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  1. Tapestry 5
  2. TAP5-2032

GenericsUtils does not handle generics properly when extracting the actual type



    • Type: Bug
    • Status: In Progress
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 5.3.6, 5.5.0, 5.4.3
    • Fix Version/s: None
    • Component/s: tapestry-ioc
    • Labels:


      We have the following interfaces / classes

      public interface IPersonWithRoleAssociation<A> extends IEntityAssociationWithInfo<A, Person> {
      	PersonRole getRole();
      	void setRole(PersonRole role);
      public interface IEntityAssociationWithInfo<P, C> {
      	P getParent();
      	void setParent(P parent);
      	C getChild();
      	void setChild(C child);
      public class Person implements Serializable {
      	String name;
      	public String getName() {
      		return name;

      and the page:

      public class EditPersonsWithRoles {
      	@Property(write=false) IPersonWithRoleAssociation<A> personWithRole;

      and the template snippet:

      <t:textfield t:id="personSex" t:value="personWithRole.child.name"/>

      Leads to the following exception:

      Exception generating conduit for expression 'personWithRole.child.name': ...
      Caused by: java.lang.ArrayIndexOutOfBoundsException: 1
      	at org.apache.tapestry5.ioc.internal.util.GenericsUtils.resolve(GenericsUtils.java:388) ~[tapestry-ioc-5.3.6.jar:na]
      	at org.apache.tapestry5.ioc.internal.util.GenericsUtils.resolve(GenericsUtils.java:128) ~[tapestry-ioc-5.3.6.jar:na]
      	at org.apache.tapestry5.ioc.internal.util.GenericsUtils.extractActualType(GenericsUtils.java:74) ~[tapestry-ioc-5.3.6.jar:na]
      	at org.apache.tapestry5.internal.services.PropertyConduitSourceImpl$PropertyConduitBuilder.buildGetterMethodAccessTerm(PropertyConduitSourceImpl.java:1119) ~[tapestry-core-5.3.6.jar:na]

      At GenericsUtils.java:388 we have:

      resolved = ((ParameterizedType) t).getActualTypeArguments()[i];


      i = 1
      resolved = C
      ((ParameterizedType) t).getActualTypeArguments() = [org.topfive.entities.IPersonWithRoleAssociation<P>]

      so the problem seems to be that the code assumes that it can find the type information for C as the second generic parameter for IPersonWithRoleAssociation, when in fact is is the second generic parameter for the superclass IEntityAssociationWithInfo which IPersonWithRoleAssociation extends and passes C explicitly (Person). Everything is fine, if I use a marker interface for Person (IPerson) and declare:

      public interface IPersonWithRoleAssociation<A, P extends IPerson> extends IEntityAssociationWithInfo<A, P>


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              • Assignee:
                thiagohp Thiago Henrique De Paula Figueiredo
                fhackenberger DI Florian Hackenberger
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                • Created: