package com.fasterxml.jackson.databind.node; import java.io.IOException; import com.fasterxml.jackson.core.*; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.JsonSerializable; import com.fasterxml.jackson.databind.SerializerProvider; import com.fasterxml.jackson.databind.jsontype.TypeSerializer; /** * Abstract base class common to all standard {@link JsonNode} * implementations. * The main addition here is that we declare that sub-classes must * implement {@link JsonSerializable}. * This simplifies object mapping aspects a bit, as no external serializers are needed. */ public abstract class BaseJsonNode extends JsonNode implements JsonSerializable { protected BaseJsonNode() { } /* /********************************************************** /* Basic definitions for non-container types /********************************************************** */ @Override public final JsonNode findPath(String fieldName) { JsonNode value = findValue(fieldName); if (value == null) { return MissingNode.getInstance(); } return value; } // Also, force (re)definition (2.7) @Override public abstract int hashCode(); /* /********************************************************** /* Support for traversal-as-stream /********************************************************** */ @Override public JsonParser traverse() { return new TreeTraversingParser(this); } @Override public JsonParser traverse(ObjectCodec codec) { return new TreeTraversingParser(this, codec); } /** * Method that can be used for efficient type detection * when using stream abstraction for traversing nodes. * Will return the first {@link JsonToken} that equivalent * stream event would produce (for most nodes there is just * one token but for structured/container types multiple) */ @Override public abstract JsonToken asToken(); /** * Returns code that identifies type of underlying numeric * value, if (and only if) node is a number node. */ @Override public JsonParser.NumberType numberType() { // most types non-numeric, so: return null; } /* /********************************************************** /* JsonSerializable /********************************************************** */ /** * Method called to serialize node instances using given generator. */ @Override public abstract void serialize(JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException; /** * Type information is needed, even if JsonNode instances are "plain" JSON, * since they may be mixed with other types. */ @Override public abstract void serializeWithType(JsonGenerator jgen, SerializerProvider provider, TypeSerializer typeSer) throws IOException, JsonProcessingException; }