JSON Module

Properties   Methods   Events   Config Settings   Errors  

The JSON module can be used to parse and write JSON documents.

Syntax

IPWorksMQ.JSON

Remarks

The JSON class offers a fast and simple way to parse and write information in JSON documents.

Parsing JSON

The JSON class parses JSON documents and verifies that they are well-formed. The results are provided through a set of events.

In addition, the document structure may be queried through an XPath mechanism that supports a subset of the XPath and JSONPath specification.

The parser is optimized for read applications, with a very fast engine that builds internal DOM structures with close to zero heap allocations. Additionally, BuildDOM can be set to False, which reduces the overhead of creating the DOM and offers a fast forward-only parsing implementation that fires events to provide the parsed data.

When parsing a document, events will fire to provide information about the parsed data. After Parse returns the document, it may be navigated by setting XPath if BuildDOM is True (default). If BuildDOM is False, parsed data are accessible only through the events.

The following events will fire during parsing:

If BuildDOM is True (default), XPath may be set after this method returns. XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

The path is a series of one or more element accessors separated by '/'. The path can be absolute (starting with '/') or relative to the current XPath location.

The following are possible values for an element accessor:

'name'A particular element name.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

Input Properties

The class will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops.

If parsing multiple documents, call Reset between documents to reset the parser.

Writing JSON

The JSON class also can be used to create a JSON document.

The document is written to the selected output property. In addition, as the document is written, the JSON event will fire. The Text event parameter contains the part of the document currently being written.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

Example. Writing a JSON Document:

Writing a simple JSON document describing a pet: Json json = new Json(); json.OutputFile = "C:\\temp\\fido.json"; json.StartObject(); json.PutProperty("name", "fido", 2); json.PutName("previousOwners"); json.StartArray(); json.PutValue("Steve Widgetson", 2); json.PutValue("Wanda Widgetson", 2); json.PutValue("Randy Cooper", 2); json.PutValue("Linda Glover", 2); json.EndArray(); json.PutProperty("weightUnit", "lbs", 2); json.PutProperty("weight", "62", 3); json.EndObject(); json.Flush();

This example results in the following JSON: 

{
  "name": "fido",
  "previousOwners": [
    "Steve Widgetson",
    "Wanda Widgetson",
    "Randy Cooper",
    "Linda Glover"
  ],
  "weightUnit": "lbs",
  "weight": 62
}

When writing multiple documents, call Reset between documents to reset the writer.

Modifying JSON

The JSON class also allows for modifying existing JSON documents. After loading a JSON document with Parse the document may be edited. The class supports inserting new values, renaming or overwriting existing values, and removing values. After editing is complete, call Save to output the updated JSON document.

The following methods are applicable when modifying a JSON document:

When Save is called, the modified JSON is written to the specified output location.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

Example 1. Inserting New Values:

To insert new values in a JSON document, first load the existing document with Parse. Next set XPath to the sibling or parent of the data to be inserted. Call InsertProperty or InsertValue and pass the ValueType and Position parameters to indicate the type of data being inserted and the position.

The ValueType parameter of these methods specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter of these methods specifies the position of Value. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

For example:

Given the following JSON: 

{
    "store": {
        "books": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
            }
        ]    
    }
}

Insert a new property "price" for each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("price", "8.95", 3, 3); //3 - Number, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("price", "12.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    }
    ]
  }
}

To add a new book to the array:

json.XPath = "/json/store/books"; json.InsertValue("", 0, 3); //0 - Object, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("category", "fiction", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("author", "Herman Melville", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("title", "Moby Dick", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("price", "8.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To add a new array property to each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[1]/tags"; json.InsertValue("quotes", 2, 3); //2 - String, 3 - Last Child json.InsertValue("british", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[2]/tags"; json.InsertValue("trilogy", 2, 3); //2 - String, 3 - Last Child json.InsertValue("war", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[3]/tags"; json.InsertValue("classic", 2, 3); //2 - String, 3 - Last Child json.InsertValue("whales", 2, 3); //2 - String, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["quotes", "british"],
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 2. Removing Values:

To remove existing values, set XPath and call the Remove method. Continuing with example 1, to remove the first book: json.XPath = "/json/store/books/[1]"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To remove the "category" properties from each book: json.XPath = "/json/store/books/[1]/category"; json.Remove(); json.XPath = "/json/store/books/[2]/category"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 3. Updating Existing Names and Values:

The SetName and SetValue methods may be used to modify existing names and values. Continuing with the preceding JSON in example 2, to rename "tags" to "meta" and update values within the array and prices:

