JPA: How to perform a LIKE with a NUMBER column in a static JPA MetaModel?

Question

I do have a static metamodel with a NUMBER (actually, BigDecimal, don\'t ask why) column. Now I would like to do a LIKE query against that number column:

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Answer 1

No, it does not fail because of bug, it works as specified (for example in Javadoc):

Perform a typecast upon the expression, returning a new expression object. This method does not cause type conversion: the runtime type is not changed. Warning: may result in a runtime failure.

Method you use performs cast and you need conversion. In general there is no support to convert from BigDecimal to String in JPA.

Answer 2

For the people, who are still looking for a solution.

Knowing that HQLstr function does the job (at least for Hibernate v. 3.6.9.Final) one can implement his own FunctionExpression like:

//plagiarized from org.hibernate.ejb.criteria.expression.function.CastFunction
public class StrFunction<Y extends Number> extends BasicFunctionExpression<String> implements FunctionExpression<String>, Serializable {
    public static final String FCT_NAME = "str";

    private final Selection<Y> selection;

    public StrFunction(CriteriaBuilder criteriaBuilder, Selection<Y> selection) {
        super((CriteriaBuilderImpl) criteriaBuilder, String.class, FCT_NAME);
        this.selection = selection;
    }

    @Override
    public void registerParameters(ParameterRegistry registry) {
        Helper.possibleParameter(selection, registry);
    }

    @Override
    public String render(CriteriaQueryCompiler.RenderingContext renderingContext) {
        return FCT_NAME + '(' + ((Renderable) selection).render(renderingContext) + ')';
    }
}

and then use it:

cb.like(new StrFunction<Long> (cb, root.get(MyObject_.id)), "%mySearchTerm%");