package com.fasterxml.jackson.databind.deser.std;

import java.io.IOException;
import java.util.Collection;
import java.util.Objects;

import com.fasterxml.jackson.annotation.JsonFormat;

import com.fasterxml.jackson.core.*;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
import com.fasterxml.jackson.databind.deser.NullValueProvider;
import com.fasterxml.jackson.databind.deser.ValueInstantiator;
import com.fasterxml.jackson.databind.introspect.AnnotatedWithParams;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.LogicalType;

Specifically optimized version for Collections that contain String values; reason is that this is a very common type and we can make use of the fact that Strings are final.
/** * Specifically optimized version for {@link java.util.Collection}s * that contain String values; reason is that this is a very common * type and we can make use of the fact that Strings are final. */
@JacksonStdImpl public final class StringCollectionDeserializer extends ContainerDeserializerBase<Collection<String>> implements ContextualDeserializer { private static final long serialVersionUID = 1L; // // Configuration
Value deserializer to use, if NOT the standard one (if it is, will be null).
/** * Value deserializer to use, if NOT the standard one * (if it is, will be null). */
protected final JsonDeserializer<String> _valueDeserializer; // // Instance construction settings:
Instantiator used in case custom handling is needed for creation.
/** * Instantiator used in case custom handling is needed for creation. */
protected final ValueInstantiator _valueInstantiator;
Deserializer that is used iff delegate-based creator is to be used for deserializing from JSON Object.
/** * Deserializer that is used iff delegate-based creator is * to be used for deserializing from JSON Object. */
protected final JsonDeserializer<Object> _delegateDeserializer; // NOTE: no PropertyBasedCreator, as JSON Arrays have no properties /* /********************************************************** /* Life-cycle /********************************************************** */ public StringCollectionDeserializer(JavaType collectionType, JsonDeserializer<?> valueDeser, ValueInstantiator valueInstantiator) { this(collectionType, valueInstantiator, null, valueDeser, valueDeser, null); } @SuppressWarnings("unchecked") protected StringCollectionDeserializer(JavaType collectionType, ValueInstantiator valueInstantiator, JsonDeserializer<?> delegateDeser, JsonDeserializer<?> valueDeser, NullValueProvider nuller, Boolean unwrapSingle) { super(collectionType, nuller, unwrapSingle); _valueDeserializer = (JsonDeserializer<String>) valueDeser; _valueInstantiator = valueInstantiator; _delegateDeserializer = (JsonDeserializer<Object>) delegateDeser; } protected StringCollectionDeserializer withResolved(JsonDeserializer<?> delegateDeser, JsonDeserializer<?> valueDeser, NullValueProvider nuller, Boolean unwrapSingle) { if ((Objects.equals(_unwrapSingle, unwrapSingle)) && (_nullProvider == nuller) && (_valueDeserializer == valueDeser) && (_delegateDeserializer == delegateDeser)) { return this; } return new StringCollectionDeserializer(_containerType, _valueInstantiator, delegateDeser, valueDeser, nuller, unwrapSingle); } @Override // since 2.5 public boolean isCachable() { // 26-Mar-2015, tatu: Important: prevent caching if custom deserializers via annotations // are involved return (_valueDeserializer == null) && (_delegateDeserializer == null); } @Override // since 2.12 public LogicalType logicalType() { return LogicalType.Collection; } /* /********************************************************** /* Validation, post-processing /********************************************************** */ @Override public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException { // May need to resolve types for delegate-based creators: JsonDeserializer<Object> delegate = null; if (_valueInstantiator != null) { // [databind#2324]: check both array-delegating and delegating AnnotatedWithParams delegateCreator = _valueInstantiator.getArrayDelegateCreator(); if (delegateCreator != null) { JavaType delegateType = _valueInstantiator.getArrayDelegateType(ctxt.getConfig()); delegate = findDeserializer(ctxt, delegateType, property); } else if ((delegateCreator = _valueInstantiator.getDelegateCreator()) != null) { JavaType delegateType = _valueInstantiator.getDelegateType(ctxt.getConfig()); delegate = findDeserializer(ctxt, delegateType, property); } } JsonDeserializer<?