Class EditCommand<T>

  • Type Parameters:
    T - object type
    Direct Known Subclasses:
    DeleteCommand, InsertCommand, KeepCommand

    public abstract class EditCommand<T>
    extends java.lang.Object
    Abstract base class for all commands used to transform an objects sequence into another one.

    When two objects sequences are compared through the StringsComparator.getScript method, the result is provided has a script containing the commands that progressively transform the first sequence into the second one.

    There are only three types of commands, all of which are subclasses of this abstract class. Each command is associated with one object belonging to at least one of the sequences. These commands are InsertCommand which correspond to an object of the second sequence being inserted into the first sequence, DeleteCommand which correspond to an object of the first sequence being removed and KeepCommand which correspond to an object of the first sequence which equals an object in the second sequence. It is guaranteed that comparison is always performed this way (i.e. the equals method of the object from the first sequence is used and the object passed as an argument comes from the second sequence) ; this can be important if subclassing is used for some elements in the first sequence and the equals method is specialized.

    This code has been adapted from Apache Commons Collections 4.0.

    Since:
    1.0
    See Also:
    StringsComparator, EditScript
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private T object
      Object on which the command should be applied.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected EditCommand​(T object)
      Constructs a new instance of EditCommand.
    • Field Detail

      • object

        private final T object
        Object on which the command should be applied.
    • Constructor Detail

      • EditCommand

        protected EditCommand​(T object)
        Constructs a new instance of EditCommand.
        Parameters:
        object - reference to the object associated with this command, this refers to an element of one of the sequences being compared
    • Method Detail

      • accept

        public abstract void accept​(CommandVisitor<T> visitor)
        Accepts a visitor.

        This method is invoked for each commands belonging to an EditScript, in order to implement the visitor design pattern

        Parameters:
        visitor - the visitor to be accepted
      • getObject

        protected T getObject()
        Gets the object associated with this command.
        Returns:
        The object on which the command is applied