com.fasterxml.jackson.databind.node.BaseJsonNode Maven / Gradle / Ivy
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.
*
* 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 {@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;
}
/*
/**********************************************************
/* Other traversal
/**********************************************************
*/
@Override
public ObjectNode withObject(JsonPointer ptr,
OverwriteMode overwriteMode, boolean preferIndex)
{
// Degenerate case of using with "empty" path; ok if ObjectNode
if (ptr.matches()) {
if (this instanceof ObjectNode) {
return (ObjectNode) this;
}
_reportWrongNodeType("Can only call `withObject()` with empty JSON Pointer on `ObjectNode`, not `%s`",
getClass().getName());
}
// Otherwise check recursively
ObjectNode n = _withObject(ptr, ptr, overwriteMode, preferIndex);
if (n == null) {
_reportWrongNodeType("Cannot replace context node (of type `%s`) using `withObject()` with JSON Pointer '%s'",
getClass().getName(), ptr);
}
return n;
}
protected ObjectNode _withObject(JsonPointer origPtr,
JsonPointer currentPtr,
OverwriteMode overwriteMode, boolean preferIndex)
{
// Three-part logic:
//
// 1) If we are at the end of JSON Pointer; if so, return
// `this` if Object node, `null` if not (for caller to handle)
// 2) If not at the end, if we can follow next segment, call recursively
// handle non-null (existing Object node, return)
// vs `null` (must replace; may not be allowed to)
// 3) Can not follow the segment? Try constructing, adding path
//
// But the default implementation assumes non-container behavior so
// it'll simply return `null`
return null;
}
protected void _withXxxVerifyReplace(JsonPointer origPtr,
JsonPointer currentPtr,
OverwriteMode overwriteMode, boolean preferIndex,
JsonNode toReplace)
{
if (!_withXxxMayReplace(toReplace, overwriteMode)) {
_reportWrongNodeType(
"Cannot replace `JsonNode` of type `%s` for property \"%s\" in JSON Pointer \"%s\" (mode `OverwriteMode.%s`)",
toReplace.getClass().getName(), currentPtr.getMatchingProperty(),
origPtr, overwriteMode);
}
}
protected boolean _withXxxMayReplace(JsonNode node, OverwriteMode overwriteMode) {
switch (overwriteMode) {
case NONE:
return false;
case NULLS:
return node.isNull();
case SCALARS:
return !node.isContainerNode();
default:
case ALL:
return true;
}
}
@Override
public ArrayNode withArray(JsonPointer ptr,
OverwriteMode overwriteMode, boolean preferIndex)
{
// Degenerate case of using with "empty" path; ok if ObjectNode
if (ptr.matches()) {
if (this instanceof ArrayNode) {
return (ArrayNode) this;
}
_reportWrongNodeType("Can only call `withArray()` with empty JSON Pointer on `ArrayNode`, not `%s`",
getClass().getName());
}
// Otherwise check recursively
ArrayNode n = _withArray(ptr, ptr, overwriteMode, preferIndex);
if (n == null) {
_reportWrongNodeType("Cannot replace context node (of type `%s`) using `withArray()` with JSON Pointer '%s'",
getClass().getName(), ptr);
}
return n;
}
protected ArrayNode _withArray(JsonPointer origPtr,
JsonPointer currentPtr,
OverwriteMode overwriteMode, boolean preferIndex)
{
// Similar logic to "_withObject()" but the default implementation
// used for non-container behavior so it'll simply return `null`
return null;
}
/*
/**********************************************************
/* JsonSerializable
/**********************************************************
*/
/**
* Method called to serialize node instances using given generator.
*/
@Override
public abstract void serialize(JsonGenerator g, SerializerProvider ctxt)
throws IOException;
/**
* 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 g, SerializerProvider ctxt,
TypeSerializer typeSer)
throws IOException;
/*
/**********************************************************
/* Standard method overrides
/**********************************************************
*/
@Override
public String toString() {
return InternalNodeMapper.nodeToString(this);
}
@Override
public String toPrettyString() {
return InternalNodeMapper.nodeToPrettyString(this);
}
/*
/**********************************************************
/* Other helper methods for subtypes
/**********************************************************
*/
/**
* Helper method that throws {@link UnsupportedOperationException} as a result of
* this node being of wrong type
*/
protected T _reportWrongNodeType(String msgTemplate, Object...args) {
throw new UnsupportedOperationException(String.format(msgTemplate, args));
}
protected T _reportWrongNodeOperation(String msgTemplate, Object...args) {
throw new UnsupportedOperationException(String.format(msgTemplate, args));
}
// @since 2.14
protected JsonPointer _jsonPointerIfValid(String exprOrProperty) {
if (exprOrProperty.isEmpty() || exprOrProperty.charAt(0) == '/') {
return JsonPointer.compile(exprOrProperty);
}
return null;
}
}