bson::BSONElement Class Reference

BSONElement represents an "element" in a BSONObj. More...

#include <bsonelement.h>

Public Member Functions
string	String () const
	These functions, which start with a capital letter, throw a UserException if the element is not of the required type.
Date_t	Date () const
double	Number () const
double	Double () const
long long	Long () const
bsonDecimal	Decimal () const
int	Int () const
bool	Bool () const
vector< BSONElement >	Array () const
bson::OID	OID () const
void	Null () const
void	OK () const
BSONObj	Obj () const
void	Val (Date_t &v) const
	populate v with the value of the element.
void	Val (long long &v) const
void	Val (bool &v) const
void	Val (BSONObj &v) const
void	Val (bson::OID &v) const
void	Val (int &v) const
void	Val (double &v) const
void	Val (string &v) const
void	Val (bsonDecimal &v) const
bool	ok () const
	Use ok() to check if a value is assigned: if( myObj["foo"].ok() ) ...
string	toString (bool includeFieldName=true, bool full=false) const
void	toString (StringBuilder &s, bool includeFieldName=true, bool full=false) const
string	jsonString (JsonStringFormat format, bool includeFieldNames=true, int pretty=0) const
	operator string () const
BSONType	type () const
	Returns the type of the element.
BSONElement	operator[] (const string &field) const
	retrieve a field within this element throws exception if *this is not an embedded object
int	canonicalType () const
	returns the type of the element fixed for the main type the main purpose is numbers.
bool	eoo () const
	Indicates if it is the end-of-object element, which is present at the end of every BSON object.
int	size (int maxLen) const
	Size of the element.
int	size () const
BSONObj	wrap () const
	Wrap this element up as a singleton object.
BSONObj	wrap (const char *newName) const
	Wrap this element up as a singleton object with a new name.
const char *	fieldName () const
	field name of the element.
const char *	value () const
	raw data of the element's value (so be careful).
int	valuesize () const
	size in bytes of the element's value (when applicable).
bool	isBoolean () const
bool	boolean () const
bool	booleanSafe () const
Date_t	date () const
	Retrieve a java style date value from the element.
bool	trueValue () const
	Convert the value to boolean, regardless of its type, in a javascript-like fashion (i.e., treats zero and null and eoo as false).
bool	isSimpleType () const
	True if number, string, bool, date, OID.
bool	isNumber () const
	True if element is of a numeric type.
double	_numberDouble () const
	Return double value for this field.
int	_numberInt () const
	Return double value for this field.
long long	_numberLong () const
	Return double value for this field.
int	numberInt () const
	Retrieve int value for the element safely.
long long	numberLong () const
	Retrieve long value for the element safely.
bsonDecimal	numberDecimal () const
	Retrieve long value for the element safely.
double	numberDouble () const
	Retrieve the numeric value of the element.
double	number () const
	Retrieve the numeric value of the element.
const bson::OID &	__oid () const
	Retrieve the object ID stored in the object.
bool	isNull () const
	True if element is null.
int	valuestrsize () const
	Size (length) of a string element.
int	objsize () const
const char *	valuestr () const
	Get a string's value.
const char *	valuestrsafe () const
	Get the string value of the element.
string	str () const
	Get the string value of the element.
const char *	codeWScopeCode () const
	Get javascript code of a CodeWScope data element.
const char *	codeWScopeScopeData () const
	Get the scope SavedContext of a CodeWScope data element.
BSONObj	embeddedObject () const
	Get the embedded object this element holds.
BSONObj	embeddedObjectUserCheck () const
BSONObj	codeWScopeObject () const
const char *	binData (int &len) const
	Get raw binary data.
const char *	binDataClean (int &len) const
	Get binary data.
BinDataType	binDataType () const
const char *	regex () const
	Retrieve the regex string for a Regex element.
const char *	regexFlags () const
	Retrieve the regex flags (options) for a Regex element.
string	code () const
	Retrieve the code string for a Code element.
bool	valuesEqual (const BSONElement &r) const
	like operator== but doesn't check the fieldname, just the value.
bool	operator== (const BSONElement &r) const
	Returns true if elements are equal.
int	woCompare (const BSONElement &e, bool considerFieldName=true) const
	Well ordered comparison.
const char *	rawdata () const
int	getGtLtOp (int def=0) const
	0 == Equality, just not defined yet
	BSONElement ()
	Constructs an empty element.
void	validate () const
	Check that data is internally consistent.
bool	mayEncapsulate () const
	True if this element may contain subobjects.
bool	isABSONObj () const
	True if this element can be a BSONObj.
Date_t	timestampTime () const
unsigned int	timestampInc () const
const char *	dbrefNS () const
const bson::OID &	dbrefOID () const
bool	operator< (const BSONElement &other) const
	this does not use fieldName in the comparison, just the value
	BSONElement (const char *d, int maxLen)
	BSONElement (const char *d)
string	_asCode () const
OpTime	_opTime () const

Friends
class	BSONObjIterator
class	BSONObj

Detailed Description

BSONElement represents an "element" in a BSONObj.

So for the object { a : 3, b : "abc" }, 'a : 3' is the first element (key+value).

The BSONElement object points into the BSONObj's data. Thus the BSONObj must stay in scope for the life of the BSONElement.

internals: <type><fieldName>

-----— size() ---------— -fieldNameSize- value() type()

Member Function Documentation

const bson::OID& bson::BSONElement::__oid ( ) const

inline

Retrieve the object ID stored in the object.

