com.itextpdf.text.pdf.ArrayBasedStringTokenizer Maven / Gradle / Ivy

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/*
 * $Id: 9922102629e674a5d80ddf8a3cbee30ca9735e92 $
 *
 * This file is part of the iText (R) project.
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 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
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 * following permission added to Section 15 as permitted in Section 7(a):
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package com.itextpdf.text.pdf;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Tokenizes the given text based on a given array of Strings. On assembling the output array, 
 * you should be able to get back the original text.
 * 
 * @author Palash Ray
 * 
 */
public class ArrayBasedStringTokenizer {
    
    private final Pattern regex;
    
    public ArrayBasedStringTokenizer(String[] tokens) {
        this.regex = Pattern.compile(getRegexFromTokens(tokens));
    }
    
    public String[] tokenize(String text) {
        
        List tokens = new ArrayList();
        
        Matcher matcher = regex.matcher(text);
        
        int endIndexOfpreviousMatch = 0;
        
        while (matcher.find()) {
            
            int startIndexOfMatch = matcher.start();
            
            String previousToken = text.substring(endIndexOfpreviousMatch, startIndexOfMatch);
            
            if (previousToken.length() > 0) {
                tokens.add(previousToken);
            }
            
            String currentMatch = matcher.group();
            
//            System.out.println("currentMatch=" + currentMatch); 
            
            tokens.add(currentMatch);
            
            endIndexOfpreviousMatch = matcher.end();
            
        }
        
        String tail = text.substring(endIndexOfpreviousMatch, text.length());
        
        if (tail.length() > 0) {
            tokens.add(tail);
        }
        
        return tokens.toArray(new String[0]);
        
    }
    
    private String getRegexFromTokens(String[] tokens) {
        StringBuilder regexBuilder = new StringBuilder(100);
        
        for (String token : tokens) {
            regexBuilder.append("(").append(token).append(")|");
        }
        
        regexBuilder.setLength(regexBuilder.length() - 1); 
        
        String regex = regexBuilder.toString();
        
        return regex;
    }

}