MongoDB  1.8.5
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mongo::BSONObj Class Reference

C++ representation of a "BSON" object -- that is, an extended JSON-style object in a binary representation. More...

#include <bsonobj.h>

Inheritance diagram for mongo::BSONObj:
mongo::BSONArray

List of all members.

Classes

class  Holder

Public Types

enum  MatchType {
  Equality = 0, LT = 0x1, LTE = 0x3, GTE = 0x6,
  GT = 0x4, opIN = 0x8, NE = 0x9, opSIZE = 0x0A,
  opALL = 0x0B, NIN = 0x0C, opEXISTS = 0x0D, opMOD = 0x0E,
  opTYPE = 0x0F, opREGEX = 0x10, opOPTIONS = 0x11, opELEM_MATCH = 0x12,
  opNEAR = 0x13, opWITHIN = 0x14, opMAX_DISTANCE = 0x15
}
typedef BSONObjIterator iterator

Public Member Functions

 BSONObj (const char *msgdata, bool ifree=false)
 Construct a BSONObj from data in the proper format.
 BSONObj (const Record *r)
 BSONObj ()
 Construct an empty BSONObj -- that is, {}.
bool isOwned () const
 A BSONObj can use a buffer it "owns" or one it does not.
BSONObj getOwned () const
BSONObj copy () const
string toString (bool isArray=false, bool full=false) const
 Readable representation of a BSON object in an extended JSON-style notation.
void toString (StringBuilder &s, bool isArray=false, bool full=false) const
string jsonString (JsonStringFormat format=Strict, int pretty=0) const
 Properly formatted JSON string.
int addFields (BSONObj &from, set< string > &fields)
 note: addFields always adds _id even if not specified
int nFields () const
 returns # of top level fields in the object note: iterates to count the fields
int getFieldNames (set< string > &fields) const
 adds the field names to the fields set.
BSONElement getFieldDotted (const char *name) const
 return has eoo() true if no match supports "." notation to reach into embedded objects
BSONElement getFieldDotted (const string &name) const
 return has eoo() true if no match supports "." notation to reach into embedded objects
void getFieldsDotted (const StringData &name, BSONElementSet &ret) const
 Like getFieldDotted(), but expands multikey arrays and returns all matching objects.
BSONElement getFieldDottedOrArray (const char *&name) const
 Like getFieldDotted(), but returns first array encountered while traversing the dotted fields of name.
BSONElement getField (const StringData &name) const
 Get the field of the specified name.
BSONElement operator[] (const char *field) const
 Get the field of the specified name.
BSONElement operator[] (const string &field) const
BSONElement operator[] (int field) const
bool hasField (const char *name) const
const char * getStringField (const char *name) const
BSONObj getObjectField (const char *name) const
int getIntField (const char *name) const
bool getBoolField (const char *name) const
BSONObj extractFieldsUnDotted (BSONObj pattern) const
 sets element field names to empty string If a field in pattern is missing, it is omitted from the returned object.
BSONObj extractFields (const BSONObj &pattern, bool fillWithNull=false) const
 extract items from object which match a pattern object.
BSONObj filterFieldsUndotted (const BSONObj &filter, bool inFilter) const
BSONElement getFieldUsingIndexNames (const char *fieldName, const BSONObj &indexKey) const
const char * objdata () const
int objsize () const
bool isValid ()
 performs a cursory check on the object's size only.
bool okForStorage () const
bool isEmpty () const
void dump () const
string hexDump () const
 Alternative output format.
int woCompare (const BSONObj &r, const Ordering &o, bool considerFieldName=true) const
 wo='well ordered'.
int woCompare (const BSONObj &r, const BSONObj &ordering=BSONObj(), bool considerFieldName=true) const
 wo='well ordered'.
bool operator< (const BSONObj &other) const
bool operator<= (const BSONObj &other) const
bool operator> (const BSONObj &other) const
bool operator>= (const BSONObj &other) const
int woSortOrder (const BSONObj &r, const BSONObj &sortKey, bool useDotted=false) const
bool woEqual (const BSONObj &r) const
 This is "shallow equality" -- ints and doubles won't match.
BSONElement firstElement () const
bool hasElement (const char *name) const
bool getObjectID (BSONElement &e) const
 Get the _id field from the object.
int hash () const
BSONObj clientReadable () const
BSONObj replaceFieldNames (const BSONObj &obj) const
 Return new object with the field names replaced by those in the passed object.
bool valid () const
 true unless corrupt
string md5 () const
bool operator== (const BSONObj &other) const
void elems (vector< BSONElement > &) const
 add all elements of the object to the specified vector
void elems (list< BSONElement > &) const
 add all elements of the object to the specified list
template<class T >
void Vals (vector< T > &) const
 add all values of the object to the specified vector.
template<class T >
void Vals (list< T > &) const
 add all values of the object to the specified list.
template<class T >
void vals (vector< T > &) const
 add all values of the object to the specified vector.
template<class T >
void vals (list< T > &) const
 add all values of the object to the specified list.
BSONObjIterator begin ()
 use something like this: for( BSONObj::iterator i = myObj.begin(); i.more(); ) { BSONElement e = i.next(); ...
void appendSelfToBufBuilder (BufBuilder &b) const

