PackageUtil.java

/*
 * $RCSfile: PackageUtil.java,v $
 *
 * 
 * Copyright (c) 2005 Sun Microsystems, Inc. All  Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met: 
 * 
 * - Redistribution of source code must retain the above copyright 
 *   notice, this  list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in 
 *   the documentation and/or other materials provided with the
 *   distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
 * EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL 
 * NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF 
 * USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR 
 * ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL,
 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
 * INABILITY TO USE THIS SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES. 
 * 
 * You acknowledge that this software is not designed or intended for 
 * use in the design, construction, operation or maintenance of any 
 * nuclear facility. 
 *
 * $Revision: 1.3 $
 * $Date: 2006/03/31 19:43:38 $
 * $State: Exp $
 */
package com.github.jaiimageio.impl.common;

import java.security.AccessController;
import java.security.PrivilegedAction;
//import com.sun.medialib.codec.jiio.Util;

public class PackageUtil {
    /**
     * Flag indicating whether codecLib is available.
     */
    private static boolean isCodecLibAvailable = false;

    /**
     * Implementation version derived from Manifest.
     */
    private static String version = "1.0";

    /**
     * Implementation vendor derived from Manifest.
     */
    private static String vendor = "Sun Microsystems, Inc.";

    /**
     * Specification Title derived from Manifest.
     */
    private static String specTitle = "Java Advanced Imaging Image I/O Tools";

    /**
     * Set static flags.
     */
    static {
        // Set codecLib flag.
//        try {
//            // Check for codecLib availability.
//            isCodecLibAvailable = Util.isCodecLibAvailable();
//        } catch(Throwable e) {
            // A Throwable is equivalent to unavailable. Throwable is used
            // in case an Error rather than an Exception is thrown.
            isCodecLibAvailable = false;
//        }

        // Set version and vendor strings.
        try {
            Class thisClass =
                Class.forName("com.github.jaiimageio.impl.common.PackageUtil");
            Package thisPackage = thisClass.getPackage();
            if (thisPackage.getImplementationVersion()!= null && thisPackage.getImplementationVendor() != null) {
            	version = thisPackage.getImplementationVersion();
            	vendor = thisPackage.getImplementationVendor();
            	specTitle = thisPackage.getSpecificationTitle();
            }
        } catch(ClassNotFoundException e) {
        }
    }

    /**
     * Returns a <code>boolean</code> indicating whether codecLib is available.
     */
    public static final boolean isCodecLibAvailable() {
        // Retrieve value of system property here to allow this to be
        // modified dynamically.
        Boolean result = (Boolean)
            AccessController.doPrivileged(new PrivilegedAction() {
                    public Object run() {
                        String property = null;
                        try {
                            property =
                                System.getProperty("com.github.jaiimageio.disableCodecLib");
                        } catch(SecurityException se) {
                            // Do nothing: leave 'property' null.
                        }
                        return (property != null &&
                                property.equalsIgnoreCase("true")) ?
                            Boolean.TRUE : Boolean.FALSE;
                    }
                });
        boolean isCodecLibDisabled = result.booleanValue();

        return isCodecLibAvailable && !isCodecLibDisabled;
    }

    /**
     * Return a version string for the package.
     */
    public static final String getVersion() {
        return version;
    }

    /**
     * Return a vendor string for the package.
     */
    public static final String getVendor() {
        return vendor;
    }

    /**
     * Return the Specification Title string for the package.
     */
    public static final String getSpecificationTitle() {
        return specTitle;
    }
}