I don't see what you're talking about in the error printout, but do see a
bunch of other things. One thing I found out the hard way is that you
can't serialize a sublist - I have always assumed that it contains ties
back to the original list, which would cause issues when serializing (like
the framework would have to send the whole list anyway because of the
back-link to it).
So, there may be other problems that are causing the initial problem, and
then not-so-clear error messages implying something else.
Also, if I was going to have an Object field, I would type it as
Serializable instead.
On Friday, November 8, 2013 1:37:37 PM UTC-5, James Clough wrote:
>
> I am trying to return the result of a calculation from an RPC call, and
> having trouble with the GWT compiler. Specifically, the class I am
> returning has a field of type Object in it. This field can contain:
> String, Integer, Double, Long, Boolean or Date.
>
> If I change the Object field to type String, the compiler is happy.
>
> The thing that has me stumped is that I have other methods in the same RPC
> service that return similar objects containing Object fields and these are
> working correctly. I also have an RPC-based event mechanism that is
> returning event classes that contain Map<String,Object> and these appear to
> work correctly. I of course have to have another interface (a whitelist)
> that refers to the types I want to return in the Object fields to get
> serialization code generated for those types.
>
> Am I doing something wrong? I see the documentation says I can't return
> Object, but it's been working for a couple of years.
>
> Is there a better way to accomplish this?
>
>
> Here's the class of the object I'm trying to return:
>
> public class CalculationResult implements Serializable {
> private static final long serialVersionUID = 1L;
>
> private Object value = null;
> private PropertyType type;
> private List<LocalizedMessage> errors;
> public CalculationResult() {
> super();
> }
> public Object getValue() {
> return value;
> }
> public void setValue(Object value) {
> this.value = value;
> }
> public PropertyType getType() {
> return type;
> }
> public void setType(PropertyType type) {
> this.type = type;
> }
> public List<LocalizedMessage> getErrors() {
> if( this.errors == null ) {
> this.errors = new ArrayList<LocalizedMessage>();
> }
> return this.errors;
> }
> public void setErrors(List<LocalizedMessage> errors) {
> this.errors = errors;
> }
>
> }
>
> PropertyType is a simple enum.
> LocalizedMessage is a serializable class containing only String and
> List<String> fields and is used extensively in other RPC calls.
>
> When I compile my project with GWTC, I get the following:
>
> [java] Compiling module com.XX.XXXXXXXXXXXXXXXXXXXXXXXXXXx
> [java] Computing all possible rebind results for
> 'com.XX.gwt.ui.client.rpc.PMRPCService'
> [java] Rebinding com.XX.gwt.ui.client.rpc.PMRPCService
> [java] Invoking generator
> com.google.gwt.user.rebind.rpc.ServiceInterfaceProxyGenerator
> [java] Generating client proxy for remote service
> interface 'com.XX.gwt.ui.client.rpc.PMRPCService'
> [java] Checking type argument 0 of type
> 'java.util.Arrays.ArrayList<E>' because it is exposed as an array with a
> maximum dimension
> of 1 in this type or one of its subtypes (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.editor.client.adapters.ListEditorWrapper<T, E> is not
> default instantiable (it must have a zero-argu
> ment constructor or no constructors at all) and has no custom serializer.
> (reached via com.XX.core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.user.client.ui.DelegatingChangeListenerCollection is not
> default instantiable (it must have a zero-a
> rgument constructor or no constructors at all) and has no custom
> serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.user.client.ui.DelegatingClickListenerCollection is not
> default instantiable (it must have a zero-ar
> gument constructor or no constructors at all) and has no custom
> serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.user.client.ui.DelegatingFocusListenerCollection is not
> default instantiable (it must have a zero-ar
> gument constructor or no constructors at all) and has no custom
> serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.user.client.ui.DelegatingKeyboardListenerCollection is not
> default instantiable (it must have a zero
> -argument constructor or no constructors at all) and has no custom
> serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.gwt.view.client.ListDataProvider<T>.ListWrapper<> is not default
> instantiable (it must have a zero-argum
> ent constructor or no constructors at all) and has no custom serializer.
> (reached via com.XX.core.resources.calculation.CalculationResult)
> [java] [ERROR]
> com.google.web.bindery.autobean.shared.impl.SplittableList<E> is not
> default instantiable (it must have a zero-argu
> ment constructor or no constructors at all) and has no custom serializer.
> (reached via com.XX.core.resources.calculation.CalculationResult)
> [java] [ERROR] java.util.AbstractList.SubList<E> is
> not default instantiable (it must have a zero-argument constructor or no
> const
> ructors at all) and has no custom serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> java.util.Collections.UnmodifiableList<T> is not default instantiable (it
> must have a zero-argument constructor or
> no constructors at all) and has no custom serializer. (reached via com.XX
> .core.resources.calculation.CalculationResult)
> [java] [ERROR]
> java.util.Collections.UnmodifiableRandomAccessList<T> is not default
> instantiable (it must have a zero-argument con
> structor or no constructors at all) and has no custom serializer. (reached
> via com.XX.core.resources.calculation.CalculationResult)
> [java] [ERROR] Errors in
> 'com/XX/gwt/ui/client/ClientFactoryImpl.java'
> [java] [ERROR] Line 327: Failed to resolve
> 'com.XX.gwt.ui.client.rpc.PMRPCService'
> via deferred binding
>
> This error seems to be having trouble with the list, but if I simply
> remove the Object field or change it to String, these go away, too.
>
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