As for validation group usage - you can leverage using the groups if you need to pass the same Order object into multiple different methods/interfaces where a different set of validation rules need to be applied in each of them. Let's say, in one case, you have to create an order, and half of the fields can be null, but then in the other - you want to update it, and everything should be present.
I want to change my session proviced to statically typed - I just hate typing strings because of many many errors I do.
What technology am I using? ASP.NET MVC via EXT.NET MVC
I was trying to do that using web.config but the problem is that after add session state to it visual is not going to compile my code because of that session should be using strings as keys.
I want to use session by enums such as :
public enum SessionEnum{Model}
public class Bar{
void foo(){
Session[SessionEnum.Model] = "blah";
}
}
I am aware that I can create wrapper converting enums to strings but it's not very satisfying solution for me.
public class StorageWrapper{
public object this[SessionEnum enum]{ get{return Session[enum.toString()]}; //+set
}
What I did was create static object for base class for all of my controllers and then I was able to use it across them but after closing and opening the page again I wasn't able to get values from it. I guess I should serialize them somehow but I have no idea how.
Is there any way to do that?
EDIT
My session now looks like this :
[Serializable]
public abstract class DataWrapper<T> : HttpSessionStateBase
{
Dictionary<T, object> Dictionary { get; set; } = new Dictionary<T, object>();
public object this[T a]
{
get
{
try
{
return Dictionary[a];
}
catch
{
return null;
}
}
set { Dictionary[a] = value; }
}
}
[Serializable]
public class SessionWrapper : DataWrapper<SessionNames>
{}
public enum SessionNames { Model, Login, LastOpenedFile }
It's very simple.
Create a UserSession object which does everything you want (holds your values as enum etc), instantiate it, then put it in the session.
var US = new UserSession();
US.stuff = somestuff;
Session["UserSess"] = US
Then you can just always use Session["UserSess"].stuff;
Mmmm, wouldn't you use static const string instead of an enum?
using System.Web;
public static class SessionEnum
{
public static const string Model = "_Session_Model";
public static const string Login = "_Session_Login";
public static const string LastOpenedFile = "_Session_LastOpenedFile ";
}
class test
{
void test()
{
Session[SessionEnum.Model] = "blah";
}
}
By default convention, strings properties in an entity model that are not explicitly given a max length are set to nvarchar(max) in the database. We wish to override this convention and give strings a max length of nvarchar(100) if they are not already explicitly set otherwise.
I discovered the PropertyMaxLengthConvention built-in convention, which by its description and documentation would seem to be what I am looking for. However, it either doesn't work or I'm using it wrong or it just doesn't do what I think it does.
I've tried simply adding the convention:
modelBuilder.Conventions.Add(new PropertyMaxLengthConvention(100));
Then I thought maybe the default one is already being used, so I tried removing it first:
modelBuilder.Conventions.Remove<PropertyMaxLengthConvention>();
modelBuilder.Conventions.Add(new PropertyMaxLengthConvention(100));
I even tried explictly adding the convention before and after the default one:
modelBuilder.Conventions.AddBefore<PropertyMaxLengthConvention>(new PropertyMaxLengthConvention(100));
modelBuilder.Conventions.AddAfter<PropertyMaxLengthConvention>(new PropertyMaxLengthConvention(100));
No joy. When I add migrations, the columns are still created as nvarchar(max).
Is there a way to use that convention to do what I want? If not, can I write a custom convention that will default string properties to nvarchar(100) but will still allow me to explicitly set them to a different value including maxlength?
After tracking down the source code for the aforementioned convention, I discovered that it only sets the default max length for properties that are specified to have fixed length. (Bizarre!)
So I took the source code and modified it to create my own convention. Now string properties with unspecified max length will have a default max length instead of being nvarchar(max). The only downside is there doesn't appear to be a way to detect when the IsMaxLength() configuration is explicitly applied. So if I have a column that I do want to have created as nvarchar(max) I can't use IsMaxLength() to do it.
To address this, I created an extension method for StringPropertyConfiguration called ForceMaxLength() that configures the property with HasMaxLength(int.MaxValue) - ordinarily an invalid value, but one for which I can easily test in my custom convention. When I detect it, I simply set the MaxLength back to null and set the IsMaxLength to true and let the property configuration continue as normal.