You must ensure the element is of type jstOID first.

double bson::BSONElement::_numberDouble ( ) const

inline

Return double value for this field.

MUST be NumberDouble type.

int bson::BSONElement::_numberInt ( ) const

inline

Return double value for this field.

MUST be NumberInt type.

long long bson::BSONElement::_numberLong ( ) const

inline

Return double value for this field.

MUST be NumberLong type.

const char* bson::BSONElement::binData ( int &  len ) const

inline

Get raw binary data.

Element must be of type BinData. Doesn't handle type 2 specially

const char* bson::BSONElement::binDataClean ( int &  len ) const

inline

Get binary data.

Element must be of type BinData. Handles type 2

bool bson::BSONElement::boolean ( ) const

inline

Returns

value of a boolean element. You must assure element is a boolean before calling.

int bson::BSONElement::canonicalType ( ) const

inline

returns the type of the element fixed for the main type the main purpose is numbers.

any numeric type will return NumberDouble

Note: if the order changes, indexes have to be re-built or than can be corruption

const char* bson::BSONElement::codeWScopeCode ( ) const

inline

Get javascript code of a CodeWScope data element.

const char* bson::BSONElement::codeWScopeScopeData ( ) const

inline

Get the scope SavedContext of a CodeWScope data element.

Date_t bson::BSONElement::date ( ) const

inline

Retrieve a java style date value from the element.

Ensure element is of type Date before calling.

See Also

Bool(), trueValue()

BSONObj bson::BSONElement::embeddedObject

(

)

const

Get the embedded object this element holds.

const char* bson::BSONElement::fieldName ( ) const

inline

field name of the element.

e.g., for name : "Joe" "name" is the fieldname

bool bson::BSONElement::isNull ( ) const

inline

True if element is null.

bool bson::BSONElement::isNumber ( ) const

inline

True if element is of a numeric type.

Returns

true if element is of a numeric type.

bool bson::BSONElement::mayEncapsulate ( ) const

inline

True if this element may contain subobjects.

double bson::BSONElement::number ( ) const

inline

Retrieve the numeric value of the element.

If not of a numeric type, returns 0. Note: casts to double, data loss may occur with large (>52 bit) NumberLong values.

bsonDecimal bson::BSONElement::numberDecimal ( ) const

inline

Retrieve long value for the element safely.

Zero returned if not a number.

double bson::BSONElement::numberDouble ( ) const

inline

Retrieve the numeric value of the element.

If not of a numeric type, returns 0. Note: casts to double, data loss may occur with large (>52 bit) NumberLong values.

int bson::BSONElement::numberInt ( ) const

inline

Retrieve int value for the element safely.

Zero returned if not a number.

Zero returned if not a number. Converted to int if another numeric type.

long long bson::BSONElement::numberLong ( ) const

inline

Retrieve long value for the element safely.

Zero returned if not a number.

BSONObj bson::BSONElement::Obj

(

)

const

Returns

the embedded object associated with this field. Note the returned object is a reference to within the parent bson object. If that object is out of scope, this pointer will no longer be valid. Call getOwned() on the returned BSONObj if you need your own copy. throws UserException if the element is not of type object.

bool bson::BSONElement::operator== ( const BSONElement &  r ) const

inline

Returns true if elements are equal.

int bson::BSONElement::size

(

int

maxLen

)

const

Size of the element.

Parameters

maxLen

If maxLen is specified, don't scan more than maxLen bytes to calculate size.

string bson::BSONElement::str ( ) const

inline

Get the string value of the element.

If not a string returns "".

string bson::BSONElement::String ( ) const

inline

These functions, which start with a capital letter, throw a UserException if the element is not of the required type.

Example:

       string foo = obj["foo"].String();

exception if not a string type or DNE

void bson::BSONElement::Val ( Date_t &  v ) const

inline

populate v with the value of the element.

If type does not match, throw exception. Useful in templates.

See Also

BSONObj::Vals().

void bson::BSONElement::validate

(

)

const

Check that data is internally consistent.

const char* bson::BSONElement::value ( ) const

inline

raw data of the element's value (so be careful).

int bson::BSONElement::valuesize ( ) const

inline

size in bytes of the element's value (when applicable).

const char* bson::BSONElement::valuestr ( ) const

inline

Get a string's value.

Also gives you start of the real data for an embedded object. You must assure data is of an appropriate type first – see also valuestrsafe().

const char* bson::BSONElement::valuestrsafe ( ) const

inline

Get the string value of the element.

If not a string returns "".

int bson::BSONElement::valuestrsize ( ) const

inline

Size (length) of a string element.

You must assure of type String first.

Returns

string size including terminating null

int bson::BSONElement::woCompare	(	const BSONElement &	e,
		bool	considerFieldName = true
	)		const

Well ordered comparison.

Returns

<0: l<r. 0:l==r. >0:l>r order by type, field name, and field value. If considerFieldName is true, pay attention to the field name.

BSONObj bson::BSONElement::wrap

(

)

const

Wrap this element up as a singleton object.

BSONObj bson::BSONElement::wrap

(

const char *

newName

)

const

Wrap this element up as a singleton object with a new name.

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The documentation for this class was generated from the following file:

• bsonelement.h