[Java] Adjust Java Dto generateComputeEncodedLength to acount for character encoding (aeron-io#1072)

Author: marc-adaptive

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/java/JavaDtoGenerator.java

@@ -371,14 +371,20 @@ private void generateComputeEncodedLength(
  .append(formatPropertyName(propertyName)).append("HeaderLength();\n");
 
  final String characterEncoding = varDataToken.encoding().characterEncoding();
- final String lengthAccessor = characterEncoding == null ? ".length" : ".length()";
- lengthBuilder.append(indent).append(INDENT).append("encodedLength += ")
- .append("this.").append(fieldName).append(lengthAccessor);
+ lengthBuilder.append(indent).append(INDENT).append("encodedLength += ");
 
- final int elementByteLength = varDataToken.encoding().primitiveType().size();
- if (elementByteLength != 1)
+ if (characterEncoding == null)
+ {
+ lengthBuilder.append("this.").append(fieldName).append(".length");
+ }
+ else if (JavaUtil.isAsciiEncoding(characterEncoding))
+ {
+ lengthBuilder.append("this.").append(fieldName).append(".length()");
+ }
+ else
  {
- lengthBuilder.append(" * ").append(elementByteLength);
+ lengthBuilder.append("this.").append(fieldName)
+ .append(".getBytes(").append(JavaUtil.charset(characterEncoding)).append(").length");
  }
 
  lengthBuilder.append(";\n\n");