org.accada.reader.hal.ControllerProperties.java Source code

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Here is the source code for org.accada.reader.hal.ControllerProperties.java

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/*
 * Copyright (C) 2007 ETH Zurich
 *
 * This file is part of Accada (www.accada.org).
 *
 * Accada is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software Foundation.
 *
 * Accada 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Accada; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

package org.accada.reader.hal;

import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * The <code>ControllerProperties</code> class encapsulates the methods responsible for
 * the parameter setting. It can be seen as a helper class that frees the user from implementing
 * the related methods and function calls in his concrete <code>AutoIdController</code> imlementation.
 * As a convention the properties file associated with a certain reader has to be named according to its
 * class name.
 * 
 * @version 19.01.2004
 * @author Stefan Schlegel (schlstef@student.ethz.ch)
 * 
 * Modified 06.10.2004 (Roland Schneider schnerol):
 * Instead of using the class name to locate the properties file newly the reader ID defines
 * the properties file name. see new constructor. 
 * 
 */

public class ControllerProperties {

    //-------------------------------------------fields------------------------------------------//
    /** the logger */
    static private Log log = LogFactory.getLog(ControllerProperties.class);
    /** the name of the properties file */
    private String propsFile = null;

    //-------------------------------------------constructors--------------------------------------//   

    public ControllerProperties(String readerId) {
        this.propsFile = readerId + "Properties.properties";
        log.debug("PropertiesFile:  " + propsFile);

    }

    //---------------------------------------------methods--------------------------------------------//   

    /**
     * Gets the parameter with the specified name from the appropriate properties file.
     * 
     * @param param parameter name.
     * @return the value of the parameter.
     * @throws Exception.
     */
    public String getParameter(String param) throws Exception {
        String value = null;
        InputStream in;
        Properties props = new Properties();
        log.debug("Trying to get Parameter " + param + " from file " + propsFile);

        //possible Errors are propageted and further processed as HardwareExceptions
        in = this.getClass().getResourceAsStream("/props/" + propsFile);
        if (in == null) {
            log.debug("Properties-File not found.");
            throw new IOException("Properties file not found.");
        }
        //possible Errors are propageted and further processed as HardwareExceptions      
        props.load(in);
        in.close();

        if (props.containsKey(param)) {
            value = props.getProperty(param);
            log.debug("Property found: " + param + " = " + value);
            return value;
        } else {
            String message = "Property not found: " + param;
            log.debug(message);
            throw new Exception(message);
        }
    }

    /**
     * Sets the specified parameter.
     * 
     * @param param The parameter that has to be set.
     * @param value The new value for the parameter.
     */
    public void setParameter(String param, String value) {
        /* Mit dieser Implemetation werden alle Kommentare im File berschrieben.
             
        Properties propertyFile = new Properties();
        InputStream input = null;
        OutputStream output = null;
            
        try{
           input = new FileInputStream("./props/"+propsFile);
           propertyFile.load(input);
           input.close();
           if (propertyFile.containsKey(param)){
        output = new FileOutputStream("./props/"+propsFile);
        propertyFile.setProperty(param,value);
        propertyFile.store(output,null);
        output.close();
           }
           else {
        String message ="Unkown Parameter: "+ param + ". Value: "+value+ " not set." 
        log.debug(message);
        throw new Exception(message);
           }
        }catch(IOException ex){
           ex.printStackTrace();
           throw new Exception(ex.getMessage());
        }
        */
    }

    /**
     * Gets the names of the configurable parameters.
     * 
     * @return The parameter names.
     * 
     * @throws Exception
     */
    public String[] getParameterNames() throws Exception {
        String[] names = null;
        InputStream in;
        Properties props = new Properties();
        log.debug("Trying to get Parameters");

        //possible Errors are propageted and further processed as HardwareExceptions
        in = this.getClass().getResourceAsStream("/props/" + propsFile);
        //possible Errors are propageted and further processed as HardwareExceptions
        props.load(in);
        in.close();
        Enumeration propNames = props.propertyNames();
        names = new String[props.size()];
        int i = 0;
        while (propNames.hasMoreElements()) {
            names[i] = (String) propNames.nextElement();
            i++;
        }
        return names;
    }
}