Write Behind HibernateCacheStore with Composite id entity

Question

I am creating a cache map whose key is the primary key of a table, and it is composite. Coherence is not letting me store these composite objects using HibernateCacheStore, and throws the following error.
Conflicting identifier information between entity IntradayMarketData@1784427 and id IntradayMarketDataPK@ad455e8d
Coherence document says the following.
Hibernate entities accessed via the HibernateCacheStore module must use the "assigned" ID generator and also have a defined ID property.
When I remove the composite key, and keep a single column as pk, it works fine.
Any help regarding this would be appreciated.
Thanks in advance
Booshan

Answer 1

Hi Booshan,
I believe, you mix things up a bit.
It is required by Coherence that the cache key must be the primary key as Hibernate uses it, so that when Coherence tries to resolve a cache miss (you request the value for a key which is not already in the cache, it will request that object from Hibernate by the cache key used where Hibernate expects the primary key. From what you write, this requirement is satisfied.
The HibernateCacheStore requires that an assigned ID generator should be used only means that you must assign the new primary key value to an object yourself, you cannot rely on Hibernate to do so. This is required so that you are able to satisfy the previous requirement, and the primary key fields must be set within the cached value to the same value represented by the primary key object.
So all you need is to set the primary key attributes in the entity to the same value as contained in the composite primary key object as used by Hibernate. Also this class must implement java.io.Serializable, but that is required by Hibernate, too.
Also, for being able to use the key class as a key in a hash-based collection, the key class must properly override hashCode() and equals(). Please look at the requirements for this in the Javadoc of java.lang.Object.
For performance reasons it is recommended for the key class to also implement com.tangosol.io.ExternalizableLite.
E.g. in your case, using what I can from your example, your key class would look something like:
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import com.tangosol.io.ExternalizableLite;
import com.tangosol.util.ExternalizableHelper;
public class IntradayMarketDataPK implements ExternalizableLite
    private String left;
    private long right;
     * Parameterless constructor required by implementing ExternalizableLite
    public IntradayMarketDataPK() {
    public String getLeft()
        return left;
    public void setLeft(String left)
        this.left = left;
    public long getRight()
        return right;
    public void setRight(long right)
        this.right = right;
    @Override
    public void readExternal(DataInput input) throws IOException
        left = ExternalizableHelper.readSafeUTF(input);
        right = ExternalizableHelper.readLong(input);
    @Override
    public void writeExternal(DataOutput output) throws IOException
        ExternalizableHelper.writeSafeUTF(output, left);
        ExternalizableHelper.writeLong(output, right);
    @Override
    public boolean equals(Object obj)
        if (obj == this) {
            return true;
        if (obj == null) {
            return false;
        if (obj.getClass() == this.getClass()) {
            IntradayMarketDataPK other = (IntradayMarketDataPK)obj;
            if (other.right != right) {
                return false;
            if (left == null) {
                return other.left == null;
            } else {
                return left.equals(other.left);
        return false;
    @Override
    public int hashCode()
        int hash = (int)(right ^ (right >>> 32));
        if (left != null) {
            hash ^= left.hashCode();
        return hash;
}Your entity mapping should contain something like the following:
<class name="IntradayMarketData" table="INTRADAY_MARKET_DATA">
  <composite-id name="pk" class="IntradayMarketDataPK">
    <key-property name="left" column="LEFT" />
    <key-property name="right" column="RIGHT" />
  </composite-id>
</class>Your entity class should be something like:
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.Serializable;
import com.tangosol.io.ExternalizableLite;
import com.tangosol.util.ExternalizableHelper;
public class IntradayMarketData implements ExternalizableLite
    private IntradayMarketDataPK pk;
     * Public parameterless constructor required by implementing ExternalizableLite
    public IntradayMarketData() {
    public IntradayMarketDataPK getPk()
        return pk;
    public void setPk(IntradayMarketDataPK pk)
        this.pk = pk;
    @Override
    public void readExternal(DataInput input) throws IOException
        IntradayMarketDataPK pk = new IntradayMarketDataPK();
        pk.readExternal(input);
        this.pk = pk;
    @Override
    public void writeExternal(DataOutput output) throws IOException
        pk.writeExternal(output);
}You should always ensure that if you put an IntradayMarketData object to the cache, then the pk attribute on it must already be set to the object used as a cache key.
Best regards,
Robert