I am filtering PrimeFaces DataTables using dynamic filters.I have this working using Spring org.springframework.data.jpa.domain.Specification.Now I am wondring how to do the same using QueryDSL.
Using specification I can use javax.persistence.criteria.Root to get a javax.persistence.criteria.Join, use javax.persistence.criteria.Expression.as(Class<String> type) to cast it to String and finally use javax.persistence.criteria.CriteriaBuilder.like(Expression<String> x, String pattern, char escapeChar).
How do I do the same in QueryDSL ? I can get PathBuilder using new PathBuilder<T>(clazz, "entity") (do you really have to use the variable here? I would like my class to be generic...) but then the com.mysema.query.types.path.PathBuilder.get(String property) returns new PathBuilder instead of an Expression.
If I try to use com.mysema.query.types.path.PathBuilder.getString(String property) I get java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.lang.Integer].
Seems like the part I am missing is the cast.
I'm quite sure someone was dealing with the same thing already.
Thanks.
Edit: Stack trace for IllegalArgumentException
Trying to search for text "1" inside integer column using com.mysema.query.types.path.PathBuilder.getString(String property) - that's where I need the cast to happen :
Caused by: java.lang.IllegalArgumentException: Parameter value [1] did not match expected type [java.lang.Integer]
at org.hibernate.ejb.AbstractQueryImpl.validateParameterBinding(AbstractQueryImpl.java:375)
at org.hibernate.ejb.AbstractQueryImpl.registerParameterBinding(AbstractQueryImpl.java:348)
at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:375)
at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:442)
at org.hibernate.ejb.QueryImpl.setParameter(QueryImpl.java:72)
at com.mysema.query.jpa.impl.JPAUtil.setConstants(JPAUtil.java:44)
at com.mysema.query.jpa.impl.AbstractJPAQuery.createQuery(AbstractJPAQuery.java:130)
at com.mysema.query.jpa.impl.AbstractJPAQuery.createQuery(AbstractJPAQuery.java:97)
at com.mysema.query.jpa.impl.AbstractJPAQuery.list(AbstractJPAQuery.java:240)
at org.springframework.data.jpa.repository.support.QueryDslJpaRepository.findAll(QueryDslJpaRepository.java:102)
...
To get a valid condition you will need to take the types of the properties into account, e.g.
pathBuilder.getNumber(Integer.class, property).stringValue().like(likePattern)
I was researching a similar topic until I came across this aged question. I hope my answer will be helpful to some.
I think the possible solution lies (exclusively) outside of QueryDSL. You can use common Java reflection to obtain the field type, something like
Class type = clazz.getDeclaredField(criteria.getKey()).getType();
// don't forget to catch exception if field doesn't exist ..
switch(type.getSimpleName()) {
case "String":
StringExpression exp = entityPath.getString(...);
}
That way you can have a reasonably dynamic implementation.
Related
I'm using Authorize.net API and they require card expiration field to be formated as "yyyy-mm". We did that with this simple line of code:
expirationDate = model.Year.ToString("D4") & "-" & model.Month.ToString("D2")
and this absolutelly worked. I still have cards stored in the system that were saved using this method! But today I was testing something completelly unrelated, and wanted to add another card, and bam, this code exploded with this exception:
System.InvalidCastException: 'Conversion from string "D4" to type 'Integer' is not valid.'
Inner exception to that one is:
Input string was not in a correct format.
This just... doesn't make sense to me. Why in the world is it trying to convert format specifier (D4) into an integer? What input string? What in the world changed in two days?
The problem is that your are using a Nullable(Of Integer). This is a different structure that does not support the overloads of the ToString method a normal Integer has.
You can view the overloads of the Nullable structure here.
I suggest you use the GetValueOrDefault() method to get the proper Integer and also apply the value you expect in case the value is Nothing.
If it is impossible that a instance with a Nothing set for the year reaches this method you can simply use the Value property.
I still do not fully understand why you get this strange error message. Maybe you could check out what the actual method that is called is? Pointing at the method should give you that information. It can't be Nullable(Of Integer).ToString
Well, I found a workable solution and something of an answer thanks to #Nitram's comment. The type of Year/Month property has been changed from Integer to Integer?. Obviously, this isn't a very satisfying answer because I still don't understand why the nullable int can't be formatted, and yet the code compiles perfectly. The working solution for me has been using static format method on String as so:
expirationDate = String.Format("{0:D4}-{1:D2}", model.Year, model.Month)
This works fine even with nullable types.
I've a simple class like this:
Public Class CalculationParameter{
public Long TariffId{get;set;}
}
In a workflow activity, I've an Assign like this:
(From tariffDetail In db.Context.TariffDetails
Where tariffDetial.TariffId = calculationParameter.TariffId).FirstOrDefault()
Dto is passed to Activity as an Input Argument.
It raise following error and I'm wondering how to assign Id. Any Idea?
LINQ to Entities does not recognize the method 'Int64
GetValue[Int64](System.Activities.LocationReference)' method, and this
method cannot be translated into a store expression.
