minify_json.java

//
//  Minify.java
//  jsonminifier - Ported from https://github.com/getify/JSON.minify
//
//  Created by Bernhard Gass on 8/01/13.
//  Copyright © 2013 Bernhard Gass. All rights reserved.

package com.changeme.json;

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

import org.junit.Test;

public class Minify {
  
	public String minify(String jsonString) {
		String tokenizer = "\"|(/\\*)|(\\*/)|(//)|\\n|\\r";
		String magic = "(\\\\)*$";
		Boolean in_string = false;
		Boolean in_multiline_comment = false;
		Boolean in_singleline_comment = false;
		String tmp = "";
		String tmp2 = "";
		List<String> new_str = new ArrayList<String>();
		Integer from = 0;
		String lc = "";
		String rc = "";

		Pattern pattern = Pattern.compile(tokenizer);
		Matcher matcher = pattern.matcher(jsonString);
		
		Pattern magicPattern = Pattern.compile(magic);
		Matcher magicMatcher = null;
		Boolean foundMagic = false;
		
		if (!matcher.find())
			return jsonString;
		else
			matcher.reset();

		while (matcher.find()) {
			lc = jsonString.substring(0, matcher.start());
			rc = jsonString.substring(matcher.end(), jsonString.length());
			tmp = jsonString.substring(matcher.start(), matcher.end());

			if (!in_multiline_comment && !in_singleline_comment) {
				tmp2 = lc.substring(from);
				if (!in_string) 
					tmp2 = tmp2.replaceAll("(\\n|\\r|\\s)*", "");
				
				new_str.add(tmp2);
			}
			from = matcher.end();	
			
			 if (tmp.charAt(0) == '\"' && !in_multiline_comment && !in_singleline_comment) {
				 magicMatcher = magicPattern.matcher(lc);
				 foundMagic = magicMatcher.find();
				 if (!in_string || !foundMagic || (magicMatcher.end() - magicMatcher.start()) % 2 == 0) { 
					 in_string = !in_string;
				 }
				 from--; 
				 rc = jsonString.substring(from);
			 }
			 else 
			 if (tmp.startsWith("/*") && !in_string && !in_multiline_comment && !in_singleline_comment) {
				 in_multiline_comment = true;
			 }
			 else 
			 if (tmp.startsWith("*/") && !in_string && in_multiline_comment && !in_singleline_comment) {
				 in_multiline_comment = false;
			 }
			 else 
		     if (tmp.startsWith("//") && !in_string && !in_multiline_comment && !in_singleline_comment) {
		    	 in_singleline_comment = true;
			 }
			 else 
		     if ((tmp.startsWith("\n") || tmp.startsWith("\r")) && !in_string && !in_multiline_comment && in_singleline_comment) {
		    	 in_singleline_comment = false;
			 }
		     else 
		     if (!in_multiline_comment && !in_singleline_comment && !tmp.substring(0, 1).matches("\\n|\\r|\\s")) {
		    		new_str.add(tmp);
		     }
		}

		new_str.add(rc);		
		StringBuffer sb = new StringBuffer();
		for (String str : new_str)
			sb.append(str);
		
		return sb.toString();
	}
	
	@Test
	public void testMinify() {
		System.out.println("!! Assertions will only be executed if the -ea vm argument is set !!");
	
		System.out.println("Running test1...");
	    String test1 = "// this is a JSON file with comments\n" +
	    		"{\n" +
	    		"\"foo\": \"bar\",    // this is cool\n" +
	    		"\"bar\": [\n" +
	    		"\"baz\", \"bum\", \"zam\"\n" +
	    		"],\n" +
	    		"/* the rest of this document is just fluff\n" + 
	    		"in case you are interested. */\n" + 
	    		"\"something\": 10,\n" + 
	    		"\"else\": 20\n" +
	    		"}\n" +
		    	"/* NOTE: You can easily strip the whitespace and comments\n" +
		    	"   from such a file with the JSON.minify() project hosted \n"+
		    	"   here on github at http://github.com/getify/JSON.minify \n"+
		    	"*/";
	     
	    String test1_res = "{\"foo\":\"bar\",\"bar\":[\"baz\",\"bum\",\"zam\"],\"something\":10,\"else\":20}";
	    assert(minify(test1).equals(test1_res));
	    
		System.out.println("Running test2..."); 
	    String test2 = "{\"/*\":\"*/\",\"//\":\"\",/*\"//\"*/\"/*/\"://\n" +
	    		       "\"//\"}" +
			           "";
	    
	    String test2_res = "{\"/*\":\"*/\",\"//\":\"\",\"/*/\":\"//\"}";
	    assert(minify(test2).equals(test2_res));
	    
		System.out.println("Running test3...");	    
	    String test3 =  "/*\n" +
					    "this is a\n" +
					    "multi line comment */{\n" +
				        "\n" +
					    "\"foo\"\n" +
					    ":" +
					    "    \"bar/*\"// something\n" +
					    "    ,    \"b\\\"az\":/*\n" +
					    "something else */\"blah\"\n" +
				        "\n" +
					    "}";
	    
	    String test3_res = "{\"foo\":\"bar/*\",\"b\\\"az\":\"blah\"}";
	    assert(minify(test3).equals(test3_res));

		System.out.println("Running test4...");
	    String test4 = "{\"foo\": \"ba\\\"r//\", \"bar\\\\\": \"b\\\\\\\"a/*z\", \n" + 
	    	    	   "\"baz\\\\\\\\\": /*  yay */ \"fo\\\\\\\\\\\"*/o\"\n" + 
	    	    		"}"; 
	    String test4_res = "{\"foo\":\"ba\\\"r//\",\"bar\\\\\":\"b\\\\\\\"a/*z\",\"baz\\\\\\\\\":\"fo\\\\\\\\\\\"*/o\"}";
	    assert(minify(test4).equals(test4_res));

		System.out.println("Running test5...");
	    String test5 = 	"// this is a comment //\n" +
	    		"{ // another comment\n" +
	    		"   true, \"foo\", // 3rd comment\n" +
	    		"   \"http://www.ariba.com\" // comment after URL\n" +
	    		"   \n" +
	    		"}";
	    String test5_res = "{true,\"foo\",\"http://www.ariba.com\"}";
	    assert(minify(test5).equals(test5_res));
	    System.out.println(test5);
	    System.out.println(minify(test5));
	}

}