content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.
   */
  package org.apache.asterix.common.transactions;
  
  import org.apache.asterix.common.exceptions.ACIDException;
  
  /**
   * Interface for the lockManager
   *
   * @author pouria
   * @author kisskys
   */
  public interface ILockManager {
  
      /**
       * The method to request a specific lock mode on a specific resource by a
       * specific transaction
       * - The requesting transaction would succeed to grab the lock if its
       * request does not have any conflict with the currently held locks on the
       * resource AND if no other transaction is waiting "for conversion".
       * Otherwise the requesting transaction will be sent to wait.
       * - If the transaction already has the "same" lock, then a redundant lock
       * call would be called on the resource - If the transaction already has a
       * "stronger" lock mode, then no action would be taken - If the transaction
       * has a "weaker" lock, then the request would be interpreted as a convert
       * request
       * Waiting transaction would eventually garb the lock, or get timed-out
       *
       * @param datasetId
       * @param entityHashValue
       * @param lockMode
       * @param txnContext
       * @throws ACIDException
       */
      public void lock(DatasetId datasetId, int entityHashValue, byte lockMode, ITransactionContext txnContext)
              throws ACIDException;
  
      /**
       * The method releases "All" the locks taken/waiting-on by a specific
       * transaction on "All" resources Upon releasing each lock on each resource,
       * potential waiters, which can be waken up based on their requested lock
       * mode and the waiting policy would be waken up
       *
       * @param txnContext
       * @throws ACIDException
       */
      public void releaseLocks(ITransactionContext txnContext) throws ACIDException;
  
      /**
       * @param datasetId
       * @param entityHashValue
       * @param lockMode
       * @param txnContext
       * @throws ACIDException
       * @return
       */
      public void unlock(DatasetId datasetId, int entityHashValue, byte lockMode, ITransactionContext txnContext)
              throws ACIDException;
  
      /**
       * Call to lock and unlock a specific resource in a specific lock mode
       *
       * @param datasetId
       * @param entityHashValue
       * @param lockMode
       * @param context
       * @return
       * @throws ACIDException
       */
      public void instantLock(DatasetId datasetId, int entityHashValue, byte lockMode, ITransactionContext context)
              throws ACIDException;
  
      /**
       * @param datasetId
       * @param entityHashValue
       * @param lockMode
       * @param context
       * @return
       * @throws ACIDException
       */
      public boolean tryLock(DatasetId datasetId, int entityHashValue, byte lockMode, ITransactionContext context)
              throws ACIDException;
  
      /**
       * @param datasetId
       * @param entityHashValue
       * @param lockMode
       * @param txnContext
       * @return
       * @throws ACIDException
       */
      boolean instantTryLock(DatasetId datasetId, int entityHashValue, byte lockMode, ITransactionContext txnContext)
              throws ACIDException;
  
      /**
       * Prints out the contents of the transactions' table in a readable fashion
       *
       * @return
       * @throws ACIDException
       */
      public String prettyPrint() throws ACIDException;
  
  }
  