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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2009, 2015 Oracle and/or its affiliates. All rights reserved.
*
*/
using System;
using System.Collections.Generic;
using System.Text;
using BerkeleyDB.Internal;
namespace BerkeleyDB {
/// <summary>
/// A class to represent what lock request(s) should be rejected during
/// deadlock resolution.
/// </summary>
public class DeadlockPolicy {
private uint flag;
internal uint policy { get { return flag; } }
private DeadlockPolicy(uint val) {
flag = val;
}
internal static DeadlockPolicy fromPolicy(uint val) {
switch (val) {
case DbConstants.DB_LOCK_DEFAULT:
return DEFAULT;
case DbConstants.DB_LOCK_EXPIRE:
return EXPIRE;
case DbConstants.DB_LOCK_MAXLOCKS:
return MAX_LOCKS;
case DbConstants.DB_LOCK_MAXWRITE:
return MAX_WRITE;
case DbConstants.DB_LOCK_MINLOCKS:
return MIN_LOCKS;
case DbConstants.DB_LOCK_MINWRITE:
return MIN_WRITE;
case DbConstants.DB_LOCK_OLDEST:
return OLDEST;
case DbConstants.DB_LOCK_RANDOM:
return RANDOM;
case DbConstants.DB_LOCK_YOUNGEST:
return YOUNGEST;
}
throw new ArgumentException("Invalid deadlock policy.");
}
/// <summary>
/// If no DeadlockPolicy has yet been specified, use
/// <see cref="RANDOM"/>.
/// </summary>
public static DeadlockPolicy DEFAULT =
new DeadlockPolicy(DbConstants.DB_LOCK_DEFAULT);
/// <summary>
/// Reject lock requests which have timed out. No other deadlock
/// detection is performed.
/// </summary>
public static DeadlockPolicy EXPIRE =
new DeadlockPolicy(DbConstants.DB_LOCK_EXPIRE);
/// <summary>
/// Reject the lock request for the locker ID with the most locks.
/// </summary>
public static DeadlockPolicy MAX_LOCKS =
new DeadlockPolicy(DbConstants.DB_LOCK_MAXLOCKS);
/// <summary>
/// Reject the lock request for the locker ID with the most write locks.
/// </summary>
public static DeadlockPolicy MAX_WRITE =
new DeadlockPolicy(DbConstants.DB_LOCK_MAXWRITE);
/// <summary>
/// Reject the lock request for the locker ID with the fewest locks.
/// </summary>
public static DeadlockPolicy MIN_LOCKS =
new DeadlockPolicy(DbConstants.DB_LOCK_MINLOCKS);
/// <summary>
/// Reject the lock request for the locker ID with the fewest write
/// locks.
/// </summary>
public static DeadlockPolicy MIN_WRITE =
new DeadlockPolicy(DbConstants.DB_LOCK_MINWRITE);
/// <summary>
/// Reject the lock request for the locker ID with the oldest lock.
/// </summary>
public static DeadlockPolicy OLDEST =
new DeadlockPolicy(DbConstants.DB_LOCK_OLDEST);
/// <summary>
/// Reject the lock request for a random locker ID.
/// </summary>
public static DeadlockPolicy RANDOM =
new DeadlockPolicy(DbConstants.DB_LOCK_RANDOM);
/// <summary>
/// Reject the lock request for the locker ID with the youngest lock.
/// </summary>
public static DeadlockPolicy YOUNGEST =
new DeadlockPolicy(DbConstants.DB_LOCK_YOUNGEST);
}
}
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