/*

 * Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.lang.management.RuntimeMXBean;

import java.lang.management.ManagementFactory;

import java.util.List;

/**

 * This class provides access to the input arguments to the VM.

 */

public class InputArguments {

    private static final List<String> args;

    static {

        RuntimeMXBean runtimeMxBean = ManagementFactory.getRuntimeMXBean();

        args = runtimeMxBean.getInputArguments();

    }

    /**

     * Returns true if {@code arg} is an input argument to the VM.

     *

     * This is useful for checking boolean flags such as -XX:+UseSerialGC or

     * -XX:-UsePerfData.

     *

     * @param arg The name of the argument.

     * @return {@code true} if the given argument is an input argument,

     *         otherwise {@code false}.

     */

    public static boolean contains(String arg) {

        return args.contains(arg);

    }

    /**

     * Returns true if {@code prefix} is the start of an input argument to the

     * VM.

     *

     * This is useful for checking if flags describing a quantity, such as

     * -XX:+MaxMetaspaceSize=100m, is set without having to know the quantity.

     * To check if the flag -XX:MaxMetaspaceSize is set, use

     * {@code InputArguments.containsPrefix("-XX:MaxMetaspaceSize")}.

     *

     * @param prefix The start of the argument.

     * @return {@code true} if the given argument is the start of an input

     *         argument, otherwise {@code false}.

     */

    public static boolean containsPrefix(String prefix) {

        for (String arg : args) {

            if (arg.startsWith(prefix)) {

                return true;

            }

        }

        return false;

    }

}