/*
* Copyright (c) 2011 Google Inc.
*
* All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse
* Public License v1.0 which accompanies this distribution, and is available at
*
* http://www.eclipse.org/legal/epl-v10.html
*/
package com.google.eclipse.protobuf.conversion;
import static java.lang.Double.NEGATIVE_INFINITY;
import static java.lang.Double.NaN;
import static java.lang.Double.POSITIVE_INFINITY;
import static org.eclipse.xtext.util.Strings.isEmpty;
import static com.google.common.collect.Maps.newHashMap;
import java.util.Map;
import org.eclipse.xtext.conversion.ValueConverterException;
import org.eclipse.xtext.conversion.impl.AbstractLexerBasedConverter;
import org.eclipse.xtext.nodemodel.INode;
/**
* Converts floating-point numbers to {@code double}s.
*
* @author alruiz@google.com (Alex Ruiz)
*/
public class DOUBLEValueConverter extends AbstractLexerBasedConverter<Double> {
private static final Map<String, Double> PREDEFINED_VALUES = newHashMap();
static {
PREDEFINED_VALUES.put("nan", NaN);
PREDEFINED_VALUES.put("inf", POSITIVE_INFINITY);
PREDEFINED_VALUES.put("-inf", NEGATIVE_INFINITY);
}
/**
* Creates an {@code float} from the given input, if the given input represents a floating-point number.
* @param string the given input.
* @param node the parsed node including hidden parts.
* @return the new {@code float}.
* @throws ValueConverterException if the given input is {@code null}, empty or does not represent a floating-point
* number.
*/
@Override public Double toValue(String string, INode node) throws ValueConverterException {
if (isEmpty(string)) {
throw new ValueConverterException("Couldn't convert empty string to double.", node, null);
}
Double predefinedValue = PREDEFINED_VALUES.get(string);
if (predefinedValue != null) {
return predefinedValue;
}
try {
return Double.parseDouble(string);
} catch (NumberFormatException e) {
throw parsingError(string, node, e);
}
}
private ValueConverterException parsingError(String string, INode node, Exception cause) {
return new ValueConverterException("Couldn't convert '" + string + "' to double.", node, cause);
}
}