com.creativewidgetworks.goldparser.simple3.rulehandlers.Expression Maven / Gradle / Ivy
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Java implementation of Devin Cook's GOLD Parser engine
package com.creativewidgetworks.goldparser.simple3.rulehandlers;
import java.math.RoundingMode;
import com.creativewidgetworks.goldparser.engine.ParserException;
import com.creativewidgetworks.goldparser.engine.Reduction;
import com.creativewidgetworks.goldparser.parser.GOLDParser;
import com.creativewidgetworks.goldparser.parser.ProcessRule;
import com.creativewidgetworks.goldparser.parser.Variable;
import com.creativewidgetworks.goldparser.simple3.Simple3;
@ProcessRule(rule={
" ::= > ",
" ::= < ",
" ::= <= ",
" ::= >= ",
" ::= '==' ",
" ::= <> ",
" ::= ",
" ::= '+' ",
" ::= - ",
" ::= & ",
" ::= ",
" ::= '*' ",
" ::= '/' ",
" ::= ",
" ::= "
})
/**
* Rule handler for the expression rules.
*
* @author Ralph Iden (http://www.creativewidgetworks.com)
* @version 5.0.0
*/
public class Expression extends Reduction {
private static final int PRECISION = 5;
private static final RoundingMode ROUNDING_MODE = RoundingMode.HALF_UP;
private static final String validOperators = "== <> < <= > >= + - * / & ";
private GOLDParser theParser;
private String theOperator;
private Reduction leftExpression;
private Reduction rightExpression;
public Expression(GOLDParser parser) {
theParser = parser;
Reduction reduction = parser.getCurrentReduction();
if (reduction != null) {
if (reduction.size() == 3) {
leftExpression = reduction.get(0).asReduction();
theOperator = reduction.get(1).asString();
rightExpression = reduction.get(2).asReduction();
if (validOperators.indexOf(theOperator + " ") == -1) {
parser.raiseParserException(Simple3.formatMessage("error.invalid_operator", validOperators, theOperator));
}
} else {
parser.raiseParserException(Simple3.formatMessage("error.param_count", "3", String.valueOf(reduction.size())));
}
} else {
parser.raiseParserException(Simple3.formatMessage("error.no_reduction"));
}
}
@Override
public Variable getValue() throws ParserException {
Variable result = null;
Variable lValue = leftExpression.getValue();
Variable rValue = rightExpression.getValue();
boolean b = false;
if (theOperator.equals("==")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) == 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreBooleans()) {
b = lValue.asBool() == rValue.asBool();
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) == 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) == 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("<>")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) != 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreBooleans()) {
b = lValue.asBool() != rValue.asBool();
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) != 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) != 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("<")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) < 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) < 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) < 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("<=")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) <= 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) <= 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) <= 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals(">")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) > 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) > 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) > 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals(">=")) {
if (bothValuesAreNumbers()) {
b = lValue.asNumber().compareTo(rValue.asNumber()) >= 0;
result = new Variable(Boolean.valueOf(b));
} else if (bothValuesAreTimestamps()) {
b = lValue.asTimestamp().compareTo(rValue.asTimestamp()) >= 0;
result = new Variable(Boolean.valueOf(b));
} else if (oneOrBothValuesAreStrings()) {
b = lValue.toString().compareTo(rValue.toString()) >= 0;
result = new Variable(Boolean.valueOf(b));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("+")) {
if (bothValuesAreNumbers()) {
result = new Variable(lValue.asNumber().add(rValue.asNumber()));
} else {
// I prefer to overload + depending upon type
result = new Variable(lValue.toString() + rValue.toString());
}
} else if (theOperator.equals("-")) {
if (bothValuesAreNumbers()) {
result = new Variable(lValue.asNumber().subtract(rValue.asNumber()));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("&")) {
// String concatenation
if (oneOrBothValuesAreStrings()) {
result = new Variable(lValue.toString() + rValue.toString());
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("*")) {
if (bothValuesAreNumbers()) {
result = new Variable(lValue.asNumber().multiply(rValue.asNumber()));
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
} else if (theOperator.equals("/")) {
if (bothValuesAreNumbers()) {
try {
// This path will strip off extraneous decimal places, but will fail
// with numbers that repeat (e.g., 1/3 = .33333333333)
result = new Variable(lValue.asNumber().divide(rValue.asNumber()));
} catch (Exception e) {
// This path will handle the repeating numbers
result = new Variable(lValue.asNumber().divide(rValue.asNumber(),PRECISION, ROUNDING_MODE));
}
} else {
theParser.raiseParserException(Simple3.formatMessage("error.type_mismatch"));
}
}
return result;
}
/*----------------------------------------------------------------------------*/
public boolean bothValuesAreBooleans() throws ParserException {
return leftExpression.getValue().asBoolean() != null && rightExpression.getValue().asBoolean() != null;
}
public boolean bothValuesAreNumbers() throws ParserException {
return leftExpression.getValue().asNumber() != null && rightExpression.getValue().asNumber() != null;
}
public boolean bothValuesAreTimestamps() throws ParserException {
return leftExpression.getValue().asTimestamp() != null && rightExpression.getValue().asTimestamp() != null;
}
public boolean oneOrBothValuesAreStrings() throws ParserException {
return leftExpression.getValue().asString() != null || rightExpression.getValue().asString() != null;
}
}
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