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package com.fasterxml.jackson.databind.node;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Map;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.json.JsonMapper;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
/**
* Helper class used to implement {@code toString()} method for
* {@link BaseJsonNode}, by embedding a private instance of
* {@link JsonMapper}, only to be used for node serialization.
*
* @since 2.10 (but not to be included in 3.0)
*/
final class InternalNodeMapper {
private final static JsonMapper JSON_MAPPER = new JsonMapper();
private final static ObjectWriter STD_WRITER = JSON_MAPPER.writer();
private final static ObjectWriter PRETTY_WRITER = JSON_MAPPER.writer()
.withDefaultPrettyPrinter();
private final static ObjectReader NODE_READER = JSON_MAPPER.readerFor(JsonNode.class);
// // // Methods for `JsonNode.toString()` and `JsonNode.toPrettyString()`
public static String nodeToString(BaseJsonNode n) {
try {
return STD_WRITER.writeValueAsString(_wrapper(n));
} catch (IOException e) { // should never occur
throw new RuntimeException(e);
}
}
public static String nodeToPrettyString(BaseJsonNode n) {
try {
return PRETTY_WRITER.writeValueAsString(_wrapper(n));
} catch (IOException e) { // should never occur
throw new RuntimeException(e);
}
}
// // // Methods for JDK serialization support of JsonNodes
public static byte[] valueToBytes(Object value) throws IOException {
return JSON_MAPPER.writeValueAsBytes(value);
}
public static JsonNode bytesToNode(byte[] json) throws IOException {
return NODE_READER.readValue(json);
}
private static JsonSerializable _wrapper(BaseJsonNode root) {
return new WrapperForSerializer(root);
}
/**
* Intermediate serializer we need to implement non-recursive serialization of
* {@link BaseJsonNode}.
*
* NOTE: not designed as thread-safe; instances must NOT be shared or reused.
*
* @since 2.14
*/
protected static class WrapperForSerializer
extends JsonSerializable.Base
{
protected final BaseJsonNode _root;
// Non-final as passed when `serialize()` is called
protected SerializerProvider _context;
public WrapperForSerializer(BaseJsonNode root) {
_root = root;
}
@Override
public void serialize(JsonGenerator g, SerializerProvider ctxt) throws IOException {
_context = ctxt;
_serializeNonRecursive(g, _root);
}
@Override
public void serializeWithType(JsonGenerator g, SerializerProvider ctxt, TypeSerializer typeSer)
throws IOException
{
// Should not really be called given usage, so
serialize(g, ctxt);
}
protected void _serializeNonRecursive(JsonGenerator g, JsonNode node) throws IOException
{
if (node instanceof ObjectNode) {
g.writeStartObject(this, node.size());
_serializeNonRecursive(g, new IteratorStack(), node.fields());
} else if (node instanceof ArrayNode) {
g.writeStartArray(this, node.size());
_serializeNonRecursive(g, new IteratorStack(), node.elements());
} else {
node.serialize(g, _context);
}
}
protected void _serializeNonRecursive(JsonGenerator g, IteratorStack stack,
final Iterator rootIterator)
throws IOException
{
Iterator currIt = rootIterator;
while (true) {
// First: any more elements from the current iterator?
while (currIt.hasNext()) {
JsonNode value;
// Otherwise we do have another Map or Array element to handle
Object elem = currIt.next();
if (elem instanceof Map.Entry) {
@SuppressWarnings("unchecked")
Map.Entry en = (Map.Entry) elem;
g.writeFieldName(en.getKey());
value = en.getValue();
} else {
value = (JsonNode) elem;
}
if (value instanceof ObjectNode) {
stack.push(currIt);
currIt = value.fields();
g.writeStartObject(value, value.size());
} else if (value instanceof ArrayNode) {
stack.push(currIt);
currIt = value.elements();
g.writeStartArray(value, value.size());
} else {
value.serialize(g, _context);
}
}
if (g.getOutputContext().inArray()) {
g.writeEndArray();
} else {
g.writeEndObject();
}
currIt = stack.popOrNull();
if (currIt == null) {
return;
}
}
}
}
/**
* Optimized variant similar in functionality to (a subset of)
* {@link java.util.ArrayDeque}; used to hold enclosing Array/Object
* nodes during recursion-as-iteration.
*/
final static class IteratorStack
{
private Iterator[] _stack;
private int _top, _end;
public IteratorStack() { }
public void push(Iterator it)
{
if (_top < _end) {
_stack[_top++] = it; // lgtm [java/dereferenced-value-may-be-null]
return;
}
if (_stack == null) {
_end = 10;
_stack = new Iterator[_end];
} else {
// grow by 50%, for most part
_end += Math.min(4000, Math.max(20, _end>>1));
_stack = Arrays.copyOf(_stack, _end);
}
_stack[_top++] = it;
}
public Iterator popOrNull() {
if (_top == 0) {
return null;
}
// note: could clean up stack but due to usage pattern, should not make
// much difference since the whole stack is discarded after serialization done
return _stack[--_top];
}
}
}