/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://jaxp.dev.java.net/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * https://jaxp.dev.java.net/CDDLv1.0.html
 * If applicable add the following below this CDDL HEADER
 * with the fields enclosed by brackets "[]" replaced with
 * your own identifying information: Portions Copyright
 * [year] [name of copyright owner]
 */

/*
 * $Id: FactoryFinder.java,v 1.5.2.1 2006/12/04 18:45:41 spericas Exp $
 * @(#)FactoryFinder.java	1.18 07/01/24
 *
 * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
 */

package javax.xml.transform;

import java.io.File;
import java.io.FileInputStream;

import java.util.Properties;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;

/**
 * <p>Implements pluggable Datatypes.</p>
 * 
 * <p>This class is duplicated for each JAXP subpackage so keep it in
 * sync.  It is package private for secure class loading.</p>
 *
 * @author Santiago.PericasGeertsen@sun.com
 */
class FactoryFinder {
    
    /**
     * Internal debug flag.
     */
    private static boolean debug = false;
    
    /**
     * Cache for properties in java.home/lib/jaxp.properties
     */
    static Properties cacheProps = new Properties();
    
    /**
     * Flag indicating if properties from java.home/lib/jaxp.properties 
     * have been cached.
     */
    static boolean firstTime = true;
    
    /**
     * Security support class use to check access control before
     * getting certain system resources.
     */
    static SecuritySupport ss = new SecuritySupport();

    // Define system property "jaxp.debug" to get output
    static {
        // Use try/catch block to support applets, which throws
        // SecurityException out of this code.
        try {
            String val = ss.getSystemProperty("jaxp.debug");
            // Allow simply setting the prop to turn on debug
            debug = val != null && !"false".equals(val);
        } 
        catch (SecurityException se) {
            debug = false;
        }
    }
    
    private static void dPrint(String msg) {
        if (debug) {
            System.err.println("JAXP: " + msg);
        }
    }
    
    /**
     * Attempt to load a class using the class loader supplied. If that fails
     * and fall back is enabled, the current (i.e. bootstrap) class loader is
     * tried. 
     * 
     * If the class loader supplied is <code>null</code>, first try using the
     * context class loader followed by the current (i.e. bootstrap) class
     * loader. 
     */