DatastoreAbstractArrayStoreSpecialization.java :  » Google-tech » datanucleus-appengine » org » datanucleus » store » appengine » Java Open Source

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Copyright (c) 2009 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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package org.datanucleus.store.appengine;

import org.datanucleus.ClassLoaderResolver;
import org.datanucleus.ManagedConnection;
import org.datanucleus.StateManager;
import org.datanucleus.store.mapped.exceptions.MappedDatastoreException;
import org.datanucleus.store.mapped.scostore.AbstractArrayStore;
import org.datanucleus.store.mapped.scostore.AbstractArrayStoreSpecialization;
import org.datanucleus.store.mapped.scostore.ElementContainerStore;
import org.datanucleus.util.Localiser;

/**
 * Datastore-specific implementation of {@link AbstractArrayStoreSpecialization}.
 *
 * @author Max Ross <maxr@google.com>
 */
public class DatastoreAbstractArrayStoreSpecialization extends DatastoreAbstractCollectionStoreSpecialization
  implements AbstractArrayStoreSpecialization {

  public DatastoreAbstractArrayStoreSpecialization(Localiser localiser, ClassLoaderResolver clr,
      DatastoreManager storeMgr) {
    super(localiser, clr, storeMgr);
  }

  public void clear(StateManager ownerSM, ElementContainerStore ecs) {
    // The purpose of this method is to null out the fk on the child table,
    // but the only the fks the datastore supports (currently) are parent
    // keys that are part of the child key.  There is no way to modify
    // a key once it has been written to the datastore, so nulling out
    // the parent key isn't possible.  We need to treat this method as
    // a no-op because datanucleus persists modifications to arrays by
    // clearing and then rewriting all the fks.
  }

  public int[] internalAdd(StateManager ownerSM, AbstractArrayStore aas, Object element,
      ManagedConnection mconn, boolean batched, int orderId,
      boolean executeNow) throws MappedDatastoreException {
    // TODO(maxr) Figure out when this gets called.
    throw new UnsupportedOperationException();
  }

  public void processBatchedWrites(ManagedConnection mconn) throws MappedDatastoreException {
    throw new UnsupportedOperationException("Google App Engine does not support batched writes.");
  }
}