CamelCaseSeparatorNamingPolicy.java

/*
 * Copyright (C) 2008 Google Inc.
 *
 * 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.smartandroid.sa.json;

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Collection;

import com.smartandroid.sa.json.internal.$Gson$Preconditions;

/**
 * Converts the field name that uses camel-case define word separation into
 * separate words that are separated by the provided {@code separatorString}.
 * 
 * <p>
 * The following is an example:
 * </p>
 * 
 * <pre>
 * class IntWrapper {
 * 	public int integerField = 0;
 * }
 * 
 * CamelCaseSeparatorNamingPolicy policy = new CamelCaseSeparatorNamingPolicy("_");
 * String translatedFieldName = policy.translateName(IntWrapper.class
 * 		.getField("integerField"));
 * 
 * assert ("integer_Field".equals(translatedFieldName));
 * </pre>
 * 
 * @author Joel Leitch
 */
final class CamelCaseSeparatorNamingPolicy extends RecursiveFieldNamingPolicy {
	private final String separatorString;

	/**
	 * Constructs a new CamelCaseSeparatorNamingPolicy object that will add the
	 * {@code separatorString} between each of the words separated by camel
	 * case.
	 * 
	 * @param separatorString
	 *            the string value to place between words
	 * @throws IllegalArgumentException
	 *             thrown if the {@code separatorString} parameter is null or
	 *             empty.
	 */
	public CamelCaseSeparatorNamingPolicy(String separatorString) {
		$Gson$Preconditions.checkNotNull(separatorString);
		$Gson$Preconditions.checkArgument(!"".equals(separatorString));
		this.separatorString = separatorString;
	}

	@Override
	protected String translateName(String target, Type fieldType,
			Collection<Annotation> annnotations) {
		StringBuilder translation = new StringBuilder();
		for (int i = 0; i < target.length(); i++) {
			char character = target.charAt(i);
			if (Character.isUpperCase(character) && translation.length() != 0) {
				translation.append(separatorString);
			}
			translation.append(character);
		}

		return translation.toString();
	}
}