Executor.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.api.promises.client.js;

import com.google.gwt.core.client.JavaScriptObject;

/**
 * The executor is the conclusion callback, a js function with two parameters, usually named
 * resolve and reject. The first argument fulfills the promise, the second argument rejects it.
 *
 * @param <V>
 *         the type of the promised value
 * @author Mickaël Leduque
 * @author Artem Zatsarynnyi
 */
public class Executor<V> extends JavaScriptObject {

    /** JSO mandated protected constructor. */
    protected Executor() {
    }

    /**
     * Creates an executor.
     *
     * @param executorBody
     *         the body of the executor
     * @param <V>
     *         the fulfillment value
     * @return the new executor
     */
    public static final native <V> Executor<V> create(ExecutorBody<V> executorBody) /*-{
        return function (resolve, reject) {
            try {
                executorBody.@org.eclipse.che.api.promises.client.js.Executor.ExecutorBody::apply(*)(resolve, reject);
            } catch (e) {
                reject(e);
            }
        }
    }-*/;

    /**
     * The definition of an executor.
     *
     * @param <V>
     *         the type of the fulfillment value
     */
    public interface ExecutorBody<V> {
        /**
         * The executor describes what the promise must do in order to be fulfilled.
         * It will execute some code to process or retrieve some value,
         * then use the {@code resolve} or {@code reject} callback to conclude.
         *
         * @param resolve
         *         what to do on success
         * @param reject
         *         what to do on failure
         */
        void apply(ResolveFunction<V> resolve, RejectFunction reject);
    }
}