com.fasterxml.jackson.jr.ob.impl.ValueWriterLocator Maven / Gradle / Ivy
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package com.fasterxml.jackson.jr.ob.impl;
import java.lang.reflect.*;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
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.ValueWriter;
/**
* 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 ValueWriterLocator extends ValueLocatorBase
{
protected final static BeanPropertyWriter[] NO_PROPS_FOR_WRITE = new BeanPropertyWriter[0];
/*
/**********************************************************************
/* Helper objects, serialization
/**********************************************************************
*/
/**
* Mapping from classes to resolved type constants or indexes, to use
* for serialization.
*/
protected final ConcurrentHashMap _knownSerTypes;
protected final CopyOnWriteArrayList _knownWriters;
/**
* Provider for custom writers, if any; may be null.
*
* @since 2.10
*/
protected final ReaderWriterProvider _writerProvider;
/**
* Provider for reader customizer, if any; may be null.
*
* @since 2.11
*/
protected final ReaderWriterModifier _writerModifier;
/*
/**********************************************************************
/* Instance configuration
/**********************************************************************
*/
protected final int _features;
protected final JSONWriter _writeContext;
/*
/**********************************************************************
/* Instance state, caching
/**********************************************************************
*/
/**
* Reusable lookup key; only used by per-thread instances.
*/
private final ClassKey _key;
private Class _prevClass;
private int _prevType;
/*
/**********************************************************************
/* Construction
/**********************************************************************
*/
/**
* Constructor for the blueprint instance (and variations)
*/
protected ValueWriterLocator(int features,
ReaderWriterProvider rwp, ReaderWriterModifier rwm)
{
_features = features;
_knownSerTypes = new ConcurrentHashMap(20, 0.75f, 2);
_knownWriters = new CopyOnWriteArrayList();
_writeContext = null;
_writerProvider = rwp;
_writerModifier = rwm;
// should not be needed for blueprint instance
_key = null;
}
// for per-call instances
protected ValueWriterLocator(ValueWriterLocator base,
int features, JSONWriter w)
{
_features = features;
_writeContext = w;
_knownSerTypes = base._knownSerTypes;
_knownWriters = base._knownWriters;
_writerProvider = base._writerProvider;
_writerModifier = base._writerModifier;
_key = new ClassKey();
}
public final static ValueWriterLocator blueprint(ReaderWriterProvider rwp, ReaderWriterModifier rwm) {
return new ValueWriterLocator(0, rwp, rwm);
}
public ValueWriterLocator with(ReaderWriterProvider rwp) {
if (rwp == _writerProvider) {
return this;
}
// nothing much to reuse if so, use blueprint ctor
return new ValueWriterLocator(_features, rwp, _writerModifier);
}
public ValueWriterLocator with(ReaderWriterModifier rwm) {
if (rwm == _writerModifier) {
return this;
}
// nothing much to reuse if so, use blueprint ctor
return new ValueWriterLocator(_features, _writerProvider, rwm);
}
public ValueWriterLocator perOperationInstance(JSONWriter w, int features) {
return new ValueWriterLocator(this, features & CACHE_FLAGS, w);
}
/*
/**********************************************************************
/* Public API: writer lookup
/**********************************************************************
*/
public ValueWriter getValueWriter(int index) {
// for simplicity, let's allow caller to pass negative id as is
if (index < 0) {
index = -(index+1);
}
return _knownWriters.get(index);
}
/**
* The main lookup method used to find type identifier for
* given raw class; including Bean types (if allowed).
*/
public final int findSerializationType(Class raw)
{
if (raw == _prevClass) {
return _prevType;
}
if (raw == String.class && (_writerModifier == null)) {
return SER_STRING;
}
final ClassKey k = _key.with(raw, _features);
int type;
Integer I = _knownSerTypes.get(k);
if (I == null) {
type = _findPOJOSerializationType(raw);
_knownSerTypes.put(new ClassKey(raw, _features), Integer.valueOf(type));
} else {
type = I.intValue();
}
_prevType = type;
_prevClass = raw;
return type;
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
protected POJODefinition _resolveBeanDef(Class raw) {
try {
if (_writerModifier != null) {
POJODefinition def = _writerModifier.pojoDefinitionForSerialization(_writeContext, raw);
if (def != null) {
return def;
}
}
return BeanPropertyIntrospector.instance().pojoDefinitionForSerialization(_writeContext, raw);
} catch (Exception e) {
throw new IllegalArgumentException(String.format
("Failed to introspect ClassDefinition for type '%s': %s",
raw.getName(), e.getMessage()), e);
}
}
/**
* Method called to locate a serializer for given type and return numeric id.
