| /* |
| * Copyright 2009 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| * use this file except in compliance with the License. You may obtain a copy of |
| * the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| package com.google.gwt.core.client.prefetch; |
| |
| import com.google.gwt.core.client.GWT; |
| import com.google.gwt.core.client.impl.AsyncFragmentLoader; |
| |
| import java.util.Arrays; |
| |
| /** |
| * This class allows requesting the download of resources before they are |
| * strictly needed. See the classes that implement {@link PrefetchableResource}. |
| * Currently, the only supported resource type is {@link RunAsyncCode}. |
| */ |
| public class Prefetcher { |
| /** |
| * Specify which resources should be prefetched. |
| */ |
| public static void prefetch(Iterable<? extends PrefetchableResource> resources) { |
| if (!GWT.isScript()) { |
| // Nothing to do in development mode |
| return; |
| } |
| |
| // No range checking in web mode means we needn't precompute the size. |
| int[] runAsyncSplitPoints = new int[0]; |
| int i = 0; |
| for (PrefetchableResource resource : resources) { |
| if (resource instanceof RunAsyncCode) { |
| RunAsyncCode resourceRunAsync = (RunAsyncCode) resource; |
| int splitPoint = resourceRunAsync.getSplitPoint(); |
| if (splitPoint >= 0) { // Skip placeholders, which have a -1 split point |
| runAsyncSplitPoints[i++] = splitPoint; |
| } |
| continue; |
| } |
| |
| throw new IllegalArgumentException("Unknown resource type: " |
| + resource.getClass()); |
| } |
| |
| AsyncFragmentLoader.BROWSER_LOADER.setPrefetchQueue(runAsyncSplitPoints); |
| } |
| |
| /** |
| * Helper method to call {@link #prefetch(Iterable)} with a single resource. |
| */ |
| public static void prefetch(PrefetchableResource resource) { |
| prefetch(Arrays.asList(resource)); |
| } |
| |
| /** |
| * Start prefetching. |
| */ |
| public static void start() { |
| if (!GWT.isScript()) { |
| // Nothing to do in development mode |
| return; |
| } |
| |
| AsyncFragmentLoader.BROWSER_LOADER.startPrefetching(); |
| } |
| |
| /** |
| * Stop prefetching. |
| */ |
| public static void stop() { |
| if (!GWT.isScript()) { |
| // Nothing to do in development mode |
| return; |
| } |
| |
| AsyncFragmentLoader.BROWSER_LOADER.stopPrefetching(); |
| } |
| } |