content: package com.alibaba.fastjson.parser.deserializer;
  
  import java.lang.reflect.Type;
  import java.math.BigDecimal;
  
  import com.alibaba.fastjson.JSONException;
  import com.alibaba.fastjson.parser.DefaultJSONParser;
  import com.alibaba.fastjson.parser.Feature;
  import com.alibaba.fastjson.parser.JSONLexer;
  import com.alibaba.fastjson.parser.JSONToken;
  import com.alibaba.fastjson.util.TypeUtils;
  
  public class NumberDeserializer implements ObjectDeserializer {
  
      public final static NumberDeserializer instance = new NumberDeserializer();
  
      @SuppressWarnings("unchecked")
      public <T> T deserialze(DefaultJSONParser parser, Type clazz, Object fieldName) {
          final JSONLexer lexer = parser.lexer;
          if (lexer.token() == JSONToken.LITERAL_INT) {
              if (clazz == double.class || clazz  == Double.class) {
                  String val = lexer.numberString();
                  lexer.nextToken(JSONToken.COMMA);
                  return (T) Double.valueOf(Double.parseDouble(val));
              }
              
              long val = lexer.longValue();
              lexer.nextToken(JSONToken.COMMA);
  
              if (clazz == short.class || clazz == Short.class) {
                  if (val > Short.MAX_VALUE || val < Short.MIN_VALUE) {
                      throw new JSONException("short overflow : " + val);
                  }
                  return (T) Short.valueOf((short) val);
              }
  
              if (clazz == byte.class || clazz == Byte.class) {
                  if (val > Byte.MAX_VALUE || val < Byte.MIN_VALUE) {
                      throw new JSONException("short overflow : " + val);
                  }
  
                  return (T) Byte.valueOf((byte) val);
              }
  
              if (val >= Integer.MIN_VALUE && val <= Integer.MAX_VALUE) {
                  return (T) Integer.valueOf((int) val);
              }
              return (T) Long.valueOf(val);
          }
  
          if (lexer.token() == JSONToken.LITERAL_FLOAT) {
              if (clazz == double.class || clazz == Double.class) {
                  String val = lexer.numberString();
                  lexer.nextToken(JSONToken.COMMA);
                  return (T) Double.valueOf(Double.parseDouble(val));
              }
  
              if (clazz == short.class || clazz == Short.class) {
                  BigDecimal val = lexer.decimalValue();
                  lexer.nextToken(JSONToken.COMMA);
                  short shortValue = TypeUtils.shortValue(val);
                  return (T) Short.valueOf(shortValue);
              }
  
              if (clazz == byte.class || clazz == Byte.class) {
                  BigDecimal val = lexer.decimalValue();
                  lexer.nextToken(JSONToken.COMMA);
                  byte byteValue = TypeUtils.byteValue(val);
                  return (T) Byte.valueOf(byteValue);
              }
  
              BigDecimal val = lexer.decimalValue();
              lexer.nextToken(JSONToken.COMMA);
  
              if (lexer.isEnabled(Feature.UseBigDecimal)) {
                  return (T) val;
              } else {
                  return (T) Double.valueOf(val.doubleValue());
              }
          }
  
          if (lexer.token() == JSONToken.IDENTIFIER && "NaN".equals(lexer.stringVal())) {
              lexer.nextToken();
              Object nan = null;
              if (clazz == Double.class) {
                  nan = Double.NaN;
              } else if (clazz == Float.class) {
                  nan = Float.NaN;
              }
              return (T) nan;
          }
  
          Object value = parser.parse();
  
          if (value == null) {
              return null;
          }
  
          if (clazz == double.class || clazz == Double.class) {
              try {
                  return (T) TypeUtils.castToDouble(value);
              } catch (Exception ex) {
                  throw new JSONException("parseDouble error, field : " + fieldName, ex);
              }
          }
  
          if (clazz == short.class || clazz == Short.class) {
              try {
                  return (T) TypeUtils.castToShort(value);
              } catch (Exception ex) {
                  throw new JSONException("parseShort error, field : " + fieldName, ex);
              }
          }
  
          if (clazz == byte.class || clazz == Byte.class) {
              try {
                  return (T) TypeUtils.castToByte(value);
              } catch (Exception ex) {
                  throw new JSONException("parseByte error, field : " + fieldName, ex);
              }
          }
  
          return (T) TypeUtils.castToBigDecimal(value);
      }
  
      public int getFastMatchToken() {
          return JSONToken.LITERAL_INT;
      }
  }
  