001: /*
002: * $Id: ModFunction.java,v 1.8 2005/05/02 22:28:41 ahimanikya Exp $
003: * =======================================================================
004: * Copyright (c) 2002-2005 Axion Development Team. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above
011: * copyright notice, this list of conditions and the following
012: * disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The names "Tigris", "Axion", nor the names of its contributors may
020: * not be used to endorse or promote products derived from this
021: * software without specific prior written permission.
022: *
023: * 4. Products derived from this software may not be called "Axion", nor
024: * may "Tigris" or "Axion" appear in their names without specific prior
025: * written permission.
026: *
027: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
028: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
029: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
030: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
031: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
032: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
033: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
034: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
035: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
036: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
037: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
038: * =======================================================================
039: */
040:
041: package org.axiondb.functions;
042:
043: import java.math.BigDecimal;
044:
045: import org.axiondb.AxionException;
046: import org.axiondb.DataType;
047: import org.axiondb.FunctionFactory;
048: import org.axiondb.RowDecorator;
049: import org.axiondb.types.BigDecimalType;
050:
051: /**
052: * @version $Revision: 1.8 $ $Date: 2005/05/02 22:28:41 $
053: * @author Sudhendra Seshachala
054: * @author Ahimanikya Satapathy
055: * @author Jonathan Giron
056: */
057: public class ModFunction extends BaseFunction implements
058: ScalarFunction, FunctionFactory {
059:
060: /** Creates a new instance of Class */
061: public ModFunction() {
062: super ("MOD");
063: }
064:
065: public ConcreteFunction makeNewInstance() {
066: return new ModFunction();
067: }
068:
069: /** {@link BigDecimalType} */
070: public DataType getDataType() {
071: return (_datatype == null) ? new BigDecimalType() : _datatype;
072: }
073:
074: public Object evaluate(RowDecorator row) throws AxionException {
075: Object rawDividend = getArgument(0).evaluate(row);
076: Object rawDivisor = getArgument(1).evaluate(row);
077:
078: if (null == rawDividend || null == rawDivisor) {
079: return null;
080: }
081:
082: // Per ISO/ANSI spec, dividend and divisor must be an exact numeric value with
083: // scale 0. We accept numeric values with fractional components, but they will be
084: // truncated.
085: BigDecimal dividend = getArgument(0).getDataType()
086: .toBigDecimal(rawDividend).setScale(0,
087: BigDecimal.ROUND_DOWN);
088: BigDecimal divisor = getArgument(1).getDataType().toBigDecimal(
089: rawDivisor).setScale(0, BigDecimal.ROUND_DOWN);
090:
091: BigDecimal result = null;
092: try {
093: BigDecimal divideResult = dividend.divide(divisor, 0,
094: BigDecimal.ROUND_DOWN);
095: result = dividend.subtract(divisor.multiply(divideResult));
096: } catch (ArithmeticException e) {
097: throw new AxionException(22012);
098: }
099:
100: // Per ISO/ANSI spec, return datatype must match that of the divisor. If the
101: // divisor is a non-exact numeric type, we should return an appropriately sized
102: // BigDecimal with scale 0.
103: DataType divisorDatatype = getArgument(1).getDataType();
104: _datatype = (divisor instanceof DataType.ExactNumeric) ? divisorDatatype
105: : getEquivalentExactNumericType(divisorDatatype);
106:
107: return _datatype.convert(result);
108: }
109:
110: private DataType getEquivalentExactNumericType(DataType datatype) {
111: return new BigDecimalType(datatype.getPrecision(), 0);
112: }
113:
114: public boolean isValid() {
115: return (getArgumentCount() == 2);
116: }
117:
118: private DataType _datatype = null;
119: }
|