//Rename "tags" to "meta" for 1st book json.XPath = "/json/store/books/[1]/tags"; json.SetName("meta"); //Update Price json.XPath = "/json/store/books/[1]/price"; json.SetValue("13.99", 3); //3 - Number //Rename "tags" to "meta" for 2nd book json.XPath = "/json/store/books/[2]/tags"; json.SetName("meta"); //Update tag "whales" to "revenge" json.XPath = "/json/store/books/[2]/meta/[2]"; json.SetValue("revenge", 2); //2 - String //Update Price json.XPath = "/json/store/books/[2]/price"; json.SetValue("9.99", 3); //3 - Number json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "meta": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 13.99
    },
    {
      "meta": ["classic", "revenge"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 9.99
    }
    ]
  }
}

Property List

The following is the full list of the properties of the module with short descriptions. Click on the links for further details.

BuildDOMWhen True, an internal object model of the JSON document is created.
InputDataThis property includes the JSON data to parse.
InputFileThis property specifies the file to process.
OutputDataThis property includes the output JSON after processing.
OutputFileThis is the path to a local file where the output will be written.
OverwriteThis property indicates whether or not the module should overwrite files.
ValidateThis property controls whether documents are validated during parsing.
XChildrenThis property includes a collection of child elements of the current element.
XElementThis property includes the name of the current element.
XElementTypeThis property indicates the data type of the current element.
XErrorPathThis property includes an XPath to check the server response for errors.
XParentThe parent of the current element.
XPathThis property provides a way to point to a specific element in the response.
XSubTreeThis property includes a snapshot of the current element in the document.
XTextThis property includes the text of the current element.

Method List

The following is the full list of the methods of the module with short descriptions. Click on the links for further details.

ConfigSets or retrieves a configuration setting.
EndArrayThis method writes the closing bracket of a JSON array.
EndObjectThis method writes the closing brace of a JSON object.
FlushThis method flushes the parser's or writer's buffers.
HasXPathThis method determines whether a specific element exists in the document.
InsertPropertyThis method inserts the specified name and value at the selected position.
InsertValueThis method inserts the specified value at the selected position.
ParseThis method parses the specified JSON data.
PutNameThis method writes the name of a property.
PutPropertyThis method writes a property and value.
PutRawThis method writes a raw JSON fragment.
PutValueThis method writes a value of a property.
RemoveThis method removes the element or value set in XPath.
ResetThis method resets the module.
SaveThis method saves the modified JSON document.
SetNameThis method sets a new name for the element specified by XPath.
SetValueThis method sets a new value for the element specified by XPath.
StartArrayThis method writes the opening bracket of a JSON array.
StartObjectThis event writes the opening brace of a JSON object.
TryXPathThis method navigates to the specified XPath if it exists.

Event List

The following is the full list of the events fired by the module with short descriptions. Click on the links for further details.

CharactersThis event is fired for plaintext segments of the input stream.
EndDocumentThis event fires when the end of a JSON document is encountered.
EndElementThis event is fired when an end-element tag is encountered.
ErrorFired when information is available about errors during data delivery.
IgnorableWhitespaceThis event is fired when a section of ignorable whitespace is encountered.
JSONThis event fires with the JSON data being written.
StartDocumentThis event fires when the start of a new JSON document is encountered.
StartElementThis event is fired when a new element is encountered in the document.

Config Settings

The following is a list of config settings for the module with short descriptions. Click on the links for further details.

CacheContentIf true, the original JSON is stored internally in a buffer.
ElementXPathThe XPath value for the current element in the document.
EscapeForwardSlashesWhether to escape forward slashes when writing a JSON object.
InputFormatSpecifies the input format used in JSON streaming.
PrettyPrintDetermines whether output is on one line or "pretty printed".
RecordEndDelimiterThe character sequence after the end of a JSON document.
RecordStartDelimiterThe character sequence before the start of a JSON document.
StringProcessingOptionsDefines options to use when processing string values.
XPathNotationSpecifies the expected format when setting XPath.

BuildDOM Property (JSON Module)

When True, an internal object model of the JSON document is created.

Syntax

public var buildDOM: Bool {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=buildDOM,setter=setBuildDOM:) BOOL buildDOM;

- (BOOL)buildDOM;
- (void)setBuildDOM :(BOOL)newBuildDOM;

Default Value

True

Remarks

Set this property to True when you need to browse the current document through XPath.

InputData Property (JSON Module)

This property includes the JSON data to parse.

Syntax

public var inputData: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=inputData,setter=setInputData:) NSString* inputData;

- (NSString*)inputData;
- (void)setInputData :(NSString*)newInputData;

Default Value

""

Remarks

This property specifies the JSON to be processed. Set this property before calling Parse.

