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WTSupported in traditional Synergy on Windows
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WNSupported in Synergy .NET on Windows
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USupported on UNIX
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VSupported on OpenVMS
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namespace Json public class JsonDocument
The JsonDocument class provides a way to examine the structural content of a JSON value without automatically instantiating data values.
public static Parse(json), @JsonDocument
Parses the text in json, which is a string or memory handle (@string or D_HANDLE), into a JSON document.
public RootElement, @JsonElement
Gets the root element of this JsonDocument.
Discussion
JsonDocument acts as a single reference point for all of its associated JsonElement objects. All resulting JsonElement objects that come from this JsonDocument, its properties, and its method are only valid while the JsonDocument is alive and valid. JsonElement objects do not maintain a reference count back to their parent JsonDocument and will not be valid if the JsonDocument is destroyed.
JsonDocument reduces the burden of garbage collection by using resources from pooled memory. If you don’t dispose of this object properly, memory won’t be returned to the pool, which will negatively affect performance.
Example
import System.Text
import System.Text.Json
.define SAMPLE_FILE, "C:\temp\mysample.json"
; There is definitely no requirement to make these properties defines/const,
; but always a good idea to reduce your magic strings in code
.region "Json Property Strings"
.define JSON_NAMEPROP, "Name"
.define JSON_SAMPLEARRAYPROP, "SampleArray"
.define JSON_IDPROP, "Id"
.define JSON_BOOLEANDATAPROP, "BooleanData"
.define JSON_STRINGDATAPROP, "StringData"
.endregion
;;; <summary>
;;; Sample program that demonstrates first writing some Json data,
;;; then reading that data back in and displaying it to the console.
;;; </summary>
main
proc
JsonSample.WriteSampleData(SAMPLE_FILE)
JsonSample.ReadSampleData(SAMPLE_FILE)
Console.ReadLine()
endmain
namespace JsonSample
class JsonSample
;;; <summary>
;;; Method demonstrating using Utf8JsonWriter to output a JSON file
;;; </summary>
public static method WriteSampleData, void
filename, string
endparams
proc
begin
data jsonBuffer = new StringBuilder()
data jsonWriter = Utf8JsonWriter.CreateUtf8JsonWriter(jsonBuffer)
data writeChannel, i4
data iterator, i4
data stringData = "Hello World Hello World Hello World"
jsonWriter.WriteStartObject()
jsonWriter.WriteString(JSON_NAMEPROP, "MySampleObject")
jsonWriter.WriteStartArray(JSON_SAMPLEARRAYPROP)
for iterator from 1 thru 10 by 1
begin
jsonWriter.WriteStartObject()
jsonWriter.WriteNumber(JSON_IDPROP, iterator)
jsonWriter.WriteBoolean(JSON_BOOLEANDATAPROP, GetRandomBool())
jsonWriter.WriteString(JSON_STRINGDATAPROP, stringData(iterator:11))
jsonWriter.WriteEndObject()
end
jsonWriter.WriteEndArray()
jsonWriter.WriteEndObject()
jsonWriter.Flush()
jsonWriter.Reset()
open(writeChannel = 0, O, filename)
writes(writeChannel, jsonBuffer.ToString())
close writeChannel
end
endmethod
;;; <summary>
;;; Demonstrate the basic API for getting information out of a JsonDocument and JsonElements
;;;
;;; IMPORTANT NOTE:
;;; The JsonDocument object is the lifeblood of the rest of the objects. If it gets
;;; disposed or the scope ends, all of the child JsonElement objects will also be
;;; disposed. If you need them to leave the scope intact, make sure you keep the
;;; JsonDocument object alive
;;; </summary>
public static method ReadSampleData, void
filename, string
endparams
proc
begin
data jsDoc, @JsonDocument
data myElement, @JsonElement
data elementName, @JsonElement
data elementArray, @JsonElement
data arrayLength, i4
data arrayIterator, i4
jsDoc = Parse(filename)
myElement = jsDoc.RootElement
elementName = myElement.GetProperty(JSON_NAMEPROP)
elementArray = myElement.GetProperty(JSON_SAMPLEARRAYPROP)
arrayLength = elementArray.GetArrayLength()
for arrayIterator from 0 thru arrayLength-1 by 1
begin
data itemId = elementArray[arrayIterator].GetProperty(JSON_IDPROP).GetInt32()
data boolData = elementArray[arrayIterator].GetProperty(JSON_BOOLEANDATAPROP).GetBoolean()
data stringData = elementArray[arrayIterator].GetProperty(JSON_STRINGDATAPROP).GetString()
Console.WriteLine("Read in item " + %string(itemId) + " [" + %string(boolData) + ", " + stringData + "]")
end
end
endmethod
;;; <summary>
;;; Get a "random" boolean. Just to add flavor to the sample data.
;;; </summary>
;;; <returns>true or false, pseudo-randomly</returns>
private static method GetRandomBool, boolean
endparams
record
number, int
endrecord
proc
number = Utilities.GetRandomNumber()
mreturn %rnd(number) > 16383
endmethod
;;; <summary>
;;; Utility method to read in a file from disk and return that file
;;; content parsed through JsonDocument.Parse
;;; </summary>
;;; <param name="filePath"></param>
;;; <returns></returns>
public static method Parse, @JsonDocument
req in filePath, string
endparams
record
jsonFileContent, @StringBuilder
firstBrace, int
channel, int
buffer, a1024
plays,string
endrecord
proc
jsonFileContent = new StringBuilder()
open(channel = 0, I, filePath)
while (true)
begin
reads(channel, buffer, eof)
if (firstBrace < 1)
begin
xcall instr(1, buffer, '{', firstBrace)
if (firstBrace >= 1)
buffer = buffer(firstBrace:1024-firstBrace)
end
jsonFileContent.Append(%atrim(buffer))
nextloop
eof,
jsonFileContent.Append(%atrim(buffer))
exitloop
end
close(channel)
plays=jsonFileContent.ToString()
mreturn JsonDocument.Parse(jsonFileContent.ToString())
endmethod
endclass
.region "Utilities"
static class Utilities
;;; Stores the seed used by GetRandomNumber
private static randomSeed, int, 1
;;; <summary>
;;; Synergy randm() does not work particularly well when hit with the same
;;; seeds in the same millisecond/second. This method tracks its own random
;;; seed and produces a random number based on seed and time.
;;; </summary>
;;; <returns></returns>
public static method GetRandomNumber, int
endparams
record
number, int
ctime, int
endrecord
proc
xcall time(ctime)
xcall randm(randomSeed, randomSeed, ctime)
xcall randm(number, randomSeed, ctime)
mreturn number
endmethod
endclass
.endregion
endnamespace
