GeneralJSONObjectStateMacine.java

package com.firefly.utils.json.parser;

import java.io.IOException;

import com.firefly.utils.json.JsonArray;
import com.firefly.utils.json.JsonObject;
import com.firefly.utils.json.JsonReader;
import com.firefly.utils.json.exception.JsonException;

abstract public class GeneralJSONObjectStateMacine {

	public static JsonObject toJsonObject(final JsonReader reader) throws IOException {
		if(!reader.isObject()) {
			throw new JsonException("It is not a JSON object, the position is " + reader.position());
		}
		
		JsonObject map = new JsonObject();
		
		if(reader.isEmptyObject())
			return map;
		
		fieldLoop:
		while(true) {
			char[] field = reader.readChars();
			if(!reader.isColon()) {
				throw new JsonException("The error occur, near by the key \"" + String.valueOf(field) + "\", the position is " + reader.position());
			}
			
			char ch = reader.readAndSkipBlank();
			reader.decreasePosition();
			
			switch (ch) {
			case '{':
				map.put(String.valueOf(field), toJsonObject(reader));
				break;
			case '[':
				map.put(String.valueOf(field), toJsonArray(reader));
				break;
			case '"':
				map.put(String.valueOf(field), reader.readString());
				break;
			default:
				map.put(String.valueOf(field), reader.readValueAsString());
				break;
			}
			
			char fieldEndCh = reader.readAndSkipBlank();
			switch (fieldEndCh) {
			case '}':
				break fieldLoop;
			case ',':
				break;
			default:
				throw new JsonException("The error is at position " + reader.position());
			}
		}
		return map;
	}
	
	public static JsonArray toJsonArray(final JsonReader reader) throws IOException {
		if(!reader.isArray()) {
			throw new JsonException("It is not a JSON array, the position is " + reader.position());
		}
		
		JsonArray array = new JsonArray();
		if(reader.isEmptyArray())
			return array;
		
		arrayElementLoop:
		while(true) {
			char ch = reader.readAndSkipBlank();
			reader.decreasePosition();
			
			switch (ch) {
			case '{':
				array.add(toJsonObject(reader));
				break;
			case '[':
				array.add(toJsonArray(reader));
				break;
			case '"':
				array.add(reader.readString());
				break;
			default:
				array.add(reader.readValueAsString());
				break;
			}
			
			char fieldEndCh = reader.readAndSkipBlank();
			switch (fieldEndCh) {
			case ']':
				break arrayElementLoop;
			case ',':
				break;
			default:
				throw new JsonException("The error is at position " + reader.position());
			}
		}
		return array;
	}
}