How can I assign the calculationParameter.TariffId to tariffDetial.TariffId?!
UPDATE:
Screen shot attached shows that how I'm trying to assign calculationParameter.TariffId to tariffDetail.TariffId (car.Id = Dto.Id) and the query result should assign to CurrentTrafficDetail object.
Here's your problem. I don't know if there is a solution to it.
As you said in a (now deleted, unfortunately necessitating that I answer) comment, the exception you're getting is
LINQ to Entities does not recognize the method Int64 GetValue[Int64](System.Activities.LocationReference) method, and this method cannot be translated into a store expression.
in your Linq query, calculationParameter is a Variable defined on the workflow. That Variable is actually an instance that extends the type System.Activities.LocationReference and NOT CalculationParameter.
Normally, when the workflow executes, the LocationReference holds all the information it needs to find the value which is assigned to it. That value isn't retrieved until the last possible moment. At runtime, the process of retrieval (getting the executing context, getting the value, converting it to the expected type) is managed by the workflow.
However, when you introduce Linq into the mix, we have the issue you are experiencing. As you may or may not know, your expression gets compiled into the extension method version of the same.
(From tariffDetail In db.Context.TariffDetails
Where tariffDetial.TariffId = calculationParameter.TariffId)
.FirstOrDefault()
is compiled to
db.Context.TariffDetails
.Where(x => x.TariffId = calculationParameter.TariffId)
.FirstOrDefault();
When this executes, L2E doesn't actually execute this code. It gets interpreted and converted into a SQL query which is executed against the database.
As the interpreter isn't omniscient, there are a well defined set of limitations on what methods you can use in a L2S query.
Unfortunately for you, getting the current value of a LocationReference is not one of them.
TL:DR You cannot do this.
As for workarounds, the only thing I think you can do is create a series of extension methods on your data context type or add methods to your CalculationParameter class that you can call from within the Expression Editor. You can create your Linq to Entities queries within these methods, as all types will already have been dereferenced by the workflow runtime, which means you won't have to worry about the L2E interpreter choking on LocationReferences.
*Edit: A workaround can be found here (thanks to Slauma who mentioned this in a comment on the question)
I am using Javassist to add and modify annotations on a package-info "class".
In some cases, I need to deal with the following edge case. Someone has (incorrectly) specified an #XmlJavaTypeAdapters annotation on the package-info package, but has not supplied a value attribute (which is defined as being required). So it looks like this:
#XmlJavaTypeAdapters // XXX incorrect; value() is required, but javac has no problem
package com.foobar;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapters;
In Javassist, this comes through slightly oddly.
The javassist.bytecode.annotation.Annotation representing the #XmlJavaTypeAdapters annotation does not have a member value (getMemberValue("value") returns null), as expected.
It is of course possible to add a value() member value, and that is what I've done:
if (adaptersAnnotation.getMemberValue("value") == null) {
final ArrayMemberValue amv = new ArrayMemberValue(new AnnotationMemberValue(constantPool), constantPool);
adaptersAnnotation.addMemberValue("value", amv);
annotationsAttribute.addAnnotation(adaptersAnnotation);
}
In the code snippet above, I've created a new member value to hold an array of annotations, because the value() attribute of #XmlJavaTypeAdapters is an array of #XmlJavaTypeAdapter. I've specified its array type by trying to divine the Zen-like documentation's intent—it seems that if you supply another MemberValue that this MemberValue will somehow serve as the array's type. In my case I want the type of the array to be #XmlJavaTypeAdapter, which is an annotation, so the only kind of MemberValue that seemed appropriate was AnnotationMemberValue. So I've created an empty one of those and set it as the array type.
This works fine as far as it goes, as long as you stay "within" Javassist.
However, something seems to have gone wrong. If I ask Javassist to convert all of its proprietary annotations into genuine Java java.lang.annotation.Annotations, then when I try to access the value() attribute of this #XmlJavaTypeAdapters annotation, Javassist tells me that there is no default value. Huh?
In other words, that's fine—indeed there is not—but I have specified what I had hoped was a zero-length array (that is, the default value shouldn't be used; my explicitly specified zero-length array should be used instead):
final List<Object> annotations = java.util.Arrays.asList(packageInfoClass.getAnnotations());
for (final Object a : annotations) {
System.out.println("*** class annotation: " + a); // OK; one of these is #XmlJavaTypeAdapters
System.out.println(" ...of type: " + a.getClass()); // OK; resolves to XmlJavaTypeAdapters
System.out.println(" ...assignable to java.lang.annotation.Annotation? " + java.lang.annotation.Annotation.class.isInstance(a)); // OK; returns true
if (a instanceof XmlJavaTypeAdapters) {
final XmlJavaTypeAdapters x = (XmlJavaTypeAdapters)a;
System.out.println(" ...value: " + java.util.Arrays.asList(x.value())); // XXX x.value() throws an exception
}
}
So why is Javassist looking for a default value in this case?
