org.datanucleus.store.hbase.fieldmanager.FetchEmbeddedFieldManager Maven / Gradle / Ivy

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Plugin providing persistence to HBase datastores.
There is a newer version: 5.1.0-release
/**********************************************************************
Copyright (c) 2011 Andy Jefferson and others. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Contributors:
   ...
**********************************************************************/
package org.datanucleus.store.hbase.fieldmanager;

import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.hbase.client.Result;
import org.datanucleus.ClassLoaderResolver;
import org.datanucleus.metadata.AbstractClassMetaData;
import org.datanucleus.metadata.AbstractMemberMetaData;
import org.datanucleus.metadata.EmbeddedMetaData;
import org.datanucleus.metadata.MetaDataUtils;
import org.datanucleus.metadata.RelationType;
import org.datanucleus.state.ObjectProvider;
import org.datanucleus.store.fieldmanager.FieldManager;
import org.datanucleus.store.schema.table.MemberColumnMapping;
import org.datanucleus.store.schema.table.Table;

/**
 * FieldManager for the retrieval of a related embedded object (1-1 relation).
 */
public class FetchEmbeddedFieldManager extends FetchFieldManager
{
    /** Metadata for the embedded member (maybe nested) that this FieldManager represents). */
    protected List mmds;

    public FetchEmbeddedFieldManager(ObjectProvider sm, Result result, List mmds, Table table)
    {
        super(sm, result, table);
        this.mmds = mmds;
    }

    protected MemberColumnMapping getColumnMapping(int fieldNumber)
    {
        List embMmds = new ArrayList(mmds);
        embMmds.add(cmd.getMetaDataForManagedMemberAtAbsolutePosition(fieldNumber));
        return table.getMemberColumnMappingForEmbeddedMember(embMmds);
    }

    /* (non-Javadoc)
     * @see org.datanucleus.store.fieldmanager.AbstractFieldManager#fetchObjectField(int)
     */
    @Override
    public Object fetchObjectField(int fieldNumber)
    {
        ClassLoaderResolver clr = ec.getClassLoaderResolver();
        AbstractMemberMetaData mmd = cmd.getMetaDataForManagedMemberAtAbsolutePosition(fieldNumber);
        RelationType relationType = mmd.getRelationType(clr);
        EmbeddedMetaData embmd = mmds.get(0).getEmbeddedMetaData();
        if (mmds.size() == 1 && embmd != null && embmd.getOwnerMember() != null && embmd.getOwnerMember().equals(mmd.getName()))
        {
            // Special case of this being a link back to the owner. TODO Repeat this for nested and their owners
            ObjectProvider[] ownerOps = ec.getOwnersForEmbeddedObjectProvider(op);
            return (ownerOps != null && ownerOps.length > 0 ? ownerOps[0].getObject() : null);
        }

        if (relationType != RelationType.NONE && MetaDataUtils.getInstance().isMemberEmbedded(ec.getMetaDataManager(), clr, mmd, relationType, null))
        {
            // Embedded field
            if (RelationType.isRelationSingleValued(relationType))
            {
                // TODO Cater for null value detection

                List embMmds = new ArrayList(mmds);
                embMmds.add(mmd);

                AbstractClassMetaData embCmd = ec.getMetaDataManager().getMetaDataForClass(mmd.getType(), clr);
                ObjectProvider embOP = ec.getNucleusContext().getObjectProviderFactory().newForEmbedded(ec, embCmd, op, fieldNumber);
                FieldManager ffm = new FetchEmbeddedFieldManager(embOP, result, embMmds, table);
                embOP.replaceFields(embCmd.getAllMemberPositions(), ffm);
                return embOP.getObject();
            }
        }

        return fetchNonEmbeddedObjectField(mmd, relationType, clr);
    }
}