operatorservice.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as 
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version. 
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.tools;

import edu.udo.cs.yale.Yale;
import edu.udo.cs.yale.tools.LogService;
import edu.udo.cs.yale.tools.param.OperatorParams;
import edu.udo.cs.yale.tools.xml.XML2ObjectParser;
import edu.udo.cs.yale.tools.op.OperatorSetTag;
import edu.udo.cs.yale.tools.op.OperatorTag;
import edu.udo.cs.yale.tools.xml.XMLException;

import java.io.File;
import java.io.FileReader;
import java.io.Reader;
import java.io.IOException;
import java.util.List;
import java.util.Iterator;

/** This class reads the description of the YALE operators. These descriptions are entries in a XML File like: <br>
 *  <code>
 *    &lt;operators&gt;<br>
 *    &nbsp;&nbsp;&lt;operator &gt;<br>
 *    &nbsp;&nbsp;&nbsp;&nbsp;name="longOperatorName" <br>
 *    &nbsp;&nbsp;&nbsp;&nbsp;short="shortOperatorName" <br>
 *    &nbsp;&nbsp;&nbsp;&nbsp;path="java.classpath.operator" <br> 
 *    /&gt;<br>
 *  </code><br>
 *  
 *  @author Ingo
 *  @version 01.03.2002
 */

public class OperatorService {

    /** Namen der Klassen zu den Parametern.
     */
    private static final Class[] TAG_CLASS =
    { OperatorSetTag.class, OperatorTag.class };

    /** Parameternamen in der Beschreibungsdatei.
     */
    private static final String[] TAG_NAME =
    { "operators", "operator" };


    /** XML-Parser zum Einlesen der Operatorbeschreibungsdatei. 
     */
    private static XML2ObjectParser parser;

    /** Reads an operator description file. */
    public static List readFile(Reader reader) {
	OperatorSetTag operators = null;
	parser = new XML2ObjectParser(TAG_NAME, TAG_CLASS);
	
	try {
	    List blocks = parser.parseAll(reader);
	    reader.close();

	    // bloecke durchgehen.
	    Iterator i = blocks.iterator();
	    while (i.hasNext()) {
		Object o = i.next();
		if (o instanceof OperatorSetTag) {
		    operators = (OperatorSetTag)o;
		    break;
		}
	    } 
	} catch (XMLException e) {
	    LogService.logMessage("Cannot read operator description file",
				  LogService.FATAL);
	    Yale.quit(1);
	} catch (IOException e) {
	    LogService.logMessage("Cannot read operator description file:" + e,
				  LogService.FATAL);
	    Yale.quit(1);
	}

	if (operators == null) {
	    LogService.logMessage("Operator description file corrupted!", LogService.FATAL);
	    Yale.quit(1);
	}
	return operators.getOperators();
    }


    public static void registerOperators(String name, 
					 Reader operatorsXML, 
					 ClassLoader classLoader) {
	//if (classLoader == null) classLoader = ClassLoader.getSystemClassLoader();
	if (classLoader == null) classLoader = OperatorService.class.getClassLoader();
	LogService.logMessage("Loading operators from '"+name+"'.", LogService.INIT);
	List operators = null;
	try {
	    operators = readFile(operatorsXML);
	} catch (Throwable e) {
	    LogService.logMessage("Cannot read operator description file '"+name+"': "+e, 
				  LogService.ERROR);
	    return;
	}
	try {
	    OperatorParams.registerOperators(operators, classLoader);
	} catch (Throwable e) {
	    LogService.logMessage("Cannot register operators from '"+name+"': "+e, LogService.ERROR);
	}
    }
}