/*

 * Copyright (c) 1999, 2008, 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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 */

package java.util.regex;

/**

 * Unchecked exception thrown to indicate a syntax error in a

 * regular-expression pattern.

 *

 * @author  unascribed

 * @since 1.4

 * @spec JSR-51

 */

public class PatternSyntaxException

    extends IllegalArgumentException

{

    private static final long serialVersionUID = -3864639126226059218L;

    private final String desc;

    private final String pattern;

    private final int index;

    /**

     * Constructs a new instance of this class.

     *

     * @param  desc

     *         A description of the error

     *

     * @param  regex

     *         The erroneous pattern

     *

     * @param  index

     *         The approximate index in the pattern of the error,

     *         or <tt>-1</tt> if the index is not known

     */

    public PatternSyntaxException(String desc, String regex, int index) {

        this.desc = desc;

        this.pattern = regex;

        this.index = index;

    }

    /**

     * Retrieves the error index.

     *

     * @return  The approximate index in the pattern of the error,

     *         or <tt>-1</tt> if the index is not known

     */

    public int getIndex() {

        return index;

    }

    /**

     * Retrieves the description of the error.

     *

     * @return  The description of the error

     */

    public String getDescription() {

        return desc;

    }

    /**

     * Retrieves the erroneous regular-expression pattern.

     *

     * @return  The erroneous pattern

     */

    public String getPattern() {

        return pattern;

    }

    private static final String nl = System.lineSeparator();

    /**

     * Returns a multi-line string containing the description of the syntax

     * error and its index, the erroneous regular-expression pattern, and a

     * visual indication of the error index within the pattern.

     *

     * @return  The full detail message

     */

    public String getMessage() {

        StringBuffer sb = new StringBuffer();

        sb.append(desc);

        if (index >= 0) {

            sb.append(" near index ");

            sb.append(index);

        }

        sb.append(nl);

        sb.append(pattern);

        if (index >= 0) {

            sb.append(nl);

            for (int i = 0; i < index; i++) sb.append(' ');

            sb.append('^');

        }

        return sb.toString();

    }

}