com.ovea.tajin.json.JSONParser Maven / Gradle / Ivy
/**
* Copyright (C) 2011 Ovea
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.ovea.tajin.json;
import java.io.IOException;
import java.io.Reader;
import java.util.LinkedList;
/**
* @author Mathieu Carbou ([email protected])
*/
final class JSONParser {
public static final int S_INIT = 0;
public static final int S_IN_FINISHED_VALUE = 1;//string,number,boolean,null,object,array
public static final int S_IN_OBJECT = 2;
public static final int S_IN_ARRAY = 3;
public static final int S_PASSED_PAIR_KEY = 4;
public static final int S_IN_ERROR = -1;
private LinkedList statusStack = new LinkedList<>();
private LinkedList valueStack = new LinkedList<>();
private Yylex lexer = new Yylex((Reader) null);
private Yytoken token = null;
private int status = S_INIT;
private int peekStatus(LinkedList statusStack) {
if (statusStack.size() == 0)
return -1;
return (Integer) statusStack.getFirst();
}
private void reset(Reader in) {
statusStack.clear();
valueStack.clear();
lexer.yyreset(in);
token = null;
status = S_INIT;
}
public JSONType parse(Reader in) {
reset(in);
do {
try {
token = lexer.yylex();
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
}
if (token == null)
token = new Yytoken(Yytoken.TYPE_EOF, null);
switch (status) {
case S_INIT:
switch (token.type) {
case Yytoken.TYPE_VALUE:
status = S_IN_FINISHED_VALUE;
statusStack.addFirst(status);
valueStack.addFirst(JSONValue.valueOf(token.value));
break;
case Yytoken.TYPE_LEFT_BRACE:
status = S_IN_OBJECT;
statusStack.addFirst(status);
valueStack.addFirst(new JSONObject());
break;
case Yytoken.TYPE_LEFT_SQUARE:
status = S_IN_ARRAY;
statusStack.addFirst(status);
valueStack.addFirst(new JSONArray());
break;
default:
status = S_IN_ERROR;
}//inner switch
break;
case S_IN_FINISHED_VALUE:
if (token.type == Yytoken.TYPE_EOF)
return valueStack.removeFirst();
else
return null;
case S_IN_OBJECT:
switch (token.type) {
case Yytoken.TYPE_COMMA:
break;
case Yytoken.TYPE_VALUE:
if (token.value instanceof String) {
String key = (String) token.value;
valueStack.addFirst(JSONValue.valueOf(key));
status = S_PASSED_PAIR_KEY;
statusStack.addFirst(status);
} else {
status = S_IN_ERROR;
}
break;
case Yytoken.TYPE_RIGHT_BRACE:
if (valueStack.size() > 1) {
statusStack.removeFirst();
valueStack.removeFirst();
status = peekStatus(statusStack);
} else {
status = S_IN_FINISHED_VALUE;
}
break;
default:
status = S_IN_ERROR;
break;
}//inner switch
break;
case S_PASSED_PAIR_KEY:
switch (token.type) {
case Yytoken.TYPE_COLON:
break;
case Yytoken.TYPE_VALUE:
statusStack.removeFirst();
String key = valueStack.removeFirst().asString();
JSONObject parent = (JSONObject) valueStack.getFirst();
parent.put(key, token.value);
status = peekStatus(statusStack);
break;
case Yytoken.TYPE_LEFT_SQUARE:
statusStack.removeFirst();
key = valueStack.removeFirst().asString();
parent = (JSONObject) valueStack.getFirst();
JSONArray newArray = new JSONArray();
parent.put(key, newArray);
status = S_IN_ARRAY;
statusStack.addFirst(status);
valueStack.addFirst(newArray);
break;
case Yytoken.TYPE_LEFT_BRACE:
statusStack.removeFirst();
key = valueStack.removeFirst().asString();
parent = (JSONObject) valueStack.getFirst();
JSONObject newObject = new JSONObject();
parent.put(key, newObject);
status = S_IN_OBJECT;
statusStack.addFirst(status);
valueStack.addFirst(newObject);
break;
default:
status = S_IN_ERROR;
}
break;
case S_IN_ARRAY:
switch (token.type) {
case Yytoken.TYPE_COMMA:
break;
case Yytoken.TYPE_VALUE:
JSONArray val = (JSONArray) valueStack.getFirst();
val.put(token.value);
break;
case Yytoken.TYPE_RIGHT_SQUARE:
if (valueStack.size() > 1) {
statusStack.removeFirst();
valueStack.removeFirst();
status = peekStatus(statusStack);
} else {
status = S_IN_FINISHED_VALUE;
}
break;
case Yytoken.TYPE_LEFT_BRACE:
val = (JSONArray) valueStack.getFirst();
JSONObject newObject = new JSONObject();
val.put(newObject);
status = S_IN_OBJECT;
statusStack.addFirst(status);
valueStack.addFirst(newObject);
break;
case Yytoken.TYPE_LEFT_SQUARE:
val = (JSONArray) valueStack.getFirst();
JSONArray newArray = new JSONArray();
val.put(newArray);
status = S_IN_ARRAY;
statusStack.addFirst(status);
valueStack.addFirst(newArray);
break;
default:
status = S_IN_ERROR;
}//inner switch
break;
case S_IN_ERROR:
return null;
}//switch
if (status == S_IN_ERROR)
return null;
} while (token.type != Yytoken.TYPE_EOF);
return null;
}
}
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