co.elastic.clients.json.JsonpDeserializer Maven / Gradle / Ivy
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/*
* Licensed to Elasticsearch B.V. under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch B.V. licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package co.elastic.clients.json;
import co.elastic.clients.util.TriFunction;
import jakarta.json.JsonValue;
import jakarta.json.stream.JsonParser;
import jakarta.json.stream.JsonParser.Event;
import java.io.StringReader;
import java.lang.reflect.Type;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.Supplier;
public interface JsonpDeserializer {
/**
* The native JSON events this deserializer accepts as a starting point. For example, native events for
* a boolean are {@link Event#VALUE_TRUE} and {@link Event#VALUE_FALSE}.
*/
EnumSet nativeEvents();
/**
* The JSON events this deserializer accepts as a starting point. For example, events for a boolean are
* {@link Event#VALUE_TRUE}, {@link Event#VALUE_FALSE} and {@link Event#VALUE_STRING}, the latter being
* converted to a boolean using {@link Boolean#parseBoolean(String)}.
*/
EnumSet acceptedEvents();
/**
* Convenience method for {@code acceptedEvents().contains(event)}
*/
default boolean accepts(Event event) {
return acceptedEvents().contains(event);
}
/**
* Deserialize a value. The value starts at the next state in the JSON stream.
*
* Default implementation delegates to {@link #deserialize(JsonParser, JsonpMapper, Event)}
* after having checked that the next event is part of the accepted events.
*
* If the next event is {@link Event#VALUE_NULL}, {@code null} is returned unless {@link Event#VALUE_NULL}
* is part of the deserializer's accepted events.
*
* @param parser the JSON parser
* @param mapper the JSON-P mapper
* @return the parsed value or null
*/
default V deserialize(JsonParser parser, JsonpMapper mapper) {
JsonParser.Event event = parser.next();
// JSON null: return null unless the deserializer can handle it
if (event == JsonParser.Event.VALUE_NULL && !accepts(Event.VALUE_NULL)) {
return null;
}
JsonpUtils.ensureAccepts(this, parser, event);
return deserialize(parser, mapper, event);
}
/**
* Deserialize a value. The value starts at the current state in the JSON stream.
*
* @param parser the JSON parser
* @param mapper the JSON-P mapper
* @param event the current state of {@code parser}, which must be part of {@link #acceptedEvents}
* @return the parsed value
*/
V deserialize(JsonParser parser, JsonpMapper mapper, Event event);
//---------------------------------------------------------------------------------------------
// /**
// * Creates a deserializer for a class that delegates to the mapper provided to
// * {@link #deserialize(JsonParser, JsonpMapper)}.
// */
// static JsonpDeserializer of(Class clazz) {
// return of((Type)clazz);
// }
/**
* Creates a deserializer for a type that delegates to the mapper provided to
* {@link #deserialize(JsonParser, JsonpMapper)}.
*/
static JsonpDeserializer of(Type type) {
return new JsonpDeserializerBase(EnumSet.allOf(JsonParser.Event.class)) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper) {
return mapper.deserialize(parser, type);
}
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, JsonParser.Event event) {
return mapper.deserialize(parser, type, event);
}
};
}
static JsonpDeserializer of(EnumSet acceptedEvents, BiFunction fn) {
return new JsonpDeserializerBase(acceptedEvents) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper) {
return fn.apply(parser, mapper);
}
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, Event event) {
throw new UnsupportedOperationException();
}
};
}
static JsonpDeserializer of(EnumSet acceptedEvents, TriFunction fn) {
return new JsonpDeserializerBase(acceptedEvents) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, Event event) {
return fn.apply(parser, mapper, event);
}
};
}
static JsonpDeserializer lazy(Supplier> ctor) {
return new LazyDeserializer<>(ctor);
}
//----- Builtin types
static JsonpDeserializer fixedValue(T value) {
return new JsonpDeserializerBase(EnumSet.noneOf(Event.class)) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, Event event) {
return value;
}
};
}
static JsonpDeserializer emptyObject(T value) {
return new JsonpDeserializerBase(EnumSet.of(Event.START_OBJECT)) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, Event event) {
if (event == Event.VALUE_NULL) {
return null;
}
JsonpUtils.expectNextEvent(parser, Event.END_OBJECT);
return value;
}
};
}
static JsonpDeserializer stringDeserializer() {
return JsonpDeserializerBase.STRING;
}
static JsonpDeserializer integerDeserializer() {
return JsonpDeserializerBase.INTEGER;
}
static JsonpDeserializer booleanDeserializer() {
return JsonpDeserializerBase.BOOLEAN;
}
static JsonpDeserializer longDeserializer() {
return JsonpDeserializerBase.LONG;
}
static JsonpDeserializer floatDeserializer() {
return JsonpDeserializerBase.FLOAT;
}
static JsonpDeserializer doubleDeserializer() {
return JsonpDeserializerBase.DOUBLE;
}
/** A {@code double} deserializer that will return a default value when the JSON value is {@code null} */
static JsonpDeserializer doubleOrNullDeserializer(double defaultValue) {
return new JsonpDeserializerBase.DoubleOrNullDeserializer(defaultValue);
}
/** An {@code integer} deserializer that will return a default value when the JSON value is {@code null} */
static JsonpDeserializer intOrNullDeserializer(int defaultValue) {
return new JsonpDeserializerBase.IntOrNullDeserializer(defaultValue);
}
static JsonpDeserializer numberDeserializer() {
return JsonpDeserializerBase.NUMBER;
}
static JsonpDeserializer jsonValueDeserializer() {
return JsonpDeserializerBase.JSON_VALUE;
}
static JsonpDeserializer voidDeserializer() {
return JsonpDeserializerBase.VOID;
}
static JsonpDeserializer> arrayDeserializer(JsonpDeserializer itemDeserializer) {
return new JsonpDeserializerBase.ArrayDeserializer<>(itemDeserializer);
}
static JsonpDeserializer> stringMapDeserializer(JsonpDeserializer itemDeserializer) {
return new JsonpDeserializerBase.StringMapDeserializer(itemDeserializer);
}
static JsonpDeserializer> enumMapDeserializer(
JsonpDeserializer keyDeserializer, JsonpDeserializer valueDeserializer
) {
return new JsonpDeserializerBase.EnumMapDeserializer<>(keyDeserializer, valueDeserializer);
}
static JsonpDeserializer> pipeSeparatedDeserializer(JsonEnum.Deserializer enumDeserializer) {
return new JsonEnums.PipeSeparatedDeserializer<>(enumDeserializer);
}
/**
* Creates a deserializer that will accept a value both as regular JSON and as JSON-in-a-string.
*/
static JsonpDeserializer jsonString(JsonpDeserializer valueDeserializer) {
EnumSet acceptedEvents = EnumSet.copyOf(valueDeserializer.acceptedEvents());
acceptedEvents.add(Event.VALUE_STRING);
EnumSet nativeEvents = EnumSet.copyOf(valueDeserializer.nativeEvents());
nativeEvents.add(Event.VALUE_STRING);
return new JsonpDeserializerBase(acceptedEvents, nativeEvents) {
@Override
public T deserialize(JsonParser parser, JsonpMapper mapper, Event event) {
if (event == Event.VALUE_STRING) {
JsonParser stringParser = mapper.jsonProvider().createParser(new StringReader(parser.getString()));
return valueDeserializer.deserialize(stringParser, mapper);
} else {
return valueDeserializer.deserialize(parser, mapper, event);
}
}
};
}
}