com.fasterxml.jackson.jr.ob.impl.ValueReaderLocator Maven / Gradle / Ivy
Show all versions of jackson-jr-objects Show documentation
package com.fasterxml.jackson.jr.ob.impl;
import java.lang.reflect.*;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import com.fasterxml.jackson.jr.ob.JSON;
import com.fasterxml.jackson.jr.ob.api.ReaderWriterModifier;
import com.fasterxml.jackson.jr.ob.api.ReaderWriterProvider;
import com.fasterxml.jackson.jr.ob.api.ValueReader;
import com.fasterxml.jackson.jr.type.ResolvedType;
import com.fasterxml.jackson.jr.type.TypeBindings;
import com.fasterxml.jackson.jr.type.TypeResolver;
/**
* Helper object used for efficient detection of type information relevant
* to our conversion needs when writing out Java Objects as JSON.
*
* Note that usage pattern is such that a single "root" instance is kept
* by each {@link com.fasterxml.jackson.jr.ob.JSON} instance; and
* an actual per-operation instance must be constructed by calling
* {@link #perOperationInstance}: reason for this is that instances
* use simple caching to handle the common case of repeating types
* within JSON Arrays.
*/
public class ValueReaderLocator
extends ValueLocatorBase
{
/**
* While we should be able to cache all types in the active working set,
* we should also avoid potential unbounded retention, since there is
* often just one big instance per JVM (or at least ClassLoader).
*/
protected final static int MAX_CACHED_READERS = 500;
/*
/**********************************************************************
/* Helper objects
/**********************************************************************
*/
/**
* For generic containers (Collections, Maps, arrays), we may need
* this guy.
*/
protected final TypeResolver _typeResolver;
/**
* Provider for custom readers, if any; may be null.
*
* @since 2.10
*/
protected final ReaderWriterProvider _readerProvider;
/**
* Provider for reader customizer, if any; may be null.
*
* @since 2.11
*/
protected final ReaderWriterModifier _readerModifier;
/*
/**********************************************************************
/* Caching
/**********************************************************************
*/
/**
* Set of {@link ValueReader}s that we have resolved
*/
protected final ConcurrentHashMap _knownReaders;
/**
* During resolution, some readers may be in-progress, but need to be
* linked: for example, with cyclic type references.
*/
protected Map _incompleteReaders;
/**
* Object used for mutex during construction of a Bean deserializer: necessary
* to avoid race conditions during handling of cyclic dependencies.
*/
protected final Object _readerLock;
/*
/**********************************************************************
/* Instance configuration
/**********************************************************************
*/
/**
* Feature flags that are enabled
*/
protected final int _features;
protected final JSONReader _readContext;
/*
/**********************************************************************
/* Instance state, caching
/**********************************************************************
*/
/**
* Reusable lookup key; only used by per-thread instances.
