package javaforce;

/**

*

* JSON parser (JavaScript Object Notation)

*

* https://en.wikipedia.org/wiki/JSON

*

* Does NOT Support multi-dimension arrays.

*

*/

import java.util.*;

import java.io.*;

/*

example:

{

"key": "value",

"key2" : ["v1", "v2"],

"key3" : {

"key" : "value",

"etc" : "value"

}

"key4" : [ "v1", "v2" ],

"key5" : [ { "t1": "v1"}, {"t2": "v2", "t2b": "v2b"}]

}

*/

public class JSON {

public static boolean debug = false;

public static class Element {

public String key;

public String value;

public ArrayList<Element> children = new ArrayList<Element>();

public Element getChild(String name) {

for(Element child : children) {

if (child.key.equals(name)) {

return child;

}

}

if (debug) JFLog.log("JSON:Child not found:" + name);

return null;

}

public Element getChild(int idx) {

return children.get(idx);

}

public int getChildCount() {

return children.size();

}

public String toString() {

StringBuilder sb = new StringBuilder();

sb.append("{");

sb.append(key + "=" + value);

if (children.size() > 0) {

sb.append("[");

boolean first = true;

for(Element child : children) {

if (first) {

first = false;

} else {

sb.append(",");

}

sb.append(child.toString());

}

sb.append("]");

}

sb.append("}\r\n");

return sb.toString();

}

public void print() {

System.out.println(toString());

}

}

/** Parses a JSON string. */

public static Element parse(String str) throws Exception {

Element root = new Element();

root.key = "root";

JSON json = new JSON();

json.json = str.trim().toCharArray();

json.len = json.json.length;

json.readElement(root);

return root;

}

/** Parses a JSON string from InputStream. */

public static Element parseStream(InputStream is) throws Exception {

try {

byte[] data = is.readAllBytes();

return parse(new String(data, "UTF-8"));

} catch (Exception e) {

JFLog.log(e);

return null;

}

}

/** Parses a JSON string from a File. */

public static Element parseFile(String file) throws Exception {

try {

FileInputStream fis = new FileInputStream(file);

Element root = parseStream(fis);

fis.close();

return root;

} catch (Exception e) {

JFLog.log(e);

return null;

}

}

private char[] json;

private int len;

private int pos;

private void trim() {

while (pos < len && Character.isWhitespace(json[pos])) {

pos++;

}

}

private void readKey(Element e) throws Exception {

if (debug) JFLog.log("readKey:pos=" + pos);

boolean quote = false;

e.key = "";

while (true) {

char ch = json[pos++];

if (ch == '\"') {

if (quote) {

quote = false;

} else {

if (e.key.length() > 0) throw new Exception("bad key name:" + e.key + ":pos=" + pos);

quote = true;

}

continue;

}

if (quote) {

e.key += ch;

} else {

switch (ch) {

case ' ':

case '\r':

case '\n':

case '\t':

case ',':

if (e.key.length() > 0) return;

break;

case '}':

pos--;

return;

case ':':

if (e.key.length() == 0) throw new Exception("no key name:pos=" + pos);

pos--;

return;

case '{':

case '[':

case ']':

throw new Exception("bad key name:" + ch + ":" + e.key + ":pos=" + pos);

default:

e.key += ch;

}

}

}

}

private void readArray(Element parent) throws Exception {

if (debug) JFLog.log("readArray [");

char open = readToken();

if (open != '[') {

throw new Exception("bad array:pos=" + pos);

}

while (true) {

trim();

char ch = json[pos];

if (ch == ']') break;

Element child = new Element();

child.key = "";

readValue(child, true);

if ((child.value.length() > 0) || (child.children.size() > 0)) {

if (child.value.length() > 0) {

if (debug) JFLog.log("value=" + child.value);

}

parent.children.add(child);

}

char next = readToken();

if (next == ']') break;

if (next == ',') continue;

throw new Exception("bad array:pos=" + pos);

}

if (debug) JFLog.log("] //end of array");

