Java tutorial
/* * Copyright 2012 Johannes Barop * * 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 org.jboss.errai.ui.nav.client.local.pushstate; import java.util.logging.Logger; import com.google.gwt.event.logical.shared.HasValueChangeHandlers; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.event.shared.GwtEvent; import com.google.gwt.event.shared.HandlerManager; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.logging.client.LogConfiguration; import com.google.gwt.user.client.History; import com.google.gwt.user.client.Window; /** * Enhances GWT's History implementation to add HTML5 pushState support. * * <p> * This class no longer inherits from HistoryImpl to allow for compatibility * with both GWT 2.6 and GWT 2.7+. HistoryImpl was moved in GWT 2.7 and is no * longer accessible. The previously inherited methods are now part of this * class. * </p> * * <p> * The complete path is treated as history token. * </p> * * <p> * The leading '/' is hidden from GWTs History API, so that the path '/' is * returned as an empty history token (''). * </p> * * @author <a href="mailto:jb@barop.de">Johannes Barop</a> * @author Christian Sadilek <csadilek@redhat.com> */ public class HistoryImplPushState implements HasValueChangeHandlers<String> { private static final Logger LOG = Logger.getLogger(HistoryImplPushState.class.getName()); private HandlerManager handlers = new HandlerManager(null); private String token = ""; public boolean init() { // initialize HistoryImpl with the current path updateHistoryToken(Window.Location.getPath() + Window.Location.getQueryString()); // initialize the empty state with the current history token nativeUpdate(token, true); // initialize the popState handler initPopStateHandler(); return true; } private void nativeUpdate(final String historyToken) { nativeUpdate(historyToken, false); } private void nativeUpdate(final String historyToken, boolean replace) { String newPushStateToken = CodeServerParameterHelper.append(encodeFragment(historyToken)); if (!newPushStateToken.startsWith("/")) { newPushStateToken = "/" + newPushStateToken; } if (replace) { replaceState(newPushStateToken); if (LogConfiguration.loggingIsEnabled()) { LOG.fine("Replaced '" + newPushStateToken + "' (" + historyToken + ")"); } } else { pushState(newPushStateToken); if (LogConfiguration.loggingIsEnabled()) { LOG.fine("Pushed '" + newPushStateToken + "' (" + historyToken + ")"); } } } /** * Set the current path as GWT History token which can later retrieved with * {@link History#getToken()}. */ private void updateHistoryToken(String path) { String[] split = path.split("\\?"); String token = split[0]; token = (token.length() > 0) ? decodeFragment(token) : ""; token = (token.startsWith("/")) ? token.substring(1) : token; String queryString = (split.length == 2) ? split[1] : ""; queryString = CodeServerParameterHelper.remove(queryString); if (queryString != null && !queryString.trim().isEmpty()) { token += "?" + queryString; } if (LogConfiguration.loggingIsEnabled()) { LOG.fine("Set token to '" + token + "'"); } this.token = token; } /** * Initialize an event handler that gets executed when the token changes. */ private native void initPopStateHandler() /*-{ var that = this; var oldHandler = $wnd.onpopstate; $wnd.onpopstate = $entry(function(e) { if (e.state && e.state.historyToken) { that.@org.jboss.errai.ui.nav.client.local.pushstate.HistoryImplPushState::onPopState(Ljava/lang/String;)(e.state.historyToken); } if (oldHandler) { oldHandler(); } }); }-*/; /** * Called from native JavaScript when an old history state was popped. */ private void onPopState(final String historyToken) { if (LogConfiguration.loggingIsEnabled()) { LOG.fine("Popped '" + historyToken + "'"); } updateHistoryToken(historyToken); fireHistoryChangedImpl(token); } /** * Add the given token to the history using pushState. */ private static native void pushState(final String token) /*-{ var state = { historyToken : token }; $wnd.history.pushState(state, $doc.title, token); }-*/; /** * Replace the given token in the history using replaceState. */ private static native void replaceState(final String token) /*-{ var state = { historyToken : token }; $wnd.history.replaceState(state, $doc.title, token); }-*/; private native String encodeFragment(String fragment) /*-{ // encodeURI() does *not* encode the '#' character. return encodeURI(fragment).replace("#", "%23"); }-*/; private native String decodeFragment(String encodedFragment) /*-{ // decodeURI() does *not* decode the '#' character. return decodeURI(encodedFragment.replace("%23", "#")); }-*/; /** * Fires the {@link ValueChangeEvent} to all handlers with the given tokens. */ public void fireHistoryChangedImpl(String newToken) { ValueChangeEvent.fire(this, newToken); } /** * Fires the {@link ValueChangeEvent} to all handlers with the current token. */ public void fireCurrentHistoryState() { ValueChangeEvent.fire(this, token); } @Override public void fireEvent(GwtEvent<?> event) { handlers.fireEvent(event); } /** * Adds a {@link ValueChangeEvent} handler to be informed of changes to the * browser's history stack. * * @param handler the handler */ public HandlerRegistration addValueChangeHandler(ValueChangeHandler<String> handler) { return handlers.addHandler(ValueChangeEvent.getType(), handler); } /** * Adds a new browser history entry. Calling this method will cause * {@link ValueChangeHandler#onValueChange(com.google.gwt.event.logical.shared.ValueChangeEvent)} * to be called as well if and only if issueEvent is true. * * @param historyToken the token to associate with the new history item * @param issueEvent true if a * {@link ValueChangeHandler#onValueChange(com.google.gwt.event.logical.shared.ValueChangeEvent)} * event should be issued */ public final void newItem(String historyToken, boolean issueEvent) { historyToken = (historyToken == null) ? "" : historyToken; if (!historyToken.equals(this.token)) { this.token = historyToken; nativeUpdate(historyToken); if (issueEvent) { fireHistoryChangedImpl(historyToken); } } } }