I need to use a method which accepts two arguments Model type and Stream Type.
public static void Write(Stream stream, Model model);
Firstly i want to create a variable of type stream and then capture what ever is written to the stream in a string and then store in database. I find that Stream class is a abstract class not sure how to override it.
Can any one please suggest ?
You could use some of the derived classes such as MemoryStream:
using (var stream = new MemoryStream())
{
// pass the memory stream to the method which will write to it
SomeClass.Write(stream, someModel);
// convert the contents to string using the default encoding
string result = Encoding.Default.GetString(stream.ToArray());
// TODO: do something with the result
}
Related
I want to convert my objects to hashmaps so I can use the Flutter method channels to send data to Android.
I've thought of iterating through and mapping them one by one, but there's got to be a more elegant way to do this...
Example:
Object
class Something {
Something(this.what, this.the, this.fiddle);
final String what;
final int the;
final bool fiddle;
}
Somewhere else
List<Something> listOStuff = List<Something>.generate(10, (int index){
return Something(index.toString(), index, false,);
});
List<Map<String, dynamic>> parseToMaps(List<Something> listOStuff){
List<Map<String, dynamic>> results;
// do something crazy to get listOStuff into Map of primitive values for each object
// preferably a built in method of some sort... otherwise, i guess i'll just iterate...
// maybe even an imported package if such thing exists
return results;
}
List<Map<String, dynamic>> listOMaps = parseToMaps(listOStuff);
Something like this in Java
You can use the map and return the object that you want:
List<Map<String, dynamic>> listOMaps = listOStuff
.map((something) => {
"what": something.what,
"the": something.the,
"fiddle": something.fiddle,
})
.toList();
I'm not sure what exactly you're looking for, but there is a way to have custom objects encoded without having to specify it directly when you call the method.
What you have to do is implement a MethodCodec and/or MessageCodec that defines how your object is encoded and decoded. The easiest way is probably to subclass StandardMethodCodec and/or StandardMessageCodec (it might be enough to override StandardMessageCodec and pass it to StandardMessageCodec).
If you implement read & write correctly for your object, then all you have to do is pass the list of objects directly to your method call and flutter will handle the encoding.
Note that there are corresponding classes on the Android & iOS sides of things that you could use to have the data decoded directly to objects, and in fact you might have to implement them to get things to work depending on how you do it.
I'm using an Azure function to pick up messages from an event hub and send out notifications via the Azure notification hub. Works great! Now I wanted to see whether I could add tags to those messages in order to allow user targeting via those tags.
The output for the notification hub has a "tag expression" parameter which you can configure. But this seems to be a static text. I need to dynamically set these tags based on the message received from the event hub instead. I'm not sure whether you can somehow put dynamic content in there?
I also found that the constructor of the GcmNotification object that I'm using has an overload which allows a tag string to be used. But when I try that I get a warning on compile time stating this is deprecated and when the function fires it shows an error because the Tag property should be empty.
So I'm not clear on a) whether this is at all possible and b) how to do it when it is. Any ideas?
Update: as suggested I tried creating a POCO object to map to my input string. The string is as follows:
[{"deviceid":"repsaj-neptune-win10pi","readingtype":"temperature1","reading":22.031614503139451,"threshold":23.0,"time":"2016-06-22T09:38:54.1900000Z"}]
The POCO object:
public class RuleMessage
{
public string deviceid;
public string readingtype;
public object reading;
public double threshold;
public DateTime time;
}
For the function I now tried both RuleMessage[] and List<RuleMessage> as parameter types, but the function complains it cannot convert the input:
2016-06-24T18:25:16.830 Exception while executing function: Functions.submerged-function-ruleout. Microsoft.Azure.WebJobs.Host: Exception binding parameter 'inputMessage'. Microsoft.Azure.WebJobs.Host: Binding parameters to complex objects (such as 'RuleMessage') uses Json.NET serialization.
1. Bind the parameter type as 'string' instead of 'RuleMessage' to get the raw values and avoid JSON deserialization, or
2. Change the queue payload to be valid json. The JSON parser failed: Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'Submission#0+RuleMessage' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly.
To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.