Here's the custom convention:
using System;
using System.Collections.Generic;
using System.Data.Entity.Core.Metadata.Edm;
using System.Data.Entity.Infrastructure;
using System.Data.Entity.ModelConfiguration.Conventions;
namespace MyProject.CustomConventions
{
public class CustomPropertyMaxLengthConvention : IConceptualModelConvention<EntityType>, IConceptualModelConvention<ComplexType>
{
private const int DefaultLength = 128;
private readonly int length;
public CustomPropertyMaxLengthConvention()
: this(DefaultLength)
{
}
public CustomPropertyMaxLengthConvention(int length)
{
if (length <= 0)
{
throw new ArgumentOutOfRangeException("length", "Invalid Max Length Size");
}
this.length = length;
}
public virtual void Apply(EntityType item, DbModel model)
{
SetLength(item.DeclaredProperties);
}
public virtual void Apply(ComplexType item, DbModel model)
{
SetLength(item.Properties);
}
private void SetLength(IEnumerable<EdmProperty> properties)
{
foreach (EdmProperty current in properties)
{
if (current.IsPrimitiveType)
{
if (current.PrimitiveType == PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.String))
{
SetStringDefaults(current);
}
if (current.PrimitiveType == PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.Binary))
{
SetBinaryDefaults(current);
}
}
}
}
private void SetStringDefaults(EdmProperty property)
{
if (property.IsUnicode == null)
{
property.IsUnicode = true;
}
SetBinaryDefaults(property);
}
private void SetBinaryDefaults(EdmProperty property)
{
if (property.MaxLength == int.MaxValue)
{
property.MaxLength = null;
property.IsMaxLength = true;
}
else if (property.MaxLength == null || !property.IsMaxLength)
{
property.MaxLength = length;
}
}
}
}
Here's the extension method:
using System.Data.Entity.ModelConfiguration.Configuration;
namespace MyProject.Model.Mapping
{
public static class MappingExtensions
{
public static void ForceMaxLength(this StringPropertyConfiguration obj)
{
obj.HasMaxLength(int.MaxValue);
}
}
}
Here's how it's used:
using System.Data.Entity.ModelConfiguration;
namespace MyProject.Model.Mapping
{
public class MyEntityMap : EntityTypeConfiguration<MyEntity>
{
public MyEntityMap()
{
Property(v => v.StringValue).ForceMaxLength();
}
}
}
Or just
public class StringConventions : Convention
{
public StringConventions()
{
this.Properties<string>().Configure(x => x.HasMaxLength(100));
}
}
In EF6 you can use a custom code first convention, but you will also need to have a way to specify nvarchar(max) data type to a string property. So, I came up with the following solution.
/// <summary>
/// Set this attribute to string property to have nvarchar(max) type for db table column.
/// </summary>
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public sealed class TextAttribute : Attribute
{
}
/// <summary>
/// Changes all string properties without System.ComponentModel.DataAnnotations.StringLength or
/// Text attributes to use string length 16 (i.e nvarchar(16) instead of nvarchar(max) by default).
/// Use TextAttribute to a property to have nvarchar(max) data type.
/// </summary>
public class StringLength16Convention : Convention
{
public StringLength16Convention()
{
Properties<string>()
.Where(p => !p.GetCustomAttributes(false).OfType<DatabaseGeneratedAttribute>().Any())
.Configure(p => p.HasMaxLength(16));
Properties()
.Where(p => p.GetCustomAttributes(false).OfType<TextAttribute>().Any())
.Configure(p => p.IsMaxLength());
}
}
public class CoreContext : DbContext, ICoreContext
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Change string length default behavior.
modelBuilder.Conventions.Add(new StringLength16Convention());
}
}
public class LogMessage
{
[Key]
public Guid Id { get; set; }
[StringLength(25)] // Explicit data length. Result data type is nvarchar(25)
public string Computer { get; set; }
//[StringLength(25)] // Implicit data length. Result data type is nvarchar(16)
public string AgencyName { get; set; }
[Text] // Explicit max data length. Result data type is nvarchar(max)
public string Message { get; set; }
}
I'm attempting to create a class level JSR-303 validation definition that checks that one property occurs before another in time. Because the this validation only makes sense for Calendar properties I was wondering if it is possible to test the property type in the initialize method.