> valueDeser = _valueDeserializer; final JavaType valueType = _containerType.getContentType(); if (valueDeser == null) { // [databind#125]: May have a content converter valueDeser = findConvertingContentDeserializer(ctxt, property, valueDeser); if (valueDeser == null) { // And we may also need to get deserializer for String valueDeser = ctxt.findContextualValueDeserializer(valueType, property); } } else { // if directly assigned, probably not yet contextual, so: valueDeser = ctxt.handleSecondaryContextualization(valueDeser, property, valueType); } // 11-Dec-2015, tatu: Should we pass basic `Collection.class`, or more refined? Mostly // comes down to "List vs Collection" I suppose... for now, pass Collection Boolean unwrapSingle = findFormatFeature(ctxt, property, Collection.class, JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY); NullValueProvider nuller = findContentNullProvider(ctxt, property, valueDeser); if (isDefaultDeserializer(valueDeser)) { valueDeser = null; } return withResolved(delegate, valueDeser, nuller, unwrapSingle); } /* /********************************************************** /* ContainerDeserializerBase API /********************************************************** */ @SuppressWarnings("unchecked") @Override public JsonDeserializer<Object> getContentDeserializer() { JsonDeserializer<?> deser = _valueDeserializer; return (JsonDeserializer<Object>) deser; } @Override public ValueInstantiator getValueInstantiator() { return _valueInstantiator; } /* /********************************************************** /* JsonDeserializer API /********************************************************** */ @SuppressWarnings("unchecked") @Override public Collection<String> deserialize(JsonParser p, DeserializationContext ctxt) throws IOException { if (_delegateDeserializer != null) { return (Collection<String>) _valueInstantiator.createUsingDelegate(ctxt, _delegateDeserializer.deserialize(p, ctxt)); } final Collection<String> result = (Collection<String>) _valueInstantiator.createUsingDefault(ctxt); return deserialize(p, ctxt, result); } @Override public Collection<String> deserialize(JsonParser p, DeserializationContext ctxt, Collection<String> result) throws IOException { // Ok: must point to START_ARRAY if (!p.isExpectedStartArrayToken()) { return handleNonArray(p, ctxt, result); } if (_valueDeserializer != null) { return deserializeUsingCustom(p, ctxt, result, _valueDeserializer); } try { while (true) { // First the common case: String value = p.nextTextValue(); if (value != null) { result.add(value); continue; } JsonToken t = p.currentToken(); if (t == JsonToken.END_ARRAY) { break; } if (t == JsonToken.VALUE_NULL) { if (_skipNullValues) { continue; } value = (String) _nullProvider.getNullValue(ctxt); } else { value = _parseString(p, ctxt); } result.add(value); } } catch (Exception e) { throw JsonMappingException.wrapWithPath(e, result, result.size()); } return result; } private Collection<String> deserializeUsingCustom(JsonParser p, DeserializationContext ctxt, Collection<String> result, final JsonDeserializer<String> deser) throws IOException { try { while (true) { /* 30-Dec-2014, tatu: This may look odd, but let's actually call method * that suggest we are expecting a String; this helps with some formats, * notably XML. Note, however, that while we can get String, we can't * assume that's what we use due to custom deserializer */ String value; if (p.nextTextValue() == null) { JsonToken t = p.currentToken(); if (t == JsonToken.END_ARRAY) { break; } // Ok: no need to convert Strings, but must recognize nulls if (t == JsonToken.VALUE_NULL) { if (_skipNullValues) { continue; } value = (String) _nullProvider.getNullValue(ctxt); } else { value = deser.deserialize(p, ctxt); } } else { value = deser.deserialize(p, ctxt); } result.add(value); } } catch (Exception e) { throw JsonMappingException.wrapWithPath(e, result, result.size()); } return result; } @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.deserializeTypedFromArray(p, ctxt); }
Helper method called when current token is not START_ARRAY. Will either throw an exception, or try to handle value as if member of implicit array, depending on configuration.
/** * Helper method called when current token is not START_ARRAY. Will either * throw an exception, or try to handle value as if member of implicit * array, depending on configuration. */
@SuppressWarnings("unchecked") private final Collection<String> handleNonArray(JsonParser p, DeserializationContext ctxt, Collection<String> result) throws IOException { // implicit arrays from single values? boolean canWrap = (_unwrapSingle == Boolean.TRUE) || ((_unwrapSingle == null) && ctxt.isEnabled(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY)); if (!canWrap) { if (p.hasToken(JsonToken.VALUE_STRING)) { return _deserializeFromString(p, ctxt); } return (Collection<String>) ctxt.handleUnexpectedToken(_containerType, p); } // Strings are one of "native" (intrinsic) types, so there's never type deserializer involved JsonDeserializer<String> valueDes = _valueDeserializer; JsonToken t = p.currentToken(); String value; if (t == JsonToken.VALUE_NULL) { // 03-Feb-2017, tatu: Does this work? if (_skipNullValues) { return result; } value = (String) _nullProvider.getNullValue(ctxt); } else { try { value = (valueDes == null) ? _parseString(p, ctxt) : valueDes.deserialize(p, ctxt); } catch (Exception e) { throw JsonMappingException.wrapWithPath(e, result, result.size()); } } result.add(value); return result; } }