Function code:
using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Microsoft.Azure.NotificationHubs;
public static void Run(List<RuleMessage> inputEventMessage, string inputBlob, out Notification notification, out string outputBlob, TraceWriter log)
{
if (inputEventMessage == null || inputEventMessage.Count != 1)
{
log.Info($"The inputEventMessage array was null or didn't contain exactly one item.");
notification = null;
outputBlob = inputBlob;
return;
}
log.Info($"C# Event Hub trigger function processed a message: {inputEventMessage[0]}");
if (String.IsNullOrEmpty(inputBlob))
inputBlob = DateTime.MinValue.ToString();
DateTime lastEvent = DateTime.Parse(inputBlob);
TimeSpan duration = DateTime.Now - lastEvent;
if (duration.TotalMinutes >= 0) {
notification = GetGcmMessage(inputMessage.First());
log.Info($"Sending notification message: {notification.Body}");
outputBlob = DateTime.Now.ToString();
}
else {
log.Info($"Not sending notification message because of timer ({(int)duration.TotalMinutes} minutes ago).");
notification = null;
outputBlob = inputBlob;
}
}
private static Notification GetGcmMessage(RuleMessage input)
{
string message;
if (input.readingtype == "leakage")
message = String.Format("[FUNCTION GCM] Leakage detected! Sensor {0} has detected a possible leak.", input.reading);
else
message = String.Format("[FUNCTION GCM] Sensor {0} is reading {1:0.0}, threshold is {2:0.0}.", input.readingtype, input.reading, input.threshold);
message = "{\"data\":{\"message\":\""+message+"\"}}";
return new GcmNotification(message);
}
public class RuleMessage
{
public string deviceid;
public string readingtype;
public object reading;
public double threshold;
public DateTime time;
}
Update 28-6-2016: I've not managed to get it working by switching ASA output to line seperated to that it doesn't generate a JSON array any more. This is a temp. fix because the Function binding now fails as soon as there is more than one line in the output (which can happen).
Anyways, I now proceeded to set the tagExpression, as per instruction I changed it to:
{
"type": "notificationHub",
"name": "notification",
"hubName": "repsaj-neptune-notifications",
"connection": "repsaj-neptune-notifications_NOTIFICATIONHUB",
"direction": "out",
"tagExpression": "deviceId:{deviceid}"
}
Where {deviceid} equals the deviceid property on my RuleMessage POCO. Unfortunately this doesn't work, when I call the function it outputs:
Exception while executing function: Functions.submerged-function-ruleout. Microsoft.Azure.WebJobs.Host: Exception binding parameter 'notification'. Microsoft.Azure.WebJobs.Host: No value for named parameter 'deviceid'.
Which is not true, I know for sure the property has been set as I've logged it to the ouput window. I also tried something like {inputEventMessage.deviceid}, but that doesn't work either (as I didn't get how the runtime would map {deviceid} to the correct input object when there's more than one.
The tagExpression binding property supports binding parameters coming from trigger input properties. For example, assume your incoming Event Hub event has properties A and B. You can use these properties in your tagExpression using the parens syntax, e.g.: My Tag {A}-{B}.
In general, most of the properties across all the binding types support binding parameters in this way.
I have a rule that looks like this:
INTEGER : [0-9]+;
myFields : uno=INTEGER COMMA dos=INTEGER
Right now to access uno I need to code:
Integer i = Integer.parseInt(myFields.uno.getText())
It would be much cleaner if I could tell antler to do that conversion for me; then I would just need to code:
Integer i = myFields.uno
What are my options?
You could write the code as action, but it would still be explicit conversion (eventually). The parser (like every parser) parses the text and then it's up to "parsing events" (achieved by listener or visitor or actions in ANTLR4) to create meaningful structures/objects.
Of course you could extend some of the generated or built-in classes and then get the type directly, but as mentioned before, at some point you'll always need to convert text to some type needed.
A standard way of handling custom operations on tokens is to embed them in a custom token class:
public class MyToken extends CommonToken {
....
public Integer getInt() {
return Integer.parseInt(getText()); // TODO: error handling
}
}
Also create
public class MyTokenFactory extends TokenFactory { .... }
to source the custom tokens. Add the factory to the lexer using Lexer#setTokenFactory().
Within the custom TokenFactory, override the method
Symbol create(int type, String text); // (typically override both factory methods)
to construct and return a new MyToken.
Given that the signature includes the target token type type, custom type-specific token subclasses could be returned, each with their own custom methods.
