content: /*
   * Copyright 2009-2013 by The Regents of the University of California
   * 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 from
   *
   *     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.
   */
  
  package org.apache.asterix.transaction.management.opcallbacks;
  
  import org.apache.asterix.common.exceptions.ACIDException;
  import org.apache.asterix.common.transactions.AbstractOperationCallback;
  import org.apache.asterix.common.transactions.DatasetId;
  import org.apache.asterix.common.transactions.ILockManager;
  import org.apache.asterix.common.transactions.ITransactionContext;
  import org.apache.asterix.transaction.management.service.transaction.TransactionManagementConstants.LockManagerConstants.LockMode;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.dataflow.common.data.accessors.ITupleReference;
  import org.apache.hyracks.storage.common.ISearchOperationCallback;
  
  /**
   * Assumes LSM-BTrees as primary indexes. Implements try/locking and unlocking on primary keys.
   * This Callback method tries to get a lock on PK (instantTryLock).
   * If it fails, this callback does nothing since its purpose is to attempt to get an instant lock
   * and get the result of it. This operation callback is used in an index-only plan.
   */
  public class SecondaryIndexInstantSearchOperationCallback extends AbstractOperationCallback
          implements ISearchOperationCallback {
  
      public SecondaryIndexInstantSearchOperationCallback(DatasetId datasetId, long resourceId, int[] entityIdFields,
              ILockManager lockManager, ITransactionContext txnCtx) {
          super(datasetId, resourceId, entityIdFields, txnCtx, lockManager);
      }
  
      @Override
      public void before(ITupleReference tuple) throws HyracksDataException {
          // This will not be used for a modification operation.
      }
  
      @Override
      public boolean proceed(ITupleReference tuple) throws HyracksDataException {
          int pkHash = computePrimaryKeyHashValue(tuple, primaryKeyFields);
          try {
              return lockManager.instantTryLock(datasetId, pkHash, LockMode.S, txnCtx);
          } catch (ACIDException e) {
              throw HyracksDataException.create(e);
          }
      }
  
      @Override
      public void reconcile(ITupleReference tuple) throws HyracksDataException {
          // No reconciled required since the purpose is instantTryLock on PK.
      }
  
      @Override
      public void cancel(ITupleReference tuple) throws HyracksDataException {
          // No cancel required since reconcile operation is empty.
      }
  
      @Override
      public void complete(ITupleReference tuple) throws HyracksDataException {
          // No cancel required since reconcile operation is empty.
      }
  
  }
  