Drizzled Public API Documentation

Json::Value Class Reference

Represents a JSON value. More...

#include <value.h>

Classes

struct  CommentInfo
class  CZString
union  ValueHolder

Public Types

typedef std::vector< std::string > Members
typedef ValueIterator iterator
typedef ValueConstIterator const_iterator
typedef Json::UInt UInt
typedef Json::Int Int
typedef UInt ArrayIndex
typedef std::map< CZString, ValueObjectValues

Public Member Functions

 Value (ValueType type=nullValue)
 Create a default Value of the given type.
 Value (Int value)
 Value (UInt value)
 Value (double value)
 Value (const char *value)
 Value (const char *beginValue, const char *endValue)
 Value (const StaticString &value)
 Constructs a value from a static string.
 Value (const std::string &value)
 Value (bool value)
 Value (const Value &other)
Valueoperator= (const Value &other)
void swap (Value &other)
ValueType type () const
bool operator< (const Value &other) const
bool operator<= (const Value &other) const
bool operator>= (const Value &other) const
bool operator> (const Value &other) const
bool operator== (const Value &other) const
bool operator!= (const Value &other) const
int compare (const Value &other)
const char * asCString () const
std::string asString () const
Int asInt () const
UInt asUInt () const
double asDouble () const
bool asBool () const
bool isNull () const
bool isBool () const
bool isInt () const
bool isUInt () const
bool isIntegral () const
bool isDouble () const
bool isNumeric () const
bool isString () const
bool isArray () const
bool isObject () const
bool isConvertibleTo (ValueType other) const
UInt size () const
 Number of values in array or object.
bool empty () const
 Return true if empty array, empty object, or null; otherwise, false.
bool operator! () const
 Return isNull()
void clear ()
void resize (UInt size)
Valueoperator[] (UInt index)
const Valueoperator[] (UInt index) const
Value get (UInt index, const Value &defaultValue) const
bool isValidIndex (UInt index) const
 Return true if index < size().
Valueappend (const Value &value)
 Append value to array at the end.
Valueoperator[] (const char *key)
 Access an object value by name, create a null member if it does not exist.
const Valueoperator[] (const char *key) const
 Access an object value by name, returns null if there is no member with that name.
Valueoperator[] (const std::string &key)
 Access an object value by name, create a null member if it does not exist.
const Valueoperator[] (const std::string &key) const
 Access an object value by name, returns null if there is no member with that name.
Valueoperator[] (const StaticString &key)
 Access an object value by name, create a null member if it does not exist.
Value get (const char *key, const Value &defaultValue) const
 Return the member named key if it exist, defaultValue otherwise.
Value get (const std::string &key, const Value &defaultValue) const
 Return the member named key if it exist, defaultValue otherwise.
Value removeMember (const char *key)
 Remove and return the named member.
Value removeMember (const std::string &key)
 Same as removeMember(const char*)
bool isMember (const char *key) const
 Return true if the object has a member named key.
bool isMember (const std::string &key) const
 Return true if the object has a member named key.
Members getMemberNames () const
 Return a list of the member names.
void setComment (const char *comment, CommentPlacement placement)
 Comments must be //... or /* ... */.
void setComment (const std::string &comment, CommentPlacement placement)
 Comments must be //... or /* ... */.
bool hasComment (CommentPlacement placement) const
std::string getComment (CommentPlacement placement) const
 Include delimiters and embedded newlines.
std::string toStyledString () const
const_iterator begin () const
const_iterator end () const
iterator begin ()
iterator end ()

Static Public Attributes

static const Value null
static const Int minInt = Int( ~(UInt(-1)/2) )
static const Int maxInt = Int( UInt(-1)/2 )
static const UInt maxUInt = UInt(-1)

Private Member Functions

ValueresolveReference (const char *key, bool isStatic)

Private Attributes

union Json::Value::ValueHolder value_
ValueType type_
bool allocated_
CommentInfocomments_

Friends

class ValueIteratorBase

Detailed Description

Represents a JSON value.

This class is a discriminated union wrapper that can represents a:

  • signed integer [range: Value::minInt - Value::maxInt]
  • unsigned integer (range: 0 - Value::maxUInt)
  • double
  • UTF-8 string
  • boolean
  • 'null'
  • an ordered list of Value
  • collection of name/value pairs (javascript object)

The type of the held value is represented by a ValueType and can be obtained using type().

values of an objectValue or arrayValue can be accessed using operator[]() methods. Non const methods will automatically create the a nullValue element if it does not exist. The sequence of an arrayValue will be automatically resize and initialized with nullValue. resize() can be used to enlarge or truncate an arrayValue.

