Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2013 gvSIG Association.

 *

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

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 3

 * of the License, or (at your option) any later version.

 *

 * This program 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 for more details.

 *

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

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.utils.console.jedit;

/*

 * KeywordMap.java - Fast keyword->id map

 * Copyright (C) 1998, 1999 Slava Pestov

 * Copyright (C) 1999 Mike Dillon

 *

 * You may use and modify this package for any purpose. Redistribution is

 * permitted, in both source and binary form, provided that this notice

 * remains intact in all source distributions of this package.

 */

import javax.swing.text.Segment;

/**

 * A <code>KeywordMap</code> is similar to a hashtable in that it maps keys

 * to values. However, the `keys' are Swing segments. This allows lookups of

 * text substrings without the overhead of creating a new string object.

 * <p>

 * This class is used by <code>CTokenMarker</code> to map keywords to ids.

 *

 * @author Slava Pestov, Mike Dillon

 * @version $Id$

 */

public class KeywordMap

{

        /**

         * Creates a new <code>KeywordMap</code>.

         * @param ignoreCase True if keys are case insensitive

         */

        public KeywordMap(boolean ignoreCase)

        {

                this(ignoreCase, 52);

                this.ignoreCase = ignoreCase;

        }

        /**

         * Creates a new <code>KeywordMap</code>.

         * @param ignoreCase True if the keys are case insensitive

         * @param mapLength The number of `buckets' to create.

         * A value of 52 will give good performance for most maps.

         */

        public KeywordMap(boolean ignoreCase, int mapLength)

        {

                this.mapLength = mapLength;

                this.ignoreCase = ignoreCase;

                map = new Keyword[mapLength];

        }

        /**

         * Looks up a key.

         * @param text The text segment

         * @param offset The offset of the substring within the text segment

         * @param length The length of the substring

         */

        public byte lookup(Segment text, int offset, int length)

        {

                if(length == 0)

                        return Token.NULL;

                Keyword k = map[getSegmentMapKey(text, offset, length)];

                while(k != null)

                {

                        if(length != k.keyword.length)

                        {

                                k = k.next;

                                continue;

                        }

                        if(SyntaxUtilities.regionMatches(ignoreCase,text,offset,

                                k.keyword))

                                return k.id;

                        k = k.next;

                }

                return Token.NULL;

        }

        /**

         * Adds a key-value mapping.

         * @param keyword The key

         * @Param id The value

         */

        public void add(String keyword, byte id)

        {

                int key = getStringMapKey(keyword);

                map[key] = new Keyword(keyword.toCharArray(),id,map[key]);

        }

        /**

         * Returns true if the keyword map is set to be case insensitive,

         * false otherwise.

         */

        public boolean getIgnoreCase()

        {

                return ignoreCase;

        }

        /**

         * Sets if the keyword map should be case insensitive.

         * @param ignoreCase True if the keyword map should be case

         * insensitive, false otherwise

         */

        public void setIgnoreCase(boolean ignoreCase)

        {

                this.ignoreCase = ignoreCase;

        }

        // protected members

        protected int mapLength;

        protected int getStringMapKey(String s)

        {

                return (Character.toUpperCase(s.charAt(0)) +

                                Character.toUpperCase(s.charAt(s.length()-1)))

                                % mapLength;

        }

        protected int getSegmentMapKey(Segment s, int off, int len)

        {

                return (Character.toUpperCase(s.array[off]) +

                                Character.toUpperCase(s.array[off + len - 1]))

                                % mapLength;

        }

        // private members

        class Keyword

        {

                public Keyword(char[] keyword, byte id, Keyword next)

                {

                        this.keyword = keyword;

                        this.id = id;

                        this.next = next;

                }

                public char[] keyword;

                public byte id;

                public Keyword next;

        }

        private Keyword[] map;

        private boolean ignoreCase;

}