add json functions

[xinyual]

Description

Here we add json related functions to align with spark

Here is the argument and description of functions

Functions	argument	description	return type	implementation
json	json(value: ANY)	return value if value is a json, otherwise, return null, e.g. json("123") = "123", json(json_object("1", "2")) = {"1": "2"}, json(1) = null	the first argument type	implement by ourselves
json_valid	json_valid(value: ANY)	return true if value is a json, otherwise, return false, e.g. json("123") = true, json(json_object("1", "2")) = true, json(1) = false	boolean	use calcite SqlStdOperatorTable.IS_JSON_VALUE
json_object	json_object(key1: String, value1: ANY, key2: string, value2 ....)	create an object using key value pairs, the key must be string	string	use calcite SqlStdOperatorTable.JSON_OBJECT
json_array	json_array(value1: ANY, value2: ANY, ...)	create an array using values	string	use SqlStdOperatorTable.JSON_ARRAY
json_array_length (this align with spark since splunk doesn't have this function)	json_array_length(value: STRING)	parse the string to json array and return size, if can't be transferred, return null	integer	implement by ourselves
json_extract	json_extract(target: ANY, path1: STRING, path2:STRING...)	it first transfer target to json, then extract value using paths. If only one path, return the value, otherwise, return the list of values. If one path cannot find value, return null as the result for this path. The path use "{}" to represent index for array, for e.g., demo = {"a": [{"b": 1}, {"b": 2}]}, json_extract(demo, "a{0}.b") = 1. "{}" means "{*}"	if one path, we return string, otherwise, return list of string	use calcite JsonFunctions::json_value, modify path to align with splunk
json_delete	json_delete(target: ANY, path1: STRING, path2:STRING...)	it first transfer target to json, then delete value using paths. return the object after deleting. If a path cannot find any value, skip it.	string. align with splunk	use calcite JsonFunctions::json_remove, modify path to align with splunk
json_set	json_set(target: ANY, path1: STRING, value1: ANY, path2:STRING, value2:ANY...)	it first transfer target to json, then set value to target path. The value can be set only when the parent node of target path is an object. Otherwise, skip it. For example, demo = {"a": [{"b": 1}, {"b": 2}]}, json_set(demo, "a{0}.b", 3) = {"a": [{"b": 3}, {"b": 2}]}. json_set(demo, "a{0}.b.d", 3) = {"a": [{"b": 1}, {"b": 2}]}.	string.align with splunk	use calcite JsonFunctions::json_set, modify path to align with splunk
json_append	json_append(target: ANY, path1: STRING, value1: ANY, path2:STRING, value2:ANY...)	it first transfer target to json, then append value to target path if the path points to an array. Otherwise, skip it. For example, demo = {"a": [{"b": 1}, {"b": 2}]}, json_append(demo, "a", 3) = {"a": [{"b": 1}, {"b": 2}, 3]}. json_append(demo, "a{0}.b", 3) = {"a": [{"b": 1}, {"b": 2}]}.	string. align with splunk	use calcite JsonFunctions::json_insert, modify path to align with splunk
json_extend	json_extend(target: ANY, path1: STRING, value1: ANY, path2:STRING, value2:ANY...)	it first transfer target to json, then extend value to target path if the path points to an array. Otherwise, skip it. For example, demo = {"a": [{"b": 1}, {"b": 2}]}, json_extend(demo, "a", json_array(1, 2)) = {"a": [{"b": 1}, {"b": 2}, 1, 2]}. json_extend(demo, "a{0}.b", 3) = {"a": [{"b": 1}, {"b": 2}]}.	string. align with splunk	use calcite JsonFunctions::json_insert, modify path to align with splunk
json_keys	json_keys(target: ANY)	it first transfer target to json object, then give the keys, otherwise, return null	string	use calcite JsonFunctions.jsonKeys

Related Issues

Resolves #[Issue number to be closed when this PR is merged]
#3565

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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[LantaoJin]

Why we didn't leverage the Calcite builtin JSON functions, for instance SqlStdOperatorTable.JSON_ARRAY

[xinyual]

Why we didn't leverage the Calcite builtin JSON functions, for instance SqlStdOperatorTable.JSON_ARRAY

I have listed the functions above and try to reuse calcite code

[LantaoJin]

CI failures CalcitePPLAppendcolTest > ... FAILED is not related.

[xinyual]

Force push to revert useless change and resolve DCO problems.