Add abstract layer for displaying elements

README.md

@@ -3,4 +3,47 @@
 [![Build Status](https://travis-ci.org/gwtplus/gwt-activity.svg?branch=master)](https://travis-ci.org/gwtplus/gwt-activity)
 [![jitpack.io](https://jitpack.io/v/gwtplus/gwt-activity.svg)](https://jitpack.io/#gwtplus/gwt-activity)
 
-Preparing for GWT 3 and j2cl
+A future-proof port of the `com.google.gwt.activity.Activity` GWT module, with no dependency on `gwt-user` (besides the Java Runtime Emulation), to prepare for GWT 3 / J2Cl.
+
+##  Migrating from `com.google.gwt.activity.Activity`
+
+1. Add the dependency to your build.
+
+   For Maven:
+
+   ```xml
+   <dependency>
+      <groupId>org.gwtproject.activity</groupId>
+      <artifactId>gwt-activity</artifactId>
+      <version>HEAD-SNAPSHOT</version>
+   </dependency>
+   ```
+
+   For Gradle:
+
+   ```gradle
+   implementation("org.gwtproject.activity:gwt-activity:HEAD-SNAPSHOT")
+   ```
+
+1. Update your GWT module to use
+
+   ```xml
+   <inherits name="org.gwtproject.activity.Activity" />
+   ```
+
+1. Change the `import`s in your Java source files:
+
+   ```java
+   import org.gwtproject.activity.*;
+   ```
+
+1. Provide implementation of `ActivityDisplay<V>` or use any of provided ones (`WidgetActivityDisplay` from `WidgetActivity` module or `ElementalActivityDisplay` from `ElementalActivity`. Note that `ActivityDisplay` uses `show()` instead od `setWidget()`.
+
+1. Specialize other `org.gwtproject.activity.*` references to `<V>`
+
+
+## Dependencies
+
+GWT Activity depends on the following modules:
+* gwt-places
+* gwt-event

pom.xml

@@ -48,7 +48,7 @@
     <project.build.outputEncoding>UTF-8</project.build.outputEncoding>
 
     <java.release>1.8</java.release>
-    <gwt.version>2.8.2</gwt.version>
+    <gwt.version>2.9.0</gwt.version>
   </properties>
 
   <dependencies>
@@ -66,6 +66,20 @@
       <version>HEAD-SNAPSHOT</version>
     </dependency>
 
+    <dependency>
+      <groupId>com.google.elemental2</groupId>
+      <artifactId>elemental2-dom</artifactId>
+      <version>1.1.0</version>
+      <optional>true</optional>
+    </dependency>
+
+    <dependency>
+      <groupId>org.gwtproject.widgets</groupId>
+      <artifactId>gwt-widgets</artifactId>
+      <version>1.0-SNAPSHOT</version>
+      <optional>true</optional>
+    </dependency>
+
     <!-- Testing -->
     <dependency>
       <groupId>junit</groupId>
@@ -177,6 +191,7 @@
         <configuration>
           <includes>
             <include>org/gwtproject/activity/ActivityJreSuite.java</include>
+            <include>org/gwtproject/activity/widget/WidgetActivityJreSuite.java</include>
           </includes>
         </configuration>
       </plugin>

src/main/java/org/gwtproject/user/package-info.java → src/main/java/org/gwtproject/activity/elemental/package-info.java

@@ -15,8 +15,6 @@
  */
 
 /**
- * Temporary port until proper dependency is not available as snapshot
- * 
- * FIXME: remove whole package
+ * Classes used to implement app navigation using elemental.
  */
-package org.gwtproject.user;
+package org.gwtproject.activity.elemental;

src/main/java/org/gwtproject/activity/elemental/shared/ElementalActivityDisplay.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2010 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 org.gwtproject.activity.elemental.shared;
+
+import org.gwtproject.activity.shared.ActivityDisplay;
+
+import elemental2.dom.HTMLElement;
+
+/**
+ * {@link ActivityDisplay} which wraps {@link HTMLElement} to provide
+ * display for {@link HTMLElement} views.
+ */
+public class ElementalActivityDisplay implements ActivityDisplay<HTMLElement> {
+
+  public ElementalActivityDisplay(HTMLElement delegate) {
+    this.delegate = delegate;
+  }
+
+  public void show(HTMLElement view) {
+
+    if (this.view == view) {
+      return;
+    }
+
+    while (delegate.firstChild != null) {
+      delegate.removeChild(delegate.firstChild);
+    }
+
+    if (view != null) {
+      delegate.appendChild(view);
+    }
+
+    this.view = view;
+  }
+
+  private final HTMLElement delegate;
+
+  private HTMLElement view;
+
+}

