I have a class that accept a Function<ByteBuffer, T> deserialize as constructor argument. I want the function to convert JSON to list of objects. Here's what I am trying to do

public Function<ByteBuffer, List<MyObject>> deserialize(
    final ObjectMapper objectMapper
) {
    return objectMapper.readValue(??, new TypeReference<List<MyObject>>(){});
}

Obviously the syntax is wrong here. How can I fix this?

CodePudding user response：

Instead of creating such a function I would rather go with utility method because ObjectMapper.readValue() throws IOException which is checked. Therefore it should be handled because we can't propagate checked exceptions outside the Function.

If you wonder how it might look like, here it is:

public Function<ByteBuffer, List<MyObject>> deserialize(ObjectMapper objectMapper) {

    return buffer -> {
        try {
            return objectMapper.readValue(buffer.array(),new TypeReference<List<MyObject>>() {
            });
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    };
}

Instead, let's consider a utility-class:

public static final ObjectMapper objectMapper = // initializing the mapper

public static List<MyObject> deserialize(ByteBuffer buffer) throws IOException {
    
    return objectMapper.readValue(buffer.array(),new TypeReference<>() {});
}