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16 package org.outerj.daisy.query.model.functions;
17
18 import org.outerj.daisy.query.QueryContext;
19 import org.outerj.daisy.query.model.AbstractFunction;
20 import org.outerj.daisy.query.model.ValueExpr;
21 import org.outerj.daisy.query.model.QValueType;
22 import org.outerj.daisy.query.model.SqlGenerationContext;
23 import org.outerj.daisy.repository.query.QueryException;
24 import org.outerj.daisy.repository.query.EvaluationContext;
25 import org.outerj.daisy.repository.Document;
26 import org.outerj.daisy.repository.Version;
27
28 import java.math.BigDecimal  ;
29 import java.util.Locale ;
30 import java.util.Iterator ;
31
32 public abstract class AbstractBinaryMathFunction extends AbstractFunction {
33 public void prepare(QueryContext context) throws QueryException {
34 super.prepare(context);
35 if (params.size() != 2)
36 throw new QueryException("\"" + getFunctionName() + "\" requires exactly two parameters.");
37
38 Iterator paramsIt = params.iterator();
39 while (paramsIt.hasNext()) {
40 ValueExpr valueExpr = (ValueExpr)paramsIt.next();
41 if (!isNumeric(valueExpr))
42 throw new QueryException("\"" + getFunctionName() + "\" can only be performed on numeric expressions, which this is not: " + valueExpr.getExpression());
43 }
44 }
45
46 static boolean isNumeric(ValueExpr valueExpr) {
47 if (valueExpr.isSymbolicIdentifier())
48 return false;
49
50 QValueType valueType = valueExpr.getValueType();
51 return valueType == QValueType.UNDEFINED || valueType == QValueType.LONG || valueType == QValueType.DOUBLE || valueType == QValueType.DECIMAL;
52 }
53
54 public Object evaluate(QValueType valueType, EvaluationContext evaluationContext) throws QueryException {
55 BigDecimal value1 = toBigDecimal(getParam(0).evaluate(QValueType.DECIMAL, evaluationContext));
56 BigDecimal value2 = toBigDecimal(getParam(1).evaluate(QValueType.DECIMAL, evaluationContext));
57 return evaluate(value1, value2);
58 }
59
60 public Object evaluate(QValueType valueType, Document document, Version version, EvaluationContext evaluationContext) throws QueryException {
61 BigDecimal value1 = toBigDecimal(getParam(0).evaluate(QValueType.DECIMAL, document, version, evaluationContext));
62 BigDecimal value2 = toBigDecimal(getParam(1).evaluate(QValueType.DECIMAL, document, version, evaluationContext));
63 return evaluate(value1, value2);
64 }
65
66 private Object evaluate(BigDecimal value1, BigDecimal value2) {
67 if (value1 == null || value2 == null)
68 return null;
69 return performCalculation(value1, value2);
70 }
71
72 protected abstract Object performCalculation(BigDecimal value1, BigDecimal value2);
73
74 static BigDecimal toBigDecimal(Object value) {
75 if (value == null)
76 return null;
77 else if (value instanceof BigDecimal )
78 return (BigDecimal )value;
79 else if (value instanceof Long )
80 return new BigDecimal (((Long )value).longValue());
81 else if (value instanceof Double )
82 return new BigDecimal (((Double )value).doubleValue());
83 else
84 throw new RuntimeException ("Unexpected type: " + value.getClass().getName());
85 }
86
87 public String getExpression() {
88 StringBuffer expression = new StringBuffer ();
89 expression.append(" (");
90 expression.append(getParam(0).getExpression());
91 expression.append(getMathSymbol());
92 expression.append(getParam(1).getExpression());
93 expression.append(") ");
94 return expression.toString();
95 }
96
97 public void generateSqlValueExpr(StringBuffer sql, SqlGenerationContext context) throws QueryException {
98 sql.append(" (");
99 getParam(0).generateSqlValueExpr(sql, context);
100 sql.append(getMathSymbol());
101 getParam(1).generateSqlValueExpr(sql, context);
102 sql.append(") ");
103 }
104
105 protected abstract String getMathSymbol();
106
107 public QValueType getValueType() {
108 return QValueType.DECIMAL;
109 }
110
111 public String getTitle(Locale locale) {
112 return getExpression();
113 }
114
115 public QValueType getOutputValueType() {
116 return QValueType.DECIMAL;
117 }
118
119 public Object getOutputValue(Document document, Version version, EvaluationContext evaluationContext) throws QueryException {
120 return evaluate(null, document, version, evaluationContext);
121 }
122 }
123 |
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