This may be set to a complete JSON document, or partial data. When setting partial data, call Parse after each chunk of data is set. For instance:

//Parse the following in chunks: { "data": 1} json.InputData = "{ \"data\"" json.Parse(); json.InputData = ": 1}" json.Parse();

Input Properties

The class will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops.

InputFile Property (JSON Module)

This property specifies the file to process.

Syntax

public var inputFile: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=inputFile,setter=setInputFile:) NSString* inputFile;

- (NSString*)inputFile;
- (void)setInputFile :(NSString*)newInputFile;

Default Value

""

Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file that will be processed.

After setting this property, call Parse to parse the document.

Input Properties

The class will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops.

OutputData Property (JSON Module)

This property includes the output JSON after processing.

Syntax

public var outputData: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=outputData,setter=setOutputData:) NSString* outputData;

- (NSString*)outputData;
- (void)setOutputData :(NSString*)newOutputData;

Default Value

""

Remarks

This property contains the resultant JSON after processing.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

OutputFile Property (JSON Module)

This is the path to a local file where the output will be written.

Syntax

public var outputFile: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=outputFile,setter=setOutputFile:) NSString* outputFile;

- (NSString*)outputFile;
- (void)setOutputFile :(NSString*)newOutputFile;

Default Value

""

Remarks

This property specifies the file to which the output will be written. This may be set to an absolute or relative path.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

Overwrite Property (JSON Module)

This property indicates whether or not the module should overwrite files.

Syntax

public var overwrite: Bool {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=overwrite,setter=setOverwrite:) BOOL overwrite;

- (BOOL)overwrite;
- (void)setOverwrite :(BOOL)newOverwrite;

Default Value

False

Remarks

This property indicates whether or not the class will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

Validate Property (JSON Module)

This property controls whether documents are validated during parsing.

Syntax

public var validate: Bool {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=validate,setter=setValidate:) BOOL validate;

- (BOOL)validate;
- (void)setValidate :(BOOL)newValidate;

Default Value

True

Remarks

When (default), the document will be validated during parsing. To disable validation set Validate to . Disabling validation may be useful in cases in which data can still be parsed even if the document is not well formed.

XChildren Property (JSON Module)

This property includes a collection of child elements of the current element.

Syntax

public var xChildren: Array<JSONElement> {
  get {...}
}


@property (nonatomic,readwrite,assign,getter=XChildCount,setter=setXChildCount:) int XChildCount;

- (int)XChildCount;
- (void)setXChildCount :(int)newXChildCount;

- (int)XChildElementType:(int)xChildIndex;

- (NSString*)XChildName:(int)xChildIndex;

- (NSString*)XChildXText:(int)xChildIndex;

Default Value

""

Remarks

This property contains a collection of child elements of the current element. The elements are provided in the collection in the same order they are found in the document.

XElement Property (JSON Module)

This property includes the name of the current element.

Syntax

public var xElement: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=XElement,setter=setXElement:) NSString* XElement;

- (NSString*)XElement;
- (void)setXElement :(NSString*)newXElement;

Default Value

""

Remarks

This property contains the name of the current element. The current element is specified through the XPath property.

XElementType Property (JSON Module)

This property indicates the data type of the current element.

Syntax

public var xElementType: JSONXElementTypes {
  get {...}
}

public enum JSONXElementTypes: Int32 {
  case etObject = 0
  case etArray = 1
  case etString = 2
  case etNumber = 3
  case etBool = 4
  case etNull = 5
}


@property (nonatomic,readonly,assign,getter=XElementType) int XElementType;

- (int)XElementType;

Default Value

0

Remarks

This property specifies the data type of the current element. After setting XPath, this property is populated. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

Note: This property is not applicable when parsing a document and BuildDOM is False.

This property is read-only.

XErrorPath Property (JSON Module)

This property includes an XPath to check the server response for errors.

Syntax

public var xErrorPath: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=XErrorPath,setter=setXErrorPath:) NSString* XErrorPath;

- (NSString*)XErrorPath;
- (void)setXErrorPath :(NSString*)newXErrorPath;

Default Value

""

Remarks

This property contains an XPath to check the server response for errors. If the XPath exists, an exception will be thrown containing the value of the element at the path.

XParent Property (JSON Module)

The parent of the current element.

Syntax

public var xParent: String {
  get {...}
}


@property (nonatomic,readonly,assign,getter=XParent) NSString* XParent;

- (NSString*)XParent;

Default Value

""

Remarks

This property contains the parent of the current element. The current element is specified via the XPath property.

This property is read-only.

XPath Property (JSON Module)

This property provides a way to point to a specific element in the response.

