MapEntryDeserializer.java
package com.fasterxml.jackson.databind.deser.std;
import java.io.IOException;
import java.util.*;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.deser.*;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.LogicalType;
/**
* Basic serializer that can take JSON "Object" structure and
* construct a {@link java.util.Map} instance, with typed contents.
*<p>
* Note: for untyped content (one indicated by passing Object.class
* as the type), {@link UntypedObjectDeserializer} is used instead.
* It can also construct {@link java.util.Map}s, but not with specific
* POJO types, only other containers and primitives/wrappers.
*/
@JacksonStdImpl
public class MapEntryDeserializer
extends ContainerDeserializerBase<Map.Entry<Object,Object>>
implements ContextualDeserializer
{
private static final long serialVersionUID = 1;
// // Configuration: typing, deserializers
/**
* Key deserializer to use; either passed via constructor
* (when indicated by annotations), or resolved when
* {@link #createContextual} is called;
*/
protected final KeyDeserializer _keyDeserializer;
/**
* Value deserializer.
*/
protected final JsonDeserializer<Object> _valueDeserializer;
/**
* If value instances have polymorphic type information, this
* is the type deserializer that can handle it
*/
protected final TypeDeserializer _valueTypeDeserializer;
/*
/**********************************************************
/* Life-cycle
/**********************************************************
*/
public MapEntryDeserializer(JavaType type,
KeyDeserializer keyDeser, JsonDeserializer<Object> valueDeser,
TypeDeserializer valueTypeDeser)
{
super(type);
if (type.containedTypeCount() != 2) { // sanity check
throw new IllegalArgumentException("Missing generic type information for "+type);
}
_keyDeserializer = keyDeser;
_valueDeserializer = valueDeser;
_valueTypeDeserializer = valueTypeDeser;
}
/**
* Copy-constructor that can be used by sub-classes to allow
* copy-on-write styling copying of settings of an existing instance.
*/
protected MapEntryDeserializer(MapEntryDeserializer src)
{
super(src);
_keyDeserializer = src._keyDeserializer;
_valueDeserializer = src._valueDeserializer;
_valueTypeDeserializer = src._valueTypeDeserializer;
}
protected MapEntryDeserializer(MapEntryDeserializer src,
KeyDeserializer keyDeser, JsonDeserializer<Object> valueDeser,
TypeDeserializer valueTypeDeser)
{
super(src);
_keyDeserializer = keyDeser;
_valueDeserializer = valueDeser;
_valueTypeDeserializer = valueTypeDeser;
}
/**
* Fluent factory method used to create a copy with slightly
* different settings. When sub-classing, MUST be overridden.
*/
@SuppressWarnings("unchecked")
protected MapEntryDeserializer withResolved(KeyDeserializer keyDeser,
TypeDeserializer valueTypeDeser, JsonDeserializer<?> valueDeser)
{
if ((_keyDeserializer == keyDeser) && (_valueDeserializer == valueDeser)
&& (_valueTypeDeserializer == valueTypeDeser)) {
return this;
}
return new MapEntryDeserializer(this,
keyDeser, (JsonDeserializer<Object>) valueDeser, valueTypeDeser);
}
@Override // since 2.12
public LogicalType logicalType() {
// Slightly tricky, could consider POJO too?
return LogicalType.Map;
}
/*
/**********************************************************
/* Validation, post-processing (ResolvableDeserializer)
/**********************************************************
*/
/**
* Method called to finalize setup of this deserializer,
* when it is known for which property deserializer is needed for.
