Interface Text

  • public interface Text
    An editable sequence of characters with a current "cursor" position. The character sequence can be any length. The cursor can be at any character in the sequence, OR at the end. When the cursor is at the end, there is no character to get() or delete(), but insert() will add a new character at the end of the sequence. There should be a no-argument constructor which creates an initially-empty sequence of text, with the cursor at the end. All operations should be O(1) worst-case or O(1) amortized time.

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      boolean canMoveLeft()
      Returns whether there is another character to the left of the cursor.
      boolean canMoveRight()
      Returns whether the cursor is NOT at the end.
      void delete()
      Deletes the character at the current cursor position.
      char get()
      Returns the character at the current cursor position.
      void insert​(char c)
      Inserts a new character before the current cursor position.
      void moveLeft()
      Moves the cursor one character to the left.
      void moveRight()
      Moves the cursor one character to the right.
      void print()
      Displays the current sequence of characters one one line, with the cursor underneath.

    • Method Detail

      • get

        char get()
  throws java.util.NoSuchElementException
        Returns the character at the current cursor position.
        Throws:
        java.util.NoSuchElementException

      • insert

        void insert​(char c)
        Inserts a new character before the current cursor position.

      • delete

        void delete()
     throws java.util.NoSuchElementException
        Deletes the character at the current cursor position. The cursor should move to the right of what was just deleted.
        Throws:
        java.util.NoSuchElementException - if the cursor is at the end.

      • canMoveLeft

        boolean canMoveLeft()
        Returns whether there is another character to the left of the cursor.

      • moveLeft

        void moveLeft()
       throws java.util.NoSuchElementException
        Moves the cursor one character to the left.
        Throws:
        java.util.NoSuchElementException - if the cursor is already at the beginning.

      • canMoveRight

        boolean canMoveRight()
        Returns whether the cursor is NOT at the end.

      • moveRight

        void moveRight()
        throws java.util.NoSuchElementException
        Moves the cursor one character to the right.
        Throws:
        java.util.NoSuchElementException - if the cursor is already at the end.

      • print

        void print()
        Displays the current sequence of characters one one line, with the cursor underneath. Two lines should always be printed to System.out. For example, if the current characters are a, b, c, d, and the cursor is at the end, we should see: abcd ^ With the same characters, but the cursor under the 'b', we would see: abcd ^