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.ContextualDeserializer;
import com.fasterxml.jackson.databind.deser.UnresolvedForwardReference;
import com.fasterxml.jackson.databind.deser.ValueInstantiator;
import com.fasterxml.jackson.databind.deser.impl.ReadableObjectId.Referring;
import com.fasterxml.jackson.databind.deser.std.ContainerDeserializerBase;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
/**
* Basic serializer that can take JSON "Array" structure and
* construct a {@link java.util.Collection} 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.List}s, but not with specific
* POJO types, only other containers and primitives/wrappers.
*/
@JacksonStdImpl
public class CollectionDeserializer
extends ContainerDeserializerBase<Collection<Object>>
implements ContextualDeserializer
{
private static final long serialVersionUID = 3917273725180652224L;
// // Configuration
protected final JavaType _collectionType;
/**
* Value deserializer.
*/
protected final JsonDeserializer<Object> _valueDeserializer;
/**
* If element instances have polymorphic type information, this
* is the type deserializer that can handle it
*/
protected final TypeDeserializer _valueTypeDeserializer;
// // Instance construction settings:
protected final ValueInstantiator _valueInstantiator;
/**
* 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
/**********************************************************
*/
/**
* Constructor for context-free instances, where we do not yet know
* which property is using this deserializer.
*/
public CollectionDeserializer(JavaType collectionType,
JsonDeserializer<Object> valueDeser,
TypeDeserializer valueTypeDeser, ValueInstantiator valueInstantiator)
{
this(collectionType, valueDeser, valueTypeDeser, valueInstantiator, null);
}
/**
* Constructor used when creating contextualized instances.
*/
protected CollectionDeserializer(JavaType collectionType,
JsonDeserializer<Object> valueDeser, TypeDeserializer valueTypeDeser,
ValueInstantiator valueInstantiator,
JsonDeserializer<Object> delegateDeser)
{
super(collectionType);
_collectionType = collectionType;
_valueDeserializer = valueDeser;
_valueTypeDeserializer = valueTypeDeser;
_valueInstantiator = valueInstantiator;
_delegateDeserializer = delegateDeser;
}
/**
* Copy-constructor that can be used by sub-classes to allow
* copy-on-write styling copying of settings of an existing instance.
*/
protected CollectionDeserializer(CollectionDeserializer src)
{
super(src._collectionType);
_collectionType = src._collectionType;
_valueDeserializer = src._valueDeserializer;
_valueTypeDeserializer = src._valueTypeDeserializer;
_valueInstantiator = src._valueInstantiator;
_delegateDeserializer = src._delegateDeserializer;
}
/**
* Fluent-factory method call to construct contextual instance.
*/
@SuppressWarnings("unchecked")
protected CollectionDeserializer withResolved(JsonDeserializer<?> dd,
JsonDeserializer<?> vd, TypeDeserializer vtd)
{
if ((dd == _delegateDeserializer) && (vd == _valueDeserializer) && (vtd == _valueTypeDeserializer)) {
return this;
}
return new CollectionDeserializer(_collectionType,
(JsonDeserializer<Object>) vd, vtd,
_valueInstantiator, (JsonDeserializer<Object>) dd);
}
/*
/**********************************************************
/* 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 CollectionDeserializer createContextual(DeserializationContext ctxt,
BeanProperty property) throws JsonMappingException
{
// May need to resolve types for delegate-based creators:
JsonDeserializer<Object> delegateDeser = null;
if ((_valueInstantiator != null) && _valueInstantiator.canCreateUsingDelegate()) {
JavaType delegateType = _valueInstantiator.getDelegateType(ctxt.getConfig());
if (delegateType == null) {
throw new IllegalArgumentException("Invalid delegate-creator definition for "+_collectionType
+": value instantiator ("+_valueInstantiator.getClass().getName()
+") returned true for 'canCreateUsingDelegate()', but null for 'getDelegateType()'");
}
delegateDeser = findDeserializer(ctxt, delegateType, property);
}
// also, often value deserializer is resolved here:
JsonDeserializer<?> valueDeser = _valueDeserializer;
// #125: May have a content converter
valueDeser = findConvertingContentDeserializer(ctxt, property, valueDeser);
if (valueDeser == null) {
valueDeser = ctxt.findContextualValueDeserializer(
_collectionType.getContentType(), property);
} else { // if directly assigned, probably not yet contextual, so:
valueDeser = ctxt.handleSecondaryContextualization(valueDeser, property);
}
// and finally, type deserializer needs context as well
TypeDeserializer valueTypeDeser = _valueTypeDeserializer;
if (valueTypeDeser != null) {
valueTypeDeser = valueTypeDeser.forProperty(property);
}
return withResolved(delegateDeser, valueDeser, valueTypeDeser);
}
/*
/**********************************************************
/* ContainerDeserializerBase API
/**********************************************************
*/
@Override
public JavaType getContentType() {
return _collectionType.getContentType();
}
@Override
public JsonDeserializer<Object> getContentDeserializer() {
return _valueDeserializer;
}
/*
/**********************************************************
/* JsonDeserializer API
/**********************************************************
*/
@SuppressWarnings("unchecked")
@Override
public Collection<Object> deserialize(JsonParser jp, DeserializationContext ctxt)
throws IOException, JsonProcessingException
{
if (_delegateDeserializer != null) {
return (Collection<Object>) _valueInstantiator.createUsingDelegate(ctxt,
_delegateDeserializer.deserialize(jp, ctxt));
}
/* [JACKSON-620]: empty String may be ok; bit tricky to check, however, since
* there is also possibility of "auto-wrapping" of single-element arrays.
