Iterator for each record. More...

#include <tkrzw_dbm_shard.h>

Public Member Functions
virtual	~Iterator ()
	Destructor. More...

	Iterator (const Iterator &rhs)=delete
	Copy and assignment are disabled. More...

Iterator &	operator= (const Iterator &rhs)=delete

Status	First () override
	Initializes the iterator to indicate the first record. More...

Status	Last () override
	Initializes the iterator to indicate the last record. More...

Status	Jump (std::string_view key) override
	Initializes the iterator to indicate a specific record. More...

Status	JumpLower (std::string_view key, bool inclusive=false) override
	Initializes the iterator to indicate the last record whose key is lower than a given key. More...

Status	JumpUpper (std::string_view key, bool inclusive=false) override
	Initializes the iterator to indicate the first record whose key is upper than a given key. More...

Status	Next () override
	Moves the iterator to the next record. More...

Status	Previous () override
	Moves the iterator to the previous record. More...

Status	Process (RecordProcessor *proc, bool writable) override
	Processes the current record with a processor. More...

Status	Get (std::string key=nullptr, std::string value=nullptr) override
	Gets the key and the value of the current record of the iterator. More...

Status	Set (std::string_view value, std::string old_key=nullptr, std::string old_value=nullptr) override
	Sets the value of the current record. More...

Status	Remove (std::string old_key=nullptr, std::string old_value=nullptr) override
	Removes the current record. More...

Public Member Functions inherited from tkrzw::DBM::Iterator
virtual Status	Process (RecordLambdaType rec_lambda, bool writable)
	Processes the current record with a lambda function. More...

virtual std::string	GetKey (std::string_view default_value="")
	Gets the key of the current record, in a simple way. More...

virtual std::string	GetValue (std::string_view default_value="")
	Gets the value of the current record, in a simple way. More...

virtual Status	Step (std::string key=nullptr, std::string value=nullptr)
	Gets the current record and moves the iterator to the next record. More...

Friends
class	ShardDBM

Detailed Description

Iterator for each record.

When the database is updated, some iterators may or may not be invalided. Operations with invalidated iterators fails gracefully with NOT_FOUND_ERROR. One iterator cannot be shared by multiple threads.

Constructor & Destructor Documentation

◆ ~Iterator()

virtual tkrzw::ShardDBM::Iterator::~Iterator ( )

virtual

Destructor.

Reimplemented from tkrzw::DBM::Iterator.

◆ Iterator()

tkrzw::ShardDBM::Iterator::Iterator ( const Iterator & rhs )

explicitdelete

Copy and assignment are disabled.

Member Function Documentation

◆ First()

Status tkrzw::ShardDBM::Iterator::First ( )

overridevirtual

Initializes the iterator to indicate the first record.

Returns: The result status.

Even if there's no record, the operation doesn't fail.

Implements tkrzw::DBM::Iterator.

◆ Last()

Status tkrzw::ShardDBM::Iterator::Last ( )

overridevirtual

Initializes the iterator to indicate the last record.

Returns: The result status.

Even if there's no record, the operation doesn't fail. This method is suppoerted only by ordered databases.

Implements tkrzw::DBM::Iterator.

◆ Jump()

Status tkrzw::ShardDBM::Iterator::Jump ( std::string_view key )

overridevirtual

Initializes the iterator to indicate a specific record.

Parameters

key	The key of the record to look for.

Returns: The result status.

Ordered databases can support "lower bound" jump; If there's no record with the same key, the iterator refers to the first record whose key is greater than the given key. The operation fails with unordered databases if there's no record with the same key.

Implements tkrzw::DBM::Iterator.

◆ JumpLower()

Status tkrzw::ShardDBM::Iterator::JumpLower	(	std::string_view	key,
		bool	inclusive = `false`
	)

overridevirtual

Initializes the iterator to indicate the last record whose key is lower than a given key.

Parameters

key	The key to compare with.
inclusive	If true, the considtion is inclusive: equal to or lower than the key.

Returns: The result status.

Even if there's no matching record, the operation doesn't fail. This method is suppoerted only by ordered databases.

Implements tkrzw::DBM::Iterator.

◆ JumpUpper()

Status tkrzw::ShardDBM::Iterator::JumpUpper	(	std::string_view	key,
		bool	inclusive = `false`
	)

overridevirtual

Initializes the iterator to indicate the first record whose key is upper than a given key.

Parameters

key	The key to compare with.
inclusive	If true, the considtion is inclusive: equal to or upper than the key.

Returns: The result status.

Even if there's no matching record, the operation doesn't fail. This method is suppoerted only by ordered databases.

Implements tkrzw::DBM::Iterator.

◆ Next()

Status tkrzw::ShardDBM::Iterator::Next ( )

overridevirtual

Moves the iterator to the next record.

Returns: The result status.

If the current record is missing, the operation fails. Even if there's no next record, the operation doesn't fail.

Implements tkrzw::DBM::Iterator.

◆ Previous()

Status tkrzw::ShardDBM::Iterator::Previous ( )

overridevirtual

Moves the iterator to the previous record.

Returns: The result status.

If the current record is missing, the operation fails. Even if there's no previous record, the operation doesn't fail. This method is suppoerted only by ordered databases.

Implements tkrzw::DBM::Iterator.

◆ Process()

Status tkrzw::ShardDBM::Iterator::Process	(	RecordProcessor *	proc,
		bool	writable
	)

overridevirtual

Processes the current record with a processor.

Parameters

proc	The pointer to the processor object.
writable	True if the processor can edit the record.

Returns: The result status.

If the current record exists, the ProcessFull of the processor is called. Otherwise, this method fails and no method of the processor is called. If the current record is removed, the iterator is moved to the next record.

Implements tkrzw::DBM::Iterator.

◆ Get()

Status tkrzw::ShardDBM::Iterator::Get	(	std::string *	key = `nullptr`,
		std::string *	value = `nullptr`
	)

overridevirtual

Gets the key and the value of the current record of the iterator.

Parameters

key	The pointer to a string object to contain the record key. If it is nullptr, the key data is ignored.
value	The pointer to a string object to contain the record value. If it is nullptr, the value data is ignored.

Returns: The result status.

Reimplemented from tkrzw::DBM::Iterator.

◆ Set()

Status tkrzw::ShardDBM::Iterator::Set	(	std::string_view	value,
		std::string *	old_key = `nullptr`,
		std::string *	old_value = `nullptr`
	)

overridevirtual

Sets the value of the current record.

Parameters

value	The value of the record.
old_key	The pointer to a string object to contain the old key. If it is nullptr, it is ignored.
old_value	The pointer to a string object to contain the old value. If it is nullptr, it is ignored.

Returns: The result status.

Reimplemented from tkrzw::DBM::Iterator.

◆ Remove()

Status tkrzw::ShardDBM::Iterator::Remove	(	std::string *	old_key = `nullptr`,
		std::string *	old_value = `nullptr`
	)

overridevirtual

Removes the current record.

Parameters

old_key	The pointer to a string object to contain the old key. If it is nullptr, it is ignored.
old_value	The pointer to a string object to contain the old value. If it is nullptr, it is ignored.

Returns: The result status.

If possible, the iterator moves to the next record.

Reimplemented from tkrzw::DBM::Iterator.

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ ~Iterator()

◆ Iterator()

Member Function Documentation

◆ First()

◆ Last()

◆ Jump()

◆ JumpLower()

◆ JumpUpper()

◆ Next()

◆ Previous()

◆ Process()

◆ Get()

◆ Set()

◆ Remove()