/*

 * Copyright (c) 2009, 2015, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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

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 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * The MIT License

 *

 * Copyright (c) 2004-2014 Paul R. Holser, Jr.

 *

 * Permission is hereby granted, free of charge, to any person obtaining

 * a copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Software, and to

 * permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be

 * included in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

package jdk.internal.joptsimple.util;

import static jdk.internal.joptsimple.internal.Strings.*;

/**

 * <p>A simple string key/string value pair.</p>

 *

 * <p>This is useful as an argument type for options whose values take on the form <kbd>key=value</kbd>, such as JVM

 * command line system properties.</p>

 *

 * @author <a href="mailto:pholser@alumni.rice.edu">Paul Holser</a>

 */

public final class KeyValuePair {

    public final String key;

    public final String value;

    private KeyValuePair( String key, String value ) {

        this.key = key;

        this.value = value;

    }

    /**

     * Parses a string assumed to be of the form <kbd>key=value</kbd> into its parts.

     *

     * @param asString key-value string

     * @return a key-value pair

     * @throws NullPointerException if {@code stringRepresentation} is {@code null}

     */

    public static KeyValuePair valueOf( String asString ) {

        int equalsIndex = asString.indexOf( '=' );

        if ( equalsIndex == -1 )

            return new KeyValuePair( asString, EMPTY );

        String aKey = asString.substring( 0, equalsIndex );

        String aValue = equalsIndex == asString.length() - 1 ? EMPTY : asString.substring( equalsIndex + 1 );

        return new KeyValuePair( aKey, aValue );

    }

    @Override

    public boolean equals( Object that ) {

        if ( !( that instanceof KeyValuePair ) )

            return false;

        KeyValuePair other = (KeyValuePair) that;

        return key.equals( other.key ) && value.equals( other.value );

    }

    @Override

    public int hashCode() {

        return key.hashCode() ^ value.hashCode();

    }

    @Override

    public String toString() {

        return key + '=' + value;

    }

}