DataSerializable with enum

[John Childress]

I recently switch from 2.6.3 to 3.0.2 and ran into an issue with querying with a enum.

The issue seems to be when the ClassLoaderUtil attempts to call the constructor for the enum

Caused by: java.lang.NoSuchMethodException: com.bobs.fun.common.entity.ISO.<init>()

at java.lang.Class.getConstructor0(Class.java:2800)

at java.lang.Class.getDeclaredConstructor(Class.java:2043)

at com.hazelcast.nio.ClassLoaderUtil.newInstance(ClassLoaderUtil.java:54)

at com.hazelcast.nio.ClassLoaderUtil.newInstance(ClassLoaderUtil.java:50)

at com.hazelcast.nio.serialization.DataSerializer.read(DataSerializer.java:104)

... 41 more

Here is how I'm running the predicate...

            AuctionTypePredicate auctionTypePredicate;

            EntryObject entryObject;

            Predicate predicate;

            IMap map;

            entryObject = new PredicateBuilder().getEntryObject();

            map = this.client.getMap(AvaxDirectory.getAuctionMapName(iso));

            auctionTypePredicate = new AuctionTypePredicate(auctionType);

            predicate = Predicates.and(auctionTypePredicate, entryObject.get("iSO").equal(iso).and(entryObject.get("open").between(start, end)));

            return new ArrayList(map.values(predicate));

Serialization seems to work fine on 3 other than this part... any thoughts?  

John

[Emin Demirci]

Could you provide me a test code to reproduce this problem ? 

Currently I can query map by object's enum fields with predicate.

-- 

Emin Demirci

Hazelcast | Open source in-memory data grid

--
You received this message because you are subscribed to the Google Groups "Hazelcast" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hazelcast+...@googlegroups.com.
To post to this group, send email to haze...@googlegroups.com.
Visit this group at http://groups.google.com/group/hazelcast.
For more options, visit https://groups.google.com/groups/opt_out.

[Peter Veentjer]

Can you also post the code of the ISO class?

[John Childress]

ISO Class is easy...  I don't know if I can get a test case out today.  I know that sound lame, but today is super busy.  I'll get one late tonight or early tomorrow morning.

-------------------

package com.bobs.fun.common.entity;

import com.hazelcast.nio.ObjectDataInput;

import com.hazelcast.nio.ObjectDataOutput;

import com.hazelcast.nio.serialization.DataSerializable;

import java.io.IOException;

public enum ISO implements DataSerializable {

    CAISO("CAISO", "C"),

    ERCOT("ERCOT", "E"),

    IESO("IESO", "O"),

    MISO("MISO", "M"),

    NEISO("NEISO", "NE"),

    NYISO("NYISO", "NY"),

    PJMISO("PJMISO", "P"),

    SPP("SPP", "S");

    private String name;

    private String abbr;

    private ISO(String name, String abbr) {

        this.name = name;

        this.abbr = abbr;

    }

    public String getName() {

        return name;

    }

    public String getAbbr() {

        return abbr;

    }

    @Override

    public String toString() {

        return this.name;

    }

    public static ISO valueOfAbbr(String abbr) {

        switch (abbr) {

            case "C":

                return ISO.CAISO;

            case "E":

                return ISO.ERCOT;

            case "O":

                return ISO.IESO;

            case "M":

                return ISO.MISO;

            case "NE":

                return ISO.NEISO;

            case "NY":

                return ISO.NYISO;

            case "P":

                return ISO.PJMISO;

            case "S":

                return ISO.SPP;

        }

        return null;

    }

    @Override

    public void writeData(ObjectDataOutput out) throws IOException {

        out.writeUTF(this.abbr);

        out.writeUTF(this.name);

    }

    @Override

    public void readData(ObjectDataInput in) throws IOException {

        this.abbr = in.readUTF();

        this.name = in.readUTF();

    }

}

-------------------

[Peter Veentjer]

I don't think you need a testcase.

The problem is that the enum doesn't have a no arg constructor and therefor ISO can't be deserialized (that is what the exception is saying).

So you need to add a no arg constructor.

[Peter Veentjer]

I just had a quick chat with Mehmet,

the simplest thing you can do is to remove the DataSerializable from the Iso class.

and use the following approach:

class Foo implements DataSerializable{

    private Iso iso = Iso....  

   public void writeData(ObjectDataOutput out) throws IOException {

      out.writeUTF(iso.getAbrv());

   }

    public void readData(ObjectDataInput in) throws IOException {

        iso = Iso.valueOfAbbr(in.readUtf());

    } 

}

[Barry Lagerweij]

Should HZ not simply provide a default serializer for Enums ? Writing the classname and name (or ordinal) to the stream, and using Class.forName and Enum.values[ordinal] (or EnumClass.valueOf(name) ) during deserialization ?

Barry

[Mehmet Dogan]

Yes, implementing a default serializer for enums is possibile/easy. But deserializing a DataSerializable enum instance is not possible without hacks.

@mmdogan

[John Childress]

Thank you very much.  I'll test/verify this in just a few... thanks.

John

[Peter Veentjer]

Support was added for enums in the 3.1-SNAPSHOT. So it will be available in 3.1

[John Childress]

Thank you very much.  I followed your suggestion and it works fine.

[Barry Lagerweij]

Excellent, nice addition. The proposed pull-request does not seem like a hack a all ;-)

Is there any pattern in the assignment of factoryIds and typeIds ? What are the uniqueness constraints ? How can we avoid collisions in user-code with the HZ provided serializers ?

Barry

[Mehmet Dogan]

Hack is not required for enum serializer. What I mean was, if you create a custom enum which implements DataSerializable interface then a reflection hack is required, since DataSerializable creates object using class.newInstance().

Hazelcast uses negative IDs, user code is not allowed to use negative values.

@mmdogan

~Sent from mobile