de.metas.procurement.webui.util.SwipeHelper.java Source code

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Here is the source code for de.metas.procurement.webui.util.SwipeHelper.java

Source

package de.metas.procurement.webui.util;

import java.util.concurrent.atomic.AtomicBoolean;

import com.google.gwt.thirdparty.guava.common.base.Preconditions;
import com.google.gwt.thirdparty.guava.common.cache.Cache;
import com.google.gwt.thirdparty.guava.common.cache.CacheBuilder;
import com.vaadin.server.VaadinSession;
import com.vaadin.ui.Component;
import com.vaadin.ui.JavaScript;
import com.vaadin.ui.JavaScriptFunction;
import com.vaadin.ui.UI;

import elemental.json.JsonArray;

/*
 * #%L
 * de.metas.procurement.webui
 * %%
 * Copyright (C) 2016 metas GmbH
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-2.0.html>.
 * #L%
 */

/**
 * Helper class to add Swipe behavior to Vaadin components
 * 
 * @author metas-dev <dev@metas-fresh.com>
 *
 */
public class SwipeHelper {
    public static final SwipeHelper getCurrent() {
        final VaadinSession session = UI.getCurrent().getSession();
        SwipeHelper swipe = session.getAttribute(SwipeHelper.class);
        if (swipe == null) {
            swipe = new SwipeHelper();
            session.setAttribute(SwipeHelper.class, swipe);
        }
        return swipe;
    }

    private static final String JS_FUNC_OnSwipe = SwipeHelper.class.getName() + ".onSwipe";

    private final AtomicBoolean jsFunctionsRegistered = new AtomicBoolean(false);
    private final Cache<Component, ComponentSwipe> component2swipe = CacheBuilder.newBuilder().weakKeys().build();

    private final Cache<String, ComponentSwipe> componentId2swipe = CacheBuilder.newBuilder().weakValues().build();

    private SwipeHelper() {
        super();
    }

    public synchronized void enable(final Component component, final SwipeHandler handler) {
        Preconditions.checkNotNull(component, "component is null");
        final String componentId = component.getId();
        Preconditions.checkNotNull(componentId, "componentId is null");

        final ComponentSwipe swipe = new ComponentSwipe(componentId, handler);

        component2swipe.put(component, swipe);
        componentId2swipe.put(componentId, swipe);

        registerJavaScriptFunctionsIfNeeded();

        final JavaScript javaScript = JavaScript.getCurrent();
        javaScript.execute("" + "if (!window.swipesMap) { window.swipesMap={}; }"
        //
                + "window.swipesMap['" + componentId + "'] = Swiped.init({" + "query: '#" + componentId + "'"
                + ", left: 300" + ", right: 300" + ", tolerance: 200" + ", onOpen: function() { " + JS_FUNC_OnSwipe
                + "('" + componentId + "'); }" + "});"
                //
                + "\n console.log('Enabled swiping for element: " + componentId + "');");
    }

    @SuppressWarnings("serial")
    private final void registerJavaScriptFunctionsIfNeeded() {
        if (jsFunctionsRegistered.getAndSet(true)) {
            return; // already registered
        }

        final JavaScript javaScript = JavaScript.getCurrent();
        javaScript.addFunction(JS_FUNC_OnSwipe, new JavaScriptFunction() {
            @Override
            public void call(final JsonArray arguments) {
                invokeOnSwipe(arguments);
            }
        });
    }

    private void invokeOnSwipe(final JsonArray arguments) {
        final String componentId = arguments.getString(0);
        final ComponentSwipe swipe = componentId2swipe.getIfPresent(componentId);
        if (swipe == null) {
            // TODO: thow exception/log
            return;
        }

        swipe.invokeOnSwipe();
    }

    public static final class ComponentSwipe {
        private final SwipeHandler handler;
        private final String componentId;

        public ComponentSwipe(final String componentId, final SwipeHandler handler) {
            super();

            this.componentId = componentId;

            Preconditions.checkNotNull(handler, "handler is null");
            this.handler = handler;
        }

        private void invokeOnSwipe() {
            handler.onSwipe(this);
        }

        public void open() {
            JavaScript.getCurrent().execute("window.swipesMap['" + componentId + "'].open();");
        }

        public void close() {
            JavaScript.getCurrent().execute("window.swipesMap['" + componentId
                    + "'].close(); console.log('swipe.close for " + componentId + "');");
        }

        public void destroy() {
            JavaScript.getCurrent().execute("window.swipesMap['" + componentId + "'].destroy(false);"); // isRemoveNode=false
        }
    }

    public static interface SwipeHandler {
        void onSwipe(final ComponentSwipe swipe);
    }
}