/*
* Copyright 2014 Daniel Kurka
*
* 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.googlecode.mgwt.css.client.updater;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NodeList;
import com.google.gwt.dom.client.StyleElement;
import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.user.client.Timer;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
public class CssUpdater {
private class Watcher extends Timer {
private int count;
private long unique;
@Override
public void run() {
Set<String> urls = styleSheetsByUrl.keySet();
final int limit = urls.size();
count = 0;
for (final String url : urls) {
RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, url + "?random=" + unique++);
requestBuilder.setCallback(new RequestCallback() {
@Override
public void onResponseReceived(Request request, Response response) {
count++;
if (response.getStatusCode() != 200) {
GWT.log("Got a nun 200 return code: " + response.getStatusCode());
} else {
String newCss = response.getText();
String oldCss = cssContentByUrl.get(url);
if (!oldCss.equals(newCss)) {
cssContentByUrl.put(url, newCss);
styleSheetsByUrl.get(url).setInnerText(newCss);
}
}
if (count == limit) {
schedule(interval);
}
}
@Override
public void onError(Request request, Throwable exception) {
count++;
GWT.log("failed to update stylesheet: " + url, exception);
if (count == limit) {
schedule(interval);
}
}
});
try {
requestBuilder.send();
} catch (RequestException e) {
GWT.log("failed to send update request for: " + url, e);
}
}
}
}
private Map<String, StyleElement> styleSheetsByUrl = new HashMap<String, StyleElement>();
private Map<String, String> cssContentByUrl = new HashMap<String, String>();
private Watcher watcher;
private final int interval;
public CssUpdater(int interval) {
this.interval = interval;
}
public void watchStyleSheet(String url) {
if (!styleSheetsByUrl.containsKey(url)) {
StyleElement styleElement = Document.get().createStyleElement();
getHead().appendChild(styleElement);
styleSheetsByUrl.put(url, styleElement);
cssContentByUrl.put(url, "");
maybeStartWatcher();
}
}
private void maybeStartWatcher() {
if (watcher == null) {
watcher = new Watcher();
watcher.schedule(1);
}
}
private Element getHead() {
NodeList<Element> nodeList = Document.get().getElementsByTagName("head");
if (nodeList.getLength() != 1) {
throw new RuntimeException("can not find head element, does your html include a head section?");
}
return nodeList.getItem(0);
}
}