src/main/java/org/gwtproject/activity/shared/AbstractActivity.java

@@ -18,8 +18,10 @@
 /**
  * Simple Activity implementation that is always willing to stop, and does
  * nothing onStop and onCancel.
+ * 
+ * @param <V> view type ({@code IsWidget}, {@code HTMLElement}, ...)
  */
-public abstract class AbstractActivity implements Activity {
+public abstract class AbstractActivity<V> implements Activity<V> {
 
   public String mayStop() {
     return null;

src/main/java/org/gwtproject/activity/shared/Activity.java

@@ -16,15 +16,16 @@
 package org.gwtproject.activity.shared;
 
 import org.gwtproject.event.shared.EventBus;
-import org.gwtproject.user.client.ui.AcceptsOneWidget;
 
 /**
  * Implemented by objects that control a piece of user interface, with a life
  * cycle managed by an {@link ActivityManager}, in response to
  * {@link org.gwtproject.place.shared.PlaceChangeEvent} events as the user
  * navigates through the app.
+ * 
+ * @param <V> view type ({@code IsWidget}, {@code HTMLElement}, ...)
  */
-public interface Activity {
+public interface Activity<V> {
 
   /**
    * Called when the user is trying to navigate away from this activity.
@@ -50,7 +51,7 @@ public interface Activity {
    * Called when the Activity should ready its widget for the user. When the
    * widget is ready (typically after an RPC response has been received),
    * receiver should present it by calling
-   * {@link AcceptsOneWidget#setWidget} on the given panel.
+   * {@link ActivityDisplay#show} on the given panel.
    * <p>
    * Any handlers attached to the provided event bus will be de-registered when
    * the activity is stopped, so activities will rarely need to hold on to the
@@ -60,5 +61,5 @@ public interface Activity {
    * @param panel the panel to display this activity's widget when it is ready
    * @param eventBus the event bus
    */
-  void start(AcceptsOneWidget panel, EventBus eventBus);
+  void start(ActivityDisplay<V> panel, EventBus eventBus);
 }

src/main/java/org/gwtproject/activity/shared/ActivityDisplay.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2010 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 org.gwtproject.activity.shared;
+
+import org.gwtproject.activity.widget.shared.WidgetActivityDisplay;
+
+/** Display used to show views of type {@code V}.
+ * 
+ * @param <V> view type ({@code IsWidget}, {@code HTMLElement}, ...)
+ */
+public interface ActivityDisplay<V> {
+
+  /**
+   * Set the element to display, replacing the previously displayed
+   * element if there was one.
+   *
+   * @param view object to display, or <code>null</code> to clear display
+   *
+   * @see WidgetActivityDisplay
+   */
+  void show(V view);
+
+}

src/main/java/org/gwtproject/activity/shared/ActivityManager.java

@@ -21,8 +21,6 @@
 import org.gwtproject.event.shared.UmbrellaException;
 import org.gwtproject.place.shared.PlaceChangeEvent;
 import org.gwtproject.place.shared.PlaceChangeRequestEvent;
-import org.gwtproject.user.client.ui.AcceptsOneWidget;
-import org.gwtproject.user.client.ui.IsWidget;
 
 import java.util.LinkedHashSet;
 import java.util.Set;
@@ -31,34 +29,37 @@
  * Manages {@link Activity} objects that should be kicked off in response to
  * {@link PlaceChangeEvent} events. Each activity can start itself
  * asynchronously, and provides a widget to be shown when it's ready to run.
+ * 
+ * @param <V> view type ({@code IsWidget}, {@code HTMLElement}, ...)
  */
-public class ActivityManager implements PlaceChangeEvent.Handler, PlaceChangeRequestEvent.Handler {
+public class ActivityManager<V> implements PlaceChangeEvent.Handler,
+  PlaceChangeRequestEvent.Handler {
 
   /**
    * Wraps our real display to prevent an Activity from taking it over if it is
    * not the currentActivity.
    */
-  private class ProtectedDisplay implements AcceptsOneWidget {
-    private final Activity activity;
+  private class ProtectedDisplay implements ActivityDisplay<V> {
+    private final Activity<V> activity;
 
