/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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 org.springframework.format.number;

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

import org.springframework.lang.Nullable;

A general-purpose number formatter using NumberFormat's number style.
Delegates to NumberFormat.getInstance(Locale). Configures BigDecimal parsing so there is no loss in precision. Allows configuration over the decimal number pattern. The AbstractNumberFormatter.parse(String, Locale) routine always returns a BigDecimal. 
Author:
Keith Donald, Juergen Hoeller
See Also:
setPattern
AbstractNumberFormatter.setLenient
Since:
4.2/**
 * A general-purpose number formatter using NumberFormat's number style.
 *
 * <p>Delegates to {@link java.text.NumberFormat#getInstance(Locale)}.
 * Configures BigDecimal parsing so there is no loss in precision.
 * Allows configuration over the decimal number pattern.
 * The {@link #parse(String, Locale)} routine always returns a BigDecimal.
 *
 * @author Keith Donald
 * @author Juergen Hoeller
 * @since 4.2
 * @see #setPattern
 * @see #setLenient
 */
public class NumberStyleFormatter extends AbstractNumberFormatter {

	@Nullable
	private String pattern;


	
Create a new NumberStyleFormatter without a pattern.
/**
	 * Create a new NumberStyleFormatter without a pattern.
	 */
	public NumberStyleFormatter() {
	}

	
Create a new NumberStyleFormatter with the specified pattern.
Params:
pattern – the format pattern
See Also:
setPattern/**
	 * Create a new NumberStyleFormatter with the specified pattern.
	 * @param pattern the format pattern
	 * @see #setPattern
	 */
	public NumberStyleFormatter(String pattern) {
		this.pattern = pattern;
	}


	
Specify the pattern to use to format number values.
If not specified, the default DecimalFormat pattern is used.
See Also:
applyPattern.applyPattern(String)/**
	 * Specify the pattern to use to format number values.
	 * If not specified, the default DecimalFormat pattern is used.
	 * @see java.text.DecimalFormat#applyPattern(String)
	 */
	public void setPattern(String pattern) {
		this.pattern = pattern;
	}


	@Override
	public NumberFormat getNumberFormat(Locale locale) {
		NumberFormat format = NumberFormat.getInstance(locale);
		if (!(format instanceof DecimalFormat)) {
			if (this.pattern != null) {
				throw new IllegalStateException("Cannot support pattern for non-DecimalFormat: " + format);
			}
			return format;
		}
		DecimalFormat decimalFormat = (DecimalFormat) format;
		decimalFormat.setParseBigDecimal(true);
		if (this.pattern != null) {
			decimalFormat.applyPattern(this.pattern);
		}
		return decimalFormat;
	}

}