org.apache.commons.collections4.sequence

Class ReplacementsFinder<T>

  • All Implemented Interfaces:
    CommandVisitor<T> 

    public class ReplacementsFinder<T>
extends Object
implements CommandVisitor<T>
    This class handles sequences of replacements resulting from a comparison.

    The comparison of two objects sequences leads to the identification of common parts and parts which only belong to the first or to the second sequence. The common parts appear in the edit script in the form of keep commands, they can be considered as synchronization objects between the two sequences. These synchronization objects split the two sequences in synchronized sub-sequences. The first sequence can be transformed into the second one by replacing each synchronized sub-sequence of the first sequence by the corresponding sub-sequence of the second sequence. This is a synthetic way to see an edit script, replacing individual delete, keep and insert commands by fewer replacements acting on complete sub-sequences.

    This class is devoted to perform this interpretation. It visits an edit script (because it implements the CommandVisitor interface) and calls a user-supplied handler implementing the ReplacementsHandler interface to process the sub-sequences.

    Since:
    4.0
    See Also:
    ReplacementsHandler, EditScript, SequencesComparator

    • Constructor Detail

      • ReplacementsFinder

        public ReplacementsFinder(ReplacementsHandler<T> handler)
        Simple constructor. Creates a new instance of ReplacementsFinder.
        Parameters:
        handler - handler to call when synchronized sequences are found

    • Method Detail

      • visitInsertCommand

        public void visitInsertCommand(T object)
        Add an object to the pending insertions set.
        Specified by:
        visitInsertCommand in interface  CommandVisitor<T>
        Parameters:
        object - object to insert

      • visitKeepCommand

        public void visitKeepCommand(T object)
        Handle a synchronization object.

        When a synchronization object is identified, the pending insertions and pending deletions sets are provided to the user handler as subsequences.

        Specified by:
        visitKeepCommand in interface  CommandVisitor<T>
        Parameters:
        object - synchronization object detected

      • visitDeleteCommand

        public void visitDeleteCommand(T object)
        Add an object to the pending deletions set.
        Specified by:
        visitDeleteCommand in interface  CommandVisitor<T>
        Parameters:
        object - object to delete