Package org.apache.commons.text.diff

Class EditCommand<T>

java.lang.Object
org.apache.commons.text.diff.EditCommand<T>
Type Parameters:
T - object type
Direct Known Subclasses:
DeleteCommand, InsertCommand, KeepCommand
public abstract class EditCommand<T>
extends 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

  • Constructor Details

    • EditCommand

      protected EditCommand​(T object)
      Simple constructor. Creates 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 Details

    • getObject

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

    • accept

      public abstract void accept​(CommandVisitor<T> visitor)
      Accept 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