HSQLDB example source code file (MainInvoker.java)

This example HSQLDB source code file (MainInvoker.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - HSQLDB tags/keywords

arraylist, arraylist, class, classnotfoundexception, illegalaccessexception, ls, ls, nosuchmethodexception, note, or\n, reflection, string, string, syntax_msg, syntax_msg, util

The HSQLDB MainInvoker.java source code

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions 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 the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.util;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;

/**
 * Invokes the static main(String[]) method from each class specified.
 *
 * This class <b>will System.exit() if any invocation fails.
 *
 * @author Blaine Simpson (blaine dot simpson at admc dot com)
 * @since    HSQLDB 1.8.0
 * @version  $Revision: 766 $, $Date: 2009-01-12 02:12:17 +0000 (Mon, 12 Jan 2009) $
 */
public class MainInvoker {

    /*
     * This class currently consists of just a static utility.
     * It may or may not make sense to make this into a class with real
     * instances that can keep track of status of stuff invoked by it.
     */
    private static String[] emptyStringArray = new String[0];

    private static void syntaxFailure() {
        System.err.println(SYNTAX_MSG);
        System.exit(2);
    }

    /**
     * Invokes the static main(String[]) method from each specified class.
     * This method <b>will System.exit() if any invocation fails.
     *
     * Note that multiple class invocations are delimited by empty-string
     * parameters.  How the user supplies these empty strings is determined
     * entirely by the caller's environment.  From Windows this can
     * generally be accomplished with double-quotes like "".  From all
     * popular UNIX shells, this can be accomplished with single or
     * double-quotes:  '' or "".
     *
     * @param sa Run java org.hsqldb.util.MainInvoker --help for syntax help
     */
    public static void main(String[] sa) {

        if (sa.length > 0 && sa[0].equals("--help")) {
            System.err.println(SYNTAX_MSG);
            System.exit(0);
        }

        ArrayList outList  = new ArrayList();
        int       curInArg = -1;

        try {
            while (++curInArg < sa.length) {
                if (sa[curInArg].length() < 1) {
                    if (outList.size() < 1) {
                        syntaxFailure();
                    }

                    invoke((String) outList.remove(0),
                           (String[]) outList.toArray(emptyStringArray));
                    outList.clear();
                } else {
                    outList.add(sa[curInArg]);
                }
            }

            if (outList.size() < 1) {
                syntaxFailure();
            }

            invoke((String) outList.remove(0),
                   (String[]) outList.toArray(emptyStringArray));
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    public static String LS = System.getProperty("line.separator");
    private static String SYNTAX_MSG =
        "    java org.hsqldb.util.MainInvoker "
        + "[package1.Class1 [arg1a arg1b...] \"\"]... \\\n"
        + "    packageX.ClassX [argXa argXb...]\n" + "OR\n"
        + "    java org.hsqldb.util.MainInvoker --help\n\n"
        + "Note that you can only invoke classes in 'named' (non-default) "
        + "packages.  Delimit multiple classes with empty strings.";
    static {
        if (!LS.equals("\n")) {
            SYNTAX_MSG = SYNTAX_MSG.replaceAll("\n", LS);
        }
    }

    /**
     * Invokes the static main(String[]) method from each specified class.
     */
    public static void invoke(String className,
                              String[] args)
                              throws ClassNotFoundException,
                                     NoSuchMethodException,
                                     IllegalAccessException,
                                     InvocationTargetException {

        Class    c;
        Method   method;
        Class[]  stringArrayCA = { emptyStringArray.getClass() };
        Object[] objectArray   = { (args == null) ? emptyStringArray
                                                  : args };

        c      = Class.forName(className);
        method = c.getMethod("main", stringArrayCA);

        method.invoke(null, objectArray);

        //System.err.println(c.getName() + ".main() invoked");
    }
}