net.mograsim.logic.model/src/net/mograsim/logic/model/util/JsonHandler.java

   1 package net.mograsim.logic.model.util;
   2
   3 import java.io.BufferedReader;
   4 import java.io.FileInputStream;
   5 import java.io.FileWriter;
   6 import java.io.IOException;
   7 import java.io.InputStream;
   8 import java.io.InputStreamReader;
   9 import java.nio.charset.StandardCharsets;
  10 import java.util.stream.Collectors;
  11
  12 import com.google.gson.Gson;
  13 import com.google.gson.GsonBuilder;
  14 import com.google.gson.JsonElement;
  15
  16 public class JsonHandler
  17 {
  18         public final static Gson parser = new GsonBuilder().setPrettyPrinting().create();
  19
  20         public static <T> T readJson(String path, Class<T> type) throws IOException
  21         {
  22                 try (FileInputStream jsonStream = new FileInputStream(path))
  23                 {
  24                         return readJson(jsonStream, type);
  25                 }
  26         }
  27
  28         /**
  29          * @param input The Stream is closed after being read
  30          */
  31         public static <T> T readJson(InputStream input, Class<T> type) throws IOException
  32         {
  33                 try (InputStreamReader reader = new InputStreamReader(input, StandardCharsets.UTF_8);
  34                                 BufferedReader bf = new BufferedReader(reader))
  35                 {
  36                         return fromJson(bf.lines().collect(Collectors.joining("\n")), type);
  37                 }
  38         }
  39
  40         public static <T> T fromJson(String src, Class<T> type)
  41         {
  42                 // throw away legacy version line
  43                 String rawJson = src.lines().dropWhile(s -> s.length() == 0 || s.charAt(0) != '{').collect(Collectors.joining());
  44                 return parser.fromJson(rawJson, type);
  45         }
  46
  47         public static <T> T fromJsonTree(JsonElement src, Class<T> type)
  48         {
  49                 return parser.fromJson(src, type);
  50         }
  51
  52         public static void writeJson(Object o, String path) throws IOException
  53         {
  54                 try (FileWriter writer = new FileWriter(path))
  55                 {
  56                         writer.write(toJson(o));
  57                 }
  58         }
  59
  60         public static String toJson(Object o)
  61         {
  62                 return parser.toJson(o);
  63         }
  64
  65         public static JsonElement toJsonTree(Object o)
  66         {
  67                 return parser.toJsonTree(o);
  68         }
  69 }