* Hence we only accept empty String here.
*/
if (jp.getCurrentToken() == JsonToken.VALUE_STRING) {
String str = jp.getText();
if (str.length() == 0) {
return (Collection<Object>) _valueInstantiator.createFromString(ctxt, str);
}
}
return deserialize(jp, ctxt, (Collection<Object>) _valueInstantiator.createUsingDefault(ctxt));
}
@Override
public Collection<Object> deserialize(JsonParser jp, DeserializationContext ctxt,
Collection<Object> result)
throws IOException, JsonProcessingException
{
// Ok: must point to START_ARRAY (or equivalent)
if (!jp.isExpectedStartArrayToken()) {
return handleNonArray(jp, ctxt, result);
}
JsonDeserializer<Object> valueDes = _valueDeserializer;
final TypeDeserializer typeDeser = _valueTypeDeserializer;
CollectionReferringAccumulator referringAccumulator =
(valueDes.getObjectIdReader() == null) ? null :
new CollectionReferringAccumulator(_collectionType.getContentType().getRawClass(), result);
JsonToken t;
while ((t = jp.nextToken()) != JsonToken.END_ARRAY) {
try {
Object value;
if (t == JsonToken.VALUE_NULL) {
value = valueDes.getNullValue();
} else if (typeDeser == null) {
value = valueDes.deserialize(jp, ctxt);
} else {
value = valueDes.deserializeWithType(jp, ctxt, typeDeser);
}
if (referringAccumulator != null) {
referringAccumulator.add(value);
} else {
result.add(value);
}
} catch (UnresolvedForwardReference reference) {
if (referringAccumulator == null) {
throw JsonMappingException
.from(jp, "Unresolved forward reference but no identity info.", reference);
}
Referring ref = referringAccumulator.handleUnresolvedReference(reference);
reference.getRoid().appendReferring(ref);
}
}
return result;
}
@Override
public Object deserializeWithType(JsonParser jp, DeserializationContext ctxt,
TypeDeserializer typeDeserializer)
throws IOException, JsonProcessingException
{
// In future could check current token... for now this should be enough:
return typeDeserializer.deserializeTypedFromArray(jp, ctxt);
}
/**
* Helper method called when current token is no START_ARRAY. Will either
* throw an exception, or try to handle value as if member of implicit
* array, depending on configuration.
*/
protected final Collection<Object> handleNonArray(JsonParser jp, DeserializationContext ctxt,
Collection<Object> result)
throws IOException, JsonProcessingException
{
// [JACKSON-526]: implicit arrays from single values?
if (!ctxt.isEnabled(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY)) {
throw ctxt.mappingException(_collectionType.getRawClass());
}
JsonDeserializer<Object> valueDes = _valueDeserializer;
final TypeDeserializer typeDeser = _valueTypeDeserializer;
JsonToken t = jp.getCurrentToken();
Object value;
if (t == JsonToken.VALUE_NULL) {
value = valueDes.getNullValue();
} else if (typeDeser == null) {
value = valueDes.deserialize(jp, ctxt);
} else {
value = valueDes.deserializeWithType(jp, ctxt, typeDeser);
}
result.add(value);
return result;
}
public final static class CollectionReferringAccumulator {
private final Class<?> _elementType;
private final Collection<Object> _result;
/**
* A list of {@link CollectionReferring} to maintain ordering.
*/
private List<CollectionReferring> _accumulator = new ArrayList<CollectionReferring>();
public CollectionReferringAccumulator(Class<?> elementType, Collection<Object> result) {
_elementType = elementType;
_result = result;
}
public void add(Object value)
{
if (_accumulator.isEmpty()) {
_result.add(value);
} else {
CollectionReferring ref = _accumulator.get(_accumulator.size() - 1);
ref.next.add(value);
}
}
public Referring handleUnresolvedReference(UnresolvedForwardReference reference)
{
CollectionReferring id = new CollectionReferring(this, reference, _elementType);
_accumulator.add(id);
return id;
}
public void resolveForwardReference(Object id, Object value) throws IOException
{
Iterator<CollectionReferring> iterator = _accumulator.iterator();
// Resolve ordering after resolution of an id. This mean either:
// 1- adding to the result collection in case of the first unresolved id.
// 2- merge the content of the resolved id with its previous unresolved id.
Collection<Object> previous = _result;
while (iterator.hasNext()) {
CollectionReferring ref = iterator.next();
if (ref.hasId(id)) {
iterator.remove();
previous.add(value);
previous.addAll(ref.next);
return;
}
previous = ref.next;
}
throw new IllegalArgumentException("Trying to resolve a forward reference with id [" + id
+ "] that wasn't previously seen as unresolved.");
}
}
/**
* Helper class to maintain processing order of value. The resolved
* object associated with {@link #_id} comes before the values in
* {@link #next}.
*/
private final static class CollectionReferring extends Referring {
private final CollectionReferringAccumulator _parent;
public final List<Object> next = new ArrayList<Object>();
private CollectionReferring(CollectionReferringAccumulator parent,
UnresolvedForwardReference reference, Class<?> contentType)
{
super(reference, contentType);
_parent = parent;
}
@Override
public void handleResolvedForwardReference(Object id, Object value) throws IOException {
_parent.resolveForwardReference(id, value);
}
}
}