-    ProtectedDisplay(Activity activity) {
+    ProtectedDisplay(Activity<V> activity) {
       this.activity = activity;
     }
 
-    public void setWidget(IsWidget view) {
+    public void show(V view) {
       if (this.activity == ActivityManager.this.currentActivity) {
         startingNext = false;
         showWidget(view);
       }
     }
   }
 
-  private static final Activity NULL_ACTIVITY = new AbstractActivity() {
-    public void start(AcceptsOneWidget panel, EventBus eventBus) {
+  private final Activity<V> nullActivity = new AbstractActivity<V>() {
+    public void start(ActivityDisplay<V> panel, EventBus eventBus) {
     }
   };
 
-  private final ActivityMapper mapper;
+  private final ActivityMapper<V> mapper;
 
   private final EventBus eventBus;
 
@@ -68,9 +69,9 @@ public void start(AcceptsOneWidget panel, EventBus eventBus) {
    */
   private final ResettableEventBus stopperedEventBus;
 
-  private Activity currentActivity = NULL_ACTIVITY;
+  private Activity<V> currentActivity = nullActivity;
 
-  private AcceptsOneWidget display;
+  private ActivityDisplay<V> display;
 
   private boolean startingNext = false;
 
@@ -84,7 +85,7 @@ public void start(AcceptsOneWidget panel, EventBus eventBus) {
    * @param eventBus source of {@link PlaceChangeEvent} and
    *          {@link PlaceChangeRequestEvent} events.
    */
-  public ActivityManager(ActivityMapper mapper, EventBus eventBus) {
+  public ActivityManager(ActivityMapper<V> mapper, EventBus eventBus) {
     this.mapper = mapper;
     this.eventBus = eventBus;
     this.stopperedEventBus = new ResettableEventBus(eventBus);
@@ -113,14 +114,14 @@ public EventBus getActiveEventBus() {
    * treatment.
    */
   public void onPlaceChange(PlaceChangeEvent event) {
-    Activity nextActivity = getNextActivity(event);
+    Activity<V> nextActivity = getNextActivity(event);
 
     Throwable caughtOnStop = null;
     Throwable caughtOnCancel = null;
     Throwable caughtOnStart = null;
 
     if (nextActivity == null) {
-      nextActivity = NULL_ACTIVITY;
+      nextActivity = nullActivity;
     }
 
     if (currentActivity.equals(nextActivity)) {
@@ -131,9 +132,9 @@ public void onPlaceChange(PlaceChangeEvent event) {
       // The place changed again before the new current activity showed its
       // widget
       caughtOnCancel = tryStopOrCancel(false);
-      currentActivity = NULL_ACTIVITY;
+      currentActivity = nullActivity;
       startingNext = false;
-    } else if (!currentActivity.equals(NULL_ACTIVITY)) {
+    } else if (!currentActivity.equals(nullActivity)) {
       showWidget(null);
 
       /*
@@ -146,7 +147,7 @@ public void onPlaceChange(PlaceChangeEvent event) {
 
     currentActivity = nextActivity;
 
-    if (currentActivity.equals(NULL_ACTIVITY)) {
+    if (currentActivity.equals(nullActivity)) {
       showWidget(null);
     } else {
       startingNext = true;
@@ -189,7 +190,7 @@ public void onPlaceChangeRequest(PlaceChangeRequestEvent event) {
    * 
    * @param display an instance of AcceptsOneWidget
    */
-  public void setDisplay(AcceptsOneWidget display) {
+  public void setDisplay(ActivityDisplay<V> display) {
     boolean wasActive = (null != this.display);
     boolean willBeActive = (null != display);
     this.display = display;
@@ -198,7 +199,7 @@ public void setDisplay(AcceptsOneWidget display) {
     }
   }
 
-  private Activity getNextActivity(PlaceChangeEvent event) {
+  private Activity<V> getNextActivity(PlaceChangeEvent event) {
     if (display == null) {
       /*
        * Display may have been nulled during PlaceChangeEvent dispatch. Don't
@@ -210,9 +211,9 @@ private Activity getNextActivity(PlaceChangeEvent event) {
     return mapper.getActivity(event.getNewPlace());
   }
 
-  private void showWidget(IsWidget view) {
+  private void showWidget(V view) {
     if (display != null) {
-      display.setWidget(view);
+      display.show(view);
     }
   }