Syntax

public var xPath: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=XPath,setter=setXPath:) NSString* XPath;

- (NSString*)XPath;
- (void)setXPath :(NSString*)newXPath;

Default Value

""

Remarks

XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

The path is a series of one or more element accessors separated by '/'. The path can be absolute (starting with '/') or relative to the current XPath location.

The following are possible values for an element accessor:

'name'A particular element name.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

If an error occurs when setting this property an error will not be thrown. This property has a related method which will throw an error:

public func setXPath(xPath: String) throws

XSubTree Property (JSON Module)

This property includes a snapshot of the current element in the document.

Syntax

public var xSubTree: String {
  get {...}
}


@property (nonatomic,readonly,assign,getter=XSubTree) NSString* XSubTree;

- (NSString*)XSubTree;

Default Value

""

Remarks

The current element is specified through this property. For this property to work, you must have the CacheContent set to True.

This property is read-only.

XText Property (JSON Module)

This property includes the text of the current element.

Syntax

public var xText: String {
  get {...}
  set {...}
}


@property (nonatomic,readwrite,assign,getter=XText,setter=setXText:) NSString* XText;

- (NSString*)XText;
- (void)setXText :(NSString*)newXText;

Default Value

""

Remarks

This property contains the text of the current element. The current element is specified through the XPath property.

Config Method (JSON Module)

Sets or retrieves a configuration setting.

Syntax

public func config(configurationString: String) throws -> String

- (NSString*)config:(NSString*)configurationString;

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

EndArray Method (JSON Module)

This method writes the closing bracket of a JSON array.

Syntax

public func endArray() throws -> Void

- (void)endArray;

Remarks

This method writes the closing bracket of a JSON array to the output. An array must already have been opened by calling StartArray.

EndObject Method (JSON Module)

This method writes the closing brace of a JSON object.

Syntax

public func endObject() throws -> Void

- (void)endObject;

Remarks

This method writes the closing brace of a JSON object. An object must have been started previously by calling StartObject.

Flush Method (JSON Module)

This method flushes the parser's or writer's buffers.

Syntax

public func flush() throws -> Void

- (void)flush;

Remarks

When Flush is called, the component flushes all of its buffers, firing events as necessary.

When parsing, the end state of the JSON is checked. If Validate is also True, the parser verifies that all open elements were closed, returning an error if not.

When writing, the resultant JSON is available in one of the output properties.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

HasXPath Method (JSON Module)

This method determines whether a specific element exists in the document.

Syntax

public func hasXPath(xPath: String) throws -> Bool

- (BOOL)hasXPath:(NSString*)XPath;

Remarks

This method determines whether a particular XPath exists within the document. This may be used to check if a path exists before setting it through XPath.

This method returns True if the xpath exists, and False if not.

See XPath for details on the XPath syntax.

InsertProperty Method (JSON Module)

This method inserts the specified name and value at the selected position.

Syntax

public func insertProperty(name: String, value: String, valueType: Int32, position: Int32) throws -> Void

- (void)insertProperty:(NSString*)name :(NSString*)value :(int)valueType :(int)position;

Remarks

This method inserts a property and its corresponding value relative to the element specified by XPath. Before calling this method, a valid JSON document must first be loaded by calling Parse.

The Name parameter specifies the name of the property.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter specifies the position of Value relative to the element specified by XPath. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

See Save for details.

InsertValue Method (JSON Module)

This method inserts the specified value at the selected position.

Syntax

public func insertValue(value: String, valueType: Int32, position: Int32) throws -> Void

- (void)insertValue:(NSString*)value :(int)valueType :(int)position;

Remarks

This method inserts a value relative to the element specified by XPath. Before calling this method, a valid JSON document must first be loaded by calling Parse.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter specifies the position of Value relative to the element specified by XPath. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

See Save for details.

Parse Method (JSON Module)

This method parses the specified JSON data.

Syntax

public func parse() throws -> Void

- (void)parse;

Remarks

This method parses the specified JSON data.

When parsing a document, events will fire to provide information about the parsed data. After Parse returns the document, it may be navigated by setting XPath if BuildDOM is True (default). If BuildDOM is False, parsed data are accessible only through the events.

The following events will fire during parsing:

If BuildDOM is True (default), XPath may be set after this method returns. XPath may be set to navigate to specific elements within the JSON document. This will be the path to a specified value within the document. Because arrays in JSON only contain values, and no associated object name, an empty name will be used for these values. To reach an array element at position 1, the path must be set to "[1]". In addition, a root element named "json" will be added to each JSON document in the parser.

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

The XPath property accepts both XPath and JSONPath formats. Please review the following notes on both formats.

XPath

The path is a series of one or more element accessors separated by '/'. The path can be absolute (starting with '/') or relative to the current XPath location.

