Interface of iterator for each record. More...

#include <tkrzw_dbm.h>

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

virtual Status	First ()=0
	Initializes the iterator to indicate the first record. More...

virtual Status	Last ()=0
	Initializes the iterator to indicate the last record. More...

virtual Status	Jump (std::string_view key)=0
	Initializes the iterator to indicate a specific record. More...

virtual Status	JumpLower (std::string_view key, bool inclusive=false)=0
	Initializes the iterator to indicate the last record whose key is lower than a given key. More...

virtual Status	JumpUpper (std::string_view key, bool inclusive=false)=0
	Initializes the iterator to indicate the first record whose key is upper than a given key. More...

virtual Status	Next ()=0
	Moves the iterator to the next record. More...

virtual Status	Previous ()=0
	Moves the iterator to the previous record. More...

virtual Status	Process (RecordProcessor *proc, bool writable)=0
	Processes the current record with a processor. More...

virtual Status	Process (RecordLambdaType rec_lambda, bool writable)
	Processes the current record with a lambda function. More...

virtual Status	Get (std::string key=nullptr, std::string value=nullptr)
	Gets the key and the value of the current record of the iterator. 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	Set (std::string_view value, std::string old_key=nullptr, std::string old_value=nullptr)
	Sets the value of the current record. More...

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

Detailed Description

Interface of iterator for each record.

Constructor & Destructor Documentation

◆ ~Iterator()

virtual tkrzw::DBM::Iterator::~Iterator ( )

virtualdefault

Destructor.

Reimplemented in tkrzw::PolyDBM::Iterator, tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

Member Function Documentation

◆ First()

virtual Status tkrzw::DBM::Iterator::First ( )

pure virtual

Initializes the iterator to indicate the first record.

Returns: The result status.

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

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Last()

virtual Status tkrzw::DBM::Iterator::Last ( )

pure virtual

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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Jump()

virtual Status tkrzw::DBM::Iterator::Jump ( std::string_view key )

pure virtual

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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ JumpLower()

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

pure virtual

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 condition 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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ JumpUpper()

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

pure virtual

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 condition 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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Next()

virtual Status tkrzw::DBM::Iterator::Next ( )

pure virtual

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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Previous()

virtual Status tkrzw::DBM::Iterator::Previous ( )

pure virtual

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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Process() [1/2]

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

pure virtual

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.

Implemented in tkrzw::TreeDBM::Iterator, tkrzw::TinyDBM::Iterator, tkrzw::StdTreeDBM::Iterator, tkrzw::StdHashDBM::Iterator, tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, tkrzw::PolyDBM::Iterator, tkrzw::HashDBM::Iterator, tkrzw::CacheDBM::Iterator, and tkrzw::BabyDBM::Iterator.

◆ Process() [2/2]

virtual Status tkrzw::DBM::Iterator::Process	(	RecordLambdaType	rec_lambda,
		bool	writable
	)

virtual

Processes the current record with a lambda function.

Parameters

rec_lambda	The lambda function to process a record. The first parameter is the key of the record. The second parameter is the value of the existing record. The return value is a string reference to RecordProcessor::NOOP, RecordProcessor::REMOVE, or the new record value.
writable	True if the processor can edit the record.

Returns: The result status.

◆ Get()

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

virtual

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 in tkrzw::SkipDBM::Iterator, tkrzw::ShardDBM::Iterator, and tkrzw::PolyDBM::Iterator.

◆ GetKey()

virtual std::string tkrzw::DBM::Iterator::GetKey ( std::string_view default_value = "" )

virtual

Gets the key of the current record, in a simple way.

Parameters

default_value The value to be returned on failure.

Returns: The key of the current record on success, or the default value on failure.

◆ GetValue()

virtual std::string tkrzw::DBM::Iterator::GetValue ( std::string_view default_value = "" )

virtual

Gets the value of the current record, in a simple way.

Parameters

default_value The value to be returned on failure.

Returns: The value of the current record on success, or the default value on failure.

◆ Set()

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

virtual

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 in tkrzw::ShardDBM::Iterator, and tkrzw::PolyDBM::Iterator.

◆ Remove()

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

virtual

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 in tkrzw::ShardDBM::Iterator, and tkrzw::PolyDBM::Iterator.

◆ Step()

virtual Status tkrzw::DBM::Iterator::Step	(	std::string *	key = `nullptr`,
		std::string *	value = `nullptr`
	)

virtual

Gets the current record and moves the iterator to the next record.

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.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Iterator()

Member Function Documentation

◆ First()

◆ Last()

◆ Jump()

◆ JumpLower()

◆ JumpUpper()

◆ Next()

◆ Previous()

◆ Process() [1/2]

◆ Process() [2/2]

◆ Get()

◆ GetKey()

◆ GetValue()

◆ Set()

◆ Remove()

◆ Step()