CamelCaseSplittingFieldNamingStrategy.java

/*
 * Copyright 2014 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.mapping.model;

import java.util.ArrayList;
import java.util.List;

import org.springframework.data.mapping.PersistentProperty;
import org.springframework.data.util.ParsingUtils;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Configurable {@link FieldNamingStrategy} that splits up camel-case property names and reconcatenates them using a
 * configured delimiter. Individual parts of the name can be manipulated using {@link #preparePart(String)}.
 * 
 * @author Oliver Gierke
 * @since 1.9
 */
public class CamelCaseSplittingFieldNamingStrategy implements FieldNamingStrategy {

	private final String delimiter;

	/**
	 * Creates a new {@link CamelCaseSplittingFieldNamingStrategy}.
	 * 
	 * @param delimiter must not be {@literal null}.
	 */
	public CamelCaseSplittingFieldNamingStrategy(String delimiter) {

		Assert.notNull(delimiter, "Delimiter must not be null!");
		this.delimiter = delimiter;
	}

	/*
	 * (non-Javadoc)
	 * @see org.springframework.data.mapping.model.FieldNamingStrategy#getFieldName(org.springframework.data.mapping.PersistentProperty)
	 */
	@Override
	public String getFieldName(PersistentProperty<?> property) {

		List<String> parts = ParsingUtils.splitCamelCaseToLower(property.getName());
		List<String> result = new ArrayList<>();

		for (String part : parts) {

			String candidate = preparePart(part);

			if (StringUtils.hasText(candidate)) {
				result.add(candidate);
			}
		}

		return StringUtils.collectionToDelimitedString(result, delimiter);
	}

	/**
	 * Callback to prepare the uncapitalized part obtained from the split up of the camel case source. Default
	 * implementation returns the part as is.
	 * 
	 * @param part
	 * @return
	 */
	protected String preparePart(String part) {
		return part;
	}
}