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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
/**
* @class document::ValueUpdate
* @ingroup document
*
* @brief Superclass for all types of field value update operations.
*
* It declares the interface required for all value updates.
*
* Furthermore, this class inherits from Printable without implementing its
* virtual {@link Printable#print} function, so that all subclasses must also
* implement a human readable output format.
*
* This class is a serializable, serializing its content to a buffer. It is
* however not a deserializable, as it does not serialize the datatype of the
* content it serializes, such that it needs to get a datatype specified upon
* deserialization.
*/
#pragma once
#include "updatevisitor.h"
#include <vespa/document/util/identifiableid.h>
#include <vespa/vespalib/objects/nbostream.h>
#include <vespa/vespalib/util/xmlstream.h>
namespace document {
class DocumentTypeRepo;
class Field;
class FieldValue;
class DataType;
class ValueUpdate
{
protected:
using nbostream = vespalib::nbostream;
public:
using XmlOutputStream = vespalib::xml::XmlOutputStream;
/**
* Create a value update object from the given stream.
*
* @param type A data type that describes the content of the buffer.
* @param buffer The stream that containes the serialized update.
*/
static std::unique_ptr<ValueUpdate> createInstance(const DocumentTypeRepo& repo, const DataType& type, nbostream & buffer);
/** Define all types of value updates. */
enum ValueUpdateType {
Add = IDENTIFIABLE_CLASSID(AddValueUpdate),
Arithmetic = IDENTIFIABLE_CLASSID(ArithmeticValueUpdate),
Assign = IDENTIFIABLE_CLASSID(AssignValueUpdate),
Clear = IDENTIFIABLE_CLASSID(ClearValueUpdate),
Map = IDENTIFIABLE_CLASSID(MapValueUpdate),
Remove = IDENTIFIABLE_CLASSID(RemoveValueUpdate),
TensorModify = IDENTIFIABLE_CLASSID(TensorModifyUpdate),
TensorAdd = IDENTIFIABLE_CLASSID(TensorAddUpdate),
TensorRemove = IDENTIFIABLE_CLASSID(TensorRemoveUpdate)
};
virtual ~ValueUpdate() = default;
virtual bool operator==(const ValueUpdate&) const = 0;
bool operator != (const ValueUpdate & rhs) const { return ! (*this == rhs); }
/**
* Recursively checks the compatibility of this value update as
* applied to the given document field.
*
* @throws IllegalArgumentException Thrown if this value update is not compatible.
*/
virtual void checkCompatibility(const Field& field) const = 0;
/**
* Applies this value update to the given field value.
*
* @return True if value is updated, false if value should be removed.
*/
virtual bool applyTo(FieldValue& value) const = 0;
/**
* Deserializes the given stream into an instance of an update object.
*
* @param type A data type that describes the content of the stream.
* @param buffer The stream that contains the serialized update object.
*/
virtual void deserialize(const DocumentTypeRepo& repo, const DataType& type, nbostream & stream) = 0;
/** @return The operation type. */
ValueUpdateType getType() const noexcept { return _type; }
const char * className() const noexcept;
/**
* Visit this fieldvalue for double dispatch.
*/
virtual void accept(UpdateVisitor &visitor) const = 0;
virtual void print(std::ostream& out, bool verbose, const std::string& indent) const = 0;
virtual void printXml(XmlOutputStream& out) const = 0;
protected:
ValueUpdate(ValueUpdateType type) : _type(type) { }
private:
static std::unique_ptr<ValueUpdate> create(ValueUpdateType type);
ValueUpdateType _type;
};
std::ostream& operator<<(std::ostream& out, const ValueUpdate & p);
}
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