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package com.fasterxml.jackson.jr.ob.impl;
import java.lang.reflect.*;
import java.util.*;
import com.fasterxml.jackson.jr.ob.JSON;
import com.fasterxml.jackson.jr.ob.impl.POJODefinition.Prop;
import com.fasterxml.jackson.jr.ob.impl.POJODefinition.PropBuilder;
/**
* Helper class that jackson-jr uses by default to introspect POJO properties
* (represented as {@link POJODefinition}) to build general POJO readers
* (deserializers) and writers (serializers).
*
* Note that most of the usage is via {@link ValueReaderLocator} and
* {@link ValueWriterLocator}
*
* @since 2.11
*/
public class BeanPropertyIntrospector
{
protected final static Prop[] NO_PROPS = new Prop[0];
private final static BeanPropertyIntrospector INSTANCE = new BeanPropertyIntrospector();
public BeanPropertyIntrospector() { }
public static BeanPropertyIntrospector instance() { return INSTANCE; }
public POJODefinition pojoDefinitionForDeserialization(JSONReader r, Class pojoType) {
return _introspectDefinition(pojoType, false, r.features(),
RecordsHelpers.isRecordType(pojoType));
}
public POJODefinition pojoDefinitionForSerialization(JSONWriter w, Class pojoType) {
return _introspectDefinition(pojoType, true, w.features(),
RecordsHelpers.isRecordType(pojoType));
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
private POJODefinition _introspectDefinition(Class beanType,
boolean forSerialization, int features, boolean isRecord)
{
// 21-Oct-2024, tatu: [jackson-jr#167] Need to retain property order
// for Deserialization, to keep Record properties ordered.
// For Serialization OTOH we need sorting (although would probably
// be better to sort after the fact, maybe in future)
Map propsByName = forSerialization ?
new TreeMap<>() : new LinkedHashMap<>();
_introspect(beanType, propsByName, features, isRecord);
final BeanConstructors constructors;
if (forSerialization) {
constructors = null;
} else {
constructors = new BeanConstructors(beanType);
if (isRecord) {
Constructor canonical = RecordsHelpers.findCanonicalConstructor(beanType);
if (canonical == null) { // should never happen
throw new IllegalArgumentException(
"Unable to find canonical constructor of Record type `"+beanType.getClass().getName()+"`");
}
constructors.addRecordConstructor(canonical);
} else {
for (Constructor ctor : beanType.getDeclaredConstructors()) {
Class[] argTypes = ctor.getParameterTypes();
if (argTypes.length == 0) {
constructors.addNoArgsConstructor(ctor);
} else if (argTypes.length == 1) {
Class argType = argTypes[0];
if (argType == String.class) {
constructors.addStringConstructor(ctor);
} else if (argType == Integer.class || argType == Integer.TYPE) {
constructors.addIntConstructor(ctor);
} else if (argType == Long.class || argType == Long.TYPE) {
constructors.addLongConstructor(ctor);
}
}
}
}
}
final int len = propsByName.size();
Prop[] props;
if (len == 0) {
props = NO_PROPS;
} else {
props = new Prop[len];
int i = 0;
for (PropBuilder builder : propsByName.values()) {
props[i++] = builder.build();
}
}
return new POJODefinition(beanType, props, constructors);
}
private static void _introspect(Class currType, Map props,
int features, boolean isRecord)
{
if (currType == null || currType == Object.class) {
return;
}
// First, check base type
_introspect(currType.getSuperclass(), props, features, isRecord);
final boolean noStatics = JSON.Feature.INCLUDE_STATIC_FIELDS.isDisabled(features);
// 14-Jun-2024, tatu: Need to enable "matching getters" naming style for Java Records
// too, regardless of `Feature.USE_FIELD_MATCHING_GETTERS`
final boolean isFieldNameGettersEnabled = isRecord
|| JSON.Feature.USE_FIELD_MATCHING_GETTERS.isEnabled(features);
final Map fieldNameMap = isFieldNameGettersEnabled ? new LinkedHashMap<>() : null;
// then public fields (since 2.8); may or may not be ultimately included
// but at this point still possible
for (Field f : currType.getDeclaredFields()) {
// First things first: skip synthetics, Enum constants
if (f.isEnumConstant() || f.isSynthetic()) {
continue;
}
// Only include static members if (a) inclusion feature enabled and
// (b) not final (cannot deserialize final fields)
if (Modifier.isStatic(f.getModifiers()) && (noStatics || Modifier.isFinal(f.getModifiers()))) {
continue;
}
// But for possible renaming, even non-public Fields have effect so:
if (fieldNameMap != null) {
fieldNameMap.put(f.getName(), f);
}
if (Modifier.isPublic(f.getModifiers())) {
_propFrom(props, f.getName()).withField(f);
} else if (isRecord) {
// 21-Oct-2024, tatu: [jackson-jr#167] Need to retain ordering of Record
// properties. One way is to pre-create properties like so.
