/*
* 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.
*/
/*
* Created on May 15, 2005
*
*/
package org.apache.poi.hssf.record.formula.functions;
import org.apache.poi.hssf.record.formula.eval.BlankEval;
import org.apache.poi.hssf.record.formula.eval.BoolEval;
import org.apache.poi.hssf.record.formula.eval.ErrorEval;
import org.apache.poi.hssf.record.formula.eval.Eval;
import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
import org.apache.poi.hssf.record.formula.eval.RefEval;
import org.apache.poi.hssf.record.formula.eval.StringEval;
import org.apache.poi.hssf.record.formula.eval.ValueEval;
/**
* @author Amol S. Deshmukh < amolweb at ya hoo dot com >
* Here are the general rules concerning Boolean functions:
* <ol>
* <li> Blanks are not either true or false
* <li> Strings are not either true or false (even strings "true"
* or "TRUE" or "0" etc.)
* <li> Numbers: 0 is false. Any other number is TRUE.
* <li> References are evaluated and above rules apply.
* <li> Areas: Individual cells in area are evaluated and checked to
* see if they are blanks, strings etc.
* </ol>
*/
public abstract class BooleanFunction implements Function {
protected ValueEval singleOperandEvaluate(Eval eval, int srcRow, short srcCol, boolean stringsAreBlanks) {
ValueEval retval;
if (eval instanceof RefEval) {
RefEval re = (RefEval) eval;
ValueEval ve = re.getInnerValueEval();
retval = internalResolve(ve, true);
}
else {
retval = internalResolve(eval, stringsAreBlanks);
}
return retval;
}
private ValueEval internalResolve(Eval ve, boolean stringsAreBlanks) {
ValueEval retval = null;
// blankeval is returned as is
if (ve instanceof BlankEval) {
retval = BlankEval.INSTANCE;
}
// stringeval
else if (ve instanceof StringEval) {
retval = stringsAreBlanks ? (ValueEval) BlankEval.INSTANCE : (StringEval) ve;
}
// bools are bools :)
else if (ve instanceof BoolEval) {
retval = (BoolEval) ve;
}
// convert numbers to bool
else if (ve instanceof NumericValueEval) {
NumericValueEval ne = (NumericValueEval) ve;
double d = ne.getNumberValue();
retval = Double.isNaN(d)
? (ValueEval) ErrorEval.VALUE_INVALID
: (d != 0)
? BoolEval.TRUE
: BoolEval.FALSE;
}
// since refevals
else {
retval = ErrorEval.VALUE_INVALID;
}
return retval;
}
}