ObjectExtend.java

package com.lizard.fastdb.util;

import java.util.Map;

/**
 * 对象属性值合并
 * 
 * @author SHEN.GANG
 */
public final class ObjectExtend<K, V>
{
	/**
	 * 对 <K, V> 对象的属性值进行合并，并返回目标对象<br>
	 * 注意：参数 objs 的第一个参数即为目标对象<br>
	 * <code>
	 * Map<String, Object> m1 = ...<br>
	 * Map<String, Object> m2 = ...<br>
	 * Map<String, Object> m3 = ObjectExtend.extend(m1, m2); //m1 为目标对象 <br>
	 * Map<String, Object> m4 = ObjectExtend.extend(new HashMap<String, Object>(), m1, m2); //new HashMap<String, Object>()为目标对象 <br>
	 * </code> 
	 * Properties p1 = ...<br>
	 * Properties p2 = ...<br>
	 * Properties p3 = ...<br>
	 * Properties p4 = ObjectExtend.extend(p1, p2, p3);<br>
	 * 
	 * @param <K>
	 * @param <V>
	 * @param <T>
	 * @param deep
	 *            是否深度递归合并
	 * @param objs
	 *            要合并属性值的对象（objs的个数至少为2个，即：可以合并2...n个<K,V>到一个目标对象中）
	 * @return
	 */
	@SuppressWarnings("unchecked")
	private static <K, V, T> T doExtend(Class<? extends T> clazz, boolean isDeep, Object... objs)
	{
		if ( objs == null )
		{
			return null;
		}

		if ( objs.length < 2 )
		{
			return (T) objs[0];
		}

		// 合并后返回的目标对象 target
		Map<K, V> target = null;
		try
		{
			target = (Map<K, V>)clazz.newInstance();
		} catch (InstantiationException e)
		{
			e.printStackTrace();
		} catch (IllegalAccessException e)
		{
			e.printStackTrace();
		}
		
		Map<K, V> options = null;
		V src = null;
		V copy = null;

		int len = objs.length;
		int i = 0;

		for ( ; i < len; i++ )
		{
			options = (Map<K, V>)objs[i];

			//if ( options != null && options instanceof Map )
			if ( options != null )
			{
				//for ( K key : options.keySet() )
				for( Map.Entry<K, V> e : options.entrySet())
				{
					src = target.get(e.getKey());
					copy = e.getValue();//options.get(key);

					if ( target == copy || target.equals(copy) )
					{
						continue;
					}

					if ( isDeep && copy != null && copy instanceof Map )
					{
						target.put(e.getKey(), (V)doExtend(clazz, isDeep, src, copy));
					}
					else
					{
						target.put(e.getKey(), copy);
					}

				}
			}

		}

		return (T)target;
	}

	/**
	 * 对 <code><K, V></code> 对象的属性值进行合并，并返回目标对象<br>
	 * 注意：该方法不进行深度合并，如需深度合并，请使用 ObjectExtend.extend( boolean deep, Object...
	 * objs ); 方法
	 * 
	 * @param <K>
	 * @param <V>
	 * @param <T>
	 * @param objs
	 *            要合并属性值的对象（objs的个数至少为2个，即：可以合并2...n个<K,V>到一个目标对象中）
	 * @return
	 */
	public static <K, V, T> T extend(Class<? extends T> clazz, Object... objs)
	{
		return doExtend( clazz, false, objs );
	}
	
	public static <K, V, T> T extend(Class<? extends T> clazz, boolean isDeep, Object... objs)
	{
		return doExtend( clazz, isDeep, objs );
	}
	
	public static void main(String[] args)
	{
		/*
		Properties m1_1 = new Properties();
		m1_1.put("code", "");
		m1_1.put("state", "1");
		
		Map<String, Object> m1 = new HashMap<String, Object>();
		m1.put("name", "SHEN.GANG");
		m1.put("age", 25);
		m1.put("code", m1_1);

		
		HashMap<String, Object> m2_1 = new HashMap<String, Object>();
		m2_1.put("code", "x5080");
		m2_1.put("state", "2");

		HashMap<String, Object> m2 = new HashMap<String, Object>();
		m2.put("name", "ss");
		m2.put("age", 26);
		m2.put("address", "苏州市吴江区同理镇");
		m2.put("code", m2_1);

		Map<String, Object> m = doExtend( HashMap.class, true, m1, m2);
		for ( String key : m.keySet() )
		{
			System.out.println(key + " : " + m.get(key));
		}
		System.out.println("------------------------------------");
		for ( String key : m1.keySet() )
		{
			System.out.println(key + " : " + m1.get(key));
		}
		*/
		/*
		Properties PROP = new Properties();
		PROP.setProperty("max-connection", "100");
		PROP.setProperty("min-connection", "10");
		PROP.setProperty("init-connection", "2");
		PROP.setProperty("connection-provider", "com.lizard.fast.connection.proxool.ProxoolConnectionProvider");

		Properties ds1 = new Properties();
		ds1.setProperty("max-connection", "50");
		ds1.setProperty("init-connection", "5");
		ds1.setProperty("connection-provider", "com.lizard.fast.connection.c3p0.C3p0ConnectionProvider");

		Properties ds2 = new Properties();
		ds2.setProperty("load-on-startup", "true");
		ds2.setProperty("show-sql", "show-sql");

		Properties p = doExtend(Properties.class, false, PROP, ds1, ds2);
		for ( Enumeration e = p.propertyNames(); e.hasMoreElements(); )
		{
			String key = e.nextElement().toString();
			System.out.println(key + " : " + p.getProperty(key));
		}
		*/
	}

}