refactor(systems/github): make final changes

src/main/java/de/hftstuttgart/unifiedticketing/core/TicketSystem.java

 package de.hftstuttgart.unifiedticketing.core;
 
 import de.hftstuttgart.unifiedticketing.exceptions.AssertionException;
+import de.hftstuttgart.unifiedticketing.systems.github.GithubTicketSystem;
 import de.hftstuttgart.unifiedticketing.systems.gitlab.GitlabTicketSystem;
 
 import java.util.HashMap;
@@ -57,6 +58,9 @@ public abstract class TicketSystem<T extends Ticket, TS extends TicketSystem, TB
 
         switch (matcher.group(2))
         {
+            case "github":
+                return GithubTicketSystem.fromUri(matcher.group(3));
+
             case "gitlab":
                 return GitlabTicketSystem.fromUri(matcher.group(3));
 

src/main/java/de/hftstuttgart/unifiedticketing/systems/github/GithubTicket.java

@@ -29,7 +29,7 @@ public class GithubTicket extends Ticket<GithubTicketSystem, GithubTicket>
         GithubTicket ret = new GithubTicket(parent);
         ret.description = response.body;
         ret.id = String.valueOf(response.number);
-        ret.open = response.state.equalsIgnoreCase("open");
+        ret.open = response.state == null || response.state.equalsIgnoreCase("open");
         ret.title = response.title;
 
         if (response.assignees != null)
@@ -265,4 +265,22 @@ public class GithubTicket extends Ticket<GithubTicketSystem, GithubTicket>
 
         return GithubTicket.fromTicketResponse(this.parent, ticketResponse);
     }
+
+    /**
+     * compares a given Object to this one, including all data fields.
+     * The normal {@link #equals(Object)} method does only compare Ticket Type and id,
+     * but not the data fields like this one.
+     * @param o Object to compare to this
+     * @return true if the given object is equal in terms of type, id and content to this
+     */
+    public boolean deepEquals(Object o)
+    {
+        if (!equals(o)) return false;
+        GithubTicket t = (GithubTicket) o;
+
+        return Objects.equals(title, t.title)
+            && Objects.equals(description, t.description)
+            && Objects.equals(labels, t.labels)
+            && Objects.equals(assignees, t.assignees);
+    }
 }

src/main/java/de/hftstuttgart/unifiedticketing/systems/github/GithubTicketSystem.java

 package de.hftstuttgart.unifiedticketing.systems.github;
 
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import de.hftstuttgart.unifiedticketing.core.*;
-import de.hftstuttgart.unifiedticketing.exceptions.AssertionException;
-import de.hftstuttgart.unifiedticketing.exceptions.UnifiedticketingException;
+import de.hftstuttgart.unifiedticketing.exceptions.*;
+import okhttp3.*;
 
-import java.util.List;
+import java.io.IOException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import java.util.regex.Matcher;
@@ -106,21 +108,93 @@ public class GithubTicketSystem extends TicketSystem<GithubTicket, GithubTicketS
         return new GithubFilter(this);
     }
 
+    protected OkHttpClient getHttpClient() { return new OkHttpClient(); }
+
     @Override
     public GithubTicket getTicketById(String id)
     {
-        logger.log(Level.FINER, "redirecting request to find method");
-        List<GithubTicket> ret = this.find()
-            .withId(id)
+        ObjectMapper mapper = new ObjectMapper()
+            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+
+        Request.Builder requestBuilder = new Request.Builder()
+            .url(String.format("%s/%s", baseUrl, id))
+            .addHeader("accept", acceptHeader)
             .get();
 
-        if (ret == null) return null;
-        else if (ret.size() != 1)
+        if (username != null && apiKey != null)
+        {
+            requestBuilder.addHeader("Authorization", Credentials.basic(username, apiKey));
+            logger.log(Level.FINEST, "added token authentication header");
+        }
+
+        HttpUrl.Builder urlBuilder = requestBuilder.build().url().newBuilder();
+
+        requestBuilder.url(urlBuilder.build());
+
+        OkHttpClient client = getHttpClient();
+        Response response;
+
+        try
+        {
+            Request request = requestBuilder.build();
+            logger.log(Level.FINEST, String.format(
+                "created request:\n%s",
+                (apiKey != null)
+                    ? request.toString().replace(apiKey, "SECRET")
+                    : request.toString()
+            ));
+
+            response = client.newCall(request).execute();
+        }
+        catch (IOException e)
+        {
+            logger.log(Level.SEVERE, String.format("get request FAILED with: %s", e.getMessage()));
+
+            if (getConfigTrue(TicketSystem.ConfigurationOptions.RETURN_NULL_ON_ERROR)) return null;
+            else throw new HttpReqeustException(e);
+        }
+
+        if (response.code() >= 400)
         {
-            if (getConfigTrue(ConfigurationOptions.RETURN_NULL_ON_ERROR)) return null;
-            else throw new UnifiedticketingException("more or less than 1 dedicated ticket found");
+            logger.log(Level.SEVERE, String.format(
+                "request failed with response code %d",
+                response.code()
+            ));
+
+            if (getConfigTrue(TicketSystem.ConfigurationOptions.RETURN_NULL_ON_ERROR)) return null;
+            else throw new HttpResponseException(
+                String.format("ticket query failed, error response code: %d", response.code()),
+                response.code());
         }
-        else return ret.get(0);
+
+        logger.log(Level.FINEST, "response received\n");
+
+        ResponseBody responseBody;
+        responseBody = response.body();
+
+        if (responseBody == null)
+        {
+            logger.log(Level.SEVERE, "query didn't deliver a body in response");
+
+            if (getConfigTrue(TicketSystem.ConfigurationOptions.RETURN_NULL_ON_ERROR)) return null;
+            else throw new HttpResponseException("ticket query failed, no response body", response.code());
+        }
+
+        GithubTicketResponse tr;
+        try
+        {
+            tr = mapper.readValue(responseBody.bytes(), GithubTicketResponse.class);
+
+            logger.log(Level.FINER, "parsed response body to ticketResponse instance");
+        } catch (IOException e)
+        {
+            logger.log(Level.SEVERE, String.format("parsing query response FAILED with: %s", e.getMessage()));
+
+            if (getConfigTrue(TicketSystem.ConfigurationOptions.RETURN_NULL_ON_ERROR)) return null;
+            else throw new DeserializationException(e);
+        }
+
+        return GithubTicket.fromTicketResponse(this, tr);
     }
 
     @Override

src/main/java/de/hftstuttgart/unifiedticketing/systems/github/GithubTicketSystemBuilder.java

@@ -2,6 +2,7 @@ package de.hftstuttgart.unifiedticketing.systems.github;
 
 import de.hftstuttgart.unifiedticketing.core.Logging;
 import de.hftstuttgart.unifiedticketing.core.TicketSystemBuilder;
+import de.hftstuttgart.unifiedticketing.exceptions.AssertionException;
 
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -69,6 +70,14 @@ public class GithubTicketSystemBuilder extends TicketSystemBuilder<GithubTicketS
     @Override
     public GithubTicketSystem build()
     {
+        if (baseUrl == null
+            || owner == null
+            || repo == null)
+        {
+            String msg = "one of mandatory fields 'baseUrl', 'owner' or 'repo' missing!";
+            throw new AssertionException(msg);
+        }
+
         return new GithubTicketSystem(
             acceptHeader,
             String.format(