The following are possible values for an element accessor:

'name'A particular element name.
[i]The i-th subelement of the current element.
..the parent of the current element.
When XPath is set to a valid path, the following properties are updated:

BuildDOM must be set to True before parsing the document for the XPath functionality to be available.

Simple JSON Document

{
  "firstlevel": {
    "one": "value",
    "two": ["first", "second"],
    "three": "value three"
  }
}
Example 1. Setting XPath:

Document root JsonControl.XPath = "/"
Specific Element JsonControl.XPath = "/json/firstlevel/one/"
i-th Child JsonControl.XPath = "/json/firstlevel/two/[i]/"
Note: When using XPath notation, the root element is always referred to as "json". As in the previous examples, this means all paths will begin with "/json".

JSONPath

This property implements a subset of the JSONPath notation. This may be set to point to a specific element in the JSON document.

The JSONPath is a series of one or more accessors in either dot-notation 

$.store.book[0].title
or in bracket-notation, as follows: 
$['store']['book'][0]['title']

After setting XPath, the following properties are populated:

Example 2. Setting JSONPath:

Given the following JSON document: 

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
}
The following code shows several examples.

Get the first book's author:

json.XPath = "$.store.book[0].author"; Console.WriteLine(json.XText); //Output //"Nigel Rees" Select the first book and inspect the children:

json.XPath = "$.store.book[0]"; Console.WriteLine("Child Count: " + json.XChildren.Count); Console.WriteLine(json.XChildren[1].Name + ": " + json.XChildren[1].XText); //Output //Child Count: 4 //author: "Nigel Rees" Get the price of the second book:

json.XPath = "$['store']['book'][1]['price']"; Console.WriteLine(json.XText); //Output //12.99 Get the second to last book's author:

json.XPath = "$['store']['book'][last() - 1]['author']"; Console.WriteLine(json.XText); Console.WriteLine(json.XPath); //Note that "last() - 1" is resolved to "3". //Output //"Herman Melville" //$['store']['book'][3]['author'] Display the full subtree at the current path:

json.XPath = "$.store.book[0]"; Console.WriteLine(json.XSubTree); //Output // { // "category": "reference", // "author": "Nigel Rees", // "title": "Sayings of the Century", // "price": 8.95 // }

Input Properties

The class will determine the source of the input based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops.

If parsing multiple documents, call Reset between documents to reset the parser.

PutName Method (JSON Module)

This method writes the name of a property.

Syntax

public func putName(name: String) throws -> Void

- (void)putName:(NSString*)name;

Remarks

This method writes the name of a property. The Name parameter specifies the value to write.

PutProperty Method (JSON Module)

This method writes a property and value.

Syntax

public func putProperty(name: String, value: String, valueType: Int32) throws -> Void

- (void)putProperty:(NSString*)name :(NSString*)value :(int)valueType;

Remarks

This method writes a property and its corresponding value to the output.

The Name parameter specifies the name of the property.

The Value parameter specifies the value of the property.

The ValueType parameter specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

PutRaw Method (JSON Module)

This method writes a raw JSON fragment.

Syntax

public func putRaw(text: String) throws -> Void

- (void)putRaw:(NSString*)text;

Remarks

This method writes raw data to the output. This may be used to write any data of any format directly to the output.

PutValue Method (JSON Module)

This method writes a value of a property.

Syntax

public func putValue(value: String, valueType: Int32) throws -> Void

- (void)putValue:(NSString*)value :(int)valueType;

Remarks

This method writes the value of a property to the output. The Value parameter specifies the value. The ValueType parameter specifies the type of data. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

Remove Method (JSON Module)

This method removes the element or value set in XPath.

Syntax

public func remove() throws -> Void

- (void)remove;

Remarks

This method removes the current object at the specified XPath. This is used when editing previously loaded JSON documents.

See Save for details.

Reset Method (JSON Module)

This method resets the component.

Syntax

public func reset() throws -> Void

- (void)reset;

Remarks

This method resets the JSON parser.

Save Method (JSON Module)

This method saves the modified JSON document.

Syntax

public func save() throws -> Void

- (void)save;

Remarks

This method saves the modified JSON data. This is used after editing a previously loaded JSON document.

After loading a JSON document with Parse the document may be edited. The class supports inserting new values, renaming or overwriting existing values, and removing values. After editing is complete, call Save to output the updated JSON document.

The following methods are applicable when modifying a JSON document:

When Save is called, the modified JSON is written to the specified output location.

Output Properties

The class will determine the destination of the output based on which properties are set.

The order in which the output properties are checked is as follows:

  • OutputFile
  • OutputData: The output data are written to this property if no other destination is specified.

