Expose cancelBuildsOnUpdate to dsl

Closes #628

Author: bjoernhaeuser

src/main/java/org/jenkinsci/plugins/ghprb/jobdsl/GhprbCancelBuildsOnUpdateContext.java

@@ -0,0 +1,18 @@
+package org.jenkinsci.plugins.ghprb.jobdsl;
+
+import javaposse.jobdsl.dsl.Context;
+
+class GhprbCancelBuildsOnUpdateContext implements Context {
+    private Boolean overrideGlobal;
+
+    public Boolean getOverrideGlobal() {
+        return overrideGlobal;
+    }
+
+    /**
+     * sets the overrideGlobal value
+     */
+    public void overrideGlobal(Boolean overrideGlobal) {
+        this.overrideGlobal = overrideGlobal;
+    }
+}

src/main/java/org/jenkinsci/plugins/ghprb/jobdsl/GhprbExtensionContext.java

@@ -3,6 +3,7 @@
 import javaposse.jobdsl.dsl.Context;
 import javaposse.jobdsl.plugin.ContextExtensionPoint;
 import org.jenkinsci.plugins.ghprb.extensions.GhprbExtension;
+import org.jenkinsci.plugins.ghprb.extensions.build.GhprbCancelBuildsOnUpdate;
 import org.jenkinsci.plugins.ghprb.extensions.comments.GhprbBuildStatus;
 import org.jenkinsci.plugins.ghprb.extensions.status.GhprbSimpleStatus;
 
@@ -40,6 +41,16 @@ void buildStatus(Runnable closure) {
         extensions.add(new GhprbBuildStatus(context.getCompletedStatus()));
     }
 
+    /**
+     * Overrides global settings for cancelling builds when a PR was updated
+     */
+    void cancelBuildsOnUpdate(Runnable closure) {
+        GhprbCancelBuildsOnUpdateContext context = new GhprbCancelBuildsOnUpdateContext();
+        ContextExtensionPoint.executeInContext(closure, context);
+
+        extensions.add(new GhprbCancelBuildsOnUpdate(context.getOverrideGlobal()));
+    }
+
     public List<GhprbExtension> getExtensions() {
         return extensions;
     }