/**
 * Copyright (c) 2005-2011 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: Fixtures.java 1593 2011-05-11 10:37:12Z calvinxiu $
 */
package com.key.common.plugs.mapper;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.commons.lang.StringUtils;

import com.key.common.utils.ReflectionUtils;

/**
 * 提出集合中的元素对象的属性(通过Getter函数),组合成新的集合.
 *
 */
public class CollectionMapper {

	/**
	 * 提取集合中的对象的属性(通过Getter函数), 组合成Map.
	 * 
	 * @param collection 来源集合.
	 * @param keyPropertyName 要提取为Map中的Key值的属性名.
	 * @param valuePropertyName 要提取为Map中的Value值的属性名.
	 */
	public static Map extractToMap(final Collection collection, final String keyPropertyName,
			final String valuePropertyName) {
		Map map = new HashMap();

		try {
			for (Object obj : collection) {
				map.put(PropertyUtils.getProperty(obj, keyPropertyName),
						PropertyUtils.getProperty(obj, valuePropertyName));
			}
		} catch (Exception e) {
			throw ReflectionUtils.convertReflectionExceptionToUnchecked(e);
		}

		return map;
	}

	/**
	 * 提取集合中的对象的属性(通过Getter函数), 组合成List.
	 * 
	 * @param collection 来源集合.
	 * @param propertyName 要提取的属性名.
	 */
	public static List extractToList(final Collection collection, final String propertyName) {
		List list = new ArrayList();

		try {
			for (Object obj : collection) {
				list.add(PropertyUtils.getProperty(obj, propertyName));
			}
		} catch (Exception e) {
			throw ReflectionUtils.convertReflectionExceptionToUnchecked(e);
		}

		return list;
	}

	/**
	 * 提取集合中的对象的属性(通过Getter函数), 组合成由分割符分隔的字符串.
	 * 
	 * @param collection 来源集合.
	 * @param propertyName 要提取的属性名.
	 * @param separator 分隔符.
	 */
	public static String extractToString(final Collection collection, final String propertyName, final String separator) {
		List list = extractToList(collection, propertyName);
		return StringUtils.join(list, separator);
	}
}
