Fixed VAvailabilityFactory support

src/main/groovy/net/fortuna/ical4j/model/component/VAvailabilityFactory.groovy

@@ -39,7 +39,6 @@ import net.fortuna.ical4j.model.PropertyList
  */
 class VAvailabilityFactory extends AbstractComponentFactory{
 
-
      Object newInstance(FactoryBuilderSupport builder, Object name, Object value, Map attributes) throws InstantiationException, IllegalAccessException {
          VAvailability availability
          if (FactoryBuilderSupport.checkValueIsType(value, name, VAvailability.class)) {
@@ -54,4 +53,13 @@ class VAvailabilityFactory extends AbstractComponentFactory{
      protected Object newInstance(PropertyList properties) {
          return new VAvailability(properties)
      }
+
+    void setChild(FactoryBuilderSupport build, Object parent, Object child) {
+        if (child instanceof Available) {
+            parent.available.add child
+        }
+        else {
+            super.setChild(build, parent, child)
+        }
+    }
 }

src/test/groovy/net/fortuna/ical4j/model/component/VAvailabilityFactoryTest.groovy

@@ -0,0 +1,25 @@
+package net.fortuna.ical4j.model.component
+
+import net.fortuna.ical4j.model.ContentBuilder
+import spock.lang.Specification
+
+class VAvailabilityFactoryTest extends Specification {
+
+    def 'verify vavailability creation'() {
+        given: 'a content builder'
+        ContentBuilder builder = []
+
+        when: 'a vavailability spec is provided'
+        VAvailability availability = builder.vavailability() {
+            uid '1'
+            available {
+                uid '11'
+            }
+        }
+
+        then: 'result is as expected'
+        availability.getProperty('UID').value == '1'
+        availability.available.size() == 1
+        availability.available[0].getProperty('UID').value == '11'
+    }
+}