src/org/apache/taglibs/rdc/scxml/env/Tracer.java

/*
 *    
 *   Copyright 2004 The Apache Software Foundation.
 *
 *  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 org.apache.taglibs.rdc.scxml.env;

import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.taglibs.rdc.scxml.ErrorReporter;
import org.apache.taglibs.rdc.scxml.SCXMLListener;
import org.apache.taglibs.rdc.scxml.model.SCXML;
import org.apache.taglibs.rdc.scxml.model.State;
import org.apache.taglibs.rdc.scxml.model.Transition;
import org.apache.taglibs.rdc.scxml.model.TransitionTarget;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 * A simple logger connected to Jakarta Commons Logging.
 * 
 * @author Jaroslav Gergic
 */
public class Tracer implements ErrorReporter, SCXMLListener, ErrorHandler {

	private static Log log = LogFactory.getLog(Tracer.class);
	
	/**
	 * Constructor
	 */
	public Tracer() {
	}

	/**
	 * @see org.apache.taglibs.rdc.scxml.ErrorReporter#onError(java.lang.String, java.lang.String, java.lang.Object)
	 */
	public void onError(String errCode, String errDetail, Object errCtx) {
		//Note: the if-then-else below is based on the actual usage
		// (codebase search), it has to be kept up-to-date as the code changes
		errCode = errCode.intern();
		StringBuffer msg = new StringBuffer();
		msg.append(errCode).append(" (");
		msg.append(errDetail).append("): ");
		if (errCode == ErrorReporter.NO_INITIAL) {
			if (errCtx instanceof SCXML) {
				//determineInitialStates
				msg.append("<SCXML>");
			} else if (errCtx instanceof State) {
				//determineInitialStates
				//determineTargetStates
				msg.append("State " + Tracer.getTTPath((State)errCtx));
			}
		} else if (errCode == ErrorReporter.UNKNOWN_ACTION) {
			//executeActionList
			msg.append("Action: " + errCtx.getClass().getName());
		} else if (errCode == ErrorReporter.NON_DETERMINISTIC) {
			//filterTransitionSet
			msg.append(" [");
			if(errCtx instanceof HashSet) {
				Iterator i = ((HashSet)errCtx).iterator();
				while(i.hasNext()) {
					Transition t = (Transition)i.next();
					msg.append(transToString(t.getParent(), t.getTarget(), t));
					if(i.hasNext()) {
						msg.append(", ");
					}
				}
			}
			msg.append(']');
		} else if (errCode == ErrorReporter.ILLEGAL_CONFIG) {
			//isLegalConfig
			if (errCtx instanceof Map.Entry) {
				TransitionTarget tt = (TransitionTarget)(((Map.Entry)errCtx).getKey());
				HashSet vals = (HashSet)(((Map.Entry)errCtx).getValue());
				msg.append(Tracer.getTTPath(tt) + " : [");
				Iterator i = vals.iterator();
				while(i.hasNext()) {
					TransitionTarget tx = (TransitionTarget)i.next();
					msg.append(Tracer.getTTPath(tx));
					if(i.hasNext()) {
						msg.append(", ");
					}
				}
				msg.append(']');
			} else if (errCtx instanceof HashSet) {
				HashSet vals = (HashSet)(errCtx);
				msg.append("<SCXML> : [");
				Iterator i = vals.iterator();
				while(i.hasNext()) {
					TransitionTarget tx = (TransitionTarget)i.next();
					msg.append(Tracer.getTTPath(tx));
					if(i.hasNext()) {
						msg.append(", ");
					}
				}
				msg.append(']');
			}
		}
		log.warn(msg.toString());
	}

	/**
	 * @see org.apache.taglibs.rdc.scxml.SCXMLListener#onEntry(org.apache.taglibs.rdc.scxml.model.TransitionTarget)
	 */
	public void onEntry(TransitionTarget state) {
		log.info(Tracer.getTTPath(state));
	}

	/**
	 * @see org.apache.taglibs.rdc.scxml.SCXMLListener#onExit(org.apache.taglibs.rdc.scxml.model.TransitionTarget)
	 */
	public void onExit(TransitionTarget state) {
		log.info(Tracer.getTTPath(state));
	}

	/**
	 * @see org.apache.taglibs.rdc.scxml.SCXMLListener#onTransition(org.apache.taglibs.rdc.scxml.model.TransitionTarget, org.apache.taglibs.rdc.scxml.model.TransitionTarget, org.apache.taglibs.rdc.scxml.model.Transition)
	 */
	public void onTransition(TransitionTarget from, TransitionTarget to,
			Transition transition) {
		log.info(transToString(from, to, transition));
	}
	
	private static final String transToString(TransitionTarget from,
			TransitionTarget to, Transition transition) {
		StringBuffer buf = new StringBuffer("transition (");
		buf.append("event = ").append(transition.getEvent());
		buf.append(", cond = ").append(transition.getCond());
		buf.append(", from = ").append(Tracer.getTTPath(from));
		buf.append(", to = ").append(Tracer.getTTPath(to));
		buf.append(')');
		return buf.toString();
	}

	/**
	 * @see org.xml.sax.ErrorHandler#warning(org.xml.sax.SAXParseException)
	 */
	public void warning(SAXParseException exception) throws SAXException {
		log.warn(exception.getMessage(), exception);
	}

	/**
	 * @see org.xml.sax.ErrorHandler#error(org.xml.sax.SAXParseException)
	 */
	public void error(SAXParseException exception) throws SAXException {
		log.error(exception.getMessage(), exception);
	}

	/**
	 * @see org.xml.sax.ErrorHandler#fatalError(org.xml.sax.SAXParseException)
	 */
	public void fatalError(SAXParseException exception) throws SAXException {
		log.fatal(exception.getMessage(), exception);
	}

	private static final String getTTPath(TransitionTarget tt) {
		if(tt.getParent() == null) {
			return "/" + tt.getId();
		} else {
			LinkedList ll = new LinkedList();
			while(tt != null) {
				ll.addFirst(tt);
				tt = tt.getParent();
			}
			Iterator i = ll.iterator();
			StringBuffer names = new StringBuffer();
			while(i.hasNext()) {
				TransitionTarget tmp = (TransitionTarget)i.next();
				names.append('/').append(tmp.getId());
			}
			return names.toString();
		}
	}

}