}

private void readValue(Element e, boolean array) throws Exception {

if (debug) JFLog.log("readValue:array=" + array + ":pos=" + pos);

boolean quote = false, escape = false;

e.value = "";

while (true) {

if (!quote) trim();

char ch = json[pos++];

if ((ch == '\"') && (!escape)) {

if (quote) {

return;

} else {

if (e.value.length() > 0) throw new Exception("bad value:pos=" + pos);

quote = true;

}

continue;

}

if ((ch == '\\') && (!escape)) {

escape = true;

continue;

}

if (quote) {

if (escape) {

switch (ch) {

case 'n': e.value += "\n"; break;

case 'r': e.value += "\r"; break;

case 't': e.value += "\t"; break;

case 'b': e.value += "\b"; break;

case 'f': e.value += "\f"; break;

default: e.value += ch; break;

}

escape = false;

} else {

e.value += ch;

}

} else {

switch (ch) {

case ',':

pos--;

return;

case ':':

if (e.value.length() > 0) throw new Exception("bad value:pos=" + pos);

break;

case '{':

if (e.value.length() > 0) throw new Exception("bad value:pos=" + pos);

pos--;

readElement(e);

return;

case '}':

if (array) throw new Exception("bad array:pos=" + pos);

pos--;

return;

case '[':

if (e.value.length() > 0) throw new Exception("bad value:pos=" + pos);

pos--;

readArray(e);

return;

case ']':

if (!array) throw new Exception("bad array:pos=" + pos);

pos--;

return;

default: {

if (escape) {

switch (ch) {

case 'n': e.value += "\n"; break;

case 'r': e.value += "\r"; break;

case 't': e.value += "\t"; break;

case 'b': e.value += "\b"; break;

case 'f': e.value += "\f"; break;

default: e.value += ch; break;

}

escape = false;

} else {

e.value += ch;

}

}

}

}

}

}

private char readToken() throws Exception {

trim();

return json[pos++];

}

private void readElement(Element e) throws Exception {

//str = { ... }

if (debug) JFLog.log("readElement {");

char open = readToken();

if (open != '{') {

throw new Exception("bad element:pos=" + pos);

}

while (pos < len) {

trim();

char ch = json[pos];

if (ch == '}') break;

Element child = new Element();

readKey(child);

if (debug) JFLog.log("key=" + child.key);

char eq = readToken();

if (eq != ':') {

throw new Exception("bad element:pos=" + pos);

}

readValue(child, false);

if (debug) JFLog.log("value=" + child.value);

e.children.add(child);

char next = readToken();

if (next == '}') break;

if (next == ',') continue;

throw new Exception("bad element:next=" + next + ":pos=" + pos);

}

if (debug) JFLog.log("} //end of element");

}

/** Escape string to valid json text. */

public static String escape(String in) {

if (in == null) return "null";

StringBuilder sb = new StringBuilder();

char ca[] = in.toCharArray();

for(char ch : ca) {

if (ch < ' ') {

sb.append(String.format("\\u%04x", (int)ch)); //UTF-16

} else if (ch == '"') {

sb.append("\\\"");

} else if (ch == '\\') {

sb.append("\\\\");

} else {

sb.append(ch);

}

}

return sb.toString();

}

/* //remove JSON to XML support for now

public static XML toXML(Element e) {

XML xml = new XML();

xml.root.setName(e.key);

xml.root.setContent(e.value);

addXML(e, xml, xml.root);

return xml;

}

private static void addXML(Element e, XML xml, XML.XMLTag tag) {

for(int a=0;a<e.children.size();a++) {

Element c = e.children.get(a);

XML.XMLTag child = xml.addTag(tag, c.key, "", c.value);

addXML(c, xml, child);

}

}

*/

public static void main(String[] args) {

try {

if (args.length > 1) {

if (args[1].equals("debug")) {

JSON.debug = true;

}

}

Element test = JSON.parseFile(args[0]);

test.print();

} catch (Exception e) {

JFLog.log(e);

}

}

}