debugtrace5.java

运行时获得方法调用位置

/**
 * 
 */
package com.fishelf.debug;

import com.fishelf.util.Directory;
import com.fishelf.util.PropertiesManager;

/**
 * @author fishelf
 * 
 */
public class DebugTrace
{
	// 当前DebugTrace对象
	private static DebugTrace currentDT = null;
	
	//当前jvm运行时堆栈小于3时提示
	private static final String UNKNOW_SOURCE = "unknow source";
	
	//默认配置文件路径
	private static final String PROPERTITES_FILE_DIRECTORY = "WEB-INF/Debugger.propertites";
	
	//配置文件中字段名
	private static final String PROPERTY_KEY = "is_print_model_on";
	
	//jvm堆栈number因子
	private static final int jvmStackNum = 3;
	
	//是否打印测试信息
	private boolean isPrintModelOn = true;

	private DebugTrace()// 私有constructor
		{
		}

	/**
	 * 通过StackTraceElement类获得当前jvm运行堆栈再获得调用者具体信息
	 * 
	 * @return String 取得调用DEBUG具体位置
	 */
	protected String getCaller()
		{
			String result = "";
			int[] int4Exp = new int[2];
			try
				{
					@SuppressWarnings("unused")
					int tempInt = int4Exp[2];
				}
			catch (IndexOutOfBoundsException iobe)
				{
//					iobe.printStackTrace();
					StackTraceElement[] ste = iobe.getStackTrace();
					if (ste.length < jvmStackNum)
						{
							return UNKNOW_SOURCE;
						}
					
					// 1.当前getCaller方法; 2.lazy单态工厂
					result = "caller: " + ste[jvmStackNum - 1].getClassName() + "."
							+ ste[jvmStackNum - 1].getMethodName() + " (line "
							+ ste[jvmStackNum - 1].getLineNumber() + " [file: "
							+ ste[jvmStackNum - 1].getFileName() + "])";
				}

			return result;
		}

	/**
	 * DebugTrace的lazy singleton工厂
	 * 
	 * @return DebugTrace 返回唯一实例,必须实现线程安全
	 */
	public static synchronized DebugTrace DebugTraceFactory()
		{
			
			if (currentDT == null)
				{
					currentDT = new DebugTrace();
					String propertiesRealPath = Directory
							.GetProjectRealPath(Directory.class);
					propertiesRealPath = propertiesRealPath
							.concat(PROPERTITES_FILE_DIRECTORY);
					String IsPrintModelOnString = PropertiesManager
							.getProperties(propertiesRealPath,
									PROPERTY_KEY);
					currentDT.setIsPrintModelOn(IsPrintModelOnString
							.equals("true") ? true : false);
	
				}
			return currentDT;
				
		}

	/**
	 * 私有setter 设置print model
	 * 
	 * @param isPrintModelOn
	 */
	protected void setIsPrintModelOn(boolean isPrintModelOn)
		{
			this.isPrintModelOn = isPrintModelOn;
		}

	public void printMsg(String msg)
		{
			if (this.isPrintModelOn == false)
				{
					return;
				}
			else
				{
					String aimStr = this.getCaller() + "\n" + "message: " + msg;
					char[] marks = new char[((aimStr.length() - msg.length()) < 80 
							? (aimStr.length() - msg.length()) : 80)];
					
					for (int i = 0; i < marks.length; i++)
						{
							marks[i] = '=';
						}
					System.err.println(marks);
					System.err.println(aimStr);
				}
		}

}