*/
private ClassKey _key;
/*
/**********************************************************************
/* Construction
/**********************************************************************
*/
/**
* Constructor for the blueprint instance
*/
protected ValueReaderLocator(ReaderWriterProvider rwp, ReaderWriterModifier rwm)
{
_features = 0;
_readerProvider = rwp;
_readerModifier = rwm;
_knownReaders = new ConcurrentHashMap(10, 0.75f, 2);
_typeResolver = new TypeResolver();
_readerLock = new Object();
_readContext = null;
}
protected ValueReaderLocator(ValueReaderLocator base, int features,
JSONReader r) {
_features = features;
_readContext = r;
_readerProvider = base._readerProvider;
_readerModifier = base._readerModifier;
_knownReaders = base._knownReaders;
_typeResolver = base._typeResolver;
_readerLock = base._readerLock;
}
protected ValueReaderLocator(ValueReaderLocator base,
ReaderWriterProvider rwp, ReaderWriterModifier rwm)
{
// create new cache as there may be custom writers:
_knownReaders = new ConcurrentHashMap(10, 0.75f, 2);
_readerLock = new Object();
_features = base._features;
_readContext = base._readContext;
_readerProvider = rwp;
_readerModifier = rwm;
_typeResolver = base._typeResolver;
}
public final static ValueReaderLocator blueprint(ReaderWriterProvider rwp, ReaderWriterModifier rwm) {
return new ValueReaderLocator(rwp, rwm);
}
public ValueReaderLocator with(ReaderWriterProvider rwp) {
if (rwp == _readerProvider) {
return this;
}
return new ValueReaderLocator(this, rwp, _readerModifier);
}
public ValueReaderLocator with(ReaderWriterModifier rwm) {
if (rwm == _readerModifier) {
return this;
}
return new ValueReaderLocator(this, _readerProvider, rwm);
}
public ValueReaderLocator perOperationInstance(JSONReader r, int features) {
return new ValueReaderLocator(this, features & CACHE_FLAGS, r);
}
/*
/**********************************************************************
/* Public API, config access
/**********************************************************************
*/
public ReaderWriterProvider readerWriterProvider() { return _readerProvider; }
public ReaderWriterModifier readerWriterModifier() { return _readerModifier; }
/*
/**********************************************************************
/* Public API, operations
/**********************************************************************
*/
/**
* Method used during deserialization to find handler for given
* non-generic type: will first check for already resolved (and cached) readers
* -- and return if one found -- and then if no cached reader found, create
* one, cache, return.
*
* @param raw Type-erased type of value to find reader for
*
* @return ValueReader to use for given type
*/
public ValueReader findReader(Class raw)
{
ClassKey k = (_key == null) ? new ClassKey(raw, _features) : _key.with(raw, _features);
ValueReader vr = _knownReaders.get(k);
if (vr != null) {
return vr;
}
vr = createReader(null, raw, raw);
// 15-Jun-2016, tatu: Let's limit maximum number of readers to prevent
// unbounded memory retention (at least wrt readers)
if (_knownReaders.size() >= MAX_CACHED_READERS) {
_knownReaders.clear();
}
_knownReaders.putIfAbsent(new ClassKey(raw, _features), vr);
return vr;
}
/**
* Factory method for creating standard readers of any declared type.
*
* @param contextType Context for resolving generic type parameters
* @param type Type-erased type of value to construct reader for
* @param genericType Full (possibly) generic type of value to construct reader for (important
* for {@link java.util.Map}, {@link java.util.Collection}).
*/
protected ValueReader createReader(Class contextType, Class type, Type genericType)
{
ValueReader r = _createReader(contextType, type, genericType);
if (_readerModifier != null) {
r = _readerModifier.modifyValueReader(_readContext, type, r);
if (r == null) { // sanity check
throw new IllegalArgumentException("ReaderWriterModifier.modifyValueReader() returned null");
}
}
return r;
}
protected ValueReader _createReader(Class contextType, Class type, Type genericType)
{
if (type == Object.class) {
return AnyReader.std;
}
if (type.isArray()) {
return arrayReader(contextType, type);
}
if (type.isEnum()) {
if (_readerProvider != null) {
ValueReader r = _readerProvider.findValueReader(_readContext, type);
if (r != null) {
return r;
}
}
return enumReader(type);
}
if (Collection.class.isAssignableFrom(type)) {
return collectionReader(contextType, genericType);
}
if (Map.class.isAssignableFrom(type)) {
return mapReader(contextType, genericType);
}
// Unlike with other types, check custom handler here before
// simple type check, to allow overriding handling of `String` etc
if (_readerProvider != null) {
ValueReader r = _readerProvider.findValueReader(_readContext, type);
if (r != null) {
return r;
}
}
int typeId = _findSimpleType(type, false);
if (typeId > 0) {
return new SimpleValueReader(type, typeId);
}
return beanReader(type);
}
/*
/**********************************************************************
/* Factory methods for non-Bean readers
/**********************************************************************
*/
protected ValueReader arrayReader(Class contextType, Class arrayType) {
// TODO: maybe allow custom array readers?
