Package org.apache.sling.discovery.commons

Class InstancesDiff

  • public final class InstancesDiff
extends Object
    The InstancesDiff allows to combine and filter two collections of InstanceDescription instances, an "old" collection and a "new" collection.

    The comparison between InstanceDescription instances is done only on the basis of the Sling identifier. Two instances with the same Sling identifier are considered as equal.

    Note: Each collection must contain only unique instances (no two instances with the same Sling identifier). Using the InstancesDiff with collections containing duplicated Sling id will throw an IllegalArgumentException.

    Since:
    1.0.0

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      class  InstancesDiff.InstanceCollection
      The InstanceCollection collection allows to filter the instances using a set of custom filter either implementing InstanceFilter or pre-defined ones.

    • Constructor Summary

      Constructors 
      Constructor Description
      InstancesDiff​(@NotNull Collection<T> oldInstances, @NotNull Collection<T> newInstances)
      Create a new InstancesDiff based on the provided old and new Collection collections of instances.
      InstancesDiff​(@NotNull ClusterView oldView, @NotNull ClusterView newView)
      Create a new InstancesDiff based on the instances from the old and new ClusterView cluster views provided.
      InstancesDiff​(@NotNull TopologyEvent event)
      Create a new InstancesDiff based on the instances from the old and new TopologyView topology views contained in the TopologyEvent event provided.
      InstancesDiff​(@NotNull TopologyView oldView, @NotNull TopologyView newView)
      Create a new InstancesDiff based on the instances from the old and new TopologyView topology views provided.

    • Constructor Detail

      • InstancesDiff

        public InstancesDiff​(@NotNull
                     @NotNull TopologyEvent event)
        Create a new InstancesDiff based on the instances from the old and new TopologyView topology views contained in the TopologyEvent event provided.
        Parameters:
        event - the non null event from which the old and new topology views are used for computing. If either of the topology views are null, then they will be substituted by an empty collection of instances.
        Throws:
        IllegalArgumentException - if either of the collections contains duplicated Sling identifiers.

      • InstancesDiff

        public InstancesDiff​(@NotNull
                     @NotNull TopologyView oldView,
                     @NotNull
                     @NotNull TopologyView newView)
        Create a new InstancesDiff based on the instances from the old and new TopologyView topology views provided.
        Parameters:
        oldView - the non null old topology view from which the old collection is used for computing.
        newView - the non null new topology view form which the new collection is used for computing.
        Throws:
        IllegalArgumentException - if either of the collections contains duplicated Sling identifiers.

      • InstancesDiff

        public InstancesDiff​(@NotNull
                     @NotNull ClusterView oldView,
                     @NotNull
                     @NotNull ClusterView newView)
        Create a new InstancesDiff based on the instances from the old and new ClusterView cluster views provided.
        Parameters:
        oldView - the non null old cluster view used for computing.
        newView - the non null new cluster view used for computing.
        Throws:
        IllegalArgumentException - if either of the collections contains duplicated Sling identifiers.

      • InstancesDiff

        public InstancesDiff​(@NotNull
                     @NotNull Collection<T> oldInstances,
                     @NotNull
                     @NotNull Collection<T> newInstances)
        Create a new InstancesDiff based on the provided old and new Collection collections of instances.
        Type Parameters:
        T - the type of instance which must extend InstanceDescription.
        Parameters:
        oldInstances - the non null old collection of instances used for computing.
        newInstances - the non null new collection of instances used for computing.
        Throws:
        IllegalArgumentException - if either of the collections contains duplicated Sling identifiers.

    • Method Detail

      • all

        @NotNull
public @NotNull InstancesDiff.InstanceCollection all​(boolean retainFromNewCollection)
        Returns the InstanceSet set containing the InstanceDescription instances that are contained in either the old or the new collection.

        For InstanceDescription instances contained in both the old and the new collections, the method will retain those from either of the collections depending on the parameter #retainFromNewView.

        Parameters:
        retainFromNewCollection - true in order to retain the instances from the new collection ; false in order to retain the instances from the old collection.
        Returns:
        the InstanceCollection collection containing the InstanceDescription instances from both collections.

      • added

        @NotNull
public @NotNull InstancesDiff.InstanceCollection added()
        Returns the InstanceCollection collection containing the InstanceDescription instances that are contained in the new collection but not in the old collection.
        Returns:
        the InstanceCollection collection containing the instances in the new topology collection but not in the old collection.

      • removed

        @NotNull
public @NotNull InstancesDiff.InstanceCollection removed()
        Returns the InstanceCollection collection containing the InstanceDescription instances that are contained in the old collection but not in the new collection.
        Returns:
        the InstanceSet set containing the instances in the old collection but not in the new collection.

      • retained

        @NotNull
public @NotNull InstancesDiff.InstanceCollection retained​(boolean retainFromNewCollection)
        Returns the InstanceSet collection containing the InstanceDescription instances that are contained in both the old collection and the new collection.

        The method will retain the InstanceDescription instances from either of the collections depending on the parameter #retainFromNewView.

        Parameters:
        retainFromNewCollection - true in order to retain the instances from the new collection ; false in order to retain the instances from the old collection.
        Returns:
        the InstanceCollection collection containing the InstanceDescription instances contained in both collections.

      • retained

        @NotNull
public @NotNull InstancesDiff.InstanceCollection retained​(boolean retainFromNewCollection,
                                                          boolean propertyChanged)
        Returns the InstanceCollection collection containing the InstanceDescription instances that are contained in both the old and the new collections.

        The method will retain the InstanceDescription instances from either of the collections depending on the parameter #retainFromNewView.

        Parameters:
        retainFromNewCollection - true in order to retain the instances from the new collection ; false in order to retain the instances from the old collection.
        propertyChanged - true in order to keep only the instances which properties have changed between the old and new collections ; false in order to keep only the instances which properties have not changed.
        Returns:
        the InstanceCollection collection containing the InstanceDescription instances contained in both views.