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Utilities for use in developing GWT applications.
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//
// $Id$
//
// OOO GWT Utils - utilities for creating GWT applications
// Copyright (C) 2009-2010 Three Rings Design, Inc., All Rights Reserved
// http://code.google.com/p/ooo-gwt-utils/
//
// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License as published
// by the Free Software Foundation; either version 2.1 of the License, or
// (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

package com.threerings.gwt.util;

import com.google.common.base.Function;

import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.HasEnabled;

/**
 * Utility methods relating to {@link AsyncCallback} and our various callback-related helper
 * classes.
 */
public class Callbacks
{
    /**
     * Creates a chained callback that maps the result using the supplied function and passes the
     * mapped result to the target callback.
     */
    public static  AsyncCallback map (AsyncCallback target, final Function f)
    {
        return new ChainedCallback(target) {
            @Override public void onSuccess (T result) {
                forwardSuccess(f.apply(result));
            }
        };
    }

    /**
     * Creates a chained callback that calls the supplied pre-operation before passing the result
     * on to the supplied target callback.
     */
    public static  AsyncCallback before (AsyncCallback target,
                                               final Function preOp)
    {
        return new ChainedCallback(target) {
            @Override public void onSuccess (T result) {
                preOp.apply(result);
                forwardSuccess(result);
            }
        };
    }

    /**
     * Immediately disables the specified widgets, and wraps the supplied callback in one that will
     * reenable those widgets when the callback returns successfully or with failure.
     */
    public static  AsyncCallback disabler (AsyncCallback callback,
                                                 final HasEnabled... disablees)
    {
        for (HasEnabled widget : disablees) {
            widget.setEnabled(false);
        }
        return new ChainedCallback(callback) {
            @Override public void onSuccess (T result) {
                for (HasEnabled widget : disablees) {
                    widget.setEnabled(true);
                }
                forwardSuccess(result);
            }
            @Override public void onFailure (Throwable cause) {
                for (HasEnabled widget : disablees) {
                    widget.setEnabled(true);
                }
                super.onFailure(cause);
            }
        };
    }
}