Class elemType = arrayType.getComponentType();
if (!elemType.isPrimitive()) {
return new ArrayReader(arrayType, elemType,
createReader(contextType, elemType, elemType));
}
int typeId = _findSimpleType(arrayType, false);
if (typeId > 0) {
return new SimpleValueReader(arrayType, typeId);
}
throw new IllegalArgumentException("Deserialization of "+arrayType.getName()+" not (yet) supported");
}
protected ValueReader enumReader(Class enumType) {
// Call pojoDefinitionForDeserialization so that the annotation support extension can get custom names for
// enum values
POJODefinition def = null;
if (_readerModifier != null) {
def = _readerModifier.pojoDefinitionForDeserialization(_readContext, enumType);
}
Map byName =
JSON.Feature.ACCEPT_CASE_INSENSITIVE_ENUMS.isEnabled(_features)
? new TreeMap(String.CASE_INSENSITIVE_ORDER)
// Note: we might want to retain declaration order with LHM in future
// for error reporting; but not needed yet
: new HashMap();
Object[] enums = enumType.getEnumConstants();
if (def == null) {
for (Object e : enums) {
byName.put(e.toString(), e);
}
} else {
for (POJODefinition.Prop e : def.getProperties()) {
if (e.field != null && e.field.isEnumConstant()) {
try {
byName.put(e.name, e.field.get(null));
} catch (IllegalAccessException ex) {
// Don't believe that this should be possible, but raise it up just in case
throw new RuntimeException(ex);
}
}
}
}
return new EnumReader(enumType, enums, byName);
}
protected ValueReader collectionReader(Class contextType, Type collectionType)
{
ResolvedType t = _typeResolver.resolve(_bindings(contextType), collectionType);
List params = t.typeParametersFor(Collection.class);
return collectionReader(t.erasedType(), params.get(0));
}
protected ValueReader collectionReader(Class collectionType, ResolvedType valueType)
{
final Class rawValueType = valueType.erasedType();
final ValueReader valueReader;
if (Collection.class.isAssignableFrom(rawValueType)) {
List params = valueType.typeParametersFor(Collection.class);
valueReader = collectionReader(rawValueType, params.get(0));
} else if (Map.class.isAssignableFrom(rawValueType)) {
List params = valueType.typeParametersFor(Map.class);
valueReader = mapReader(rawValueType, params.get(1));
} else {
valueReader = findReader(rawValueType);
}
if (_readerProvider != null) {
ValueReader r = _readerProvider.findCollectionReader(_readContext,
collectionType, valueType, valueReader);
if (r != null) {
return r;
}
}
return new CollectionReader(collectionType, valueReader);
}
protected ValueReader mapReader(Class contextType, Type mapType)
{
ResolvedType t = _typeResolver.resolve(_bindings(contextType), mapType);
List params = t.typeParametersFor(Map.class);
return mapReader(t.erasedType(), params.get(1));
}
protected ValueReader mapReader(Class mapType, ResolvedType valueType)
{
final Class rawValueType = valueType.erasedType();
final ValueReader valueReader;
if (Collection.class.isAssignableFrom(rawValueType)) {
List params = valueType.typeParametersFor(Collection.class);
valueReader = collectionReader(rawValueType, params.get(0));
} else if (Map.class.isAssignableFrom(rawValueType)) {
List params = valueType.typeParametersFor(Map.class);
valueReader = mapReader(rawValueType, params.get(1));
} else {
valueReader = findReader(rawValueType);
}
if (_readerProvider != null) {
ValueReader r = _readerProvider.findMapReader(_readContext,
mapType, valueType, valueReader);
if (r != null) {
return r;
}
}
return new MapReader(mapType, valueReader);
}
protected ValueReader beanReader(Class type)
{
// NOTE: caller (must) handle custom reader lookup earlier, not done here
final ClassKey key = new ClassKey(type, _features);
synchronized (_readerLock) {
if (_incompleteReaders == null) {
_incompleteReaders = new HashMap();
} else { // perhaps it has already been resolved?
