/*
* 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 com.google.gwt.cell.client;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.EventTarget;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* <p>
* A {@link Cell} that is composed of other {@link Cell}s.
* </p>
*
* <p>
* When this cell is rendered, it will render each component {@link Cell} inside
* a span. If the component {@link Cell} uses block level elements (such as a
* Div), the component cells will stack vertically.
* </p>
*
* @param <C> the type that this Cell represents
*/
public class CompositeCell<C> extends AbstractCell<C> {
/**
* The events consumed by this cell.
*/
private Set<String> consumedEvents;
/**
* Indicates whether or not this cell depends on selection.
*/
private boolean dependsOnSelection;
/**
* Indicates whether or not this cell handles selection.
*/
private boolean handlesSelection;
/**
* The cells that compose this {@link Cell}.
*
* NOTE: Do not add add/insert/remove hasCells methods to the API. This cell
* assumes that the index of the cellParent corresponds to the index in the
* hasCells array.
*/
private final List<HasCell<C, ?>> hasCells;
/**
* Construct a new {@link CompositeCell}.
*
* @param hasCells the cells that makeup the composite
*/
public CompositeCell(List<HasCell<C, ?>> hasCells) {
// Create a new array so cells cannot be added or removed.
this.hasCells = new ArrayList<HasCell<C, ?>>(hasCells);
// Get the consumed events and depends on selection.
Set<String> theConsumedEvents = null;
for (HasCell<C, ?> hasCell : hasCells) {
Cell<?> cell = hasCell.getCell();
Set<String> events = cell.getConsumedEvents();
if (events != null) {
if (theConsumedEvents == null) {
theConsumedEvents = new HashSet<String>();
}
theConsumedEvents.addAll(events);
}
if (cell.dependsOnSelection()) {
dependsOnSelection = true;
}
if (cell.handlesSelection()) {
handlesSelection = true;
}
}
if (theConsumedEvents != null) {
this.consumedEvents = Collections.unmodifiableSet(theConsumedEvents);
}
}
@Override
public boolean dependsOnSelection() {
return dependsOnSelection;
}
@Override
public Set<String> getConsumedEvents() {
return consumedEvents;
}
@Override
public boolean handlesSelection() {
return handlesSelection;
}
@Override
public void onBrowserEvent(Context context, Element parent, C value,
NativeEvent event, ValueUpdater<C> valueUpdater) {
int index = 0;
EventTarget eventTarget = event.getEventTarget();
if (Element.is(eventTarget)) {
Element target = eventTarget.cast();
Element container = getContainerElement(parent);
Element wrapper = container.getFirstChildElement();
while (wrapper != null) {
if (wrapper.isOrHasChild(target)) {
onBrowserEventImpl(context, wrapper, value, event, valueUpdater,
hasCells.get(index));
}
index++;
wrapper = wrapper.getNextSiblingElement();
}
}
}
@Override
public void render(Context context, C value, SafeHtmlBuilder sb) {
for (HasCell<C, ?> hasCell : hasCells) {
render(context, value, sb, hasCell);
}
}
@Override
public boolean resetFocus(Context context, Element parent, C value) {
Element curChild = getContainerElement(parent).getFirstChildElement();
for (HasCell<C, ?> hasCell : hasCells) {
// The first child that takes focus wins. Only one child should ever be in
// edit mode, so this is safe.
if (resetFocusImpl(context, curChild, value, hasCell)) {
return true;
}
curChild = curChild.getNextSiblingElement();
}
return false;
}
@Override
public void setValue(Context context, Element parent, C object) {
Element curChild = getContainerElement(parent).getFirstChildElement();
for (HasCell<C, ?> hasCell : hasCells) {
setValueImpl(context, curChild, object, hasCell);
curChild = curChild.getNextSiblingElement();
}
}
/**
* Get the element that acts as the container for all children. If children
* are added directly to the parent, the parent is the container. If children
* are added in a table row, the row is the parent.
*
* @param parent the parent element of the cell
* @return the container element
*/
protected Element getContainerElement(Element parent) {
return parent;
}
/**
* Render the composite cell as HTML into a {@link SafeHtmlBuilder}, suitable
* for passing to {@link Element#setInnerHTML} on a container element.
*
* <p>
* Note: If your cell contains natively focusable elements, such as buttons or
* input elements, be sure to set the tabIndex to -1 so that they do not steal
* focus away from the containing widget.
* </p>
*
* @param context the {@link Context} of the cell
* @param value the cell value to be rendered
* @param sb the {@link SafeHtmlBuilder} to be written to
* @param hasCell a {@link HasCell} instance containing the cells to be
* rendered within this cell
*/
protected <X> void render(Context context, C value,
SafeHtmlBuilder sb, HasCell<C, X> hasCell) {
Cell<X> cell = hasCell.getCell();
sb.appendHtmlConstant("<span>");
cell.render(context, hasCell.getValue(value), sb);
sb.appendHtmlConstant("</span>");
}
private <X> void onBrowserEventImpl(Context context, Element parent,
final C object, NativeEvent event, final ValueUpdater<C> valueUpdater,
final HasCell<C, X> hasCell) {
ValueUpdater<X> tempUpdater = null;
final FieldUpdater<C, X> fieldUpdater = hasCell.getFieldUpdater();
if (fieldUpdater != null) {
tempUpdater = new ValueUpdater<X>() {
public void update(X value) {
fieldUpdater.update(-1, object, value);
if (valueUpdater != null) {
valueUpdater.update(object);
}
}
};
}
Cell<X> cell = hasCell.getCell();
cell.onBrowserEvent(context, parent, hasCell.getValue(object), event,
tempUpdater);
}
private <X> boolean resetFocusImpl(Context context, Element cellParent,
C value, HasCell<C, X> hasCell) {
X cellValue = hasCell.getValue(value);
return hasCell.getCell().resetFocus(context, cellParent, cellValue);
}
private <X> void setValueImpl(Context context, Element cellParent, C object,
HasCell<C, X> hasCell) {
hasCell.getCell().setValue(context, cellParent, hasCell.getValue(object));
}
}