NumberConverters.java

/*
 * Copyright 2012 - 2013 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.data.solr.core.convert;

import org.springframework.core.convert.converter.Converter;
import org.springframework.data.convert.WritingConverter;

/**
 * Converts a Number values into a solr readable String that can be directly used within the {@code q} parameter.
 * Negative values will be escaped accordingly.
 * 
 * @author Christoph Strobl
 */
public final class NumberConverters {

	@WritingConverter
	public enum NumberConverter implements Converter<Number, String> {
		INSTANCE;

		@Override
		public String convert(Number source) {
			if (source == null) {
				return null;
			}

			if (source.doubleValue() < 0d) {
				return "\\" + source.toString();
			}
			return source.toString();
		}

	}

}