The get() methods can be used to obtanis default value in the case the required element does not exist.

It is possible to iterate over the list of a objectValue values using the getMemberNames() method.

Definition at line 149 of file value.h.

Constructor & Destructor Documentation

Json::Value::Value ( ValueType  type = nullValue)

Create a default Value of the given type.

  This is a very useful constructor.
  To create an empty array, pass arrayValue.
  To create an empty object, pass objectValue.
  Another Value can then be set to this one by assignment.

This is useful since clear() and resize() will not alter types.

  Examples:
Json::Value null_value; // null
Json::Value arr_value(Json::arrayValue); // []
Json::Value obj_value(Json::objectValue); // {}

Definition at line 304 of file json_value.cpp.

References Json::arrayValue, Json::booleanValue, Json::intValue, Json::nullValue, Json::objectValue, Json::realValue, Json::stringValue, and Json::uintValue.

Referenced by operator[](), and resize().

Json::Value::Value ( const StaticString value)

Constructs a value from a static string.

Like other value string constructor but do not duplicate the string for internal storage. The given string must remain alive after the call to this constructor. Example of usage:

Json::Value aValue( StaticString("some text") );

Definition at line 418 of file json_value.cpp.

Member Function Documentation

Value & Json::Value::append ( const Value value)

Append value to array at the end.

Equivalent to jsonvalue[jsonvalue.size()] = value;

Definition at line 1153 of file json_value.cpp.

References size().

void Json::Value::clear ( )

Remove all object members and array elements.

Precondition
type() is arrayValue, objectValue, or nullValue
Postcondition
type() is unchanged

Definition at line 961 of file json_value.cpp.

References Json::arrayValue, Json::nullValue, and Json::objectValue.

Referenced by resize().

Value Json::Value::get ( UInt  index,
const Value defaultValue 
) const

If the array contains at least index+1 elements, returns the element value, otherwise returns defaultValue.

Definition at line 1081 of file json_value.cpp.

Value::Members Json::Value::getMemberNames ( ) const

Return a list of the member names.

If null, return an empty list.

Precondition
type() is objectValue or nullValue
Postcondition
if type() was nullValue, it remains nullValue

Definition at line 1240 of file json_value.cpp.

References Json::nullValue, and Json::objectValue.

Value & Json::Value::operator[] ( UInt  index)

Access an array element (zero based index ). If the array contains less than index element, then null value are inserted in the array so that its size is index+1. (You may need to say 'value[0u]' to get your compiler to distinguish this from the operator[] which takes a string.)

Definition at line 1010 of file json_value.cpp.

References Json::arrayValue, Json::nullValue, and Value().

const Value & Json::Value::operator[] ( UInt  index) const

Access an array element (zero based index ) (You may need to say 'value[0u]' to get your compiler to distinguish this from the operator[] which takes a string.)

Definition at line 1031 of file json_value.cpp.

References Json::arrayValue, and Json::nullValue.

Value & Json::Value::operator[] ( const StaticString key)

Access an object value by name, create a null member if it does not exist.

If the object as no entry for that name, then the member name used to store the new entry is not duplicated. Example of use:

Json::Value object;
static const StaticString code("code");
object[code] = 1234;

Definition at line 1130 of file json_value.cpp.

Value Json::Value::removeMember ( const char *  key)

Remove and return the named member.

Do nothing if it did not exist.

Returns
the removed Value, or null.
Precondition
type() is objectValue or nullValue
Postcondition
type() is unchanged

Definition at line 1176 of file json_value.cpp.

References Json::nullValue, and Json::objectValue.

Referenced by removeMember().

void Json::Value::resize ( UInt  size)

Resize the array to size elements. New elements are initialized to null. May only be called on nullValue or arrayValue.

Precondition
type() is arrayValue or nullValue
Postcondition
type() is arrayValue

Definition at line 986 of file json_value.cpp.

References Json::arrayValue, clear(), Json::nullValue, size(), and Value().

void Json::Value::swap ( Value other)

Swap values.

Note
Currently, comments are intentionally not swapped, for both logic and efficiency.

Definition at line 551 of file json_value.cpp.


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