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com.kttdevelopment.mal4j.Json Maven / Gradle / Ivy
/*
* Copyright (C) 2021-2022 Katsute
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package com.kttdevelopment.mal4j;
import java.io.*;
import java.util.*;
import java.util.function.Function;
import java.util.regex.*;
/**
* A massively simplified json parsing class. Supports the bare minimum read requirements for the REST API responses.
*/
@SuppressWarnings("SpellCheckingInspection")
class Json {
/*
* Notable issues:
* - Allows dangling commas on last item in map and list
*/
// [\{\}\[\],]
@SuppressWarnings("RegExpRedundantEscape") // android requires this syntax (#133)
private static final Pattern split = Pattern.compile("[\\{\\}\\[\\],]");
// (? unicodeReplacer = matchResult -> String.valueOf((char) Integer.parseInt(matchResult.group(1), 16));
// \\"|\\\/|\\\\
@SuppressWarnings("RegExpRedundantEscape") // android requires this syntax (#133)
private static final Pattern escapedCharacters =
Pattern.compile("\\\\\"|\\\\\\/|\\\\\\\\");
private static final Function escapedReplacer = matchResult -> {
final String chars = matchResult.group(0);
switch(chars){
case "\\\"":
return "\"";
case "\\/":
return "/";
case "\\\\":
return "\\\\"; // this needs to be \\ to return \ for some reason
default:
return chars;
}
};
// ^\s*(?.+(?-?\d+\.\d+) *,?|(?-?\d+) *,?|(?\Qtrue\E|\Qfalse\E) *,?|(?\Qnull\E) *,?|(?.*(?\[)|(?\{))\s*$
private static final Pattern mapType =
Pattern.compile("^\\s*(?.+(?-?\\d+\\.\\d+) *,?|(?-?\\d+) *,?|(?\\Qtrue\\E|\\Qfalse\\E) *,?|(?\\Qnull\\E) *,?|(?.*(?\\[)|(?\\{))\\s*$");
// ^\s*} *,?\s*$
@SuppressWarnings("RegExpRedundantEscape") // android requires this syntax (#133)
private static final Pattern mapClose =
Pattern.compile("^\\s*\\} *,?\\s*$");
// ^\s*((?-?\d+\.\d+) *,?|(?-?\d+) *,?|(?\Qtrue\E|\Qfalse\E) *,?|(?\Qnull\E) *,?|(?.*(?\[)|(?\{))\s*$
private static final Pattern arrType =
Pattern.compile("^\\s*((?-?\\d+\\.\\d+) *,?|(?-?\\d+) *,?|(?\\Qtrue\\E|\\Qfalse\\E) *,?|(?\\Qnull\\E) *,?|(?.*(?\\[)|(?\\{))\\s*$");
// ^\s*] *,?\s*$
private static final Pattern arrClose =
Pattern.compile("^\\s*] *,?\\s*$");
// \r?\n
private static final Pattern newline =
Pattern.compile("\\r?\\n");
//
private final Matcher splitMatcher = split.matcher("");
private final Matcher nonEscQuoteMatcher = nonEscQuote.matcher("");
private final Matcher arrayMatcher = arrType.matcher("");
private final Matcher mapMatcher = mapType.matcher("");
private final Matcher unicodeMatcher = escUnicode.matcher("");
private final Matcher escapedMatcher = escapedCharacters.matcher("");
private Json(){ }
// required for lambda
static Object parse(final String json){
return new Json().parseJson(json);
}
/**
* Returns json as a JsonObject or List. Mutable .
*
* @param json json string
* @return parsed json
*
* @see JsonObject
*/
private synchronized Object parseJson(final String json){
Objects.requireNonNull(json);
final String flatJson = newline.matcher(json).replaceAll("");
// split by symbols {}[], except within non-escaped quotes
final StringBuilder OUT = new StringBuilder();
int lastMatch = -1; // the index after the previous match
splitMatcher.reset(flatJson);
final Matcher quotes = nonEscQuoteMatcher.reset();
while(splitMatcher.find()){ // while still contains line splitting symbol
final int index = splitMatcher.end() - 1; // before the comma/split character
final String after = flatJson.substring(index + 1);
final long count = Regex9.count(quotes.reset(after));
if(count %2 == 0){ // even means symbol is not within quotes
if(lastMatch != -1) // if not first (no content before this)
OUT.append(flatJson, lastMatch, index); // add content between last match and here
lastMatch = index + 1;
final char ch = splitMatcher.group().charAt(0);
switch(ch){ // determine where to break line
case '{':
case '[':
case ',':
OUT.append(ch).append('\n');
break;
case '}':
case ']':
OUT.append('\n').append(ch);
break;
}
}
}
// parse line by line
final String lines = lastMatch == 0 ? json : OUT.toString();
try(final BufferedReader IN = new BufferedReader(new StringReader(lines))){
final String line = IN.readLine();
if(line != null){
final String ln = line.trim();
if(ln.equals("{"))
return openMap(IN, json);
else if(ln.equals("["))
return openArray(IN, json);
else
throw new JsonSyntaxException("Unexpected starting character: '" + ln + "' expected '{' or '['", json);
}else
throw new JsonSyntaxException("Json string was empty", json);
}catch(final IOException e){ // any exceptions caused by reader
throw new UncheckedIOException(e);
}
}
private List openArray(final BufferedReader reader, final String json) throws IOException{
final List list = new ArrayList<>();
String ln;
while((ln = reader.readLine()) != null){ // while not closing tag
ln = ln.trim();
if(arrayMatcher.reset(ln).matches()){
String raw;
if((raw = arrayMatcher.group("double")) != null)
try{
