/*
* Copyright 2000-2014 Vaadin Ltd.
*
* Licensed 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.
*/
package com.vaadin.data.util.converter;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.Locale;
/**
* A converter that converts from the number type T to {@link String} and back.
* Uses the given locale and {@link NumberFormat} for formatting and parsing.
* Automatically trims the input string, removing any leading and trailing white
* space.
* <p>
* Override and overwrite {@link #getFormat(Locale)} to use a different format.
* </p>
*
* @author Vaadin Ltd
* @since 7.1
*/
public abstract class AbstractStringToNumberConverter<T> implements
Converter<String, T> {
/**
* Returns the format used by {@link #convertToPresentation(Object, Locale)}
* and {@link #convertToModel(Object, Locale)}.
*
* @param locale
* The locale to use
* @return A NumberFormat instance
* @since 7.1
*/
protected NumberFormat getFormat(Locale locale) {
if (locale == null) {
locale = Locale.getDefault();
}
return NumberFormat.getNumberInstance(locale);
}
/**
* Convert the value to a Number using the given locale and
* {@link #getFormat(Locale)}.
*
* @param value
* The value to convert
* @param locale
* The locale to use for conversion
* @return The converted value
* @throws ConversionException
* If there was a problem converting the value
* @since 7.1
*/
protected Number convertToNumber(String value,
Class<? extends Number> targetType, Locale locale)
throws ConversionException {
if (value == null) {
return null;
}
// Remove leading and trailing white space
value = value.trim();
// Parse and detect errors. If the full string was not used, it is
// an error.
ParsePosition parsePosition = new ParsePosition(0);
Number parsedValue = getFormat(locale).parse(value, parsePosition);
if (parsePosition.getIndex() != value.length()) {
throw new ConversionException("Could not convert '" + value
+ "' to " + getModelType().getName());
}
if (parsedValue == null) {
// Convert "" to null
return null;
}
return parsedValue;
}
/*
* (non-Javadoc)
*
* @see
* com.vaadin.data.util.converter.Converter#convertToPresentation(java.lang
* .Object, java.util.Locale)
*/
@Override
public String convertToPresentation(T value,
Class<? extends String> targetType, Locale locale)
throws ConversionException {
if (value == null) {
return null;
}
return getFormat(locale).format(value);
}
/*
* (non-Javadoc)
*
* @see com.vaadin.data.util.converter.Converter#getPresentationType()
*/
@Override
public Class<String> getPresentationType() {
return String.class;
}
}