C++ Native Functions: com.teracloud.streams.json

This page documents native functions that can be invoked from SPL, including the SPL interfaces that can be used to invoke each of the native functions.

Functions

<tuple T> public T extractFromJSON(rstring jsonString, mutable T value)

Extract values from JSON string accordingly to a given tuple.

Limitations

Blob, complex, xml, timestamp and decimal type attributes are not supported.
Collections don't support nesting.
Optional types are supported for primitive types and list and set of primitive types only.
Optional bounded types are not supported.

Example


public composite ExtractFromJSON {
  type
    Flattened_t = rstring name, int32 age, list< rstring> relatives, rstring street, rstring city;
    Nested_t = tuple< rstring name, int32 age, list< rstring> relatives> person, tuple< rstring street, rstring city> address;
    
  graph
    () as Test = Custom() {
      logic
        onProcess : {
          rstring jsonString = '{"person" : {"name" : "John", "age" : 42, "relatives" : ["Jane","Mike"]}, "address" : {"street" : "Allen Street", "city" : "New York City"}}';

          mutable Flattened_t flattenedTuple = {};
          println( extractFromJSON(jsonString, flattenedTuple));

          mutable Nested_t nestedTuple = {};
          println( extractFromJSON(jsonString, nestedTuple));
        }
    }
}

Parameters

jsonString: The input JSON string.
value: A mutable tuple to save extracted values.

Returns

Reference to the input tuple.

public rstring getParseError(JsonParseStatus.status status)

Get parse error string.

Parameters

status: a status of the parser to translate to a string.

Returns

Error string.

<string S, any T> public rstring mapToJSON(map<S, T> m)

Convert a map to JSON object encoded as a serialized JSON string. Blob, complex and xml values are converted to nulls. Timestamp is converted to a date string representation.

Example


public composite SPLToJSONSample {
  type
    // Provide any hierarchical tuple
    TestTuple = tuple<rstring str, float64 num, list<int32> nums, map<rstring,timestamp> dates, tuple<boolean flag, enum{YES,NO} answer> additionalTypes>;
    // Provide a map with string key and any composite value to mapToJSON function
    TestMap = map<rstring, TestTuple>;
  graph
    () as Test = Custom() {
      logic
        onProcess : {
          TestTuple testTuple = {str = "testTuple", num = 42.42, nums = [1,2,3,4], dates = {"date1":getTimestamp()}, additionalTypes = {flag = true, answer = YES}};
          TestMap testMap = {"testMap" : testTuple};
          printStringLn( mapToJSON(testMap));
        }
    }
}

Parameters

m: Map containing key-value pairs to be converted to JSON.

Returns

Serialized JSON object containing all name-value pairs in m.

<string S, any T> public rstring mapToJSON(map<S, T> m, rstring prefixToIgnore)

Convert a map to JSON object encoded as a serialized JSON string. Blob, complex and xml values are converted to nulls.

Parameters

m: Map containing key-value pairs to be converted to JSON.
prefixToIgnore: rstring prefix to ignore in attribute name .

Returns

Serialized JSON object containing all name-value pairs in m.

<enum E> public uint32 parseJSON(rstring jsonString, E jsonIndex)

Parse JSON string (used in conjunction with queryJSON function).

Threading limitations

Call to parseJSON should not be placed in param section or state of the operator (internally a json object is shared via the thread local storage).

Example


uint32 rc = parseJSON(jsonString, JsonIndex._1);
if (rc != 0) {
  // queryJSON using JsonIndex._1
}

Parameters

jsonString: The input JSON string.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

Error code (0 - no error).

<enum E> public boolean parseJSON(rstring jsonString, mutable JsonParseStatus.status status, mutable uint32 offset, E jsonIndex)

Parse JSON string (used in conjunction with queryJSON function).

Threading limitations

Call to parseJSON should not be placed in param section or state of the operator (internally a json object is shared via the thread local storage).

Example


mutable uint32 offset = 0u;
mutable JsonStatus.status status = JsonStatus.FOUND;
boolean success = parseJSON(jsonString, status, offset, JsonIndex._1);
if (success) {
  // queryJSON using JsonIndex._1
}

Parameters

jsonString: The input JSON string.
status: indicates a status of the parser (enum JsonParseStatus.status).
offset: returns the offset in JSON string where parse error occured (use when status returns error).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

True if successfully parsed; false if parsing error. Status and offset will be updated with more info.

<floatingpoint T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, E jsonIndex)

Query JSON object for floating point value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
float32 cash = queryJSON("/person/cash", (float32) 10.25, JsonIndex._1);

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<integral T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, E jsonIndex)

Query JSON object for integral value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
uint8 age = queryJSON("/person/age", (uint8) 55, JsonIndex._1);

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<string T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, E jsonIndex)

Query JSON object for string value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
queryJSON("address/city", "", JsonIndex._1);

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<floatingpoint T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for floating point value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
mutable JsonStatus.status status = JsonStatus.FOUND;
float32 cash = queryJSON("/person/cash", (float32) 10.25, status, JsonIndex._1);
// check status

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<integral T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for integral value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
mutable JsonStatus.status status = JsonStatus.FOUND;
uint8 age = queryJSON("/person/age", (uint8) 55, status, JsonIndex._1);
// check status

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<string T, enum E> public T queryJSON(rstring jsonPath, T defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for string value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
mutable JsonStatus.status status = JsonStatus.FOUND;
queryJSON("address/city", "", status, JsonIndex._1);
// check status

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<enum E> public boolean queryJSON(rstring jsonPath, boolean defaultVal, E jsonIndex)

Query JSON object for boolean value with a given path (parseJSON function should be run before).