Example 1. Inserting New Values:

To insert new values in a JSON document, first load the existing document with Parse. Next set XPath to the sibling or parent of the data to be inserted. Call InsertProperty or InsertValue and pass the ValueType and Position parameters to indicate the type of data being inserted and the position.

The ValueType parameter of these methods specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

The Position parameter of these methods specifies the position of Value. Possible values are as follows:

  • 0 (Before the current element)
  • 1 (After the current element)
  • 2 (The first child of the current element)
  • 3 (The last child of the current element)

For example:

Given the following JSON: 

{
    "store": {
        "books": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
            }
        ]    
    }
}

Insert a new property "price" for each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("price", "8.95", 3, 3); //3 - Number, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("price", "12.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    }
    ]
  }
}

To add a new book to the array:

json.XPath = "/json/store/books"; json.InsertValue("", 0, 3); //0 - Object, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("category", "fiction", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("author", "Herman Melville", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("title", "Moby Dick", 2, 3); //2 - String, 3 - Last Child json.InsertProperty("price", "8.99", 3, 3); //3 - Number, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To add a new array property to each book:

json.XPath = "/json/store/books/[1]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[1]/tags"; json.InsertValue("quotes", 2, 3); //2 - String, 3 - Last Child json.InsertValue("british", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[2]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[2]/tags"; json.InsertValue("trilogy", 2, 3); //2 - String, 3 - Last Child json.InsertValue("war", 2, 3); //2 - String, 3 - Last Child json.XPath = "/json/store/books/[3]"; json.InsertProperty("tags", "", 1, 2); //1 - Array, 2 - First Child json.XPath = "/json/store/books/[3]/tags"; json.InsertValue("classic", 2, 3); //2 - String, 3 - Last Child json.InsertValue("whales", 2, 3); //2 - String, 3 - Last Child json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["quotes", "british"],
      "category": "reference",
      "author": "Nigel Rees",
      "title": "Sayings of the Century",
      "price": 8.95
    },
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 2. Removing Values:

To remove existing values, set XPath and call the Remove method. Continuing with example 1, to remove the first book: json.XPath = "/json/store/books/[1]"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "category": "fiction",
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "category": "fiction",
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

To remove the "category" properties from each book: json.XPath = "/json/store/books/[1]/category"; json.Remove(); json.XPath = "/json/store/books/[2]/category"; json.Remove(); json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "tags": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 12.99
    },
    {
      "tags": ["classic", "whales"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 8.99
    }
    ]
  }
}

Example 3. Updating Existing Names and Values:

The SetName and SetValue methods may be used to modify existing names and values. Continuing with the preceding JSON in example 2, to rename "tags" to "meta" and update values within the array and prices:

//Rename "tags" to "meta" for 1st book json.XPath = "/json/store/books/[1]/tags"; json.SetName("meta"); //Update Price json.XPath = "/json/store/books/[1]/price"; json.SetValue("13.99", 3); //3 - Number //Rename "tags" to "meta" for 2nd book json.XPath = "/json/store/books/[2]/tags"; json.SetName("meta"); //Update tag "whales" to "revenge" json.XPath = "/json/store/books/[2]/meta/[2]"; json.SetValue("revenge", 2); //2 - String //Update Price json.XPath = "/json/store/books/[2]/price"; json.SetValue("9.99", 3); //3 - Number json.Save();

Produces the JSON:

{
  "store": {
    "books": [
    {
      "meta": ["trilogy", "war"],
      "author": "Evelyn Waugh",
      "title": "Sword of Honour",
      "price": 13.99
    },
    {
      "meta": ["classic", "revenge"],
      "author": "Herman Melville",
      "title": "Moby Dick",
      "price": 9.99
    }
    ]
  }
}

SetName Method (JSON Module)

This method sets a new name for the element specified by XPath.

Syntax

public func setName(name: String) throws -> Void

- (void)setName:(NSString*)name;

Remarks

This method sets a new name for the element specified in XPath. This is used to modify an existing JSON document.

The Name parameter specifies the new name of the element.

See Save for details.

SetValue Method (JSON Module)

This method sets a new value for the element specified by XPath.

Syntax

public func setValue(value: String, valueType: Int32) throws -> Void

- (void)setValue:(NSString*)value :(int)valueType;

Remarks

This method sets a new value for the element specified in XPath. This is used to modify an existing JSON document.

Value specifies the new value.

ValueType specifies the type of the value. Possible values are as follows:

  • 0 (Object)
  • 1 (Array)
  • 2 (String)
  • 3 (Number)
  • 4 (Bool)
  • 5 (Null)
  • 6 (Raw)

See Save for details.

StartArray Method (JSON Module)

This method writes the opening bracket of a JSON array.

