https://github.com/FasterXML/jackson-core: Core Jackson processing abstractions (aka Streaming API), implementation for JSON (FasterXML)
  • Tatu Saloranta
  • Christopher Currie
  • Paul Brown 
/* Jackson JSON-processor.
 *
 * Copyright (c) 2007- Tatu Saloranta, tatu.saloranta@iki.fi
 */

package com.fasterxml.jackson.core;


Simple tag interface used to mark schema objects that are used by some JsonParser and JsonGenerator implementations to further specify structure of expected format. Basic JSON-based parsers and generators do not use schemas, but some data formats (like many binary data formats like Thrift, protobuf) mandate use of schemas. 
 Since there is little commonality between schemas for different data formats, this interface does not define much meaningful functionality for accessing schema details; rather, specific parser and generator implementations need to cast to schema implementations they use. This marker interface is mostly used for tagging "some kind of schema" -- instead of passing opaque Object -- for documentation purposes. 
/**
 * Simple tag interface used to mark schema objects that are used by some
 * {@link JsonParser} and {@link JsonGenerator} implementations to further
 * specify structure of expected format.
 * Basic JSON-based parsers and generators do not use schemas, but some data
 * formats (like many binary data formats like Thrift, protobuf) mandate
 * use of schemas.
 *<p>
 * Since there is little commonality between schemas for different data formats,
 * this interface does not define much meaningful functionality for accessing
 * schema details; rather, specific parser and generator implementations need
 * to cast to schema implementations they use. This marker interface is mostly
 * used for tagging "some kind of schema" -- instead of passing opaque
 * {@link java.lang.Object} -- for documentation purposes.
 */
public interface FormatSchema
{
    
Method that can be used to get an identifier that can be used for diagnostics
purposes, to indicate what kind of data format this schema is used for: typically
it is a short name of format itself, but it can also contain additional information
in cases where data format supports multiple types of schemas.

/**
     * Method that can be used to get an identifier that can be used for diagnostics
     * purposes, to indicate what kind of data format this schema is used for: typically
     * it is a short name of format itself, but it can also contain additional information
     * in cases where data format supports multiple types of schemas.
     */
    String getSchemaType();
}