_propFrom(props, f.getName());
}
}
// then get methods from within this class
for (Method m : currType.getDeclaredMethods()) {
final int flags = m.getModifiers();
// 13-Jun-2015, tatu: Skip synthetic, bridge methods altogether, for now
// at least (add more complex handling only if absolutely necessary)
if (Modifier.isStatic(flags) || m.isSynthetic() || m.isBridge() || isGroovyMetaClass(m.getReturnType())) {
continue;
}
Class argTypes[] = m.getParameterTypes();
if (argTypes.length == 0) { // getter?
// getters must be public to be used
if (!Modifier.isPublic(flags)) {
continue;
}
Class resultType = m.getReturnType();
if (resultType == Void.class) {
continue;
}
String name = m.getName();
if (name.startsWith("get")) {
if (name.length() > 3) {
name = decap(name.substring(3));
_propFrom(props, name).withGetter(m);
}
} else if (name.startsWith("is")) {
if (name.length() > 2) {
// May or may not be used, but collect for now all the same:
name = decap(name.substring(2));
_propFrom(props, name).withIsGetter(m);
}
} else if (isFieldNameGettersEnabled) {
// 10-Mar-2024: [jackson-jr#94]:
// This will allow getters with field name as their getters,
// like the ones generated by Groovy (or JDK 17 for Records).
// If method name matches with field name, & method return
// type matches the field type only then it can be considered a getter.
Field field = fieldNameMap.get(name);
if (field != null && Modifier.isPublic(m.getModifiers())
&& m.getReturnType().equals(field.getType())) {
// NOTE: do NOT decap, field name should be used as-is
_propFrom(props, name).withGetter(m);
}
}
} else if (argTypes.length == 1) { // setter?
// Non-public setters are fine if we can force access, don't yet check
// let's also not bother about return type; setters that return value are fine
String name = m.getName();
if (!name.startsWith("set") || name.length() == 3) {
continue;
}
name = decap(name.substring(3));
_propFrom(props, name).withSetter(m);
}
}
}
private static PropBuilder _propFrom(Map props, String name) {
return props.computeIfAbsent(name, Prop::builder);
}
private static String decap(String name) {
char c = name.charAt(0);
char lowerC = Character.toLowerCase(c);
if (c != lowerC) {
// First: do NOT lower case if more than one leading upper case letters:
if ((name.length() == 1)
|| !Character.isUpperCase(name.charAt(1))) {
char chars[] = name.toCharArray();
chars[0] = lowerC;
return new String(chars);
}
}
return name;
}
/**
* Helper method to detect Groovy's problematic metadata accessor type.
*
* NOTE: Groovy MetaClass have cyclic reference, and hence the class containing
* it should not be serialized without either removing that reference,
* or skipping over such references.
*/
protected static boolean isGroovyMetaClass(Class clazz) {
return "groovy.lang.MetaClass".equals(clazz.getName());
}
}