Package org.apache.lucene.index

Class NoDeletionPolicy

java.lang.Object
org.apache.lucene.index.IndexDeletionPolicy
org.apache.lucene.index.NoDeletionPolicy
public final class NoDeletionPolicy extends IndexDeletionPolicy
An IndexDeletionPolicy which keeps all index commits around, never deleting them. This class is a singleton and can be accessed by referencing INSTANCE.

  • Field Details

    • INSTANCE

      public static final IndexDeletionPolicy INSTANCE
      The single instance of this class.

  • Method Details

    • onCommit

      public void onCommit(List<? extends IndexCommit> commits)
      Description copied from class: IndexDeletionPolicy
      This is called each time the writer completed a commit. This gives the policy a chance to remove old commit points with each commit.

      The policy may now choose to delete old commit points by calling method delete() of IndexCommit.

      This method is only called when IndexWriter.commit() or IndexWriter.close() is called, or possibly not at all if the IndexWriter.rollback() is called.

      Note: the last CommitPoint is the most recent one, i.e. the "front index state". Be careful not to delete it, unless you know for sure what you are doing, and unless you can afford to lose the index content while doing that.

      Specified by:
      onCommit in class IndexDeletionPolicy
      Parameters:
      commits - List of IndexCommit, sorted by age (the 0th one is the oldest commit).

    • onInit

      public void onInit(List<? extends IndexCommit> commits)
      Description copied from class: IndexDeletionPolicy
      This is called once when a writer is first instantiated to give the policy a chance to remove old commit points.

      The writer locates all index commits present in the index directory and calls this method. The policy may choose to delete some of the commit points, doing so by calling method delete() of IndexCommit.

      Note: the last CommitPoint is the most recent one, i.e. the "front index state". Be careful not to delete it, unless you know for sure what you are doing, and unless you can afford to lose the index content while doing that.

      Specified by:
      onInit in class IndexDeletionPolicy
      Parameters:
      commits - List of current point-in-time commits, sorted by age (the 0th one is the oldest commit). Note that for a new index this method is invoked with an empty list.