001: /*
002: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
003: *
004: * This file is part of Resin(R) Open Source
005: *
006: * Each copy or derived work must preserve the copyright notice and this
007: * notice unmodified.
008: *
009: * Resin Open Source is free software; you can redistribute it and/or modify
010: * it under the terms of the GNU General Public License as published by
011: * the Free Software Foundation; either version 2 of the License, or
012: * (at your option) any later version.
013: *
014: * Resin Open Source is distributed in the hope that it will be useful,
015: * but WITHOUT ANY WARRANTY; without even the implied warranty of
016: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
017: * of NON-INFRINGEMENT. See the GNU General Public License for more
018: * details.
019: *
020: * You should have received a copy of the GNU General Public License
021: * along with Resin Open Source; if not, write to the
022: *
023: * Free Software Foundation, Inc.
024: * 59 Temple Place, Suite 330
025: * Boston, MA 02111-1307 USA
026: *
027: * @author Scott Ferguson
028: */
029:
030: package com.caucho.db.sql;
031:
032: import com.caucho.log.Log;
033:
034: import java.sql.SQLException;
035: import java.util.ArrayList;
036: import java.util.logging.Logger;
037:
038: class BooleanLiteralExpr extends Expr {
039: private static final Logger log = Log.open(NullExpr.class);
040:
041: private static BooleanLiteralExpr TRUE_EXPR = new BooleanLiteralExpr(
042: true);
043: private static BooleanLiteralExpr FALSE_EXPR = new BooleanLiteralExpr(
044: false);
045:
046: private final boolean _value;
047:
048: private BooleanLiteralExpr(boolean value) {
049: _value = value;
050: }
051:
052: static BooleanLiteralExpr create(boolean value) {
053: return value ? TRUE_EXPR : FALSE_EXPR;
054: }
055:
056: /**
057: * Returns false because the literal is never null;
058: */
059: public boolean isNull(QueryContext context) throws SQLException {
060: return false;
061: }
062:
063: /**
064: * Returns the type of the expression.
065: */
066: public Class getType() {
067: return boolean.class;
068: }
069:
070: /**
071: * Returns true if the expression returns a boolean.
072: */
073: public boolean isBoolean() {
074: return true;
075: }
076:
077: /**
078: * Returns the cost based on the given FromList.
079: */
080: public long subCost(ArrayList<FromItem> fromList) {
081: return 0;
082: }
083:
084: /**
085: * Evaluates the literal as a string.
086: */
087: public String evalString(QueryContext context) throws SQLException {
088: return _value ? "1" : "0";
089: }
090:
091: /**
092: * Evaluates the literal as a string.
093: */
094: public int evalBoolean(QueryContext context) throws SQLException {
095: return _value ? TRUE : FALSE;
096: }
097:
098: public String toString() {
099: return _value ? "TRUE" : "FALSE";
100: }
101: }
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