File Information
Library: JSON
Package: JSON
Header: Poco/JSON/Array.h
Description
Represents a JSON array. Array provides a representation based on shared pointers and optimized for performance. It is possible to convert Array to Poco::Dynamic::Array. Conversion requires copying and therefore has performance penalty; the benefit is in improved syntax, eg:
// use pointers to avoid copying
using namespace Poco::JSON;
std::string json = "[ {\"test\" : 0}, { \"test1\" : [1, 2, 3], \"test2\" : 4 } ]";
Parser parser;
Var result = parser.parse(json);
Array::Ptr arr = result.extract<Array::Ptr>();
Object::Ptr object = arr->getObject(0); // object == {\"test\" : 0}
int i = object->getElement<int>("test"); // i == 0;
Object::Ptr subObject = arr->getObject(1); // subObject == {\"test\" : 0}
Array subArr::Ptr = subObject->getArray("test1"); // subArr == [1, 2, 3]
i = result = subArr->get(0); // i == 1;
// copy/convert to Poco::Dynamic::Array
Poco::Dynamic::Array da = *arr;
i = da[0]["test"]; // i == 0
i = da[1]["test1"][1]; // i == 2
i = da[1]["test2"]; // i == 4
Member Summary
Member Functions: add, begin, clear, empty, end, get, getArray, getElement, getEscapeUnicode, getObject, isArray, isNull, isObject, makeArray, operator =, optElement, remove, set, setEscapeUnicode, size, stringify
Types Aliases
ConstIterator
using ConstIterator = std::vector < Dynamic::Var >::const_iterator;
Iterator
using Iterator = std::vector < Dynamic::Var >::iterator;
Ptr
using Ptr = SharedPtr < Array >;
ValueVec
using ValueVec = std::vector < Dynamic::Var >;
Constructors
Array
Array(
int options = 0
);
Creates an empty Array.
If JSON_ESCAPE_UNICODE is specified, when the object is stringified, all unicode characters will be escaped in the resulting string.
Array
Creates an Array by copying another one.
Array
Array(
Array && other
) noexcept;
Move constructor
Destructor
~Array
~Array();
Destroys the Array.
Member Functions
add 
Array & add(
const Dynamic::Var & value
);
Add the given value to the array
begin
ValueVec::const_iterator begin() const;
Returns the begin iterator for values.
clear
void clear();
Clears the contents of the array.
empty
bool empty() const;
Returns true if the array is empty, false otherwise.
end
ValueVec::const_iterator end() const;
Returns the end iterator for values.
get
Dynamic::Var get(
unsigned int index
) const;
Retrieves the element at the given index. Will return an empty value when the element doesn't exist.
getArray
Array::Ptr getArray(
unsigned int index
) const;
Retrieves an array. When the element is not an Array or doesn't exist, an empty SharedPtr is returned.
getElement
template < typename T > T getElement(
unsigned int index
) const;
Retrieves an element and tries to convert it to the template type. The convert<T> method of Dynamic is called which can also throw exceptions for invalid values. Note: This will not work for an array or an object.
getEscapeUnicode
bool getEscapeUnicode() const;
Returns the flag for escaping unicode.
getObject
SharedPtr < Object > getObject(
unsigned int index
) const;
Retrieves an object. When the element is not an object or doesn't exist, an empty SharedPtr is returned.
isArray
bool isArray(
unsigned int index
) const;
Returns true when the element is an array.
isArray
bool isArray(
const Dynamic::Var & value
) const;
Returns true when the element is an array.
isArray
bool isArray(
ConstIterator & value
) const;
Returns true when the element is an array.
isNull
bool isNull(
unsigned int index
) const;
Returns true when the element is null or when the element doesn't exist.
isObject
bool isObject(
unsigned int index
) const;
Returns true when the element is an object.
isObject
bool isObject(
const Dynamic::Var & value
) const;
Returns true when the element is an object.
isObject
bool isObject(
ConstIterator & value
) const;
Returns true when the element is an object.
makeArray 
static Poco::Dynamic::Array makeArray(
const JSON::Array::Ptr & arr
);
Conversion operator to Dynamic::Array. Utility function for creation of array.
operator =
Array & operator = (
const Array & other
);
Assignment operator.
operator =
Array & operator = (
Array && other
) noexcept;
Move assignment operator.
optElement
template < typename T > T optElement(
unsigned int index,
const T & def
) const;
Returns the element at the given index. When the element is null, doesn't exist or can't be converted to the given type, the default value will be returned
remove
void remove(
unsigned int index
);
Removes the element on the given index.
set
Array & set(
unsigned int index,
const Dynamic::Var & value
);
Update the element on the given index to specified value
setEscapeUnicode
void setEscapeUnicode(
bool escape = true
);
Sets the flag for escaping unicode.
size
std::size_t size() const;
Returns the size of the array.
stringify
void stringify(
std::ostream & out,
unsigned int indent = 0,
int step = - 1
) const;
Prints the array to out. When indent has zero value, the array will be printed without newline breaks and spaces between elements.