InputHandler.java

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/*
 * InputHandler.java - Manages key bindings and executes actions
 * Copyright (C) 1999 Slava Pestov
 * Copyright (C) 2000-2015 The Gridarta Developers.
 *
 * You may use and modify this package for any purpose. Redistribution is
 * permitted, in both source and binary form, provided that this notice
 * remains intact in all source distributions of this package.
 */

package net.sf.gridarta.textedit.textarea;

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.EventObject;
import javax.swing.JPopupMenu;
import org.apache.log4j.Category;
import org.apache.log4j.Logger;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public abstract class InputHandler implements KeyListener {

    private static final Category LOG = Logger.getLogger(InputHandler.class);

    @Nullable
    private ActionListener grabAction;

    private boolean repeat;

    protected int repeatCount;

    public abstract void addDefaultKeyBindings();

    public boolean isRepeatEnabled() {
        return repeat;
    }

    public void setRepeatEnabled(final boolean repeat) {
        this.repeat = repeat;
    }

    public int getRepeatCount() {
        return repeat ? Math.max(1, repeatCount) : 1;
    }

    public void setRepeatCount(final int repeatCount) {
        this.repeatCount = repeatCount;
    }

    public abstract InputHandler copy();

    public void executeAction(final ActionListener listener, final Object source, @Nullable final String actionCommand) {
        // create event
        final ActionEvent evt = new ActionEvent(source, ActionEvent.ACTION_PERFORMED, actionCommand);

        // remember old values, in case action changes them
        final boolean repeatBak = repeat;

        // execute the action
        if (listener instanceof NonRepeatable) {
            listener.actionPerformed(evt);
        } else {
            for (int i = 0; i < Math.max(1, repeatCount); i++) {
                listener.actionPerformed(evt);
            }
        }

        // do recording. Notice that we do no recording whatsoever
        // for actions that grab keys
        if (grabAction == null) {
            // If repeat was true originally, clear it
            // Otherwise it might have been set by the action, etc
            if (repeatBak) {
                repeat = false;
                repeatCount = 0;
            }
        }
    }

    @NotNull
    public static JEditTextArea getTextArea(final EventObject evt) {
        if (evt != null) {
            final Object o = evt.getSource();
            if (o instanceof Component) {
                // find the parent text area
                Component c = (Component) o;
                while (true) {
                    if (c instanceof JEditTextArea) {
                        return (JEditTextArea) c;
                    } else if (c == null) {
                        break;
                    }
                    if (c instanceof JPopupMenu) {
                        c = ((JPopupMenu) c).getInvoker();
                    } else {
                        c = c.getParent();
                    }
                }
            }
        }

        // this shouldn't happen
        LOG.fatal("BUG: getTextArea() returning null");
        LOG.fatal("Report this to Slava Pestov <sp@gjt.org>");
        assert false : "BUG: getTextArea() returning null";
        throw new Error("BUG: getTextArea() returning null");
    }

    // protected members

    protected boolean handleGrabAction(final KeyEvent evt) {
        if (grabAction == null) {
            return false;
        }

        // Clear it *before* it is executed so that executeAction()
        // resets the repeat count
        final ActionListener grabAction2 = grabAction;
        grabAction = null;
        executeAction(grabAction2, evt.getSource(), String.valueOf(evt.getKeyChar()));
        return true;
    }

    public interface NonRepeatable {

    }

}