01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17: /*
18: * Created on May 15, 2005
19: *
20: */
21: package org.apache.poi.hssf.record.formula.functions;
22:
23: import org.apache.poi.hssf.record.formula.eval.BlankEval;
24: import org.apache.poi.hssf.record.formula.eval.BoolEval;
25: import org.apache.poi.hssf.record.formula.eval.ErrorEval;
26: import org.apache.poi.hssf.record.formula.eval.Eval;
27: import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
28: import org.apache.poi.hssf.record.formula.eval.RefEval;
29: import org.apache.poi.hssf.record.formula.eval.StringEval;
30: import org.apache.poi.hssf.record.formula.eval.ValueEval;
31:
32: /**
33: * @author Amol S. Deshmukh < amolweb at ya hoo dot com >
34: * Here are the general rules concerning Boolean functions:
35: * <ol>
36: * <li> Blanks are not either true or false
37: * <li> Strings are not either true or false (even strings "true"
38: * or "TRUE" or "0" etc.)
39: * <li> Numbers: 0 is false. Any other number is TRUE.
40: * <li> References are evaluated and above rules apply.
41: * <li> Areas: Individual cells in area are evaluated and checked to
42: * see if they are blanks, strings etc.
43: * </ol>
44: */
45: public abstract class BooleanFunction implements Function {
46:
47: protected ValueEval singleOperandEvaluate(Eval eval, int srcRow,
48: short srcCol, boolean stringsAreBlanks) {
49: ValueEval retval;
50:
51: if (eval instanceof RefEval) {
52: RefEval re = (RefEval) eval;
53: ValueEval ve = re.getInnerValueEval();
54: retval = internalResolve(ve, true);
55: } else {
56: retval = internalResolve(eval, stringsAreBlanks);
57: }
58:
59: return retval;
60: }
61:
62: private ValueEval internalResolve(Eval ve, boolean stringsAreBlanks) {
63: ValueEval retval = null;
64:
65: // blankeval is returned as is
66: if (ve instanceof BlankEval) {
67: retval = BlankEval.INSTANCE;
68: }
69:
70: // stringeval
71: else if (ve instanceof StringEval) {
72: retval = stringsAreBlanks ? (ValueEval) BlankEval.INSTANCE
73: : (StringEval) ve;
74: }
75:
76: // bools are bools :)
77: else if (ve instanceof BoolEval) {
78: retval = (BoolEval) ve;
79: }
80:
81: // convert numbers to bool
82: else if (ve instanceof NumericValueEval) {
83: NumericValueEval ne = (NumericValueEval) ve;
84: double d = ne.getNumberValue();
85: retval = Double.isNaN(d) ? (ValueEval) ErrorEval.VALUE_INVALID
86: : (d != 0) ? BoolEval.TRUE : BoolEval.FALSE;
87: }
88:
89: // since refevals
90: else {
91: retval = ErrorEval.VALUE_INVALID;
92: }
93:
94: return retval;
95:
96: }
97: }
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