Syntax

public func startArray() throws -> Void

- (void)startArray;

Remarks

This method writes the opening bracket of a JSON array to the output. To close the array, call EndArray.

StartObject Method (JSON Module)

This event writes the opening brace of a JSON object.

Syntax

public func startObject() throws -> Void

- (void)startObject;

Remarks

This method writes the opening brace of a JSON object to the output. To close the object, call EndObject.

TryXPath Method (JSON Module)

This method navigates to the specified XPath if it exists.

Syntax

public func tryXPath(xpath: String) throws -> Bool

- (BOOL)tryXPath:(NSString*)xpath;

Remarks

This method will attempt to navigate to the specified XPath parameter if it exists within the document.

If the XPath exists, the XPath property will be updated and this method returns True.

If the XPath does not exist, the XPath property is not updated and this method returns False.

Characters Event (JSON Module)

This event is fired for plaintext segments of the input stream.

Syntax

func onCharacters(text: String)

- (void)onCharacters:(NSString*)text;

Remarks

The Characters event provides the plaintext content of the JSON document (i.e., the text inside the elements). The text is provided through the Text parameter.

The text includes white space as well as end-of-line characters, except for ignorable whitespace, which is fired through the IgnorableWhitespace event.

EndDocument Event (JSON Module)

This event fires when the end of a JSON document is encountered.

Syntax

func onEndDocument()

- (void)onEndDocument;

Remarks

This event fires when parsing of a JSON document ends. This event may fire multiple times if InputFormat is set to a value that accepts multiple JSON documents.

EndElement Event (JSON Module)

This event is fired when an end-element tag is encountered.

Syntax

func onEndElement(element: String)

- (void)onEndElement:(NSString*)element;

Remarks

The EndElement event is fired when the end of an element is found in the document.

The element name is provided by the Element parameter.

Error Event (JSON Module)

Fired when information is available about errors during data delivery.

Syntax

func onError(errorCode: Int32, description: String)

- (void)onError:(int)errorCode :(NSString*)description;

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class .

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

IgnorableWhitespace Event (JSON Module)

This event is fired when a section of ignorable whitespace is encountered.

Syntax

func onIgnorableWhitespace(text: String)

- (void)onIgnorableWhitespace:(NSString*)text;

Remarks

The ignorable whitespace section is provided by the Text parameter.

JSON Event (JSON Module)

This event fires with the JSON data being written.

Syntax

func onJSON(text: String)

- (void)onJSON:(NSString*)text;

Remarks

This event fires when output data are written.

Text contains the JSON data currently being written.

StartDocument Event (JSON Module)

This event fires when the start of a new JSON document is encountered.

Syntax

func onStartDocument()

- (void)onStartDocument;

Remarks

This event fires when parsing of a JSON document begins. This event may fire multiple times if InputFormat is set to a value that accepts multiple JSON documents.

StartElement Event (JSON Module)

This event is fired when a new element is encountered in the document.

Syntax

func onStartElement(element: String)

- (void)onStartElement:(NSString*)element;

Remarks

The StartElement event is fired when a new element is found in the document.

The element name is provided through the Element parameter.

JSONElement Type

This type describes an element contained within the JSON document.

Remarks

This type describes a JSON element.

The elements are inserted into the array in the same order they are found in the document.

The following fields are available:
  • ElementType
  • Name
  • XText

    • Fields

    elementType
    TXElementTypes (read-only)
    Default Value: 0

    The property indicates the data type of the element.

    Possible values are as follows:

    • 0 (Object)
    • 1 (Array)
    • 2 (String)
    • 3 (Number)
    • 4 (Bool)
    • 5 (Null)
    • 6 (Raw)

    name
    String (read-only)
    Default Value: ""

    The property provides the name of the element. For elements within an array, the property will be empty.

    xText
    String (read-only)
    Default Value: ""

    This property contains the text of the element.

    Constructors

    public init()

    Config Settings (JSON Module)

    The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

    JSON Config Settings

    CacheContent:   If true, the original JSON is stored internally in a buffer.

    This configuration setting controls whether or not the class retains the entire original JSON data in a buffer. This is used to retain the original JSON as opposed to returning generated JSON after parsing. The default value is True.

    ElementXPath:   The XPath value for the current element in the document.

    This configuration setting holds the current XPath value when the document is parsed. When queried from inside the StartElement event, the corresponding element's XPath value will be returned. For instance:

    string elementXPath = json.Config("ElementXPath");

    Note: The BuildDOM property must be set to False.

    EscapeForwardSlashes:   Whether to escape forward slashes when writing a JSON object.

    This configuration setting specifies whether forward slashes (/) are escaped when creating a JSON object using the class. This does not affect parsing of JSON. It is applicable only when JSON values are written.