* Serializer can be found using one of follow methods (in order of lookups):
*
* - Custom serializer via {@link ReaderWriterProvider}
*
* - Simple type supported out-of-the-box, for types like {@link String},
* {@link Boolean}, {@link Number} and a small number of other JDK types
*
* - Bean-style POJOs with accessors (getters, public fields)
*
*
*/
protected int _findPOJOSerializationType(Class raw)
{
// possible custom type?
if (_writerProvider != null) {
ValueWriter w = _writerProvider.findValueWriter(_writeContext, raw);
if (w != null) {
return _modifyAndRegisterWriter(raw, w);
}
}
int type = _findSimpleType(raw, true);
if (type == SER_UNKNOWN) {
if (JSON.Feature.HANDLE_JAVA_BEANS.isEnabled(_features)) {
final BeanPropertyWriter[] props = _resolveBeanForSer(raw,
_resolveBeanDef(raw));
return _modifyAndRegisterWriter(raw, new BeanWriter(raw, props));
}
} else {
if (_writerModifier != null) {
ValueWriter w = _writerModifier.overrideStandardValueWriter(_writeContext, raw, type);
if (w != null) {
return _registerWriter(raw, w);
}
}
}
return type;
}
private int _modifyAndRegisterWriter(Class rawType, ValueWriter w) {
if (_writerModifier != null) {
w = _writerModifier.modifyValueWriter(_writeContext, rawType, w);
if (w == null) { // sanity check
throw new IllegalArgumentException("ReaderWriterModifier.modifyValueWriter() returned null");
}
}
return _registerWriter(rawType, w);
}
private int _registerWriter(Class rawType, ValueWriter valueWriter) {
// Due to concurrent access, possible that someone might have added it
synchronized (_knownWriters) {
// Important: do NOT try to reuse shared instance; caller needs it
ClassKey k = new ClassKey(rawType, _features);
Integer I = _knownSerTypes.get(k);
// if it was already concurrently added, we'll just discard this copy, return earlier
if (I != null) {
return I.intValue();
}
// otherwise add at the end, use -(index+1) as id
_knownWriters.add(valueWriter);
int typeId = -_knownWriters.size();
_knownSerTypes.put(k, Integer.valueOf(typeId));
return typeId;
}
}
protected BeanPropertyWriter[] _resolveBeanForSer(Class raw, POJODefinition beanDef)
{
final List rawProps = beanDef.getProperties();
final int len = rawProps.size();
List props = new ArrayList(len);
final boolean includeReadOnly = JSON.Feature.WRITE_READONLY_BEAN_PROPERTIES.isEnabled(_features);
final boolean forceAccess = JSON.Feature.FORCE_REFLECTION_ACCESS.isEnabled(_features);
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.getter;
if (m == null) {
if (JSON.Feature.USE_IS_GETTERS.isEnabled(_features)) {
m = rawProp.isGetter;
}
}
Field f = useFields ? rawProp.field : null;
// But if neither regular nor is-getter, move on
if ((m == null) && (f == null)) {
continue;
}
// also: if setter is required to match, skip if none
if (!includeReadOnly && !rawProp.hasSetter()) {
continue;
}
Class type;
if (m != null) {
type = m.getReturnType();
if (forceAccess) {
m.setAccessible(true);
}
} else {
type = f.getType();
if (forceAccess) {
f.setAccessible(true);
}
}
int typeId = _findSimpleType(type, true);
// Give plugin the opportunity to override standard value writer
if (_writerModifier != null && typeId != 0) {
Integer I = _knownSerTypes.get(new ClassKey(type, _features));
if (I == null) {
ValueWriter w = _writerModifier.overrideStandardValueWriter(_writeContext, type, typeId);
if (w != null) {
typeId = _registerWriter(type, w);
}
}
}
props.add(new BeanPropertyWriter(typeId, rawProp.name, rawProp.field, m));
}
int plen = props.size();
BeanPropertyWriter[] propArray = (plen == 0) ? NO_PROPS_FOR_WRITE
: props.toArray(NO_PROPS_FOR_WRITE);
return propArray;
}
}