PatternReplace.java

package net.blerg.oracleToMysql.util;

import java.util.LinkedList;
import java.util.List;

public class PatternReplace {
	
	public static String replace (String string, String pattern, String replacement, char wildcard, char escapeChar, boolean ignoreCase) {
		
		//tokenise against the pattern
		List<String> tokenisedPattern = tokenise(pattern, wildcard, escapeChar, true);
		List<String> tokenisedReplacement = tokenise(replacement,wildcard,escapeChar,true);
		
		List<String> replacements = replacements(string, tokenisedPattern, wildcard);
		
		return replaceTokens(tokenisedReplacement, replacements, wildcard);
	}
	
	private static String replaceTokens(List<String> tokenisedReplacement,List<String> replacements,char wildcard) {
		StringBuffer result = new StringBuffer();
		int i=0;
		
		for (String replacementPattern:tokenisedReplacement) {
			if (replacementPattern.equals(String.valueOf(wildcard)) && replacements.size()>i) {
				result.append(replacements.get(i));
				i++;
			}else {
				result.append(replacementPattern);
			}
		}
		
		return result.toString();
	}
	
	private static List<String> replacements(String string,List<String> pattern, char wildcard){
		return replacements(string, pattern, wildcard, new LinkedList<String>());
	}
	
	private static List<String> replacements(String string,List<String> pattern, char wildcard, List<String> replacements){
		
		if (pattern.size()>0 && string.length()>0) {
			String patternElement = pattern.get(0);
			if (patternElement.equals(String.valueOf(wildcard))) {
				if (pattern.size()>1) {
					int index = string.indexOf(pattern.get(1));
					replacements.add(string.substring(0,index));
					string = string.substring(index);
				} else {
					replacements.add(string);
					string="";
				}
			}else if (patternElement.equals(string.substring(0,patternElement.length()))) {
				string=string.substring(patternElement.length());
			} else {
				throw new IllegalArgumentException();
			}
			
			pattern=pattern.subList(1, pattern.size());
			
			replacements = replacements(string,pattern,wildcard,replacements);
		}
		

		return replacements;
	}
	
	private static List<String> tokenise(String string, char splitOn, char escapeChar, boolean includeSplitCharAsToken){
		List<String> tokenised = new LinkedList<>();
		StringBuffer sb = new StringBuffer();
		boolean escape = false;
		
		for (char c:string.toCharArray()) {
			if (c==splitOn && !escape) {
				//split here
				if (sb.length()>0) {
					tokenised.add(sb.toString());
					sb=new StringBuffer();
				}
				if(includeSplitCharAsToken) {
					tokenised.add(String.valueOf(splitOn));
				}
			} else if(c==escapeChar){
				escape = true;
			} else {
				sb.append(c);
			}
		}
		
		if (sb.length()>0) {
			tokenised.add(sb.toString());
		}
		
		return tokenised;
	}
	
}