Friends

class BSONObjIterator

Detailed Description

C++ representation of a "BSON" object -- that is, an extended JSON-style object in a binary representation.

See bsonspec.org.

Note that BSONObj's have a smart pointer capability built in -- so you can pass them around by value. The reference counts used to implement this do not use locking, so copying and destroying BSONObj's are not thread-safe operations.

BSON object format:

code <unsigned totalsize>=""> {<byte bsontype>=""><cstring fieldname>=""><Data>}* EOO

totalSize includes itself.

Data: Bool: <byte> EOO: nothing follows Undefined: nothing follows OID: an OID object NumberDouble: <double> NumberInt: <int32> String: <unsigned32 strsizewithnull>=""><cstring> Date: <8bytes> Regex: <cstring regex>=""><cstring options>=""> Object: a nested object, leading with its entire size, which terminates with EOO. Array: same as object DBRef: <strlen> <cstring ns>=""> <oid> DBRef: a database reference: basically a collection name plus an Object ID BinData: <int len>=""> <byte subtype>=""> <byte[len] data> Code: a function (not a closure): same format as String. Symbol: a language symbol (say a python symbol). same format as String. Code With Scope: <total size>=""><String><Object>


Constructor & Destructor Documentation

mongo::BSONObj::BSONObj ( const char *  msgdata,
bool  ifree = false 
) [inline, explicit]

Construct a BSONObj from data in the proper format.

Parameters:
ifreetrue if the BSONObj should free() the msgdata when it destructs.
mongo::BSONObj::BSONObj ( ) [inline]

Construct an empty BSONObj -- that is, {}.


Member Function Documentation

BSONObjIterator mongo::BSONObj::begin ( ) [inline]

use something like this: for( BSONObj::iterator i = myObj.begin(); i.more(); ) { BSONElement e = i.next(); ...

}

NOINLINE_DECL BSONObj mongo::BSONObj::copy ( ) const [inline]
Returns:
a new full (and owned) copy of the object.
BSONObj mongo::BSONObj::extractFields ( const BSONObj pattern,
bool  fillWithNull = false 
) const

extract items from object which match a pattern object.

e.g., if pattern is { x : 1, y : 1 }, builds an object with x and y elements of this object, if they are present. returns elements with original field names

BSONElement mongo::BSONObj::firstElement ( ) const [inline]
Returns:
first field of the object
bool mongo::BSONObj::getBoolField ( const char *  name) const
Returns:
false if not present
BSONElement mongo::BSONObj::getField ( const StringData name) const [inline]

Get the field of the specified name.

eoo() is true on the returned element if not found.

BSONElement mongo::BSONObj::getFieldDottedOrArray ( const char *&  name) const

Like getFieldDotted(), but returns first array encountered while traversing the dotted fields of name.

The name variable is updated to represent field names with respect to the returned element.

int mongo::BSONObj::getFieldNames ( set< string > &  fields) const

adds the field names to the fields set.

does NOT clear it (appends).

int mongo::BSONObj::getIntField ( const char *  name) const
Returns:
INT_MIN if not present - does some type conversions
BSONObj mongo::BSONObj::getObjectField ( const char *  name) const [inline]
Returns:
subobject of the given name
bool mongo::BSONObj::getObjectID ( BSONElement e) const [inline]

Get the _id field from the object.

For good performance drivers should assure that _id is the first element of the object; however, correct operation is assured regardless.

Returns:
true if found
const char* mongo::BSONObj::getStringField ( const char *  name) const
Returns:
"" if DNE or wrong type
bool mongo::BSONObj::hasElement ( const char *  name) const [inline]
Returns:
true if field exists in the object
bool mongo::BSONObj::hasField ( const char *  name) const [inline]
Returns:
true if field exists
int mongo::BSONObj::hash ( ) const [inline]
Returns:
A hash code for the object
bool mongo::BSONObj::isEmpty ( ) const [inline]
Returns:
true if object is empty -- i.e., {}
bool mongo::BSONObj::isOwned ( ) const [inline]

A BSONObj can use a buffer it "owns" or one it does not.

