/**
* 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.waveprotocol.wave.client.wavepanel.impl.focus;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import org.waveprotocol.wave.client.common.util.KeyCombo;
import org.waveprotocol.wave.client.scroll.SmartScroller;
import org.waveprotocol.wave.client.wavepanel.impl.WavePanelImpl;
import org.waveprotocol.wave.client.wavepanel.view.BlipView;
import org.waveprotocol.wave.client.wavepanel.view.FocusFrameView;
import org.waveprotocol.wave.model.util.CopyOnWriteSet;
import org.waveprotocol.wave.model.util.ValueUtils;
import org.waveprotocol.wave.model.wave.SourcesEvents;
/**
* Presents the focus frame, and exposes an API for controlling it.
*
*/
public final class FocusFramePresenter
implements SourcesEvents<FocusFramePresenter.Listener>, WavePanelImpl.LifecycleListener {
public interface Listener {
void onFocusMoved(BlipView oldUi, BlipView newUi);
}
public interface FocusOrder {
BlipView getNext(BlipView current);
BlipView getPrevious(BlipView current);
}
public interface FrameKeyHandler {
boolean onKeySignal(KeyCombo key, BlipView context);
}
/** Focus frame UI. */
private final FocusFrameView view;
/** Thing that knows how to move around views. */
private final ViewTraverser traverser;
/** Listeners. */
private final CopyOnWriteSet<Listener> listeners = CopyOnWriteSet.create();
/** Scroller. */
private final SmartScroller<? super BlipView> scroller;
/** Order generator, optionally installed. */
private FocusOrder order;
/** Blip that currently has the focus frame. May be {@code null}. */
private BlipView blip;
/**
* Creates a focus-frame presenter.
*/
@VisibleForTesting
FocusFramePresenter(
FocusFrameView view, SmartScroller<? super BlipView> scroller, ViewTraverser traverser) {
this.view = view;
this.scroller = scroller;
this.traverser = traverser;
}
//
// Wave panel lifecycle.
//
@Override
public void onInit() {
}
@Override
public void onReset() {
blip = null;
}
//
// Focus movement.
//
/**
* Puts the focus frame on a blip.
*/
public void focus(BlipView blip) {
Preconditions.checkState(scroller != null);
Preconditions.checkArgument(blip != null);
focus(blip, true);
}
/**
* Puts the focus frame on a blip, without forcing it into view.
*/
public void focusWithoutScroll(BlipView blip) {
Preconditions.checkState(scroller != null);
Preconditions.checkArgument(blip != null);
focus(blip, false);
}
/**
* Moves the focus frame to the previous blip in the vertical ordering, if
* there is one. If there is no previous blip, this method does nothing.
*/
public void moveUp() {
BlipView prev = blip != null ? traverser.getPrevious(blip) : null;
if (prev != null) {
focus(prev, true);
}
}
/**
* Moves the focus frame to the next blip in the vertical ordering, if there
* is one. If there is no next blip, this method does nothing.
*/
public void moveDown() {
BlipView next = blip != null ? traverser.getNext(blip) : null;
if (next != null) {
focus(next, true);
}
}
/**
* Sets the blip that has the focus frame. If {@code blip} is null, the focus
* frame is removed.
*/
private void focus(BlipView blip, boolean scroll) {
if (!ValueUtils.equal(this.blip, blip)) {
BlipView oldUi = this.blip;
BlipView newUi = blip;
// Scroll first, before layout gets invalidated.
if (newUi != null && scroll) {
scroller.moveTo(newUi);
}
detachChrome();
this.blip = blip;
attachChrome();
fireOnFocusMoved(oldUi, newUi);
}
}
private void detachChrome() {
if (this.blip != null) {
this.blip.getMeta().removeFocusChrome(view);
}
}
private void attachChrome() {
if (this.blip != null) {
this.blip.getMeta().placeFocusFrame(view);
}
}
//
// Events.
//
@Override
public void addListener(Listener listener) {
listeners.add(listener);
}
@Override
public void removeListener(Listener listener) {
listeners.remove(listener);
}
private void fireOnFocusMoved(BlipView oldUi, BlipView newUi) {
for (Listener listener : listeners) {
listener.onFocusMoved(oldUi, newUi);
}
}
//
// Focus ordering / processing.
//
/**
* Moves to the next blip as defined by an attached
* {@link #setOrder(FocusOrder) ordering}, if there is one.
*/
public void focusNext() {
// Real condition is that blip != null implies scroller != null.
Preconditions.checkState(blip == null || scroller != null);
if (blip != null && order != null) {
BlipView next = order.getNext(blip);
if (next != null) {
focus(next);
}
else {
focusPrevious();
}
}
}
/**
* Moves to the previous blip as defined by an attached
* {@link #setOrder(FocusOrder) ordering}, if there is one.
*/
public void focusPrevious() {
// Real condition is that blip != null implies scroller != null.
Preconditions.checkState(blip == null || scroller != null);
if (blip != null && order != null) {
BlipView next = order.getPrevious(blip);
if (next != null) {
focus(next);
}
}
}
/**
* Specifies the orderer to use when moving to the next and previous
* interesting blips.
*/
public void setOrder(FocusOrder order) {
this.order = order;
}
/** @return the view that is currently focused. */
public BlipView getFocusedBlip() {
return blip;
}
}