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 JsonNode implementations. The main addition here is that we declare that sub-classes must implement JsonSerializable. This simplifies object mapping aspects a bit, as no external serializers are needed. 
 Since 2.10, all implements have been Serializable. /**
 * 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.
 *<p>
 * Since 2.10, all implements have been {@link java.io.Serializable}.
 */
public abstract class BaseJsonNode
    extends JsonNode
    implements java.io.Serializable
{
    private static final long serialVersionUID = 1L;

    // Simplest way is by using a helper
    Object writeReplace() {
        return NodeSerialization.from(this);
    }

    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();

    /*
    /**********************************************************************
    /* Improved required-ness checks for standard JsonNode implementations
    /**********************************************************************
     */

    @Override
    public JsonNode required(String fieldName) {
        return _reportRequiredViolation("Node of type `%s` has no fields",
                getClass().getSimpleName());
    }

    @Override
    public JsonNode required(int index) {
        return _reportRequiredViolation("Node of type `%s` has no indexed values",
                getClass().getSimpleName());
    }

    /*
    /**********************************************************
    /* 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 JsonToken that equivalent stream event would produce (for most nodes there is just one token but for structured/container types multiple) /**
     * 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.
/**
     * 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.
/**
     * Method called to serialize node instances using given generator.
     */
    @Override
    public abstract void serialize(JsonGenerator jgen, SerializerProvider provider)
        throws IOException;

    
Type information is needed, even if JsonNode instances are "plain" JSON,
since they may be mixed with other types.
/**
     * 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;

   /*
   /**********************************************************
   /* Standard method overrides
   /**********************************************************
    */

   @Override
   public String toString() {
       return InternalNodeMapper.nodeToString(this);
   }

   @Override
   public String toPrettyString() {
       return InternalNodeMapper.nodeToPrettyString(this);
   }
}