PGtokenizer.java

/*****************************************************************************
 * Copyright (C) 2008 EnterpriseDB Corporation.
 * Copyright (C) 2011 Stado Global Development Group.
 *
 * This file is part of Stado.
 *
 * Stado 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.
 *
 * Stado 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 Stado.  If not, see <http://www.gnu.org/licenses/>.
 *
 * You can find Stado at http://www.stado.us
 *
 ****************************************************************************/
package org.postgresql.driver.util;

import java.util.Vector;

/**
 * This class is used to tokenize the text output of org.postgres.
 * It's mainly used by the geometric classes, but is useful in parsing any
 * output from custom data types output from org.postgresql.
 *
 * @see org.postgresql.driver.geometric.PGbox
 * @see org.postgresql.driver.geometric.PGcircle
 * @see org.postgresql.driver.geometric.PGlseg
 * @see org.postgresql.driver.geometric.PGpath
 * @see org.postgresql.driver.geometric.PGpoint
 * @see org.postgresql.driver.geometric.PGpolygon
 */
public class PGtokenizer
{
    // Our tokens
    protected Vector tokens;

    /*
     * Create a tokeniser.
     *
     * <p>We could have used StringTokenizer to do this, however, we needed to
     * handle nesting of '(' ')' '[' ']' '<' and '>' as these are used
     * by the geometric data types.
     *
     * @param string containing tokens
     * @param delim single character to split the tokens
     */
    public PGtokenizer(String string, char delim)
    {
        tokenize(string, delim);
    }

    /*
     * This resets this tokenizer with a new string and/or delimiter.
     *
     * @param string containing tokens
     * @param delim single character to split the tokens
     */
    public int tokenize(String string, char delim)
    {
        tokens = new Vector();

        // nest holds how many levels we are in the current token.
        // if this is > 0 then we don't split a token when delim is matched.
        //
        // The Geometric datatypes use this, because often a type may have others
        // (usualls PGpoint) imbedded within a token.
        //
        // Peter 1998 Jan 6 - Added < and > to the nesting rules
        int nest = 0, p, s;

        for (p = 0, s = 0;p < string.length();p++)
        {
            char c = string.charAt(p);

            // increase nesting if an open character is found
            if (c == '(' || c == '[' || c == '<')
                nest++;

            // decrease nesting if a close character is found
            if (c == ')' || c == ']' || c == '>')
                nest--;

            if (nest == 0 && c == delim)
            {
                tokens.addElement(string.substring(s, p));
                s = p + 1; // +1 to skip the delimiter
            }

        }

        // Don't forget the last token ;-)



        if (s < string.length())
            tokens.addElement(string.substring(s));

        return tokens.size();
    }

    /*
     * @return the number of tokens available
     */
    public int getSize()
    {
        return tokens.size();
    }

    /*
     * @param n Token number ( 0 ... getSize()-1 )
     * @return The token value
     */
    public String getToken(int n)
    {
        return (String)tokens.elementAt(n);
    }

    /*
     * This returns a new tokenizer based on one of our tokens.
     *
     * The geometric datatypes use this to process nested tokens (usually
     * PGpoint).
     *
     * @param n Token number ( 0 ... getSize()-1 )
     * @param delim The delimiter to use
     * @return A new instance of PGtokenizer based on the token
     */
    public PGtokenizer tokenizeToken(int n, char delim)
    {
        return new PGtokenizer(getToken(n), delim);
    }

    /*
     * This removes the lead/trailing strings from a string
     * @param s Source string
     * @param l Leading string to remove
     * @param t Trailing string to remove
     * @return String without the lead/trailing strings
     */
    public static String remove
        (String s, String l, String t)
    {
        if (s.startsWith(l))
            s = s.substring(l.length());
        if (s.endsWith(t))
            s = s.substring(0, s.length() - t.length());
        return s;
    }

    /*
     * This removes the lead/trailing strings from all tokens
     * @param l Leading string to remove
     * @param t Trailing string to remove
     */
    public void remove
        (String l, String t)
    {
        for (int i = 0;i < tokens.size();i++)
        {
            tokens.setElementAt(remove
                                ((String)tokens.elementAt(i), l, t), i);
        }
    }

    /*
     * Removes ( and ) from the beginning and end of a string
     * @param s String to remove from
     * @return String without the ( or )
     */
    public static String removePara(String s)
    {
        return remove
                   (s, "(", ")");
    }

    /*
     * Removes ( and ) from the beginning and end of all tokens
     * @return String without the ( or )
     */
    public void removePara()
    {
        remove
            ("(", ")");
    }

    /*
     * Removes [ and ] from the beginning and end of a string
     * @param s String to remove from
     * @return String without the [ or ]
     */
    public static String removeBox(String s)
    {
        return remove
                   (s, "[", "]");
    }

    /*
     * Removes [ and ] from the beginning and end of all tokens
     * @return String without the [ or ]
     */
    public void removeBox()
    {
        remove
            ("[", "]");
    }

    /*
     * Removes < and > from the beginning and end of a string
     * @param s String to remove from
     * @return String without the < or >
     */
    public static String removeAngle(String s)
    {
        return remove
                   (s, "<", ">");
    }

    /*
     * Removes < and > from the beginning and end of all tokens
     * @return String without the < or >
     */
    public void removeAngle()
    {
        remove
            ("<", ">");
    }
}