Couple of issues with this, though. First, in practice, it is not typically needed: the assignment var is statically typed, so as in the the OP example,
options { TokenLabelType = "MyToken"; }
Integer i = myFields.uno.getInt(); // no cast required
If Integer is desired & expected, use getInt(). If Boolean ....
Second, ANTLR options allows setting a TokenLabelType to preclude the requirement to manually cast custom tokens. Use of only one token label type is supported. So, to use multiple token types, manual casting is required.
I need to marshal a list of entities using jax-b in a jax-rs client, without creating a wrapper class for each entity needed (there are manny entities!). I notice the service is able to marshal a list of customers like this:
<customers>
<customer>.....</customer>
<customer>.....</customer>
</customers>
Which I on the client side is able to unmarshal by finding all customer nodes and adding them to a list manually. (I guess there's a better way to do this?)
Now, the real problem here is when I want to send a list of an entity(eg. customers) to the service. I want to marshal this list into an xml string before writing this string as the payload of the request to the service. This does not work since java.util.List or its descendants is not known to the marshaller.
javax.xml.bind.Marshaller.marshal(list, StringWriter);
javax.xml.bind.Unmarshaller.unmarshal(org.w3c.dom.node)
Any help is much appreciated!
Thanks!
-Runar
Edit:
Here's a snippet from the customer class:
#XmlRootElement
#XmlAccessorType(XmlAccessType.FIELD)
public class Customer implements Serializable {
private String name;
.....
}
I'm trying to write a lightweight client using no 3rd party libraries not part of the standard implementation. Because of this I have written my own httpclient taking in payload objects, marhalling them and passing them to the payload of the request. When the response is received I read the xml and send it to unmarshalling. It would be awsome if I could do the marshalling/unmarshalling directly to/from string just as my jax-rs service does.
Ok, so I found no good solution to this. But since it seems the pattern for my jax-rs service is to generate a root node called <class name " + "s>, I did this to be able to send lists of objects to the service:
if (obj instanceof List) {
List list = (List) obj;
if (!list.isEmpty()) {
// Since the jax-b marshaller does not allow to send lists directly,
// we must attempt to create the xml as the jax-rs service would expect them,
// wrapped with the classname pluss an s.
String wrapper = list.get(0).getClass().getSimpleName() + "s";
// Make first letter in class-name lower-case
wrapper = Character.toLowerCase(wrapper.charAt(0)) +
(wrapper.length() > 1 ? wrapper.substring(1) : "");
marshaller.setProperty(javax.xml.bind.Marshaller.JAXB_FRAGMENT, true);
writer.write("<" + wrapper + ">");
for (Object o : (List) obj) {
marshaller.marshal(o, writer);
}
writer.write("</" + wrapper + ">");
}
} else {
marshaller.marshal(obj, writer);
}
I have the current method example:
public void MethodName(string param1,int param2)
{
object[] obj = new object[] { (object) param1, (object) param2 };
//Code to that uses this array to invoke dynamic methods
}
Is there a dynamic way (I am guessing using reflection) that will get the current executing method parameter values and place them in a object array? I have read that you can get parameter information using MethodBase and MethodInfo but those only have information about the parameter and not the value it self which is what I need.
So for example if I pass "test" and 1 as method parameters without coding for the specific parameters can I get a object array with two indexes { "test", 1 }?
I would really like to not have to use a third party API, but if it has source code for that API then I will accept that as an answer as long as its not a huge API and there is no simple way to do it without this API.
I am sure there must be a way, maybe using the stack, who knows. You guys are the experts and that is why I come here.
Thank you in advance, I can't wait to see how this is done.
EDIT
It may not be clear so here some extra information. This code example is just that, an example to show what I want. It would be to bloated and big to show the actual code where it is needed but the question is how to get the array without manually creating one. I need to some how get the values and place them in a array without coding the specific parameters.
Using reflection you can extract the parameters name and metadata but not the actual values :
class Program
{
static void Main(string[] args)
{
Program p = new Program();
p.testMethod("abcd", 1);
Console.ReadLine();
}
public void testMethod(string a, int b)
{
System.Diagnostics.StackTrace st = new System.Diagnostics.StackTrace();
StackFrame sf = st.GetFrame(0);
ParameterInfo[] pis = sf.GetMethod().GetParameters();
foreach (ParameterInfo pi in pis)
{
Console.Out.WriteLine(pi.Name);
}
}
}