Java tutorial
/** * Copyright 2010 The PlayN Authors * * 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 playn.html; import java.util.HashMap; import java.util.Map; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.JavaScriptException; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.ImageElement; import com.google.gwt.regexp.shared.RegExp; import com.google.gwt.resources.client.DataResource; import com.google.gwt.resources.client.ImageResource; import com.google.gwt.resources.client.ResourcePrototype; import com.google.gwt.user.client.Window; import com.google.gwt.xhr.client.ReadyStateChangeHandler; import com.google.gwt.xhr.client.XMLHttpRequest; import playn.core.AbstractCachingAssetManager; import playn.core.AutoClientBundleWithLookup; import playn.core.PlayN; import playn.core.Image; import playn.core.ResourceCallback; import playn.core.Sound; import playn.html.XDomainRequest.Handler; public class HtmlAssetManager extends AbstractCachingAssetManager { /** * Whether or not to log successful progress of {@code XMLHTTPRequest} and * {@code XDomainRequest} requests. */ private static final boolean LOG_XHR_SUCCESS = false; private String pathPrefix = ""; public void setPathPrefix(String prefix) { pathPrefix = prefix; } private Map<String, AutoClientBundleWithLookup> clientBundles = new HashMap<String, AutoClientBundleWithLookup>(); public void addClientBundle(String regExp, AutoClientBundleWithLookup clientBundle) { clientBundles.put(regExp, clientBundle); } @Override protected void doGetText(final String path, final ResourceCallback<String> callback) { final String fullPath = pathPrefix + path; /* * Except for IE, all browsers support on-domain and cross-domain XHR via * {@code XMLHTTPRequest}. IE, on the other hand, not only requires the use * of a non-standard {@code XDomainRequest} for cross-domain requests, but * doesn't allow on-domain requests to be issued via {@code XMLHTTPRequest}, * even when {@code Access-Control-Allow-Origin} includes the current * document origin. Since we here don't always know if the current request * will be cross domain, we try XHR, and then fall back to XDR if the we're * running on IE. */ try { doXhr(fullPath, callback); } catch (JavaScriptException e) { if (Window.Navigator.getUserAgent().indexOf("MSIE") != -1) { doXdr(fullPath, callback); } else { throw e; } } } private void doXdr(final String fullPath, final ResourceCallback<String> callback) { XDomainRequest xdr = XDomainRequest.create(); xdr.setHandler(new Handler() { @Override public void onTimeout(XDomainRequest xdr) { PlayN.log().error("xdr::onTimeout[" + fullPath + "]()"); callback.error(new RuntimeException("Error getting " + fullPath + " : " + xdr.getStatus())); } @Override public void onProgress(XDomainRequest xdr) { if (LOG_XHR_SUCCESS) { PlayN.log().debug("xdr::onProgress[" + fullPath + "]()"); } } @Override public void onLoad(XDomainRequest xdr) { if (LOG_XHR_SUCCESS) { PlayN.log().debug("xdr::onLoad[" + fullPath + "]()"); } callback.done(xdr.getResponseText()); } @Override public void onError(XDomainRequest xdr) { PlayN.log().error("xdr::onError[" + fullPath + "]()"); callback.error(new RuntimeException("Error getting " + fullPath + " : " + xdr.getStatus())); } }); if (LOG_XHR_SUCCESS) { PlayN.log().debug("xdr.open('GET', '" + fullPath + "')..."); } xdr.open("GET", fullPath); if (LOG_XHR_SUCCESS) { PlayN.log().debug("xdr.send()..."); } xdr.send(); } private void doXhr(final String fullPath, final ResourceCallback<String> callback) { XMLHttpRequest xhr = XMLHttpRequest.create(); xhr.setOnReadyStateChange(new ReadyStateChangeHandler() { @Override public void onReadyStateChange(XMLHttpRequest xhr) { int readyState = xhr.getReadyState(); if (readyState == XMLHttpRequest.DONE) { int status = xhr.getStatus(); // status code 0 will be returned for non-http requests, e.g. file:// if (status != 0 && (status < 200 || status >= 400)) { PlayN.log().error("xhr::onReadyStateChange[" + fullPath + "](readyState = " + readyState + "; status = " + status + ")"); callback.error( new RuntimeException("Error getting " + fullPath + " : " + xhr.getStatusText())); } else { if (LOG_XHR_SUCCESS) { PlayN.log().debug("xhr::onReadyStateChange[" + fullPath + "](readyState = " + readyState + "; status = " + status + ")"); } // TODO(fredsa): Remove try-catch and materialized exception once issue 6562 is fixed // http://code.google.com/p/google-web-toolkit/issues/detail?id=6562 try { callback.done(xhr.getResponseText()); } catch (JavaScriptException e) { if (GWT.isProdMode()) { throw e; } else { JavaScriptException materialized = new JavaScriptException(e.getName(), e.getDescription()); materialized.setStackTrace(e.getStackTrace()); throw materialized; } } } } } }); if (LOG_XHR_SUCCESS) { PlayN.log().debug("xhr.open('GET', '" + fullPath + "')..."); } xhr.open("GET", fullPath); if (LOG_XHR_SUCCESS) { PlayN.log().debug("xhr.send()..."); } xhr.send(); } @Override protected Sound loadSound(String path) { String url = pathPrefix + path; AutoClientBundleWithLookup clientBundle = getBundle(path); if (clientBundle != null) { String key = getKey(path); DataResource resource = (DataResource) getResource(key, clientBundle); if (resource != null) { url = resource.getUrl(); } } else { url += ".mp3"; } return adaptSound(url); } private Sound adaptSound(String url) { HtmlAudio audio = (HtmlAudio) PlayN.audio(); HtmlSound sound = audio.createSound(url); return sound; } @Override protected Image loadImage(String path) { String url = pathPrefix + path; AutoClientBundleWithLookup clientBundle = getBundle(path); if (clientBundle != null) { String key = getKey(path); ImageResource resource = (ImageResource) getResource(key, clientBundle); if (resource != null) { url = resource.getURL(); } } return adaptImage(url); } /** * Determine the resource key from a given path. * * @param fullPath full path, with or without a file extension * @return the key by which the resource can be looked up */ private String getKey(String fullPath) { String key = fullPath.substring(fullPath.lastIndexOf('/') + 1); int dotCharIdx = key.indexOf('.'); return dotCharIdx != -1 ? key.substring(0, dotCharIdx) : key; } private ResourcePrototype getResource(String key, AutoClientBundleWithLookup clientBundle) { ResourcePrototype resource = clientBundle.getResource(key); return resource; } private AutoClientBundleWithLookup getBundle(String collection) { AutoClientBundleWithLookup clientBundle = null; for (Map.Entry<String, AutoClientBundleWithLookup> entry : clientBundles.entrySet()) { String regExp = entry.getKey(); if (RegExp.compile(regExp).exec(collection) != null) { clientBundle = entry.getValue(); } } return clientBundle; } private Image adaptImage(String url) { ImageElement img = Document.get().createImageElement(); /* * When the server provides an appropriate {@literal * Access-Control-Allow-Origin} response header, allow images to be served * cross origin on supported, CORS enabled, browsers. */ setCrossOrigin(img, "anonymous"); img.setSrc(url); return new HtmlImage(img); } /** * Set the state of the {@code crossOrigin} attribute for CORS. * * @param elem the DOM element on which to set the {@code crossOrigin} * attribute * @param state one of {@code "anonymous"} or {@code "use-credentials"} */ private native void setCrossOrigin(Element elem, String state) /*-{ if ('crossOrigin' in elem) { elem.setAttribute('crossOrigin', state); } }-*/; }