Copyright (c) 2006 IBM Corporation and others.
All rights reserved. This program and the accompanying materials 
are made available under the terms of the Eclipse Public License v1.0
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/epl-v10.html
Contributors:
    Matthew Webster - initial implementation
/*******************************************************************************
 * Copyright (c) 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Matthew Webster - initial implementation
 *******************************************************************************/
package org.aspectj.weaver.tools;

import java.io.File;
import java.lang.reflect.Array;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.regex.Pattern;

import org.aspectj.bridge.IMessage.Kind;

public abstract class AbstractTrace implements Trace {

	private static final Pattern packagePrefixPattern = Pattern.compile("([^.])[^.]*(\\.)");

	protected Class<?> tracedClass;

	private static SimpleDateFormat timeFormat;
	
	protected AbstractTrace (Class clazz) {
		this.tracedClass = clazz;
	}
	
	public abstract void enter (String methodName, Object thiz, Object[] args);
	
	public abstract void enter(String methodName, Object thiz);

	public abstract void exit(String methodName, Object ret);

	public abstract void exit(String methodName, Throwable th);

	/*
	 * Convenience methods
	 */
	public void enter (String methodName) {
		enter(methodName,null,null);
	}

	public void enter (String methodName, Object thiz, Object arg) {
		enter(methodName,thiz,new Object[] { arg });
	}

	public void enter (String methodName, Object thiz, boolean z) {
		enter(methodName,thiz,new Boolean(z));
	}

	public void exit (String methodName, boolean b) {
		exit(methodName,new Boolean(b));
	}

	public void exit (String methodName, int i) {
		exit(methodName,new Integer(i));
	}

	public void event (String methodName, Object thiz, Object arg) {
		event(methodName,thiz,new Object[] { arg });
	}

	public void warn(String message) {
		warn(message,null);
	}

	public void error(String message) {
		error(message,null);
	}

	public void fatal (String message) {
		fatal(message,null);
	}
	
	/*
	 * Formatting
	 */
	protected String formatMessage(String kind, String className, String methodName, Object thiz, Object[] args) {
		StringBuffer message = new StringBuffer();
		Date now = new Date();
		message.append(formatDate(now)).append(" ");
		message.append(Thread.currentThread().getName()).append(" ");
		message.append(kind).append(" ");
		message.append(formatClassName(className));
		message.append(".").append(methodName);
		if (thiz != null) message.append(" ").append(formatObj(thiz));
		if (args != null) message.append(" ").append(formatArgs(args));
		return message.toString();
	}
	
	
Params:
className – full dotted class name
Returns:
short version of class name with package collapse to initials/**
	 * @param className full dotted class name
	 * @return short version of class name with package collapse to initials
	 */
	private String formatClassName(String className) {
		return packagePrefixPattern.matcher(className).replaceAll("$1.");
	}
	
	protected String formatMessage(String kind, String text, Throwable th) {
		StringBuffer message = new StringBuffer();
		Date now = new Date();
		message.append(formatDate(now)).append(" ");
		message.append(Thread.currentThread().getName()).append(" ");
		message.append(kind).append(" ");
		message.append(text);
		if (th != null) message.append(" ").append(formatObj(th));
		return message.toString();
	}
	
	private static String formatDate (Date date) {
		if (timeFormat == null) {
			timeFormat = new SimpleDateFormat("HH:mm:ss.SSS");
		}
		
		return timeFormat.format(date);
	}

	
Format objects safely avoiding toString which can cause recursion,
NullPointerExceptions or highly verbose results.
 
Params:
obj – parameter to be formatted
Returns:
the formatted parameter/**
	 * Format objects safely avoiding toString which can cause recursion,
	 * NullPointerExceptions or highly verbose results.
	 *  
	 * @param obj parameter to be formatted
	 * @return the formatted parameter
	 */
	protected Object formatObj(Object obj) {
		
		/* These classes have a safe implementation of toString() */
		if (obj == null
				|| obj instanceof String
			    || obj instanceof Number
			    || obj instanceof Boolean
			    || obj instanceof Exception
			    || obj instanceof Character
			    || obj instanceof Class
			    || obj instanceof File
			    || obj instanceof StringBuffer
			    || obj instanceof URL
			    || obj instanceof Kind
		    ) return obj;
		else if (obj.getClass().isArray()) {
			return formatArray(obj);
		}
		else if (obj instanceof Collection) {
			return formatCollection((Collection)obj);
		}
		else try {
			
			// Classes can provide an alternative implementation of toString()
			if (obj instanceof Traceable) {
				return ((Traceable)obj).toTraceString();
			}
			
			// classname@hashcode
			else return formatClassName(obj.getClass().getName()) + "@" + Integer.toHexString(System.identityHashCode(obj));
		
		/* Object.hashCode() can be override and may thow an exception */	
		} catch (Exception ex) {
			return obj.getClass().getName() + "@FFFFFFFF";
		}
	}
	
	protected String formatArray(Object obj) {
		return obj.getClass().getComponentType().getName() + "[" + Array.getLength(obj) + "]"; 
	}
	
	protected String formatCollection(Collection<?> c) {
		return c.getClass().getName() + "(" + c.size() + ")"; 
	}

	
Format arguments into a comma separated list
Params:
names – array of argument names
args – array of arguments
Returns:
the formated list/** 
	 * Format arguments into a comma separated list
	 * 
	 * @param names array of argument names
	 * @param args array of arguments
	 * @return the formated list
	 */
	protected String formatArgs(Object[] args) {
		StringBuffer sb = new StringBuffer();
		
		for (int i = 0; i < args.length; i++) {
			sb.append(formatObj(args[i]));
			if (i < args.length-1) sb.append(", ");
		}
		
		return sb.toString();
	}
	
	protected Object[] formatObjects(Object[] args) {
		for (int i = 0; i < args.length; i++) {
			args[i] = formatObj(args[i]);
		}
		
		return args;
	}
}