OWNED CASE If the BSONObj owns the buffer, the buffer can be shared among several BSONObj's (by assignment). In this case the buffer is basically implemented as a shared_ptr. Since BSONObj's are typically immutable, this works well.

UNOWNED CASE A BSONObj can also point to BSON data in some other data structure it does not "own" or free later. For example, in a memory mapped file. In this case, it is important the original data stays in scope for as long as the BSONObj is in use. If you think the original data may go out of scope, call BSONObj::getOwned() to promote your BSONObj to having its own copy.

On a BSONObj assignment, if the source is unowned, both the source and dest will have unowned pointers to the original buffer after the assignment.

If you are not sure about ownership but need the buffer to last as long as the BSONObj, call getOwned(). getOwned() is a no-op if the buffer is already owned. If not already owned, a malloc and memcpy will result.

Most ways to create BSONObj's create 'owned' variants. Unowned versions can be created with: (1) specifying true for the ifree parameter in the constructor (2) calling BSONObjBuilder::done(). Use BSONObjBuilder::obj() to get an owned copy (3) retrieving a subobject retrieves an unowned pointer into the parent BSON object

Returns:
true if this is in owned mode
bool mongo::BSONObj::isValid ( ) [inline]

performs a cursory check on the object's size only.

string mongo::BSONObj::jsonString ( JsonStringFormat  format = Strict,
int  pretty = 0 
) const

Properly formatted JSON string.

Parameters:
prettyif true we try to add some lf's and indentation
string mongo::BSONObj::md5 ( ) const
Returns:
an md5 value for this object.
const char* mongo::BSONObj::objdata ( ) const [inline]
Returns:
the raw data of the object
int mongo::BSONObj::objsize ( ) const [inline]
Returns:
total size of the BSON object in bytes
bool mongo::BSONObj::okForStorage ( ) const
Returns:
if the user is a valid user doc criter: isValid() no . or $ field names
BSONElement mongo::BSONObj::operator[] ( const char *  field) const [inline]

Get the field of the specified name.

eoo() is true on the returned element if not found.

BSONObj mongo::BSONObj::replaceFieldNames ( const BSONObj obj) const

Return new object with the field names replaced by those in the passed object.

string mongo::BSONObj::toString ( bool  isArray = false,
bool  full = false 
) const [inline]

Readable representation of a BSON object in an extended JSON-style notation.

This is an abbreviated representation which might be used for logging.

template<class T >
void mongo::BSONObj::Vals ( vector< T > &  v) const

add all values of the object to the specified vector.

If type mismatches, exception. this is most useful when the BSONObj is an array, but can be used with non-arrays too in theory.

example: bo sub = y["subobj"].Obj(); vector<int> myints; sub.Vals(myints);

template<class T >
void mongo::BSONObj::Vals ( list< T > &  v) const

add all values of the object to the specified list.

If type mismatches, exception.

template<class T >
void mongo::BSONObj::vals ( vector< T > &  v) const

add all values of the object to the specified vector.

If type mismatches, skip.

template<class T >
void mongo::BSONObj::vals ( list< T > &  v) const

add all values of the object to the specified list.

If type mismatches, skip.

int mongo::BSONObj::woCompare ( const BSONObj r,
const Ordering o,
bool  considerFieldName = true 
) const

wo='well ordered'.

fields must be in same order in each object. Ordering is with respect to the signs of the elements and allows ascending / descending key mixing.

Returns:
<0 if l<r. 0 if l==r. >0 if l>r
int mongo::BSONObj::woCompare ( const BSONObj r,
const BSONObj ordering = BSONObj(),
bool  considerFieldName = true 
) const

wo='well ordered'.

fields must be in same order in each object. Ordering is with respect to the signs of the elements and allows ascending / descending key mixing.

Returns:
<0 if l<r. 0 if l==r. >0 if l>r
bool mongo::BSONObj::woEqual ( const BSONObj r) const [inline]

This is "shallow equality" -- ints and doubles won't match.

for a deep equality test use woCompare (which is slower).

int mongo::BSONObj::woSortOrder ( const BSONObj r,
const BSONObj sortKey,
bool  useDotted = false 
) const
Parameters:
useDottedwhether to treat sort key fields as possibly dotted and expand into them

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