My larger issue is of course to handle this (unfortunately somewhat common) case where #XmlJavaTypeAdapters is specified with no further information on it. I need to add a value member value that can hold an array of #XmlJavaTypeAdapter annotations. I can't seem to figure out how to accomplish this with Javassist. As always, all help appreciated.
For posterity, it appears that in this particular case (to avoid a NullPointerException and/or a RuntimeException), you need to do this:
if (adaptersAnnotation.getMemberValue("value") == null) {
final ArrayMemberValue amv = new ArrayMemberValue(constantPool);
amv.setValue(new AnnotationMemberValue[0]);
adaptersAnnotation.addMemberValue("value", amv);
annotationsAttribute.addAnnotation(adaptersAnnotation);
}
Note in particular that I deliberately omit the array type when building the ArrayMemberValue (including one of any kind will result in an exception). Then I explicitly set its value to an empty array of type AnnotationMemberValue. Any other combination here will result in an exception.
Additionally, and very oddly, the last line in that if block is critical. Even though in this particular case the annotation itself was found, and so hence was already present in the AnnotationsAttribute, you must re-add it. If you do not, you will get a RuntimeException complaining about the lack of a default value.
I hope this helps other Javassist hackers.
I'm trying to do a like search against an integer column, what I need to do is actually cast the column to a varchar and then do the like search. Is this possible? what's the easiest way to do this using the Criteria API?
var search = "123";
criteria.Add(Restrictions.Like("Number", "%" + search + "%"))
If Number were a string, then it would be easy :
.Add(Restrictions.Like("Number", "some_value",MatchMode.Anywhere))
Since you have a number, NHibernate will check the type of Number and if you give it a string it will throw an exception.
Not sure why the NH team didn't provide an overload with object as parameter and a MatchMode parameters ....
Anyhow, you can still do it like this :
.Add(Expression.Sql("{alias}.Number like ?", "%2%", NHibernateUtil.String))
Edit
About the alias :
(i can't find where the documentation talks about this but here's my understanding of it )
{alias} returns the alias used inside by NH for the most recent CreateCriteria. So if you had :
session.CreateCriteria<User>("firstAlias")
.CreateCriteria("firstAlias.Document", "doc")
.Add(Expression.Sql("{alias}.Number like ?", "%2%",
NHibernateUtil.String)).List<User>();
{alias} in this case would be 'doc' - so you would end up with : doc.Number .
So, always use {alias} after the CreateCriteria whose alias you need to use.
Consider the following line of code:
private void DoThis() {
int i = 5;
var repo = new ReportsRepository<RptCriteriaHint>();
// This does NOT work
var query1 = repo.Find(x => x.CriteriaTypeID == i).ToList<RptCriteriaHint>();
// This DOES work
var query1 = repo.Find(x => x.CriteriaTypeID == 5).ToList<RptCriteriaHint>();
}
So when I hardwire an actual number into the lambda function, it works fine. When I use a captured variable into the expression it comes back with the following error:
No mapping exists from object type
ReportBuilder.Reporter+<>c__DisplayClass0
to a known managed provider native
type.
Why? How can I fix it?
Technically, the correct way to fix this is for the framework that is accepting the expression tree from your lambda to evaluate the i reference; in other words, it's a LINQ framework limitation for some specific framework. What it is currently trying to do is interpret the i as a member access on some type known to it (the provider) from the database. Because of the way lambda variable capture works, the i local variable is actually a field on a hidden class, the one with the funny name, that the provider doesn't recognize.
So, it's a framework problem.
If you really must get by, you could construct the expression manually, like this:
ParameterExpression x = Expression.Parameter(typeof(RptCriteriaHint), "x");
var query = repo.Find(
Expression.Lambda<Func<RptCriteriaHint,bool>>(
Expression.Equal(
Expression.MakeMemberAccess(
x,
typeof(RptCriteriaHint).GetProperty("CriteriaTypeID")),
Expression.Constant(i)),
x)).ToList();
... but that's just masochism.
Your comment on this entry prompts me to explain further.
Lambdas are convertible into one of two types: a delegate with the correct signature, or an Expression<TDelegate> of the correct signature. LINQ to external databases (as opposed to any kind of in-memory query) works using the second kind of conversion.
The compiler converts lambda expressions into expression trees, roughly speaking, by:
The syntax tree is parsed by the compiler - this happens for all code.
The syntax tree is rewritten after taking into account variable capture. Capturing variables is just like in a normal delegate or lambda - so display classes get created, and captured locals get moved into them (this is the same behaviour as variable capture in C# 2.0 anonymous delegates).
The new syntax tree is converted into a series of calls to the Expression class so that, at runtime, an object tree is created that faithfully represents the parsed text.
LINQ to external data sources is supposed to take this expression tree and interpret it for its semantic content, and interpret symbolic expressions inside the tree as either referring to things specific to its context (e.g. columns in the DB), or immediate values to convert. Usually, System.Reflection is used to look for framework-specific attributes to guide this conversion.
However, it looks like SubSonic is not properly treating symbolic references that it cannot find domain-specific correspondences for; rather than evaluating the symbolic references, it's just punting. Thus, it's a SubSonic problem.