使用protostuff，如何跳过读取删除的实体？

Question

我是一个使用原型读/写数据的团队的一员。这是从Schema类扩展的类的mergeFrom方法：

@Override
    public void mergeFrom(Input input, Entity entity) throws IOException {
        for(int number = input.readFieldNumber(this); ; number = input.readFieldNumber(this))
        {
            if ( number == 0 ) {
                break;
            } else if ( number == FIELD_DEFINITION_ID ) {
                Schema idmSchema = entity.getSchema();

                // Definition id
                int definitionId = input.readUInt32();
                NodeDefinition defn = idmSchema.getById(definitionId);
                if ( defn == null ) {
                    throw new ProtostuffException("Invalid definition id "+definitionId);
                }
                Node<?> node = defn.createNode();
                entity.add(node);

                // Node
                readAndCheckFieldNumber(input, FIELD_NODE);
                input.mergeObject(node, getSchema(node.getClass()));


            } else if ( number == FIELD_CHILD_NODE_STATE ){
                //Node state
                int intState = input.readInt32();
                State state = State.parseState(intState);
                readAndCheckFieldNumber(input, FIELD_CHILD_DEFINITION_ID);
                int childDefnId = input.readInt32();
                Schema schema = entity.getSchema();
                NodeDefinition childDefn = schema.getById(childDefnId);
                entity.childStates.put(childDefn.getName(), state);
            } else {
                throw new ProtostuffException("Unexpected field number");
            }
        }
    }

我现在的任务是跳过读取数据，其中该数据的模式已经被删除。我正在研究Input接口的handleUnknownField方法。

有没有人已经体验过这种情况？

Answer 1

这个解决方案确实非常基础。查看这个引用：Schema，并检查mergeFrom代码：

public void mergeFrom(Input input, User user) throws IOException
{
    while(true)
    {
        int number = input.readFieldNumber(this);
        switch(number)
        {
            case 0:
                return;
            case 1:
                user.setEmail(input.readString());
                break;
            case 2:
                user.setFirstName(input.readString());
                break;
            case 3:
                user.setLastName(input.readString());
                break;
            case 4:
                if(message.friends == null)
                    message.friends = new ArrayList<User>();
                message.friends.add(input.mergeObject(null, this));
                break;
            default:
                input.handleUnknownField(number, this);
        }
    }
}

我想我应该直接用input.handleUnknownField(number, this);。它正确地解决了我的问题，如下所示：

...
} else if ( number == FIELD_DEFINITION_ID ) {
            Schema idmSchema = entity.getSchema();

            // Definition id
            int definitionId = input.readUInt32();
            NodeDefinition defn = idmSchema.getById(definitionId);
            if ( defn == null ) {
                input.handleUnknownField(number, this);
                continue;
            }
            Node<?> node = defn.createNode();
            entity.add(node);

            // Node
            readAndCheckFieldNumber(input, FIELD_NODE);
            input.mergeObject(node, getSchema(node.getClass()));

        }
...

谢谢，希望这篇问答对其他人有好处！