list.add(Double.parseDouble(raw));
}catch(final NumberFormatException ignored){ // only occurs if too large
list.add(Long.parseLong(raw));
}
else if((raw = arrayMatcher.group("int")) != null)
try{
list.add(Integer.parseInt(raw));
}catch(final NumberFormatException ignored){ // only occurs if too large
list.add(Long.parseLong(raw));
}
else if((raw = arrayMatcher.group("boolean")) != null)
list.add(Boolean.parseBoolean(raw));
else if(arrayMatcher.group("null") != null)
list.add(null);
else if((raw = arrayMatcher.group("string")) != null)
list.add(decodeString(raw));
else if(arrayMatcher.group("array") != null) // open new array
list.add(openArray(reader, json));
else if(arrayMatcher.group("map") != null) // open new map
list.add(openMap(reader, json));
}else if(arrClose.matcher(ln).matches())
return list;
else if(ln.trim().length() > 0)
throw new JsonSyntaxException("Unexpected array value syntax: '" + ln + '\'', json);
}
throw new JsonSyntaxException("Object was missing closing character: ']'", json);
}
private JsonObject openMap(final BufferedReader reader, final String json) throws IOException{
final JsonObject obj = new JsonObject();
String ln;
while((ln = reader.readLine()) != null){
ln = ln.trim();
if(mapMatcher.reset(ln).matches()){
final String key = decodeString(mapMatcher.group("key"));
String raw;
if((raw = mapMatcher.group("double")) != null)
try{
obj.set(key, Double.parseDouble(raw));
}catch(final NumberFormatException ignored){ // only occurs if too large
obj.set(key, Long.parseLong(raw));
}
else if((raw = mapMatcher.group("int")) != null)
try{
obj.set(key, Integer.parseInt(raw));
}catch(final NumberFormatException ignored){ // only occurs if too large
obj.set(key, Long.parseLong(raw));
}
else if((raw = mapMatcher.group("boolean")) != null)
obj.set(key, Boolean.parseBoolean(raw));
else if(mapMatcher.group("null") != null)
obj.set(key, null);
else if((raw = mapMatcher.group("string")) != null)
obj.set(key, decodeString(raw));
else if(mapMatcher.group("array") != null) // open new array
obj.set(key, openArray(reader, json));
else if(mapMatcher.group("map") != null) // open new map
obj.set(key, openMap(reader, json));
}else if(mapClose.matcher(ln).matches())
return obj;
else if(ln.trim().length() > 0)
throw new JsonSyntaxException("Unexpected object value syntax: '" + ln + '\'', json);
}
throw new JsonSyntaxException("Object was missing closing character: '}'", json);
}
@SuppressWarnings("UnnecessaryLocalVariable")
private String decodeString(final String raw){
final String unicodeEscape = Regex9.replaceAll(raw, unicodeMatcher.reset(raw), unicodeReplacer);
final String slashEscape = Regex9.replaceAll(unicodeEscape, escapedMatcher.reset(unicodeEscape), escapedReplacer);
return slashEscape;
}
// objects
/**
* Represents map as a json object.
*/
static class JsonObject {
private final Map map = new HashMap<>();
JsonObject(){ }
public final Object get(final String key){
return map.get(key);
}
public final String getString(final String key){
final Object value = map.get(key);
return
value == null
? null
: value instanceof String
? (String) value
: value.toString();
}
public final int getInt(final String key){
final Object value = map.get(key);
return value instanceof String ? Integer.parseInt((String) value) : ((Number) value).intValue();
}
public final double getDouble(final String key){
final Object value = map.get(key);
return value instanceof String ? Double.parseDouble((String) value) : ((Number) value).doubleValue();
}
public final float getFloat(final String key){
final Object value = map.get(key);
return value instanceof String ? Float.parseFloat((String) value) : ((Number) value).floatValue();
}
public final long getLong(final String key){
final Object value = map.get(key);
return value instanceof String ? Long.parseLong((String) value) : ((Number) value).longValue();
}
public final boolean getBoolean(final String key){
final Object value = map.get(key);
return value instanceof String ? Boolean.parseBoolean((String) value) : (boolean) value;
}
public final JsonObject getJsonObject(final String key){
return (JsonObject) map.get(key);
}
public final String[] getStringArray(final String key){
final List list = (List) map.get(key);
final List arr = new ArrayList<>();
for(final Object o : list)
arr.add(o == null ? null : o instanceof String ? (String) o : o.toString());
return arr.toArray(new String[0]);
}
public final JsonObject[] getJsonArray(final String key){
final List list = (List) map.get(key);
final List arr = new ArrayList<>();
for(final Object o : list)
arr.add((JsonObject) o);
return arr.toArray(new JsonObject[0]);
}
public final boolean containsKey(final String key){
return map.containsKey(key);
}
public final int size(){
return map.size();
}
private void set(final String key, final Object value){
map.put(key, value);
}
@Override
public String toString(){
return "JsonObject{" +
"map=" + map +
'}';
}
}
}
