e862. finding a key binding in a component.txt

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Home > List of Packages > javax.swing  [141 examples] > Keystrokes and Input Maps  [6 examples] 

e862. Finding a Key Binding in a Component
This example searches all of a component's inputmaps and keymaps (if the component is a text component) for a particular keystroke. 
    FindResult r = find(KeyStroke.getKeyStroke("ctrl pressed C"), component);
    r = find(KeyStroke.getKeyStroke("ctrl released C"), component);
    r = find(KeyStroke.getKeyStroke("C"), component);
    r = find(KeyStroke.getKeyStroke("typed C"), component);
    r = find(KeyStroke.getKeyStroke(new Character('\u0002'), 0), component);
    
    // The results of a find are returned in a FindResult object
    static class FindResult {
        // Non-null if the keystroke is in an inputmap
        InputMap inputMap;
    
        // Non-null if the keystroke is in an keymap or default action
        Keymap keymap;
    
        // Non-null if the keystroke is in a default action
        // The keymap field holds the keymap containing the default action
        Action defaultAction;
    
        // If true, the keystroke is in the component's inputMap or keymap
        // and not in one of the inputMap's or keymap's parent.
        boolean isLocal;
    
        public String toString() {
            StringBuffer b = new StringBuffer();
    
            b.append("inputmap="+inputMap+",keymap="+keymap
                     +",defaultAction="+defaultAction+",isLocal="+isLocal);
            return b.toString();
        }
    }
    
    // Returns null if not found
    public static FindResult find(KeyStroke k, JComponent c) {
        FindResult result;
    
        result = find(k, c.getInputMap(JComponent.WHEN_FOCUSED));
        if (result != null) {
            return result;
        }
        result = find(k, c.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT));
        if (result != null) {
            return result;
        }
        result = find(k, c.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW));
        if (result != null) {
            return result;
        }
    
    
        // Check keymaps
        if (c instanceof JTextComponent) {
            JTextComponent tc = (JTextComponent)c;
            result = new FindResult();
    
            // Check local keymap
            Keymap kmap = tc.getKeymap();
            if (kmap.isLocallyDefined(k)) {
                result.keymap = kmap;
                result.isLocal = true;
                return result;
            }
    
            // Check parent keymaps
            kmap = kmap.getResolveParent();
            while (kmap != null) {
                if (kmap.isLocallyDefined(k)) {
                    result.keymap = kmap;
                    return result;
                }
                kmap = kmap.getResolveParent();
            }
    
            // Look for default action
            if (k.getKeyEventType() == KeyEvent.KEY_TYPED) {
                // Check local keymap
                kmap = tc.getKeymap();
                if (kmap.getDefaultAction() != null) {
                    result.keymap = kmap;
                    result.defaultAction = kmap.getDefaultAction();
                    result.isLocal = true;
                    return result;
                }
    
                // Check parent keymaps
                kmap = kmap.getResolveParent();
                while (kmap != null) {
                    if (kmap.getDefaultAction() != null) {
                        result.keymap = kmap;
                        result.defaultAction = kmap.getDefaultAction();
                        return result;
                    }
                    kmap = kmap.getResolveParent();
                }
            }
        }
        return null;
    }
    
    public static FindResult find(KeyStroke k, InputMap map) {
        // Check local inputmap
        KeyStroke[] keys = map.keys();
        for (int i=0; keys != null && i<keys.length; i++) {
            if (k.equals(keys[i])) {
                FindResult result = new FindResult();
                result.inputMap = map;
                result.isLocal = true;
                return result;
            }
        }
    
        // Check parent inputmap
        map = map.getParent();
        while (map != null) {
            keys = map.keys();
            for (int i=0; keys != null && i<keys.length; i++) {
                if (k.equals(keys[i])) {
                    FindResult result = new FindResult();
                    result.inputMap = map;
                    return result;
                }
            }
            map = map.getParent();
        }
        return null;
    }