spinjar.com.fasterxml.jackson.databind.node.NullNode 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.SerializerProvider;
/**
* This singleton value class is used to contain explicit JSON null
* value.
*/
public class NullNode
extends ValueNode
{
// // Just need a fly-weight singleton
private static final long serialVersionUID = 1L;
public final static NullNode instance = new NullNode();
/**
*
* NOTE: visibility raised to `protected` in 2.9.3 to allow custom subtypes.
*/
protected NullNode() { }
// To support JDK serialization, recovery of Singleton instance
protected Object readResolve() {
return instance;
}
public static NullNode getInstance() { return instance; }
@Override
public JsonNodeType getNodeType() {
return JsonNodeType.NULL;
}
@Override public JsonToken asToken() { return JsonToken.VALUE_NULL; }
@Override public String asText(String defaultValue) { return defaultValue; }
@Override public String asText() { return "null"; }
@SuppressWarnings("unchecked")
@Override
public JsonNode requireNonNull() {
return _reportRequiredViolation("requireNonNull() called on `NullNode`");
}
// as with MissingNode, not considered number node; hence defaults are returned if provided
/*
public int asInt(int defaultValue);
public long asLong(long defaultValue);
public double asDouble(double defaultValue);
public boolean asBoolean(boolean defaultValue);
*/
@Override
public final void serialize(JsonGenerator g, SerializerProvider provider)
throws IOException
{
provider.defaultSerializeNull(g);
}
@Override
public boolean equals(Object o) {
// 29-Aug-2019, tatu: [databind#2433] Since custom sub-classes are allowed (bad idea probably),
// need to do better comparison
return (o == this) || (o instanceof NullNode);
}
@Override
public int hashCode() {
return JsonNodeType.NULL.ordinal();
}
}