ValueReader vr = _incompleteReaders.get(key);
if (vr != null) {
return vr;
}
}
final BeanReader def = _resolveBeanForDeser(type, _resolveBeanDef(type));
try {
_incompleteReaders.put(key, def);
for (Map.Entry entry : def.propertiesByName().entrySet()) {
BeanPropertyReader prop = entry.getValue();
entry.setValue(prop.withReader(createReader(type, prop.rawSetterType(), prop.genericSetterType())));
}
} finally {
_incompleteReaders.remove(key);
}
return def;
}
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
protected POJODefinition _resolveBeanDef(Class raw) {
try {
if (_readerModifier != null) {
POJODefinition def = _readerModifier.pojoDefinitionForDeserialization(_readContext, raw);
if (def != null) {
return def;
}
}
return BeanPropertyIntrospector.instance().pojoDefinitionForDeserialization(_readContext, raw);
} catch (Exception e) {
throw new IllegalArgumentException(String.format
("Failed to introspect ClassDefinition for type '%s': %s",
raw.getName(), e.getMessage()), e);
}
}
protected BeanReader _resolveBeanForDeser(Class raw, POJODefinition beanDef)
{
Constructor defaultCtor = beanDef.defaultCtor;
Constructor stringCtor = beanDef.stringCtor;
Constructor longCtor = beanDef.longCtor;
final boolean forceAccess = JSON.Feature.FORCE_REFLECTION_ACCESS.isEnabled(_features);
if (forceAccess) {
if (defaultCtor != null) {
defaultCtor.setAccessible(true);
}
if (stringCtor != null) {
stringCtor.setAccessible(true);
}
if (longCtor != null) {
longCtor.setAccessible(true);
}
}
final boolean caseInsensitive = JSON.Feature.ACCEPT_CASE_INSENSITIVE_PROPERTIES.isEnabled(_features);
final List rawProps = beanDef.getProperties();
final int len = rawProps.size();
final Map propMap;
Map aliasMapping = null;
if (len == 0) {
propMap = Collections.emptyMap();
} else {
propMap = caseInsensitive
? new TreeMap(String.CASE_INSENSITIVE_ORDER)
// 13-May-2021, tatu: Let's retain ordering here:
: new LinkedHashMap();
final boolean useFields = JSON.Feature.USE_FIELDS.isEnabled(_features);
for (int i = 0; i < len; ++i) {
POJODefinition.Prop rawProp = rawProps.get(i);
Method m = rawProp.setter;
Field f = useFields ? rawProp.field : null;
if (m != null) {
if (forceAccess) {
m.setAccessible(true);
} else if (!Modifier.isPublic(m.getModifiers())) {
// access to non-public setters must be forced to be usable:
m = null;
}
}
// if no setter, field would do as well
if (m == null) {
if (f == null) {
continue;
}
// fields should always be public, but let's just double-check
if (forceAccess) {
f.setAccessible(true);
} else if (!Modifier.isPublic(f.getModifiers())) {
continue;
}
}
propMap.put(rawProp.name, new BeanPropertyReader(rawProp.name, f, m));
// 25-Jan-2020, tatu: Aliases are bit different because we can not tie them into
// specific reader instance, due to resolution of cyclic dependencies. Instead,
// we must link via name of primary property, unfortunately:
if (rawProp.hasAliases()) {
if (aliasMapping == null) {
aliasMapping = caseInsensitive
? new TreeMap(String.CASE_INSENSITIVE_ORDER)
: new HashMap();
}
for (String alias : rawProp.aliases()) {
aliasMapping.put(alias, rawProp.name);
}
}
}
}
return new BeanReader(raw, propMap, defaultCtor, stringCtor, longCtor,
beanDef.getIgnorableNames(), aliasMapping);
}
private TypeBindings _bindings(Class ctxt) {
if (ctxt == null) {
return TypeBindings.emptyBindings();
}
return TypeBindings.create(ctxt, (ResolvedType[]) null);
}
}