package com.quadcap.sql.lock;
/* Copyright 1999 - 2003 Quadcap Software. All rights reserved.
*
* This software is distributed under the Quadcap Free Software License.
* This software may be used or modified for any purpose, personal or
* commercial. Open Source redistributions are permitted. Commercial
* redistribution of larger works derived from, or works which bundle
* this software requires a "Commercial Redistribution License"; see
* http://www.quadcap.com/purchase.
*
* Redistributions qualify as "Open Source" under one of the following terms:
*
* Redistributions are made at no charge beyond the reasonable cost of
* materials and delivery.
*
* Redistributions are accompanied by a copy of the Source Code or by an
* irrevocable offer to provide a copy of the Source Code for up to three
* years at the cost of materials and delivery. Such redistributions
* must allow further use, modification, and redistribution of the Source
* Code under substantially the same terms as this license.
*
* Redistributions of source code must retain the copyright notices as they
* appear in each source code file, these license terms, and the
* disclaimer/limitation of liability set forth as paragraph 6 below.
*
* Redistributions in binary form must reproduce this Copyright Notice,
* these license terms, and the disclaimer/limitation of liability set
* forth as paragraph 6 below, in the documentation and/or other materials
* provided with the distribution.
*
* The Software is provided on an "AS IS" basis. No warranty is
* provided that the Software is free of defects, or fit for a
* particular purpose.
*
* Limitation of Liability. Quadcap Software shall not be liable
* for any damages suffered by the Licensee or any third party resulting
* from use of the Software.
*/
import com.quadcap.util.Debug;
/**
* Lock modes supported by this package.
*
* @author Stan Bailes
*/
public class LockMode {
public static final int NL = 0;
public static final int IS = 1;
public static final int IX = 2;
public static final int S = 3;
public static final int SIX = 4;
public static final int X = 5;
public static final int MAX = 6;
static final String[] modes = {
"NL", "IS", "IX", "S", "SIX", "X"
};
public static final String toString(int mode) {
return modes[mode];
}
static int[] impl = {
0, // NL
((1 << IS)), // IS
((1 << IX) | (1 << IS)), // IX
((1 << S) | (1 << IS)), // S
((1 << SIX) | (1 << IX) | (1 << S) | (1 << IS) | (1 << SIX)), // SIX
((1 << SIX) | (1 << IX) | (1 << S) | (1 << IS) | (1 << SIX)
| (1 << X)) // X
};
/**
* If you have mode 'a' already, do you even need to bother getting
* mode 'b'?
*/
public static boolean implies(int a, int b) {
boolean ret = ((impl[a] >> b) & 1) != 0;
// Debug.println(0, "implies(" + toString(a) + ", " + toString(b) +
// ") = " + ret);
return ret;
}
}
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