    InputFormat:   Specifies the input format used in JSON streaming.

    This configuration setting specifies how JSON documents are formatted as they are input to the class. This setting is designed for use when data are provided via JSON streaming. This means multiple documents may be parsed by the class. This setting is applicable only when BuildDOM is set to False. Possible values are as follows:

    Value Description
    0 (None - default) Only a single JSON document is expected. Use this when a single JSON document is being parsed (most cases).
    1 (Line Delimited) Multiple documents are separated by carriage return (CR), line feed (LF), or CRLF character sequences.
    2 (Record Separated) A defined start and end delimiter separate documents. See RecordStartDelimiter and RecordEndDelimiter.
    3 (Concatenated) New documents begin immediately after the previous documents end; no characters or delimiters separate the documents.

    PrettyPrint:   Determines whether output is on one line or "pretty printed".

    The value of this configuration setting determines whether output is generated as a single line of JSON or as multiple "pretty printed" lines. The following example code, provides a better understanding of this configuration setting: json.Config("PrettyPrint=true"); // false json.StartObject(); json.PutName("data"); json.StartObject(); json.PutProperty("id", "3", 3); json.PutProperty("first_name", "Emma", 2); json.PutProperty("last_name", "Wong", 2); json.PutProperty("avatar", "https://s3.amazonaws.com/uifaces/faces/twitter/olegpogodaev/128.jpg", 2); json.EndObject(); json.EndObject(); json.Flush(); Console.WriteLine(json.OutputData); With PrettyPrint set to False (the default), the output would look like this: 

    {"data":{"id":3,"first_name":"Emma","last_name":"Wong","avatar":"https:\/\/s3.amazonaws.com\/uifaces\/faces\/twitter\/olegpogodaev\/128.jpg"}}
    With PrettyPrint set to True, the output instead would look like this: 
    {
  "data": {
    "id": 3,
    "first_name": "Emma",
    "last_name": "Wong",
    "avatar": "https:\/\/s3.amazonaws.com\/uifaces\/faces\/twitter\/olegpogodaev\/128.jpg"
  }
}
    The default value is False.
    RecordEndDelimiter:   The character sequence after the end of a JSON document.

    This configuration setting is used in conjunction with InputFormat to specify the character sequence that is expected after the end of a JSON document.

    RecordStartDelimiter:   The character sequence before the start of a JSON document.

    This configuration setting is used in conjunction with InputFormat to specify the character sequence that is expected before the start of a JSON document.

    StringProcessingOptions:   Defines options to use when processing string values.

    This configuration setting determines what additional processing is performed on string values during parsing. By default, no additional processing is performed and the string is returned as is from the document. Strings also may be unquoted, unescaped, or both. Possible values follow:

    0 (none - default)No additional processing is performed.
    1 (unquote) Strings are unquoted.
    2 (unescape) Any escaped sequences are unescaped.
    3 (unquote and unescape) Values are both unquoted and unescaped.
    For instance, given the JSON element: 
    "example" : "value\ntest"
    The following table shows the resulting value for the XText of the element:
    StringProcessingOptionOutput
    0 (none) 
    "value\ntest"
    1 (unquote) 
    value\ntest
    2 (unescape) 
    "value
test"
    3 (unquote and unescape) 
    value
test
    XPathNotation:   Specifies the expected format when setting XPath.

    This configuration setting optionally specifies the expected input format when setting XPath. Possible values follow:

    • 0 (Auto - default)
    • 1 (XPath)
    • 2 (JSONPath)
    In most cases, the default of 0 (Auto) is sufficient. The class will determine whether the path value is in XPath or JSONPath format automatically. If desired, the type may be explicitly set to either XPath or JSONPath using the values above.

    Trappable Errors (JSON Module)

    JSON Errors

    10231   Unbalanced element tag.
    10232   Invalid JSON markup.
    10233   Invalid XPath.
    10234   DOM tree unavailable (set BuildDOM to True and reparse).

    XML Errors

    101   Invalid attribute index.
    102   No attributes available.
    103   Invalid namespace index.
    104   No namespaces available.
    105   Invalid element index.
    106   No elements available.
    107   Attribute does not exist.
    201   Unbalanced element tag.
    202   Unknown element prefix (cannot find namespace).
    203   Unknown attribute prefix (cannot find namespace).
    204   Invalid XML markup.
    205   Invalid end state for parser.
    206   Document contains unbalanced elements.
    207   Invalid XPath.
    208   No such child.
    209   Top element does not match start of path.
    210   DOM tree unavailable (set BuildDOM to True and reparse).
    302   Cannot open file.
    401   Invalid XML would be generated.
    402   An invalid XML name has been specified.