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/*
 * Copyright (c) 2003, PostgreSQL Global Development Group
 * See the LICENSE file in the project root for more information.
 */

package org.postgresql.util;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 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.geometric.PGbox
 * @see org.postgresql.geometric.PGcircle
 * @see org.postgresql.geometric.PGlseg
 * @see org.postgresql.geometric.PGpath
 * @see org.postgresql.geometric.PGpoint
 * @see org.postgresql.geometric.PGpolygon
 */
public class PGtokenizer {

  private static final Map CLOSING_TO_OPENING_CHARACTER = new HashMap();

  static 	{
    CLOSING_TO_OPENING_CHARACTER.put( ')', '(');

    CLOSING_TO_OPENING_CHARACTER.put( ']', '[');

    CLOSING_TO_OPENING_CHARACTER.put( '>', '<');

    CLOSING_TO_OPENING_CHARACTER.put( '"', '"');
  }

  // Our tokens
  protected List tokens = new ArrayList();

  /**
   * 

Create a tokeniser.

* *

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 */ @SuppressWarnings("method.invocation.invalid") 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 * @return number of tokens */ public int tokenize(String string, char delim) { tokens.clear(); final Deque stack = new ArrayDeque(); // stack keeps track of the levels we are in the current token. // if stack.size 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 // (usually PGpoint) embedded within a token. // // Peter 1998 Jan 6 - Added < and > to the nesting rules int p; int s; boolean skipChar = false; boolean nestedDoubleQuote = false; char c = (char)0; for (p = 0, s = 0; p < string.length(); p++) { c = string.charAt(p); // increase nesting if an open character is found if (c == '(' || c == '[' || c == '<' || (!nestedDoubleQuote && !skipChar && c == '"')) { stack.push(c); if (c == '"') { nestedDoubleQuote = true; skipChar = true; } } // decrease nesting if a close character is found if (c == ')' || c == ']' || c == '>' || (nestedDoubleQuote && !skipChar && c == '"')) { if (c == '"') { while (!stack.isEmpty() && !Character.valueOf('"').equals(stack.peek())) { stack.pop(); } nestedDoubleQuote = false; stack.pop(); } else { final Character ch = CLOSING_TO_OPENING_CHARACTER.get(c); if (!stack.isEmpty() && ch != null && ch.equals(stack.peek())) { stack.pop(); } } } skipChar = c == '\\'; if (stack.isEmpty() && c == delim) { tokens.add(string.substring(s, p)); s = p + 1; // +1 to skip the delimiter } } // Don't forget the last token ;-) if (s < string.length()) { tokens.add(string.substring(s)); } // check for last token empty if ( s == string.length() && c == delim) { tokens.add(""); } 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 tokens.get(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.set(i, remove(tokens.get(i), l, t)); } } /** * 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. */ 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. */ 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. */ public void removeAngle() { remove("<", ">"); } /** * Removes curly braces { and } from the beginning and end of a string. * * @param s String to remove from * @return String without the { or } */ public static String removeCurlyBrace(String s) { return remove(s, "{", "}"); } /** * Removes < and > from the beginning and end of all tokens. */ public void removeCurlyBrace() { remove("{", "}"); } }




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