| /* |
| * 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.user.cellview.client; |
| |
| import com.google.gwt.cell.client.Cell; |
| import com.google.gwt.cell.client.Cell.Context; |
| import com.google.gwt.cell.client.ValueUpdater; |
| import com.google.gwt.dom.client.Element; |
| import com.google.gwt.dom.client.NativeEvent; |
| import com.google.gwt.safehtml.shared.SafeHtmlBuilder; |
| |
| /** |
| * A table column header or footer. |
| * |
| * @param <H> the {@link Cell} type |
| */ |
| public abstract class Header<H> { |
| |
| private final Cell<H> cell; |
| |
| private String headerStyleNames = null; |
| private ValueUpdater<H> updater; |
| |
| /** |
| * Construct a Header with a given {@link Cell}. |
| * |
| * @param cell the {@link Cell} responsible for rendering items in the header |
| */ |
| public Header(Cell<H> cell) { |
| this.cell = cell; |
| } |
| |
| /** |
| * Return the {@link Cell} responsible for rendering items in the header. |
| * |
| * @return the header Cell |
| */ |
| public Cell<H> getCell() { |
| return cell; |
| } |
| |
| /** |
| * Get extra style names that should be applied to a cell in this header. May be overridden to |
| * get value dependent styles by calling {@link #getValue}. |
| * |
| * @return the extra styles of the given row in a space-separated list, or |
| * {@code null} if there are no extra styles for the cells in this |
| * header |
| */ |
| public String getHeaderStyleNames() { |
| return headerStyleNames; |
| } |
| |
| /** |
| * Get the key for the header value. By default, the key is the same as the |
| * value. Override this method to return a custom key. |
| * |
| * @return the key associated with the value |
| */ |
| public Object getKey() { |
| return getValue(); |
| } |
| |
| /** |
| * Return the header value. |
| * |
| * @return the header value |
| */ |
| public abstract H getValue(); |
| |
| /** |
| * Handle a browser event that took place within the header. |
| * |
| * @param context the context of the header |
| * @param elem the parent Element |
| * @param event the native browser event |
| */ |
| public void onBrowserEvent(Context context, Element elem, NativeEvent event) { |
| cell.onBrowserEvent(context, elem, getValue(), event, updater); |
| } |
| |
| /** |
| * Preview a browser event that may trigger a column sort event. Return true if the |
| * {@link CellTable} should proceed with sorting the column. Subclasses can override this method |
| * to disable column sort for some click events, or particular header/footer sections. |
| * <p> |
| * This method will be invoked even if the header's cell does not consume a click event. |
| * </p> |
| * |
| * @param context the context of the header |
| * @param elem the parent Element |
| * @param event the native browser event |
| * @return true if the {@link CellTable} should continue respond to the event (i.e., if this is |
| * a click event on a sortable column's header, fire {@link ColumnSortEvent}). False if |
| * the {@link CellTable} should stop respond to the event. |
| */ |
| public boolean onPreviewColumnSortEvent(Context context, Element elem, NativeEvent event) { |
| return true; |
| } |
| |
| /** |
| * Render the header. |
| * |
| * @param context the context of the header |
| * @param sb a {@link SafeHtmlBuilder} to render into |
| */ |
| public void render(Context context, SafeHtmlBuilder sb) { |
| cell.render(context, getValue(), sb); |
| } |
| |
| /** |
| * Set extra style names that should be applied to every cell in this header. |
| * |
| * <p> |
| * If you want to apply style names based on the header value, override |
| * {@link #getHeaderStyleNames(Object)} directly. |
| * </p> |
| * |
| * @param styleNames the extra style names to apply in a space-separated list, |
| * or {@code null} if there are no extra styles for this cell |
| */ |
| public void setHeaderStyleNames(String styleNames) { |
| this.headerStyleNames = styleNames; |
| } |
| |
| /** |
| * Set the {@link ValueUpdater}. |
| * |
| * @param updater the value updater to use |
| */ |
| public void setUpdater(ValueUpdater<H> updater) { |
| this.updater = updater; |
| } |
| } |