source: other-projects/trunk/gs3-webservices-democlient/CheckJavaVersion.java@ 15224

public class CheckJavaVersion {
    static final String MINIMUM_VERSION_PREFIX = "1.4";
    
    /**
     * @param args, arg[0] is the minium version of Java required
     * to run the program. arg[1] is the name of the program.
     * If arg[1] is left out, then no distinct program name is
     * mentioned. If arg[0] is left out as well, then Greenstone3's
     * minimum default version of 1.4.x is assumed.
     * The program exits with -1 if the Java version being used is 
     * incompatible and with 0 if it is acceptable.
     */
    public static void main(String[] args) {
        String minimumVersion = MINIMUM_VERSION_PREFIX;
        String programName = "this program"; 
        // the version of java that's in use
        String installedJavaVersion = System.getProperty("java.version");
        
        if(args.length > 0) {
            minimumVersion = args[0];
        }
        if(args.length > 1) {
            programName = args[1];
        }
        
        System.out.println("\nChecking for a compatible Java version..."
                + "\nLooking for minimum version " + minimumVersion + ".x");
        
        if(installedJavaVersion.compareTo(minimumVersion) < 0) {
            System.out.println(
                "The current Java version " 
                + installedJavaVersion 
                + " is insufficient to run " 
                + programName
            );
            System.exit(-1);
        } else {
            System.out.println("Found compatible Java version " 
                    + installedJavaVersion);
            System.exit(0);
        }
    }

}