[JENKINS-49451] Fix logstash Notifier setp (#53)

[JENKINS-49451] add getters for fields

we need getters for the fields so the UI can properly work with them
add check for valid integer
add clazz number which auto checks for integer

Author: mwinter69

src/main/java/jenkins/plugins/logstash/LogstashNotifier.java

@@ -37,13 +37,14 @@
 import hudson.tasks.BuildStepMonitor;
 import hudson.tasks.Notifier;
 import hudson.tasks.Publisher;
-
+import hudson.util.FormValidation;
 import jenkins.tasks.SimpleBuildStep;
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.io.IOException;
 
 import org.kohsuke.stapler.DataBoundConstructor;
+import org.kohsuke.stapler.QueryParameter;
 import org.jenkinsci.Symbol;
 
 /**
@@ -63,6 +64,16 @@ public LogstashNotifier(int maxLines, boolean failBuild) {
     this.failBuild = failBuild;
   }
 
+  public int getMaxLines()
+  {
+    return maxLines;
+  }
+
+  public boolean isFailBuild()
+  {
+    return failBuild;
+  }
+
   @Override
   public boolean perform(AbstractBuild<?, ?> build, Launcher launcher, BuildListener listener) {
     return perform(build, listener);
@@ -111,5 +122,19 @@ public boolean isApplicable(@SuppressWarnings("rawtypes") Class<? extends Abstra
     public String getDisplayName() {
       return Messages.DisplayName();
     }
+
+    /*
+     * Form validation methods
+     */
+    public FormValidation doCheckMaxLines(@QueryParameter("value") String value) {
+      try {
+        Integer.parseInt(value);
+      } catch (NumberFormatException e) {
+        return FormValidation.error(Messages.ValueIsInt());
+      }
+
+      return FormValidation.ok();
+    }
+
   }
 }

src/main/resources/jenkins/plugins/logstash/LogstashNotifier/config.jelly

@@ -1,7 +1,7 @@
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
   <f:block>
     <f:entry title="${%Max lines}" field="maxLines">
-      <f:number default="1000" value="${instance.maxLines}" checkUrl="'descriptorByName/LogstashInstallation/checkInteger?value='+escape(this.value)" />
+      <f:number default="1000" value="${instance.maxLines}" clazz="required number"/>
     </f:entry>
     <f:entry title="${%Can fail build}" field="failBuild">
       <f:checkbox checked="${instance.failBuild}" />