AutoComplete
- 1. package simplejavatexteditor; import java.awt.event.ActionEvent; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.util.ArrayList; import java.util.Collections; import javax.swing.AbstractAction; import javax.swing.ActionMap; import javax.swing.InputMap; import javax.swing.JTextArea; import javax.swing.KeyStroke; import javax.swing.SwingUtilities; import javax.swing.event.DocumentEvent; import javax.swing.event.DocumentListener; import javax.swing.text.BadLocationException; /** * <h1>Auto complete functionality multiple programming languages, including brackets and * parentheses</h1> * * <p> * An ArrayList is created for the keywords and the brackets. * Logic for setting the content of the ArrayList is * found in UI.java. If the word currently being typed * matches a word in the list, a Runnable inner class is * implemented to handle the word completion. * * Two other inner classes are also used. The second one handles when the enter * key is pressed in response to an auto complete suggestion. The third one * performs additional logic on brackets. * </p> * * * @author Patrick Slagle * @since 2016-12-03 */ public class AutoComplete implements DocumentListener { private ArrayList<String> brackets = new ArrayList<>(); private ArrayList<String> bracketCompletions = new ArrayList<>(); private ArrayList<String> words = new ArrayList<>(); SupportedKeywords kw; //Keep track of when code completion //has been activated private enum Mode {
- 2. INSERT, COMPLETION }; private final UI ui; private Mode mode = Mode.INSERT; private final JTextArea textArea; private static final String COMMIT_ACTION = "commit"; private boolean isKeyword; private int pos; private String content; public AutoComplete(UI ui, ArrayList<String> al) { //Set the keywords words = al; kw = new SupportedKeywords(); brackets = kw.getbrackets(); bracketCompletions = kw.getbracketCompletions(); //Access the editor this.ui = ui; textArea = ui.getEditor(); //Set the handler for the enter key InputMap im = textArea.getInputMap(); ActionMap am = textArea.getActionMap(); im.put(KeyStroke.getKeyStroke("ENTER "), COMMIT_ACTION); am.put(COMMIT_ACTION, new CommitAction()); Collections.sort(words); } /** * A character has been typed into the document. * This method performs the primary * check to find a keyword completion. * * @param e */ @Override public void insertUpdate(DocumentEvent e) { pos = e.getOffset(); content = null; try { content = textArea.getText(0, pos + 1); } catch (BadLocationException ex) { ex.printStackTrace(); } if (e.getLength() != 1) { return; }
- 3. //Before checking for a keyword checkForBracket(); //Get the beginning of the word being typed int start; for (start = pos; start >= 0; start--) { if (!Character.isLetter(content.charAt(start))) { break; } } //Auto complete will start //after two characters are typed if (pos - start < 2) { return; } //Search for a match on the word being typed //in the keywords ArrayList String prefix = content.substring(start + 1); int n = Collections.binarySearch(words, prefix); if (n < 0 && -n < words.size()) { String match = words.get(-n - 1); if (match.startsWith(prefix)) { String completion = match.substring(pos - start); isKeyword = true; SwingUtilities.invokeLater( new CompletionTask(completion, pos + 1)); } else { mode = Mode.INSERT; } } } /** * Performs a check to see if the last * key typed was one of the supported * bracket characters */ private void checkForBracket() { //String of the last typed character char c = content.charAt(pos); String s = String.valueOf(c); for (int i = 0; i < brackets.size(); i++) { if (brackets.get(i).equals(s)) { isKeyword = false; SwingUtilities.invokeLater( new CompletionTask(bracketCompletions.get(i), pos + 1));
- 4. } } } /** * So that future classes can view the keyword list in the future. * * @return the keywords */ private ArrayList<String> getKeywords() { return words; } /** * So that these keywords can be modified or added to in the future. * * @param keyword the keyword to set */ private void setKeywords(String keyword) { words.add(keyword); } /** * Handles the auto complete suggestion * generated when the user is typing a * word that matches a keyword. */ private class CompletionTask implements Runnable { private final String completion; private final int position; public CompletionTask(String completion, int position) { this.completion = completion; this.position = position; } @Override public void run() { textArea.insert(completion, position); textArea.setCaretPosition(position + completion.length()); textArea.moveCaretPosition(position); mode = Mode.COMPLETION; if (!isKeyword) { textArea.addKeyListener(new HandleBracketEvent()); } } } /**
- 5. * Enter key is pressed in response to an * auto complete suggestion. Respond * appropriately. */ private class CommitAction extends AbstractAction { @Override public void actionPerformed(ActionEvent e) { if (mode == Mode.COMPLETION) { int pos = textArea.getSelectionEnd(); if (isKeyword) { textArea.insert(" ", pos); textArea.setCaretPosition(pos + 1); mode = Mode.INSERT; } } else { mode = Mode.INSERT; textArea.replaceSelection("n"); } } } /** * Additional logic for bracket auto complete */ private class HandleBracketEvent implements KeyListener { @Override public void keyTyped(KeyEvent e) { //Bracket auto complete needs special attention. //Multiple possible responses are needed. String keyEvent = String.valueOf(e.getKeyChar()); for (String bracketCompletion : bracketCompletions) { if (keyEvent.equals(bracketCompletion)) { textArea.replaceRange("", pos, pos + 1); mode = Mode.INSERT; textArea.removeKeyListener(this); } } int currentPosition = textArea.getCaretPosition(); switch (e.getKeyChar()) { case 'n': textArea.insert("nn", currentPosition); textArea.setCaretPosition(currentPosition + 1); mode = Mode.INSERT; textArea.removeKeyListener(this); break; default: textArea.setCaretPosition(pos);
- 6. mode = Mode.INSERT; textArea.removeKeyListener(this); break; } } @Override public void keyPressed(KeyEvent e) { } @Override public void keyReleased(KeyEvent e) { } } @Override public void removeUpdate(DocumentEvent e) { } @Override public void changedUpdate(DocumentEvent e) { }
- 7. mode = Mode.INSERT; textArea.removeKeyListener(this); break; } } @Override public void keyPressed(KeyEvent e) { } @Override public void keyReleased(KeyEvent e) { } } @Override public void removeUpdate(DocumentEvent e) { } @Override public void changedUpdate(DocumentEvent e) { }