com.vaadin.data.converter.AbstractStringToNumberConverter Maven / Gradle / Ivy
/*
* Copyright (C) 2000-2024 Vaadin Ltd
*
* This program is available under Vaadin Commercial License and Service Terms.
*
* See for the full
* license.
*/
package com.vaadin.data.converter;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.Locale;
import com.vaadin.data.Converter;
import com.vaadin.data.ErrorMessageProvider;
import com.vaadin.data.Result;
import com.vaadin.data.ValueContext;
/**
* 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.
*
* Override and overwrite {@link #getFormat(Locale)} to use a different format.
*
*
* @author Vaadin Ltd
* @since 8.0
*/
public abstract class AbstractStringToNumberConverter
implements Converter {
private final ErrorMessageProvider errorMessageProvider;
private T emptyValue;
/**
* Creates a new converter instance with the given empty string value and
* error message provider.
*
* @param emptyValue
* the presentation value to return when converting an empty
* string, may be null
* @param errorMessageProvider
* the error message provider to use if conversion fails
*
* @since 8.4
*/
protected AbstractStringToNumberConverter(T emptyValue,
ErrorMessageProvider errorMessageProvider) {
this.emptyValue = emptyValue;
this.errorMessageProvider = errorMessageProvider;
}
/**
* Creates a new converter instance with the given empty string value and
* error message.
*
* @param emptyValue
* the presentation value to return when converting an empty
* string, may be null
* @param errorMessage
* the error message to use if conversion fails
*/
protected AbstractStringToNumberConverter(T emptyValue,
String errorMessage) {
this(emptyValue, ctx -> errorMessage);
}
/**
* Returns the format used by
* {@link #convertToPresentation(Object, ValueContext)} and
* {@link #convertToModel(Object, ValueContext)}.
*
* @param locale
* The locale to use
* @return A NumberFormat instance
*/
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 context
* The value context for conversion
* @return The converted value
*/
protected Result convertToNumber(String value,
ValueContext context) {
if (value == null) {
return Result.ok(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(context.getLocale().orElse(null))
.parse(value, parsePosition);
if (parsePosition.getIndex() != value.length()) {
return Result.error(getErrorMessage(context));
}
if (parsedValue == null) {
// Convert "" to the empty value
return Result.ok(emptyValue);
}
return Result.ok(parsedValue);
}
/**
* Gets the error message to use when conversion fails.
*
* @return the error message
*/
protected String getErrorMessage(ValueContext context) {
return errorMessageProvider.apply(context);
}
@Override
public String convertToPresentation(T value, ValueContext context) {
if (value == null) {
return null;
}
return getFormat(context.getLocale().orElse(null)).format(value);
}
}