com.fasterxml.jackson.databind.node.NodeCursor Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including
all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and
Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
package com.fasterxml.jackson.databind.node;
import java.util.*;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.JsonNode;
/**
* Helper class used by {@link TreeTraversingParser} to keep track
* of current location within traversed JSON tree.
*/
abstract class NodeCursor
extends JsonStreamContext
{
/**
* Parent cursor of this cursor, if any; null for root
* cursors.
*/
protected final NodeCursor _parent;
/**
* Current field name
*/
protected String _currentName;
/**
* @since 2.5
*/
protected java.lang.Object _currentValue;
public NodeCursor(int contextType, NodeCursor p)
{
super();
_type = contextType;
_index = -1;
_parent = p;
}
/*
/**********************************************************
/* JsonStreamContext impl
/**********************************************************
*/
// note: co-variant return type
@Override
public final NodeCursor getParent() { return _parent; }
@Override
public final String getCurrentName() {
return _currentName;
}
/**
* @since 2.0
*/
public void overrideCurrentName(String name) {
_currentName = name;
}
@Override
public java.lang.Object getCurrentValue() {
return _currentValue;
}
@Override
public void setCurrentValue(java.lang.Object v) {
_currentValue = v;
}
/*
/**********************************************************
/* Extended API
/**********************************************************
*/
public abstract JsonToken nextToken();
public abstract JsonNode currentNode();
public abstract NodeCursor startObject();
public abstract NodeCursor startArray();
/**
* Method called to create a new context for iterating all
* contents of the current structured value (JSON array or object)
*/
public final NodeCursor iterateChildren() {
JsonNode n = currentNode();
if (n == null) throw new IllegalStateException("No current node");
if (n.isArray()) { // false since we have already returned START_ARRAY
return new ArrayCursor(n, this);
}
if (n.isObject()) {
return new ObjectCursor(n, this);
}
throw new IllegalStateException("Current node of type "+n.getClass().getName());
}
/*
/**********************************************************
/* Concrete implementations
/**********************************************************
*/
/**
* Context for all root-level value nodes (including Arrays and Objects):
* only context for scalar values.
*/
protected final static class RootCursor
extends NodeCursor
{
protected JsonNode _node;
protected boolean _done = false;
public RootCursor(JsonNode n, NodeCursor p) {
super(JsonStreamContext.TYPE_ROOT, p);
_node = n;
}
@Override
public void overrideCurrentName(String name) {
}
@Override
public JsonToken nextToken() {
if (!_done) {
++_index;
_done = true;
return _node.asToken();
}
_node = null;
return null;
}
@Override
public JsonNode currentNode() {
// May look weird, but is necessary so as not to expose current node
// before it has been traversed
return _done ? _node : null;
}
@Override
public NodeCursor startArray() { return new ArrayCursor(_node, this); }
@Override
public NodeCursor startObject() { return new ObjectCursor(_node, this); }
}
// Cursor used for traversing JSON Array nodes
protected final static class ArrayCursor
extends NodeCursor
{
protected Iterator _contents;
protected JsonNode _currentElement;
public ArrayCursor(JsonNode n, NodeCursor p) {
super(JsonStreamContext.TYPE_ARRAY, p);
_contents = n.elements();
}
@Override
public JsonToken nextToken()
{
if (!_contents.hasNext()) {
_currentElement = null;
return JsonToken.END_ARRAY;
}
++_index;
_currentElement = _contents.next();
return _currentElement.asToken();
}
@Override
public JsonNode currentNode() { return _currentElement; }
@Override
public NodeCursor startArray() { return new ArrayCursor(_currentElement, this); }
@Override
public NodeCursor startObject() { return new ObjectCursor(_currentElement, this); }
}
// Cursor used for traversing JSON Object nodes
protected final static class ObjectCursor
extends NodeCursor
{
protected Iterator> _contents;
protected Map.Entry _current;
protected boolean _needEntry;
public ObjectCursor(JsonNode n, NodeCursor p)
{
super(JsonStreamContext.TYPE_OBJECT, p);
_contents = ((ObjectNode) n).fields();
_needEntry = true;
}
@Override
public JsonToken nextToken()
{
// Need a new entry?
if (_needEntry) {
if (!_contents.hasNext()) {
_currentName = null;
_current = null;
return JsonToken.END_OBJECT;
}
++_index;
_needEntry = false;
_current = _contents.next();
_currentName = (_current == null) ? null : _current.getKey();
return JsonToken.FIELD_NAME;
}
_needEntry = true;
return _current.getValue().asToken();
}
@Override
public JsonNode currentNode() {
return (_current == null) ? null : _current.getValue();
}
@Override
public NodeCursor startArray() { return new ArrayCursor(currentNode(), this); }
@Override
public NodeCursor startObject() { return new ObjectCursor(currentNode(), this); }
}
}
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