Threading limitations*

Call to queryJSON should not be placed in param section or state of the operator (internally a json object is shared via the thread local storage).

Example


// parseJson(..., JsonIndex._1)
boolean hasGum = queryJSON("/person/hasGum", false, JsonIndex._1);

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<enum E> public boolean queryJSON(rstring jsonPath, boolean defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object value with a given path (parseJSON function should be run before).

Example


// parseJson(..., JsonIndex._1)
mutable JsonStatus.status status = JsonStatus.FOUND;
boolean hasGum =  queryJSON("/person/hasGum", false, status, JsonIndex._1);
// check status

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<floatingpoint T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, E jsonIndex)

Query JSON object for list of floating point values with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<integral T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, E jsonIndex)

Query JSON object for list of integrals with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<string T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, E jsonIndex)

Query JSON object for list of strings with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<floatingpoint T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for list of floating point values with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<integral T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for list of integrals with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<string T, enum E> public list<T> queryJSON(rstring jsonPath, list<T> defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for list of strings with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<enum E> public list<boolean> queryJSON(rstring jsonPath, list<boolean> defaultVal, E jsonIndex)

Query JSON object for list of booleans with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<enum E> public list<boolean> queryJSON(rstring jsonPath, list<boolean> defaultVal, mutable JsonStatus.status status, E jsonIndex)

Query JSON object for list of booleans with a given path (parseJSON function should be run before).

Parameters

jsonPath: Path to a JSON attribute.
defaultVal: Default value to apply when an attribute not found.
status: indicates a status of the query (enum JsonStatus.status).
jsonIndex: Json index of enum type (e.g. enum{_1}).

Returns

JSON value.

<string S, any T> public rstring toJSON(S key, T value)

Convert a value to JSON object with a single key encoded as a serialized JSON string. Blob, complex and xml values are converted to nulls. An input value of type optional being null will generate also null in JSON.

Example


public composite SPLToJSONSample {
  type
    // Provide any hierarchical tuple
    TestTuple = tuple<rstring str, float64 num, list<int32> nums, map<rstring,timestamp> dates, tuple<boolean flag, enum{YES,NO} answer> additionalTypes>;
    // Provide a string key and any SPL value to toJSON function
    TestList = list<TestTuple>;
  graph
    () as Test = Custom() {
      logic
        onProcess : {
          TestTuple testTuple = {str = "testTuple", num = 42.42, nums = [1,2,3,4], dates = {"date1":getTimestamp()}, additionalTypes = {flag = true, answer = YES}};
          TestList testList = [testTuple];
          printStringLn( toJSON("testList", testList));
        }
    }
}

Parameters

key: Key for name-value pair to be converted to JSON.
value: Value for key.

Returns

Serialized JSON object containing single name-value pair.

<string S, any T> public rstring toJSON(S key, T value, rstring prefixToIgnore)

Convert a value to JSON object with a single key encoded as a serialized JSON string. Blob, complex and xml values are converted to nulls.

Parameters

key: Key for name-value pair to be converted to JSON.
value: Value for key.
prefixToIgnore: rstring prefix to ignore in attribute name .

Returns

Serialized JSON object containing single name-value pair.

<tuple T> public rstring tupleToJSON(T t)

Convert a tuple to JSON object encoded as a serialized JSON String.

Blob, complex and xml values are converted to nulls. Timestamp is converted to a date string representation. Optional attributes having null value are converted to null in JSON.

Example


public composite SPLToJSONSample {
  type
    // Provide any hierarchical tuple to tupleToJSON function
    TestTuple = tuple<rstring str, float64 num, list<int32> nums, map<rstring,timestamp> dates, tuple<boolean flag, enum{YES,NO} answer> additionalTypes>;
  graph
    () as Test = Custom() {
      logic
        onProcess : {
          TestTuple testTuple = {str = "testTuple", num = 42.42, nums = [1,2,3,4], dates = {"date1":getTimestamp()}, additionalTypes = {flag = true, answer = YES}};
          printStringLn( tupleToJSON(testTuple));
        }
    }
}

Parameters

t: Tuple to be converted to JSON.

Returns

Tuple encoded as a serialized JSON object.

<tuple T> public rstring tupleToJSON(T t, rstring prefixToIgnore)

Convert a tuple to JSON object encoded as a serialized JSON String. Blob, complex and xml values are converted to nulls.

Parameters

t: Tuple to be converted to JSON.
prefixToIgnore: rstring prefix to ignore in attribute name .

Returns

Tuple encoded as a serialized JSON object.