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com.fasterxml.jackson.databind.deser.std.MapEntryDeserializer Maven / Gradle / Ivy

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.
 *

* 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> 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 _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 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 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) 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 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 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) 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) ctxt.handleUnexpectedToken(handledType(), p); } final KeyDeserializer keyDes = _keyDeserializer; final JsonDeserializer 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(key, value); } @Override public Map.Entry deserialize(JsonParser p, DeserializationContext ctxt, Map.Entry 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); } }