clojure-java-import-region.el

(defconst java-import-regex "^[[:space:]]*import[[:space:]]+\\(.*\\)\\.\\(.*\\);")

(defun clojure-java-import-line-parse (line)
  (unless (string-match java-import-regex line)
    (error "No import line"))
  (let ((package (match-string-no-properties 1 line))
	(symbol (match-string-no-properties 2 line)))
    (list package symbol)))

(defun clojure-java-import-region (start end)
  "replace java import statements in text between point and mark with
corresponding Clojure namespace references"

  (interactive (list (point) (mark)))
  (unless (and start end)
    (error "The mark is not set now, so there is no region"))
  (let* ((lines (split-string (buffer-substring-no-properties start end) "[\n\r]+"))
	 (import-lines (remove-if-not (lambda (line) (string-match java-import-regex line)) lines))
	 ;; FIXME: no wildcard support in Clojure
	 ;; http://groups.google.com/group/clojure/msg/ddca7ec56ea8b51f?pli=1
	 (import-list  (mapcar 'clojure-java-import-line-parse import-lines))
	 ;; wrap up common package imports in single import 
	 (clj-import-list  (reduce (lambda (alist c)
				     (if (string= (car (first alist)) 
						  (car c))
					 (cons (cons (car c) (append (cdr c) (cdr (first alist)))) (cdr alist))
				       (cons c alist)))
				   import-list
				   :initial-value '())))
    (kill-region start end)
    (insert-string (format "(:import%s)\n" (mapconcat  (lambda (import-list)
							 (format "\t(%s)" (mapconcat 'identity import-list " ")))
						       clj-import-list "\n")))))

Convert Java import statements to Clojure

If you convert Java code to Clojure you are often in need of converting a region of java import statements to corresponding Clojure namespace import references.

Mark the region:

 import java.awt.Dimension;                       // Importliste mit allen
 import java.awt.BorderLayout;                    // benoetigten Klassen aus
 import javax.swing.UIManager;                    // dem AWT und aus den 
 import javax.swing.JLabel;                       // Swing-Komponenten
 import javax.swing.JPanel;

Invoke interactive elisp function 'clojure-java-import-region:

 (:import (javax.swing JPanel JLabel UIManager)  
          (java.awt BorderLayout Dimension)))