My annotation definition is:
#Target({TYPE, ANNOTATION_TYPE})
#Retention(RUNTIME)
#Constraint(validatedBy = TemporalSequenceValidator.class)
#Documented
public #interface TemporalSequence {
String message() default "{uk.co.zodiac2000.vcms.constraints.TemporalSequence}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
String first();
String second();
}
and the validator implementation:
public class TemporalSequenceValidator implements
ConstraintValidator<TemporalSequence, Object> {
private String firstFieldName;
private String secondFieldName;
#Override
public void initialize(final TemporalSequence constraintAnnotation) {
firstFieldName = constraintAnnotation.first();
secondFieldName = constraintAnnotation.second();
// Is it possible to test type of firstFieldName and
// secondFieldName properties here?
}
#Override
public boolean isValid(final Object value, final ConstraintValidatorContext context) {
// omitted
}
}
Is this a sensible thing to do? What approach would you suggest I use if it is? And what action should occur if the properties are not of the correct type?
You can't really do the check in initialize() since you can't access the validated object there. Instead you could check the type of the fields of the validated object in isValid() using reflection:
if ( !Calendar.class.isAssignableFrom(
value.getClass().getField( firstFieldName ).getType() ) ) {
throw new ValidationException( "Field " + firstFieldName + " is not of type Calendar." );
}
My Grails application has a large number of enums that look like this:
public enum Rating {
BEST("be"), GOOD("go"), AVERAGE("av"), BAD("ba"), WORST("wo")
final String id
private RateType(String id) {
this.id = id
}
static public RateType getEnumFromId(String value) {
values().find {it.id == value }
}
}
If I have a command object such as this:
class MyCommand {
Rating rating
}
I would like to (for example) automatically convert a request parameter with value "wo" to Rating.WORST.
The procedure for defining custom converters is described here (in the context of converting Strings to Dates). Although this procedure works fine, I don't want to have to create a class implementing PropertyEditorSupport for each of my enums. Is there a better alternative?
I found a solution I'm pretty happy with.
Step 1: Create an implementation of PropertyEditorSupport to convert text to/from the relevant Enum
public class EnumEditor extends PropertyEditorSupport {
private Class<? extends Enum<?>> clazz
public EnumEditor(Class<? extends Enum<?>> clazz) {
this.clazz = clazz
}
public String getAsText() {
return value?.id
}
public void setAsText(String text) {
value = clazz.getEnumFromId(text)
}
}
Step 2: Define a class that registers EnumEditor as a converter for the various enum classes. To change the list of enum classes that are bindable by id, just modify BINDABLE_ENUMS
public class CustomPropertyEditorRegistrar implements PropertyEditorRegistrar {
private static final String REQUIRED_METHOD_NAME = 'getEnumFromId'
// Add any enums that you want to bind to by ID into this list
private static final BINDABLE_ENUMS = [Rating, SomeOtherEnum, SomeOtherEnum2]
public void registerCustomEditors(PropertyEditorRegistry registry) {
BINDABLE_ENUMS.each {enumClass ->
registerEnum(registry, enumClass)
}
}
/**
* Register an enum to be bound by ID from a request parameter
* #param registry Registry of types eligible for data binding
* #param enumClass Class of the enum
*/
private registerEnum(PropertyEditorRegistry registry, Class<? extends Enum<?>> enumClass) {
boolean hasRequiredMethod = enumClass.metaClass.methods.any {MetaMethod method ->
method.isStatic() && method.name == REQUIRED_METHOD_NAME && method.parameterTypes.size() == 1
}
if (!hasRequiredMethod) {
throw new MissingMethodException(REQUIRED_METHOD_NAME, enumClass, [String].toArray())
}
registry.registerCustomEditor(enumClass, new EnumEditor(enumClass))
}
}
Step 3: Make Spring aware of the registry above by defining the following Spring bean in grails-app/conf/spring/resources.grooovy
customPropertyEditorRegistrar(CustomPropertyEditorRegistrar)
So the default Databinding binds on the Enum name and not a separately defined property of the Enum. You can either create your own PropertyEditor as you have mentioned or do a work-around similar to this:
class MyCommand {
String ratingId
Rating getRating() {
return Rating.getEnumFromId(this.ratingId)
}
static constraints = {
ratingId(validator:{val, obj -> Rating.getEnumFromId(val) != null })
}
}