*/
@Override
public JsonDeserializer<?> createContextual(DeserializationContext ctxt,
BeanProperty property) throws JsonMappingException
{
KeyDeserializer kd = _keyDeserializer;
if (kd == null) {
kd = ctxt.findKeyDeserializer(_containerType.containedType(0), property);
} else {
if (kd instanceof ContextualKeyDeserializer) {
kd = ((ContextualKeyDeserializer) kd).createContextual(ctxt, property);
}
}
JsonDeserializer<?> vd = _valueDeserializer;
vd = findConvertingContentDeserializer(ctxt, property, vd);
JavaType contentType = _containerType.containedType(1);
if (vd == null) {
vd = ctxt.findContextualValueDeserializer(contentType, property);
} else { // if directly assigned, probably not yet contextual, so:
vd = ctxt.handleSecondaryContextualization(vd, property, contentType);
}
TypeDeserializer vtd = _valueTypeDeserializer;
if (vtd != null) {
vtd = vtd.forProperty(property);
}
return withResolved(kd, vtd, vd);
}
/*
/**********************************************************
/* ContainerDeserializerBase API
/**********************************************************
*/
@Override
public JavaType getContentType() {
return _containerType.containedType(1);
}
@Override
public JsonDeserializer<Object> getContentDeserializer() {
return _valueDeserializer;
}
// 31-May-2020, tatu: Should probably define but we don't have it yet
// public ValueInstantiator getValueInstantiator() { }
/*
/**********************************************************
/* JsonDeserializer API
/**********************************************************
*/
@SuppressWarnings("unchecked")
@Override
public Map.Entry<Object,Object> deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
{
// Ok: must point to START_OBJECT, FIELD_NAME or END_OBJECT
JsonToken t = p.currentToken();
if (t == JsonToken.START_OBJECT) {
t = p.nextToken();
} else if (t != JsonToken.FIELD_NAME && t != JsonToken.END_OBJECT) {
// Empty array, or single-value wrapped in array?
if (t == JsonToken.START_ARRAY) {
return _deserializeFromArray(p, ctxt);
}
return (Map.Entry<Object,Object>) ctxt.handleUnexpectedToken(getValueType(ctxt), p);
}
if (t != JsonToken.FIELD_NAME) {
if (t == JsonToken.END_OBJECT) {
return ctxt.reportInputMismatch(this,
"Cannot deserialize a Map.Entry out of empty JSON Object");
}
return (Map.Entry<Object,Object>) ctxt.handleUnexpectedToken(handledType(), p);
}
final KeyDeserializer keyDes = _keyDeserializer;
final JsonDeserializer<Object> valueDes = _valueDeserializer;
final TypeDeserializer typeDeser = _valueTypeDeserializer;
final String keyStr = p.currentName();
Object key = keyDes.deserializeKey(keyStr, ctxt);
Object value = null;
// And then the value...
t = p.nextToken();
try {
// Note: must handle null explicitly here; value deserializers won't
if (t == JsonToken.VALUE_NULL) {
value = valueDes.getNullValue(ctxt);
} else if (typeDeser == null) {
value = valueDes.deserialize(p, ctxt);
} else {
value = valueDes.deserializeWithType(p, ctxt, typeDeser);
}
} catch (Exception e) {
wrapAndThrow(ctxt, e, Map.Entry.class, keyStr);
}
// Close, but also verify that we reached the END_OBJECT
t = p.nextToken();
if (t != JsonToken.END_OBJECT) {
if (t == JsonToken.FIELD_NAME) { // most likely
ctxt.reportInputMismatch(this,
"Problem binding JSON into Map.Entry: more than one entry in JSON (second field: '%s')",
p.currentName());
} else {
// how would this occur?
ctxt.reportInputMismatch(this,
"Problem binding JSON into Map.Entry: unexpected content after JSON Object entry: "+t);
}
return null;
}
return new AbstractMap.SimpleEntry<Object,Object>(key, value);
}
@Override
public Map.Entry<Object,Object> deserialize(JsonParser p, DeserializationContext ctxt,
Map.Entry<Object,Object> result) throws IOException
{
throw new IllegalStateException("Cannot update Map.Entry values");
}
@Override
public Object deserializeWithType(JsonParser p, DeserializationContext ctxt,
TypeDeserializer typeDeserializer)
throws IOException
{
// In future could check current token... for now this should be enough:
return typeDeserializer.deserializeTypedFromObject(p, ctxt);
}
}